Signal amplification in plasmonic specific-binding partner assays.
Abstract
The present invention relates to analyte detection devices and methods of employing such devices to detect very small amounts of a target analyte in a sample; In particular, the invention provides an analyte detection device comprising multiple composite metal nanostructures conjugated with analyte binding partners and a surface containing a metal nanoshell on which multiple capture molecules are immobilized; Likewise, methods for preparing composite nanostructures are described.

Term
10.4 yearsleft in the term
Expires 10 February 2037.
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51 claims: 6 independent, 45 dependent
- 1NOVEDAD DE LA INVENCIÓN REIVINDICACIONES 1. Un dispositivo de detección de analitos que comprende:múltiples conjugados de detección, en el que los conjugados comprenden nanoestructuras metálicas compuestas acopladas a compañeros de unión que son capaces de unirse específicamente a un analito objetivo, una superficie que contiene una nanocapa metálica y múltiples moléculas de captura, en el que las moléculas de captura se encuentran inmovilizadas en la nanocapa metálica y son capaces de unirse específicamente al analito objetivo.
- 2Un dispositivo de detección de analitos que comprende:múltiples conjugados de detección, en el que los conjugados comprenden nanoestructuras metálicas compuestas acopladas a analitos objetivo, una superficie que contiene una nanocapa metálica y múltiples moléculas de captura, en el que las moléculas de captura se encuentran inmovilizadas en la nanocapa metálica y son capaces de unirse específicamente a los analitos objetivo.
- 3El dispositivo de detección de analitos de conformidad con la reivindicación 1 o 2, caracterizado además porque las nanoestructuras metálicas compuestas comprenden al menos dos metales seleccionados de oro, plata, cobre, platino, paladio, cadmio, hierro, níquel y cinc.
- 4El dispositivo de detección de analitos de conformidad con la reivindicación 1 o 2, caracterizado además porque cada una de las nanoestructuras metálicas compuestas comprende un núcleo de un primer metal y un revestimiento de un segundo metal.
- 5El dispositivo de detección de analitos de conformidad con la reivindicación 4, caracterizado además porque cada una de las nanoestructuras metálicas compuestas comprende un revestimiento de oro y un núcleo de plata.
- 6El dispositivo de detección de analitos de conformidad con la reivindicación 1 o 2, caracterizado además porque cada una de las nanoestructuras metálicas compuestas es una aleación de un primer metal y de un segundo metal.
- 7El dispositivo de detección de analitos de conformidad con la reivindicación 1 o 2, caracterizado además porque las nanoestructuras metálicas compuestas son nanopartículas esféricas y tienen un diámetro de alrededor 5 nm a alrededor de 200 nm.
- 8El dispositivo de detección de analitos de conformidad con la reivindicación 1 o 2, caracterizado además porque las nanoestructuras metálicas compuestas son nanopartículas esféricas y tienen un diámetro de alrededor 10 nm a alrededor de 100 nm.
- 9El dispositivo de detección de analitos de conformidad con la reivindicación 1 o 2, caracterizado además porque las nanoestructuras metálicas compuestas son nanoplacas con /QCP Ln/Zznz/E/YIAI una longitud de borde de alrededor de 10 nm a alrededor de 800 nm y un espesor de alrededor de 1 nm a alrededor de 100 nm.
- 10El dispositivo de detección de analitos de conformidad con la reivindicación 1 o 2, caracterizado además porque los múltiples conjugados de detección se encuentran en forma de un pellet o una esfera liofilizada.
- 11El dispositivo de detección de analitos de conformidad con la reivindicación 1 o 2, caracterizado además porque la superficie es un chip, un pozo, una esfera o una pared, la cubierta y/o la parte inferior de una cubeta.
- 12El dispositivo de detección de analitos de conformidad con la reivindicación 1 o 2, caracterizado además porque la nanocapa metálica es una película metálica.
- 13El dispositivo de detección de analitos de la reivindicación 12, en el que la película metálica comprende oro, plata, cobre, platino, paladio, cadmio, cinc o un compuesto de estos.
- 14El dispositivo de detección de analitos de conformidad con la reivindicación 12, caracterizado además porque la película metálica comprende oro.
- 15El dispositivo de detección de analitos de conformidad con la reivindicación 1 o 2, caracterizado además porque la nanocapa metálica comprende múltiples nanoestructuras metálicas inmovilizadas en la superficie.
- 16El dispositivo de detección de analitos de conformidad con la reivindicación 15, caracterizado además porque las múltiples nanoestructuras metálicas comprenden oro, plata, cobre, platino, paladio, cadmio, cinc o un compuesto de estos.
- 17El dispositivo de detección de analitos de conformidad con la reivindicación 15, caracterizado además porque las múltiples nanoestructuras metálicas son nanoestructuras de oro.
- 18El dispositivo de detección de analitos de conformidad con la reivindicación 1 o 2, caracterizado además porque las nanoestructuras compuestas tienen una geometría seleccionada de nanopartículas esféricas, na no partículas piramidales, nanopartículas hexagonales, nanocascarones, nanotubos, nanovarillas, nanodots, nanoislas, nanohilos o combinaciones de estos.
- 19El dispositivo de detección de analitos de conformidad con la reivindicación 1, caracterizado además porque los compañeros de unión y/o las moléculas de captura son anticuerpos, antígenos, polipéptidos, polinucleótidos, nucleoproteínas, aptámeros, ligandos, receptores o haptenos.
- 20El dispositivo de detección de analitos de conformidad con la reivindicación 1, caracterizado además porque los compañeros de unión son anticuerpos que reconocen un primer epítopo de un analito objetivo y las moléculas de captura son anticuerpos distintos que reconocen un 7QCP ίη/ΖΖΠΖ/Ε/ΥΙΛΙ segundo epítopo de un analito objetivo.
- 21El dispositivo de detección de analitos de conformidad con la reivindicación 2, caracterizado además porque las moléculas de captura son anticuerpos, antígenos, polipéptidos, polinucleótidos, nucleoproteínas, aptámeros, ligandos, receptores o haptenos.
- 22El dispositivo de detección de analitos de conformidad con la reivindicación 1 o 2, caracterizado además porque el analito objetivo es un marcador o un antígeno asociado a una enfermedad infecciosa, un estado fisiológico o una afección patológica.
- 23El dispositivo de detección de analitos de conformidad con la reivindicación 1 o 2, caracterizado además porque el analito objetivo es helminto canino, virus de leucemia felina, parvovirus canino, proteína C-reactiva, Giardia lamblia, anticuerpo o antígeno Ehr/ichia, anticuerpo o antígeno Borre/ia, anticuerpo o antígeno Anap/asma, un antígeno de cáncer, un antígeno marcador cardíaco, hormona estimulante de la tiroides, tiroxina, troponina o péptido natriurético cerebral.
- 24Un método para detectar un analito objetivo en una muestra que comprende:mezclar la muestra con múltiples conjugados de detección, en el que los conjugados comprenden nanoestructuras metálicas compuestas acopladas a compañeros de unión que son capaces de unirse específicamente al analito objetivo si se encuentra presente en la muestra para formar complejos del conjugado de detección de analitos, poner la mezcla en contacto con una superficie que contiene una nanocapa metálica, en el que múltiples moléculas de captura se encuentran inmovilizadas en la nanocapa metálica y son capaces de unirse específicamente al analito objetivo si se encuentran presentes en la muestra, exponer la superficie a una fuente de luz a un rango de longitud de onda en el espectro ultravioleta, visible e infrarrojo y medir una señal óptica de la superficie, en el que un cambio en la señal óptica indica la presencia del analito objetivo en la muestra.
- 25El método de conformidad con la reivindicación 24, caracterizado además porque la señal óptica es una reflectancia, un espectro de absorbancia, un espectro de dispersión o un espectro de emisión.
- 26El método de conformidad con la reivindicación 24, caracterizado además porque el cambio en la señal óptica comprende una variación de longitud de onda de los picos espectrales.
- 27El método de conformidad con la reivindicación 24, caracterizado además porque se detecta la presencia de cantidades en nanogramos del analito objetivo.
- 28El método de conformidad con la reivindicación 24, caracterizado además porque se detecta la presencia de cantidades en picogramos del analito objetivo.
- 29El método de conformidad con la reivindicación 24, caracterizado además porque se detecta la presencia de cantidades en femtogramos del analito objetivo. 7QCP ίη/ΖΖΠΖ/Ε/ΥΙΛΙ
- 30El método de conformidad con la reivindicación 24, caracterizado además porque la superficie son las paredes y la parte inferior de una cubeta incorporada a un rotor de centrífuga.
- 31El método de conformidad con la reivindicación 24, caracterizado además porque las nanoestructuras metálicas compuestas comprenden al menos dos metales seleccionados de oro, plata, cobre, platino, paladio, cadmio, hierro, níquel y cinc.
- 32El método de conformidad con la reivindicación 24, caracterizado además porque cada una de las nanoestructuras metálicas compuestas comprende un núcleo de un primer /QCP ίη/ΖΖΠΖ/Ε/ΥΙΛΙ metal y un revestimiento de un segundo metal.
- 33El método de conformidad con la reivindicación 32, caracterizado además porque cada una de las nanoestructuras metálicas compuestas comprende un revestimiento de oro y un núcleo de plata.
- 34El método de conformidad con la reivindicación 24, caracterizado además porque cada una de las nanoestructuras metálicas compuestas es una aleación de un primer metal y de un segundo metal.
- 35El método de conformidad con la reivindicación 24, caracterizado además porque la nanocapa metálica es una película metálica.
- 36El método de conformidad con la reivindicación 35, caracterizado además porque la película metálica comprende oro. 37. El método de conformidad con la reivindicación 24, caracterizado además porque la nanocapa superficie. 38. metálica comprende múltiples nanoestructuras metálicas inmovilizadas en la El método de conformidad con la reivindicación 37, caracterizado además porque las múltiples nanoestructuras metálicas son nanoestructuras de oro.
- 3739. El método de conformidad con la reivindicación 24, caracterizado además porque las nanoestructuras compuestas tienen una geometría seleccionada de nanopartículas esféricas, nanopartículas piramidales, nanopartículas hexagonales, nanotubos, nanocascarones, nanovarillas, nanoislas, nanodots, nanohilos o combinaciones de estos.
- 3840. Un método para preparar nanoestructuras metálicas compuestas que comprende:preparar una primera solución que comprende una mezcla de un polímero y ácido cloroáurico, preparar una segunda solución que comprende nanoestructuras de plata o cobre e incubar la primera solución con la segunda solución durante un período de tiempo, de forma que la mezcla resultante comprende nanoestructuras de plata revestidas con oro o nanoestructuras de cobre revestidas con oro.
- 3941. El método de conformidad con la reivindicación 40, caracterizado además porque la segunda solución comprende nanoestructuras de plata y tiene un pico de absorbancia de alrededor de 550 a 750 nm.
- 4042. El método de conformidad con la reivindicación 40, caracterizado además porque el polímero es polivinilpirrolidona, alcohol polivinílico, poliacrilato, polietilenglicol o polietilenimina.
- 4143. Un complejo de ensayo que comprende:un conjugado de detección que comprende una nanoestructura metálica compuesta acoplada a un compañero de unión, un analito objetivo y una esfera revestida con una nanocapa metálica en la que se inmoviliza una molécula de captura, en la que el compañero de unión en el conjugado de detección se une a un primer epítopo en el analito objetivo y la molécula de captura se une a un segundo epítopo en el analito objetivo, de manera que forma un complejo un complejo que comprende el conjugado de detección, el analito objetivo y la molécula de captura.
- 4244. El complejo de ensayo de conformidad con la reivindicación 43, caracterizado además porque el compañero de unión es un anticuerpo y la molécula de captura es un anticuerpo diferente.
- 4345. El complejo de ensayo de conformidad con la reivindicación43, caracterizado además porque la nanocapa metálica es una película metálica.
- 4446. El complejo de ensayo de conformidad con la reivindicación45, caracterizado además porque la película metálica comprende oro, plata, cobre, platino, paladio, cadmio, cinc o un compuesto de estos.
- 4547. El complejo de ensayo de conformidad con la reivindicación46, caracterizado además porque la película metálica comprende oro.
- 4648. El complejo de ensayo de conformidad con la reivindicación43, caracterizado además porque la nanocapa metálica comprende múltiples nanoestructuras metálicas inmovilizadas en la esfera.
- 4749. El complejo de ensayo de conformidad con la reivindicación 48, caracterizado además porque las múltiples nanoestructuras metálicas comprenden oro, plata, cobre, platino, paladio, cadmio, cinc o un compuesto de estos.
- 4850. El complejo de ensayo de conformidad con la reivindicación 49, caracterizado además porque las múltiples nanoestructuras metálicas son nanoestructuras de oro.
- 4951. El complejo de ensayo de conformidad con la reivindicación 43, caracterizado además porque la nanoestructura metálica compuesta comprende al menos dos metales seleccionados de oro, plata, cobre, platino, paladio, cadmio, hierro, níquel y cinc.
- 5052. El complejo de ensayo de conformidad con la reivindicación 43, caracterizado además porque la nanoestructura metálica compuesta comprende un núcleo de un /qcp ίη/ζζηζ/Ε/γίΛΐ primer metal y un revestimiento de un segundo metal.
- 5153. El complejo de ensayo de conformidad con la reivindicación 43, caracterizado además porque la nanoestructura metálica compuesta comprende un revestimiento de oro y un núcleo de plata. 5 54. El complejo de ensayo de conformidad con la reivindicación 43, caracterizado además porque la nanoestructura metálica compuesta es una aleación de un primer metal y de un segundo metal.
Independent claims51
118 paragraphs in 10 sections, as filed
SIGNAL AMPLIFICATION IN PLASMON SPECIFIC BINDING PARTNER ASSAYS
CROSS REFERENCE TO RELATED REQUESTS
The present application claims the priority of US Provisional Application No. 62/037,071 filed on August 13, 2014 and US Provisional Application No. 62/082,468 filed on November 20, 2014, which are incorporated herein in its entirety by this reference.
FIELD OF THE INVENTION
The present invention relates to systems and methods for detecting target analytes in a sample. In particular, the present invention provides a local plasmon resonance-based analyte detection system capable of detecting a minimal amount of a target analyte in a sample.
BACKGROUND OF THE INVENTION
Current immunoassays and biomolecule binding assays typically require multiple steps and sophisticated equipment to perform. The lack of sensitivity and complexity involved in performing such heterogeneous assays derives from the specific need to separate specific labeled from unlabeled binding partners.
Attempts have been made to develop assays based on local surface plasmon resonance (LSPR) properties of noble metal nanoparticles (Tokel et al., Chem Rev., Volume 114: 5728-5752, 2014). LSPR is the collective oscillation of electrons in nanometer-sized structures induced by incident light. Metallic nanoparticles have a strong electromagnetic response to refractive index changes in their proximity and therefore variations in the resonance frequency of the nanoparticles can be measured as an indicator of the binding of molecules to the surface of the nanoparticles. . Although metallic nanoparticles, particularly gold nanoparticles, have been employed in diagnostic assays to detect binding events, such assays generally have low sensitivity and cannot be used to quantitatively monitor the kinetics of sequential binding events.
Therefore, improved test methods that employ a homogeneous format and provide greater sensitivity are necessary. Assays employing standard laboratory techniques, such as spectroscopy, would also be desirable.
BRIEF DESCRIPTION OF THE INVENTION
The present invention is based, in part, on the discovery that composite metal nanostructures can enhance optical signals induced by the attachment of a molecule to a metal nanoshell surface. The observed amplification greatly increases the sensitivity of detection of specific biomolecular binding events so that sub-picogram dimensional quantities of the biomolecule can be detected. Accordingly, the present invention provides analyte detection devices and methods for employing such devices to detect very small amounts of a target analyte in a sample.
In one embodiment, the analyte sensing devices comprise multiple sensing conjugates, a surface containing a metal nanoshell, and multiple capture molecules, wherein the capture molecules are immobilized on the metal nanoshell and can bind specifically to the target analyte. . In embodiments where the analyte detection devices are configured in a sandwich assay format, the detection conjugates comprise composite metal nanostructures coupled to binding partners capable of specifically binding to the target analyte. In embodiments where the analyte detection devices are configured in a direct competitive assay format, the detection conjugates comprise composite metal nanostructures coupled to target analytes.
Composite metal nanostructures in sensing conjugates generally comprise at least two noble metals, transition metals, alkali metals, lanthanides, or combinations of these. In some embodiments, the composite metal nanostructures comprise at least two metals selected from gold, silver, copper, platinum, palladium, cadmium, iron, nickel and zinc. In certain embodiments, each of the composite metal nanostructures comprises a core of a first metal and a coating of a second metal. In some embodiments, the core may be silver or copper with a gold coating. In other embodiments, the core of a first metal may be dissolved after coating, so as to produce a hollow structure comprising the second coating metal.
The metallic nanolayer deposited on the surface can be a metallic film or comprise multiple metallic nanostructures immobilized on the surface. Furthermore, the metal nanolayer may comprise a noble or transition metal. In some embodiments, the metallic nanolayer comprises gold, silver, copper, platinum, palladium, cadmium, zinc, or a compound thereof. In one embodiment, the metallic nanoshell comprises gold. In another embodiment, the metal nanolayer /qcp Ln/zznz/E/viAi comprises silver. In yet another embodiment, the metallic nanolayer comprises a silver nanolayer covered with a gold nanolayer.
The present invention also provides methods for detecting a target analyte in a sample with the analyte detection devices described herein. In one embodiment, the method comprises mixing the sample with multiple detection conjugates, contacting the mixture with a surface containing a metal nanoshell on which multiple capture molecules are immobilized, exposing the surface to a light source at a range of wavelength in the ultraviolet, visible and infrared spectrum, and measure an optical signal from the surface, in which the change in the optical signal indicates the presence of the target analyte in the sample. In certain embodiments, the methods of the present invention are capable of detecting femtogram to nanogram magnitude amounts of a target analyte in the sample.
The present invention includes an assay complex comprising a sensing conjugate comprising a composite metal nanostructure coupled with a binding partner, a target analyte and a sphere coated with a metal nanoshell on which a capture molecule is immobilized, in which that the binding partner in the detection conjugate binds to a first epitope on the target analyte and the capture molecule binds to a second epitope on the target analyte, so that it forms a complex that comprises the detection conjugate, the target analyte and the capture molecule. In some embodiments, the composite metallic nanostructure is a gold-coated silver nanostructure or a gold-coated copper nanostructure, and the metallic nanolayer coating on the sphere comprises gold.
In another aspect, the present invention provides a method for preparing composite metal nanostructures for use in the detection devices and methods described herein. In one embodiment, the methods comprise preparing a first solution comprising a mixture of a polymer and chloroauric acid, preparing a second solution comprising silver or copper nanostructures, and incubating the first solution with the second solution for a period of time, wherein that the resulting mixture comprises gold-coated silver nanostructures or gold-coated copper nanostructures. In certain embodiments, a reducing agent, such as ascorbic acid, is added to the reaction mixture to increase the amount of nanostructure that is produced. In one embodiment, the polymer in the first solution is polyvinylpyrrolidone. In another embodiment, the polymer in the first solution is polyvinyl alcohol.
BRIEF DESCRIPTION OF THE FIGURES /ace Ln/zznz/E/viAi
Figure 1. Graph of peak wavelength variation as a function of acquisition time for a gold nanoshell sensor coupled to bovine serum albumin (BSA) (channel 1) and gold nanoshell sensors coupled to human IgG ( channels 2-4). Arrows indicate the injection sequence and concentration of unlabeled protein A, 1 mM HCl, or colloidal gold (CGC)-labeled protein A.
Figure 2. Graph of variation in the wavelength of the peaks as a function of acquisition time for a gold nanolayer sensor coupled to an anti-CRP C7 antibody. Arrows indicate the sequence of injection of concentrations of 0 to 100 ng/ml CRP in different channels (CRP loading), 1 pg/ml unlabeled anti-CRP C6 antibody or 3 pg/ml anti-CRP C6 antibody labeled with colloidal gold (C6-CGC). No additional C6-CGC binding was observed when unlabeled anti-CRP C6 antibody occupied the sensor surface.
Figure 3. Graph of variation in the wavelength of the peaks as a function of acquisition time for a gold nanolayer sensor coupled to an anti-CRP C7 antibody. Arrows indicate the injection sequence of concentrations from 0 to 100 ng/ml of CRP in different channels (CRP loading), 1 pg/ml of anti-CRP C6 antibody labeled with colloidal gold (C6-CGC), 3 pg/ml ml of C6-CGC or 1 mM HCl (acid).
Figure 4A. Reflectance spectra of gold nanoshell sensors coupled with C7 anti-CRP antibodies loaded with 10 ng/mL CRP at the various concentrations of C6-CGC in Figure 3.
Figure 4B. Plot of peak wavelength versus acquisition time for a gold nanoshell sensor coupled to C7 anti-CRP antibody incubated with one of three concentrations of CRP after introduction of 3 pg/ml anti-CRP antibody C6 labeled with colloidal gold (C6-CGC). The table on the right illustrates the analysis of the peaks 700 seconds after the introduction of C6-CGC.
Figure 5. Graph of variation in the wavelength of the peaks as a function of acquisition time for a gold nanoshell sensor coupled to an anti-CRP C7 antibody. Arrows indicate the sequence of injection of concentrations from 0 to 100 ng/ml of CRP in different channels (CRP loading with minimized incubation time), 3 pg/ml of anti-CRP C6 antibody labeled with colloidal gold (C6-CGC ) or 1 mM HCl (acid).
Figure 6. Plot of the wavelength variation of the peaks as a function of acquisition time for traces in Figure 5 after the immediate introduction of 3 pg/ml of anti-CRP C6 antibody labeled with colloidal gold (C6-CGC ). The table on the right illustrates the peak analysis 700 seconds after the introduction of C6-CGC compared to the peak variations obtained with incubation with CRP (values illustrated in Figure 4B).
Figure 7. Plot of peak wavelength versus acquisition time for a gold nanoshell sensor coupled to anti-CRP C7 antibody incubated with
7QCP ίη/ΖΖΠΖ/Ε/ΥΙΛΙ one of three concentrations of CRP and anti-CRP C6 antibody conjugated to gold-coated silver nanostructures. The control was a gold nanoshell sensor with immobilized bovine serum albumin (BSA) instead of the C7 antibody.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is based, in part, on the discovery that significant amplification can be achieved in LSPR-based assays with binding partners labeled with composite metal nanostructures. Therefore, the present invention provides analyte sensing devices comprising an LSPR surface, e.g., a surface containing a metal nanoshell, multiple capture molecules immobilized on the metal nanoshell, and multiple sensing conjugates comprising composite metal nanostructures. coupled to biomolecules.
Analyte detection devices can be configured in a sandwich assay format or a direct competitive assay format. For example, in one embodiment, an analyte detection device in a sandwich assay format comprises (i) multiple detection conjugates, wherein the conjugates comprise composite metal nanostructures coupled to binding partners capable of specifically binding to an analyte. aim, (ii) a surface containing a metal nanoshell and (iii) multiple capture molecules immobilized on the metal nanoshell and capable of specifically binding to the target analyte. In another embodiment, an analyte detection device in a direct competitive assay format comprises (i) multiple detection conjugates comprising composite metal nanostructures coupled to target analytes, (i) a surface containing a metal nanoshell, and (iii) multiple capture molecules immobilized on the metal nanoshell and capable of specifically binding to target analytes.
The analyte detection devices of the invention comprise a surface containing a metal nanolayer. The surface may be any suitable size and shape, such as a chip, well, cuvette or sphere. In some embodiments, the surface is a rectangular chip. In other embodiments, the surface is a disk. In certain embodiments, the surface is the bottom, cover and/or interior walls of a bucket (e.g., a cylindrical or rectangular bucket). In still other embodiments, the surface is an arrangement of non-metallic particles. The surface can be produced from various metals including, but not limited to, glass, quartz, silicon, silica, polystyrene, graphite, fabrics (e.g., polystyrene fabrics), mesh, or a membrane (e.g., polystyrene membranes). latex, polyvinyl, nylon or polyester).
7QCP Ln/Zznz/E/YIAI
Preferably, a metallic nanolayer is deposited on the surface. In some embodiments, the metallic nanolayer may cover the entire surface area of the particular surface. In other embodiments, the metal nanolayer can be deposited on only a portion of the surface. For example, the surface may contain multiple depressions or wells and the metal nanolayer is deposited between the depressions or wells. In other embodiments, the metallic nanolayer can be applied to the surface in multiple separate deposits on the surface. It is possible to tune the optical properties of the metallic nanolayer by varying the thickness of the nanolayer and/or the nature of the nanostructures. In one embodiment, the nanolayer comprises metallic nanoislands. In another embodiment, the nanoshell comprises nanorods. Suitable metal nanoshell thicknesses for use in the devices and methods of the invention include about 0.5 nm to about 100 nm, about 5 nm to about 30 nm, or about 3 nm to about 10 nm. Examples of surfaces with a metallic nanolayer coating that can be used in the devices and methods of the invention include the surfaces described in US Patent Publication No. 2006/0240573, which is incorporated herein in its entirety hereby. reference.
In certain embodiments, the metal nanolayer is a metal film. Methods for depositing metal films on a substrate surface are known to those skilled in the art, including, but not limited to, atomic layer deposition, pulsed laser deposition, drop deposition, vapor deposition and adsorption. See, for example, Atanasov et al., Journal of Physics. Conference Series 514 (2014); Walters and Parkin, Journal of Materials Chemistry, 19: 574-590, 2009; and Gupta et al., J. Appl Phys. 92, 5264-5271, 2002, each of which is incorporated herein in its entirety by this reference. The metal film may comprise other components, for example, the metal film may be a polymeric film, a Langmuir-Blodgett film or an oxide film. In some embodiments, the metal film comprises two layers and each layer comprises a different metal. By way of example, the metallic film may comprise a layer of silver covered with a layer of gold.
In other embodiments, the metal nanolayer comprises multiple metal nanostructures immobilized on the surface. Metal nanostructures can be immobilized on the surface by treating the surface material with a reagent to add functional chemical groups, such as cyanide, amine, thiols, carboxyl, aldehyde, or maleimide, and reacting the metal nanostructures with the treated surface. It is known that metallic nanostructures bind to these functional groups with high affinity. In some embodiments, the metallic nanostructures comprising the metallic nanolayer are spherical nanoparticles. Such nanoparticles have diameters of less than about 300 nm, less than about 200 nm or less than about 150 nm. In some embodiments, the spherical /qcp Ln/zznz/E/YiAi nanoparticles have a diameter of about 5 nm to about 200 nm, about 10 nm to about 100 nm, or about 20 nm to about 60nm. In certain embodiments, the size of the metal nanostructures used to create the metal nanoshell are similar to the size of the composite nanostructures used in the sensing conjugates. In such embodiments, size matching the two sets of nanostructures can provide an optimal wavelength variation in a reflectance, emission or scattering spectrum.
The metal nanolayer (metal film or multiple metal nanostructures) can be composed of a noble metal or compounds thereof. In other embodiments, the metal nanolayer (metal film or multiple metal nanostructures) may be composed of a transition metal or compounds thereof. In certain embodiments, the metallic nanolayer comprises a metal selected from gold, silver, copper, platinum, palladium, ruthenium, rhodium, osmium, iridium, titanium, chromium, cadmium, zinc, iron, cobalt, nickel and compounds thereof. In a particular embodiment, the metal nanolayer (e.g., metal film or multiple metal nanostructures) comprises gold. In another particular embodiment, the metallic nanolayer (for example, metallic film or multiple metallic nanostructures) comprises silver. In certain embodiments, the metal nanolayer (e.g., metal film or multiple metal nanostructures) comprises a gold and silver or gold and copper compound. The use of alkali metals (e.g., lithium, sodium, potassium, rubidium, cesium, and francium) or lanthanides (e.g., lanthanum, cerium, praseodymium, neodymium, promised, samado, europium, gadolinium, terbium, dysprosium, holmium, erbium , thulium, ytterbium and lutetium) can enhance the intensity of LSPR peaks. Accordingly, in some embodiments, the metal nanolayer (metal film or multiple metal nanostructures) may be composed of one or more alkali or lanthanide metals. In other embodiments, the metal nanolayer (metal film or multiple metal nanostructures) may be composed of a composition of a noble metal and an alkali metal or lanthanide.
The analyte detection devices of the invention also comprise multiple capture molecules immobilized on the metal nanoshell deposited on a surface. Capture molecules are capable of specifically binding to a target analyte. As used herein, "specific binding" refers to a target molecule with high affinity, for example, an affinity of at least ΙΟ<sup>-6</sup> M. In some embodiments, capture molecules are haptens and other small molecules, drugs, hormones, biological macromolecules including, but not limited to, antibodies or fragments thereof (e.g., Fv, Fab, (Fab)2, chain simple, CDR, etc.), antigens, receptors, ligands, polynucleotides, aptamers, polypeptides, polysaccharides, lipopolysaccharides, glycopeptides, lipoproteins or nucleoproteins. In certain embodiments, the multiple capture molecules are antibodies. In other embodiments, the multiple capture molecules are antigens.
7QCP ίη/ΖΖΠΖ/Ε/ΥΙΛΙ
Those skilled in the art know methods for immobilizing molecules in metallic nanostructures or nanoshells. Such methods include conjugation chemistries, such as those involving l-ethyl-3-[3-dimethylaminopropyl]carbodamida hydrochloride (EDC), sulfo-NHS coupling, hydrophobic bonding or thioether chemistry. In some embodiments, the molecule can be coupled to the metal nanostructure or nanoshell indirectly through a longer protein or carrier molecule. Such indirect coupling is particularly useful when the molecule is small, such as a hormone, a drug and other small molecules less than 10 kD. Preferably, the carrier protein is not capable of specifically interacting with the target analyte.
Analyte detection devices of the invention may also comprise multiple detection conjugates. Sensing conjugates comprise metallic nanostructures coupled to binding partners capable of specifically binding to a target analyte or capture molecules according to the assay configuration. For example, in embodiments where the device is configured in a sandwich assay format, the detection conjugates comprise metallic nanostructures coupled or conjugated to binding partners capable of specifically binding to a target analyte. In other embodiments where the device is configured in a direct competitive assay format, the detection conjugates comprise metal nanostructures coupled or conjugated to target analytes.
Binding partners may be the same types of molecules as capture molecules including, but not limited to, haptens and other small molecules, drugs, hormones, biological macromolecules such as antibodies or fragments thereof (e.g., Fv, Fab , (Fab)?, single chain, CDR, etc.), antigens, receptors, ligands, polynucleotides, aptamers, polypeptides, polysaccharides, lipopolysaccharides, glycopeptides, lipoproteins or nucleoproteins. In some embodiments, the binding partners are the same type of molecule as capture molecules, but preferably bind to the target analyte at a location different from the binding site of the capture molecules. As an example, the binding partners and capture molecules may be antibodies that recognize a target analyte, but the epitope to which the binding partners bind the target analyte is independent of the epitope to which the capture molecules bind the target analyte. and ideally not overlapping this. Therefore, in certain embodiments, the binding partners are antibodies that recognize a first epitope of a target analyte and the capture molecules are different antibodies that recognize a second epitope of a target analyte.
Metallic nanostructures in sensing conjugates can be composed of a noble metal or compounds thereof. In some embodiments, the metal nanostructures in the sensing conjugates may be composed of a transition metal or
7QCP ίη/ΖΖΠΖ/Ε/ΥΙΛΙ compounds of this. In some embodiments, the metal nanostructures in the sensing conjugates may comprise an alkali or lanthanide metal in combination with a noble or transition metal. In certain embodiments, the metal nanostructures in the sensing conjugates comprise a metal selected from gold, silver, copper, platinum, palladium, ruthenium, radium, osmium, iridium, titanium, chromium, cadmium, zinc, iron, cobalt, nickel and compounds. of these. In one embodiment, the metallic nanostructures are gold nanostructures. In another embodiment, the metallic nanostructures are silver nanostructures.
In preferred embodiments, the metal nanostructures in the sensing conjugates are composite metal nanostructures. "Composite metal nanostructures" refers to nanostructures that comprise at least two noble metals, transition metals, alkali metals or lanthanides. The two or more metals can be found mixed together, as in an alloy, or they can be found present in independent parts of the nanostructure. For example, one metal may form the core of the nanostructure, while the second metal forms an outer shell of the nanostructure. In some embodiments, the metallic composite nanostructures comprise at least two metals selected from gold, silver, copper, platinum, palladium, ruthenium, radium, osmium, iridium, titanium, chromium, cadmium, zinc, iron, cobalt and nickel. In other embodiments, the composite metal nanostructures comprise at least two metals selected from gold, silver, copper, platinum, palladium, cadmium, iron, nickel and zinc. In a particular embodiment, the composite metallic nanostructures comprise gold and silver. In another embodiment, the composite metallic nanostructures comprise gold and copper. In yet another embodiment, the composite metallic nanostructures comprise silver and copper.
In some embodiments, each of the composite metal nanostructures is an alloy of a first metal and a second metal. In certain embodiments, each of the composite metal nanostructures comprises a core of a first metal and a coating of a second metal. In one embodiment, the core is silver and the coating is gold. In another embodiment, the core is copper and the coating is gold. In another embodiment, the core is made of avocado and the coating is made of copper. In some embodiments, each of the composite metal nanostructures comprises a dielectric core (e.g., silicon dioxide, gold sulfide, titanium dioxide, silica, and polystyrene), a first coating of a first metal, and a second coating of a second metal. metal. In a particular embodiment, the core is silica, the first coating (i.e., the inner coating) is a silver coating and the second coating (i.e., the outer coating) is a gold coating. In another embodiment, the core is silica, the first coating (i.e., the inner coating) is a copper coating, and the second coating (i.e., the outer coating) is a gold coating.
In some embodiments, the core comprising a first metal is dissolved then
7QCP ίη/ΖΖΠΖ/Ε/ΥΙΛΙ of the coating process with a second metal to create a hollow structure comprising the second metal. For example, coating a silver core with gold nanoparticles generates a gold shell around the gold core, and then the silver core dissolves or degrades, resulting in the formation of a gold shell structure. hollow nanogold.
Metallic nanostructures include spherical nanoparticles, as well as nanoplates and nanoshells. Nanoplates have lateral dimensions (e.g., edge lengths) larger than their thicknesses. Nanoplates include nanodisks, nanopolygons, nanohexagons, nanocubes, nanorings, nanostars, and nanoprisms. In some embodiments, metallic nanostructures, including composite nanostructures, have a geometry selected from composite nanoparticles, pyramidal nanoparticles, hexagonal nanoparticles, nanotubes, nanoshells, nanorods, nanodots, nanoislands, nanowires, nanodisks, nanocubes, or combinations thereof. Other shapes are also possible, even irregular shapes. In certain embodiments, the size and shape of the metallic nanostructures is not uniform, that is, the metallic nanostructures are a heterogeneous mixture of different shapes and sizes of nanostructures.
In the case of nanoparticles, suitable diameter ranges include about 5 nm to about 200 nm, about 10 nm to about 100 nm, and about 20 nm to about 60 nm. In the case of nanoplates, the edge lengths can be from about 10 nm to about 800 nm, from about 20 nm to about 500 nm, from about 50 nm to about 200 nm, from about 30 nm to about 100 nm, or from about 10 nm to about 300 nm. The thickness of the nanoplates can vary from about 1 to about 100 nm, from about 5 nm to about 80 nm, from about 10 nm to about 50 nm, or from about 5 nm to about 20 nm. .
In some embodiments, the nanoplates have an aspect ratio greater than 2. The aspect ratio is the ratio of edge length to thickness. Preferably, the nanoplates have an aspect ratio of about 2 to about 25, about 3 to about 20, about 5 to about 10, about 2 to about 15, or about 10. at around 30.
The binding partners or target analytes can be coupled or conjugated to the metal nanostructures (e.g., composite nanostructures) with similar methods, as described above for the immobilization of the capture molecules on the metal nanoshell. Such methods include, but are not limited to, EDC conjugation chemistry, sulfo-NHS coupling, hydrophobic bonding, or thioether chemistry. Binding partners or target analytes can be coupled to metal nanostructures through various functional groups including /qcp Ln/zznz/E/YiAi thiol, amine, dithiol, acrylic phosphoramidite, azide, or alkynes.
In some embodiments, the metal or metals used in the metal nanolayer deposited on the surface may be the same metal or metals with which the metal nanostructures in the detection conjugates are manufactured. For example, in one embodiment, the metal nanolayer deposited on the surface comprises a gold film or multiple gold nanostructures and the sensing conjugates comprise gold nanostructures. In other embodiments, the metal used in the metal nanolayer deposited on the surface is different from the metal or metals used to create the metal nanostructures in the detection conjugates. For example, in some embodiments, the metal nanolayer deposited on the surface comprises a silver film or multiple silver nanostructures and the sensing conjugates comprise gold nanostructures. In other embodiments, the metal nanolayer deposited on the surface comprises a gold film or multiple gold nanostructures and the sensing conjugates comprise silver nanostructures. In certain embodiments, the metal nanolayer deposited on the surface comprises a gold film or multiple gold nanostructures and the sensing conjugates comprise composite nanostructures. In related embodiments, the composite nanostructures comprise gold-coated silver nanostructures. In other particular embodiments, the metal nanolayer deposited on the surface comprises a gold film or multiple gold nanostructures and the sensing conjugates comprise composite nanostructures comprising gold-coated copper nanostructures. In still other embodiments, the metal nanolayer deposited on the surface comprises a gold film or multiple gold nanostructures and the sensing conjugates comprise composite nanostructures comprising gold-coated magnetite nanostructures. In still other embodiments, the metal nanolayer deposited on the surface comprises a gold film or multiple gold nanostructures and the sensing conjugates comprise composite nanostructures comprising gold and an alkali metal or lanthanide.
The present invention also includes kits comprising the analyte detection devices of the invention as described herein. In one embodiment, the kit comprises (i) a surface containing a metal nanolayer on which multiple capture molecules are immobilized and (i) a composition comprising multiple detection conjugates as described herein. In certain embodiments, the composition is packaged independently of the surface, so that it can be brought into contact with the surface later during implementation of the detection methods. In some embodiments, the composition comprising multiple detection conjugates is lyophilized, for example, in pellet or sphere form. In related modalities, the surface containing the metal nanolayer may be a chip, a disk, or a cuvette. In a particular embodiment, the surface containing the
7QCP ίη/ΖΖΠΖ/Ε/ΥΙΛΙ metal nanolayer is a cuvette adapted for use with a centrifuge rotor. In such embodiments, the metal nanolayer can be deposited on the cover, bottom and/or walls of the cuvette.
In certain embodiments, all components of the analyte detection systems described herein are contained in a centrifuge disk or rotor. For example, a disk or rotor may contain one or more reaction chambers in which the metal nanoshell surface containing the immobilized capture molecules and multiple detection conjugates are placed. In one embodiment, the metal nanoshell surface is a chip located at the bottom of the reaction chamber. In another embodiment, the metal nanolayer is deposited directly on the floor of the reaction chamber. In yet another embodiment, the surface of the metal nanolayer is a sphere (e.g., a plastic sphere) coated with the metal nanolayer. In all such embodiments, the capture molecules are immobilized on the surfaces of the metal nanolayers. In related embodiments, the multiple detection conjugates are present in the form of a lyophilized composition, such as a pellet or a lyophilized sphere.
In alternative embodiments, capture molecules are conjugated with metal nanostructures in colloidal suspension. The multiple detection conjugates are added to the suspension in the presence of a test sample. If the target analyte is present in the sample, complex formation will occur between the detection conjugates and the suspended nanostructures containing the capture molecules, resulting in a change in the optical signal (e.g., variation in the length peak absorbance waveform of the suspended nanostructures).
Accordingly, in some embodiments, the kits comprise a rotor or disk with one or more reaction chambers, wherein each reaction chamber comprises (i) a lyophilized composition comprising multiple detection conjugates, as described herein and (i) a sphere coated with a metallic nanoshell on which multiple capture molecules are immobilized. Such kits provide a one-stage analyte detection assay whereby the test sample is brought into contact with the rotor or disk, and application of centrifugal force to the rotor or disk delivers the test sample to the reaction chambers. , in which the sample is mixed with the multiple detection conjugates and the sphere coated with a metal nanoshell containing immobilized capture molecules. In embodiments where the rotor or disk contains more than one reaction chamber, it is possible to select the detection conjugates and capture molecules so that it is possible to detect a different analyte in each reaction chamber. Such rotor format detection devices may be configured in the sandwich assay format, the direct competitive format, or both, if the rotors comprise multiple
7QCP ίη/ΖΖΠΖ/Ε/ΥΙΛΙ reaction chambers.
It is possible to use any of the types of metal nanoshells or metal nanostructures mentioned herein with said rotor format detection devices. In some embodiments, the metal nanoshell coating the sphere is a gold nanoshell and the metal nanostructures in the sensing conjugates are gold nanostructures. In other embodiments, the metal nanolayer coating the sphere is a silver nanolayer and the metal nanostructures in the sensing conjugates are gold nanostructures. In still other embodiments, the metal nanoshell coating the sphere is a gold nanoshell and the metal nanostructures in the sensing conjugates are silver nanostructures. In one embodiment, the metal nanolayer coating the sphere is a silver nanolayer covered with a gold nanolayer and the metal nanostructures in the sensing conjugates are gold nanostructures. In certain embodiments, the metal nanolayer coating the sphere is a gold nanolayer and the metal nanostructures in the sensing conjugates are composite nanostructures. For example, in one embodiment, the composite nanostructures are silver nanostructures coated with gold. In another embodiment, the composite nanostructures are copper nanostructures coated with gold.
The kits of the invention may also include instructions for using the device to detect an analyte in a test sample, devices or tools for collecting biological samples, and/or extraction buffers for obtaining samples of solid materials, such as soil, food and biological tissues.
The present invention also provides methods for detecting a target analyte in a sample. In one embodiment, the methods comprise (i) mixing a test sample with multiple detection conjugates, as described herein, (i) contacting the mixture with a surface containing a metal nanolayer in which immobilize multiple capture molecules as described herein on the metal nanolayer, (i¡) expose the surface to a light source at a wavelength range in the ultraviolet, visible and infrared spectrum, and (iv) measuring an optical signal from the surface, where the change in the optical signal indicates the presence of the target analyte in the sample.
In some embodiments, the detection methods are sandwich assays. In such embodiments, the detection conjugates comprise metallic nanostructures coupled to binding partners capable of specifically binding to the target analyte if present in the sample to form complexes of detection conjugates and analytes. The multiple capture molecules that are immobilized on the metal nanoshell surface are also capable of specifically binding to the target analyte, if present in the sample. The metal nanoshell is exposed to a light source and an optical signal is measured, in which a change in the optical /qcp Ln/zznz/E/YiAi signal indicates the presence of analyte in the sample. By way of illustration, when a sample containing the target analyte is mixed with the multiple detection conjugates, the target analyte binds to the binding partners in the detection conjugates to form detection conjugate-analyte complexes. In turn, these complexes bind to the multiple capture molecules immobilized on the metal nanolayer surface through the analyte, bringing the metal nanostructures in the detection conjugates closer to the metal nanolayer surface. The proximity of the metal nanostructures in the complex affects the amount of light absorbed or scattered by the metal nanoshell surface and thus produces a larger variation in the peak absorption wavelength, indicating the presence of analyte. target in the sample.
In other embodiments, the detection methods are competitive assays. In said embodiments, the detection conjugates comprise metallic nanostructures coupled to the target analyte of interest. Just as in the sandwich assay method, the multiple capture molecules that are immobilized on the metal nanoshell surface are also capable of specifically binding to the target analyte. In such a type of assay, the detection conjugates will bind to the capture molecules initially. If a sample containing a target analyte were mixed with such initial complexes, the unlabeled or free target analyte in the sample will compete with the detection conjugates for binding to capture molecules. The displacement of the metal nanostructures in the sensing conjugates from the metal nanoshell surface, which proportionally reduces the wavelength shift in the absorption wavelength of the peaks, will produce a change in the optical signal in this type. of testing.
A test sample can be any type of liquid sample, including biological samples or extracts prepared from food or environmental samples. In a particular embodiment, the test sample is a biological sample. Biological samples include, but are not limited to, whole blood, plasma, serum, saliva, urine, pleural effusion, sweat, bile, cerebrospinal fluid, fecal material, vaginal fluids, sperm, ocular lens fluid, mucosa, synovial fluid, fluid peritoneal, amniotic fluid, biopsy tissues, saliva and cell lysates. The biological sample can be obtained from a human subject or an animal subject suspected of suffering from a condition or disease, such as cancer, infectious diseases (for example, viral, bacterial, parasitic or fungal infections), cardiovascular disease, metabolic disease, autoimmune disease, etc. The biological sample can also be obtained from a healthy subject (for example, human or animal) in a routine medical check-up.
In some embodiments of the method, the test sample is mixed with the multiple detection conjugates and the mixture is subsequently brought into contact with the metal nanoshell /qcp Ln/zznz/E/YiAi surface containing the immobilized capture molecules. . In other embodiments, the test sample is brought into contact with the metal nanoshell surface containing the immobilized capture molecules and then the multiple detection conjugates are added. In certain embodiments, the sample, the multiple detection conjugates, and the metal nanoshell surface containing the immobilized capture molecules are brought into contact at the same time. For example, it is possible to put the sample in contact with both reagents simultaneously in the previously described rotor format detection devices.
It is possible to use any of the analyte detection devices described above in the detection methods of the present invention. Therefore, the various metal nanoshell surfaces, capture molecules, and detection conjugates described herein are suitable for use in detection methods. For example, in some embodiments of the methods, the surface containing a metal nanoshell is a chip, well, cuvette, or sphere. In certain embodiments of the methods, the surface containing a metal nanolayer is the walls and bottom of a bucket incorporated into or adapted for use with the centrifuge rotor. In these and other embodiments, the metal nanolayer on the surface is a metal film, such as a gold film. In other embodiments of the methods, the metal nanolayer on the surface comprises multiple metal nanostructures immobilized on the surface, such as gold nanostructures.
In certain embodiments of the detection methods, the detection conjugates comprise composite metal nanostructures coupled to binding partners or target analytes. As described herein, composite metal nanostructures comprise at least two noble metals or transition metals. In some embodiments of the methods, the metallic composite nanostructures comprise at least two metals selected from gold, silver, copper, platinum, palladium, ruthenium, radium, osmium, iridium, titanium, chromium, cadmium, zinc, iron, cobalt and nickel. In other embodiments of the methods, the composite metal nanostructures comprise at least two metals selected from gold, silver, copper, platinum, palladium, cadmium, iron, nickel and zinc. In a particular embodiment, the composite metallic nanostructures comprise gold and silver. In another embodiment, the composite metallic nanostructures comprise gold and copper. In yet another embodiment, the composite metallic nanostructures comprise silver and copper. The composite metal nanostructures used in the methods of the invention may include several different geometries, such as spherical nanoparticles, pyramidal nanoparticles, hexagonal nanoparticles, nanotubes, nanoshells, nanorods, nanodots, nanoislands, nanowires, nanodisks, nanocubes or combinations of these.
In certain embodiments, the composite metal nanostructures used in the methods of the invention are alloys of a first metal and a second metal. In some
7QCP ίη/ΖΖΠΖ/Ε/ΥΙΛΙ modalities, the composite metallic nanostructures used in the methods of the invention comprise a core of a first metal and a coating of a second metal. In particular embodiments, the composite metallic nanostructures comprise a silver core and a gold coating. In other embodiments, the composite metallic nanostructures comprise a copper core and a gold coating. In another embodiment, the core is made of avocado and the coating is made of copper. In some embodiments, each of the composite metal nanostructures comprises a dielectric core (e.g., silicon dioxide, gold sulfide, titanium dioxide, silica, and polystyrene), a first coating of a first metal, and a second coating of a second metal. metal. In a particular embodiment of the detection methods, the core is silica, the first coating (i.e., the inner coating) is a silver coating and the second coating (i.e., the outer coating) is a gold coating. In another embodiment, the core is silica, the first coating (i.e., the inner coating) is a copper coating, and the second coating (i.e., the outer coating) is a gold coating.
The detection methods of the invention can be used to determine qualitative or quantitative amounts of a target analyte. Such methods are particularly useful for determining the approximate amount of a target analyte in a sample, which can be used, among other things, to diagnose certain medical conditions or evaluate the effectiveness of a drug therapy. In one embodiment, it is possible to determine the amount of a target analyte by establishing a standard curve for the particular analyte by measuring changes in the optical signals of the metal nanoshell surface as described herein for samples with an amount of known target analyte, determine the change in optical signal for a test sample and compare the change in optical signal for the test sample with respect to the values obtained for the standard curve. In some embodiments, determining the amount of a complex between a first reagent and a second reagent comprises comparing the absorbance ratio and/or reaction rate of a test sample to the absorbance ratio and/or reaction rate of a test sample. sample with a known amount of complex, so as to determine the amount of the complex in the test sample. It is possible to compare the quantitative values obtained from the test samples with predetermined threshold values, which are indicative of an abnormal or normal level of the target analyte.
The detection methods of the present invention provide a very sensitive technique for the detection of very small amounts of a target analyte in a sample. As demonstrated by working examples, plasmon resonance-based signal amplification of gold nanoshell surfaces with gold nanostructure conjugates can be achieved so that nanogram quantities of analyte can be detected.
7QCP ίη/ΖΖΠΖ/Ε/ΥΙΛΙ objective in a sample. Therefore, in one embodiment of the methods, the presence of nanogram amounts of a target analyte is detected. The inventors have surprisingly discovered that it is possible to achieve significantly higher signal amplification based on plasmon resonance of gold nanoshell surfaces with composite metal nanostructure conjugates. The use of gold-coated silver nanostructures conjugated to an analyte-specific antibody made it possible to detect pictogram amounts of the target analyte, which is a 1000-fold increase in sensitivity compared to that obtained with gold nanostructure conjugates. . See Example 3. Accordingly, in some embodiments of the methods, the presence of picogram amounts of the target analyte is detected. In other embodiments of the methods, the presence of femtogram amounts of the target analyte is detected. Higher sensitivities can be obtained by altering the composition and/or shape of the composite metal nanostructures and/or the metal nanoshell surface.
When incident light is applied to metallic nanostructures, the conduction band electrons in the metal collectively oscillate at the same frequency as the incident electromagnetic wave. As a result of these resonance oscillations, the nanostructures intensely absorb and scatter light in a specific wavelength range. For metallic nanostructures comprising transition or noble metals, this wavelength range is in the ultraviolet, visible and infrared spectrum according to the particular composition of the nanostructures. Therefore, light sources for applying electromagnetic energy suitable for use in the methods of the invention may include any source that can apply a wavelength range in the ultraviolet and visible spectrum or in the ultraviolet, visible and infrared spectrum. , including lasers and arc lamps. In some embodiments, the light source may be equipped with a monochromator, such that specific wavelengths of light may be applied to the metal nanoshell surface.
The optical properties of metallic nanostructures and nanolayers depend on their size, shape and composition. For example, solid gold nanoparticles have an absorption peak wavelength (Amax) of about 515 nm to about 560 nm depending on the particle size. Spherical gold nanoparticles having a diameter of 30 nm absorb maximally at around 520 nm with Amax varying at longer wavelengths as the particle diameter increases. Silver and copper particles have an Amax in the ultraviolet/blue or red region (e.g., from about 350 nm to about 500 nm) with increasing particle diameter, which causes a variation in Amax at different wavelengths. longer. Metallic nanorods have a transverse Amax and a longitudinal A maxz. Alloys of different metals normally exhibit absorption peaks in a range intermediate between the /QCP Ln/Zznz/E/YIAI absorption peaks of the metals they comprise. For example, nanostructures comprising a 50/50 alloy of gold and silver exhibit Amax of around 470 nm with higher amounts of gold, causing a shift in the absorption peak at longer wavelengths. The sensitivity of LSPR signals to changes in the refractive index of the local medium can be modified by changing the shape or geometry of the nanostructures. For example, non-spherical particles (e.g., nanoprisms, nanorods, nanoshells, etc.) have increased LSPR sensitivities compared to spheres. In some embodiments, the optical properties (e.g., absorption/scattering at particular wavelengths) are tailored to a particular application by varying the size, shape, or composition of the metallic nanolayer placed on the surface or metallic nanostructures employed. in the detection conjugates.
The interaction between the incident light and the metal nanoshell surface can be controlled as reflected light or transmitted light. The amount of incident light that is absorbed or scattered can be measured as an absorption spectrum in a reflection mode or the absorption spectrum in a transmission mode. In some embodiments, the optical signal measured from the metal nanolayer may be an optical reflection, an absorbance spectrum, a scattering spectrum, and/or an emission spectrum.
Plasmon coupling between the metal nanoshell and the metal nanostructures in the sensing conjugates that results from the formation of complexes between the binding partners, target analytes, and capture molecules produces a shift in the localized surface plasmon resonance spectrum of the metal nanolayer. For example, such changes may include increased optical extinction, increased optical reflection, and/or increased signal scattering and/or emission. In some embodiments, the change in optical signal indicative of the presence of the target analyte in the sample includes a variation, increase or decrease in optical dispersion or a combination of these characteristics. In certain embodiments, the change in the optical signal indicative of the presence of the target analyte in the sample is a wavelength variation of the spectral peak. In one embodiment, the wavelength shift in the optical spectral peak may be a red shift (e.g., a shift to a longer wavelength) in a spectral window from 200 nm to 1200 nm. In another embodiment, the wavelength shift in the optical spectral peak may be a blue shift (e.g., a shift to a shorter wavelength) in a spectral window of 200 nm to 1200 nm. Changes in optical signals can be measured at a particular time after a set reaction period. Additionally or alternatively, it is possible to measure changes in the optical signal during the reaction period (e.g., velocity determinations). Both types of measurements can be used for either qualitative or quantitative analysis of a target analyte.
/qcp ίη/ζζηζ/Ε/γίΛΐ
Various means are known in the art to measure optical signals at different wavelengths and to acquire extinction, scattering or emission spectra. Any spectrophotometric or photometric instruments are suitable for use in the methods described. Non-limiting examples include plate readers, Cobas Fara analyzers and Piccolo xpress® and Vetscan analyzers (Abaxis, Inc., Union City, CA), fiber optic readers (e.g., LightPath™ S4 (LamdaGen, Menlo Park, CA) ), SPR instruments (e.g. Biacore instruments available from GE Healthcare), centrifugal analyzers from Olympus, Hitachi, etc.
The present invention also includes a test complex comprising (i) a detection conjugate comprising a composite metallic nanostructure coupled with a binding partner, (i) a target analyte and (iii) a sphere coated with a metallic nanoshell on which a capture molecule is immobilized, wherein the binding partner in the detection conjugate binds to a first epitope on the target analyte and the capture molecule binds to a second epitope on the target analyte, such that a complex forms a complex comprising the conjugate detection, the target analyte and the capture molecule. In some embodiments, the test complex is contained in a cuvette adapted for use with a centrifuge rotor. In other embodiments, the test complex is contained in a reaction chamber on a centrifuge disk or rotor.
The binding partner and capture molecule in the test complex can be any type of molecule described above, including haptens and other small molecules, drugs, hormones, biological macromolecules such as antibodies or fragments thereof (e.g., Fv , Fab, (Fab)2, single chain, CDR, etc.), antigens, receptors, ligands, polynucleotides, aptamers, polypeptides, polysaccharides, lipopolysaccharides, glycopeptides, lipoproteins or nucleoproteins. In one embodiment, the binding partner is an antibody and the capture molecule is a different antibody.
Metal nanoshell and composite metal nanostructures are described in more detail above. In one embodiment, the metallic nanolayer coating the sphere (e.g., plastic or glass sphere) is a gold nanolayer. In another embodiment, the metallic nanolayer that covers the sphere is a silver nanolayer. The sphere is preferably less than 0.5 cm, but more than 0.1 mm. In certain embodiments, the composite metal nanostructures are gold-coated silver nanostructures. In other embodiments, the composite metal nanostructures are gold-coated copper nanostructures. In still other embodiments, the metallic nanostructures comprise gold altered with silver, copper ions, or both of these ions.
Any type of target analyte can be detected with the methods, devices and assay complexes of the present invention, particularly those that are
7QCP ίη/ΖΖΠΖ/Ε/ΥΙΛΙ significant in the diagnosis of diseases. A target analyte may include, but is not limited to, a protein, enzyme, antigen, antibody, peptide, nucleic acid (RNA, DNA, mRNA, miRNA), hormone, glycoprotein, polysaccharide, toxin, virus, virus particle, molecule. drug, hapten or chemical compound. In some embodiments, the target analyte is a marker or antigen associated with an infectious disease in humans and/or animals. In other embodiments, the target analyte is a marker or antigen associated with a particular physiological state or pathological condition.
In certain embodiments, the target analyte is a pathogenic antigen or an antibody against a pathogenic antigen. For example, the pathogenic antigen may be a viral antigen (e.g., feline leukemia virus, canine parvovirus, foot-and-mouth disease virus, influenza virus, hepatitis a, b, c virus, HIV virus, papillomavirus human, Epstein Barr virus, rabies virus, etc.), a bacterial antigen (e.g. Ehriichia, Borreiia, Anapiasma, Anthrax, Salmonella, BaciHus, etc.), a fungal antigen or a parasitic antigen (e.g. canine helminth, Giardia lamblia, p/asmodium falciparum, African trypanosomiasis, Trypanosoma brucei, etc.). In other embodiments, the target analyte is a disease-related antigen or an antibody against a disease-related antigen. Disease-related antigens include, but are not limited to, cancer-related markers or antigens (e.g., PSA, AFP, CA125, CA15-3, CA19-9, CEA, NY-ESO-1, MUC1, GM3, GD2, ERBB2, etc.), markers or antigens related to cardiovascular diseases (e.g., troponin, C-reactive protein, brain natriuretic peptide, CKMB, fatty acid binding protein, etc.), markers or antigens related to metabolic diseases ( For example, thyroid-stimulating hormone, thyroxine, leptin, insulin) or markers or antigens related to autoimmune diseases (for example, autoantibodies). In certain embodiments, the target analyte is an inflammatory marker or antigen (e.g., C-reactive protein, MRP14, MRP8, 25F9, etc.). In other embodiments, the target analyte is a pregnancy-related marker or antigen (e.g., a fetal antigen, human chorionic gonadotropin).
The present invention also provides a method for preparing composite metal nanostructures. In one embodiment, the method comprises preparing a first solution comprising a mixture of a polymer and chloroauric acid, preparing a second solution comprising silver or copper nanostructures and incubating the first solution with the second solution for a period of time, in which that the resulting mixture comprises gold-coated silver nanostructures or gold-coated copper nanostructures. The resulting mixture preferably has an absorbance peak of about 515 nm to about 670 nm, or about 520 nm to about 560 nm. In one embodiment, the resulting mixture has an absorbance peak of about 530 nm.
/QCP ίη/ΖΖΠΖ/Ε/ΥΙΛΙ
The polymer used in the preparation of the first solution may be any of polyvinylpyrrolidone, polyvinyl alcohol, polyacrylate, polyethylene glycol, polyethyleneimine, polyaspartic acid, polyglutamic acid, various gums, gelatin or mixed polymers comprising any of the above. In a particular embodiment, the polymer is polyvinylpyrrolidone. It is possible to obtain different types of coated nanostructures by varying the molecular weight of the polymer. Suitable molecular weight ranges of the polymer include from about 5,000 daltons to about 150,000 daltons, from about 10,000 daltons to about 100,000, from about 20,000 daltons to about 80,000 daltons. In some embodiments, the polymer has a molecular weight of less than 50,000 daltons. In other embodiments, the polymer has a molecular weight of less than 20,000 daltons. In certain embodiments, the polymer has a molecular weight of about 10,000 daltons.
The characteristics of the gold coating can be controlled by adjusting the concentration ratio of the polymer to chloroauric acid. For example, the concentration ratio of polymer to chloroauric acid is about 100:1 to about 1:100, about 2:1 to about 5:1, or about 1.5:1 to about 8. :1. In some embodiments, the concentration ratio of polymer to chloroauric acid is 1:1. Suitable polymer concentrations include, but are not limited to, about 0.1% to about 20% w/w in water or ethanol. Suitable concentrations of chloroauric acid include, but are not limited to, about 0.001 M to about 1.0 M, about 0.010 M to about 0.500 M, and about 0.050 M to about 0.100 M.
The thickness and effectiveness of the coating can also be affected by the pH and halide content of the coating solution (i.e., the first solution). In certain embodiments, the pH of the solution is maintained in a range of about 3 to about 14. The halide content of the solution is, in some embodiments, less than 150 mM. In other embodiments, the halide content of the solution is in the range of about 0 to about 50 mM.
Methods for preparing solutions of silver and copper nanostructures are known to those skilled in the art. For example, the second solution comprising silver or copper nanostructures can be prepared by any of the methods described in US Patent Publication No. 2012/0101007, US Patent Publication No. 2014/0105982, or US Patent Publication No. 2014/0105982. US Patent No. 2013/0230717, each of which is incorporated herein in its entirety by this reference. In one embodiment, the second solution comprising silver or copper nanostructures is prepared by mixing a silver or copper source with a reducing agent. A suitable silver source includes a silver salt, such as silver nitrate. Suitable copper sources include copper(II) sulfate,
7QCP ίη/ΖΖΠΖ/Ε/ΥΙΛΙ copper (II) chloride, copper (II) hydroxide and copper (II) nitrate, copper (II) acetate and copper (II) trifluoroacetate. Reducing agents that can be reacted with the silver or copper sources to form the nanostructures may include glucose, ascorbic acid, sodium borohydride, and alkaline solutions (e.g., pH greater than 7.5) of polymers, such as PVP. In certain embodiments, the reducing agent is ascorbic acid. The desired shape and optical spectral peak of silver nanostructures or copper nanostructures can be obtained by adjusting reagent ratios or concentrations, as known to those skilled in the art. By way of illustration only, high concentrations of the reducing agent can result in pentagon- and dipyramid-shaped nanostructures, while low concentrations of the reducing agent can result in nanowires or elongated tubes. In accordance with the particular shapes of the nanostructures, the second solution comprising silver or copper nanostructures may have a peak absorbance of about 550 nm to about 1000 nm, from about 600 nm to about 700 nm, from about from 630 nma around 680 nm, from around 750 nm to around 850 nm, from around 900 nma around 940 nm, from around 580 nm to around 620 nm or from around 550 nma around 750 nm. In certain embodiments, the second solution comprising silver nanostructures has a peak absorbance of about 600 nm (i.e., 595 nm to 605 nm, inclusive). In some embodiments, the second solution comprising copper nanostructures has a peak absorbance of about 585 nm (i.e., 580 nm to 590 nm, inclusive). In some embodiments, the absorbance peak of a solution comprising nanostructures is greater (i.e., red variant) than the absorbance peak of a solution comprising silver nanostructures of a similar size and shape.
In some embodiments, the incubation period of the first solution with the second solution is at least 12 hours. In other embodiments, the incubation period of the first solution with the second incubation is greater than 24 hours, preferably greater than 48 hours, more preferably, at least 72 hours. Changes in the peak absorbance of the reaction mixture can be monitored during the incubation period to adjust the incubation period accordingly. For example, changes in the absorbance peak at shorter wavelengths, for example, in the region of 520 nm to 550 nm, may indicate that the gold-coated nanostructures have stabilized. In certain embodiments, the stability of the resulting nanostructures with respect to sodium chloride (e.g., 0.25 - 1 M) is used to indicate suitable coating of the nanostructures.
In certain embodiments, the present invention provides methods for synthesizing nanostructures with optical densities greater than about 50/mL. In one embodiment, the methods comprise mixing a polymer, as described herein with /qcp ίη/ζζηζ/Ε/γίΛΐ chloroauric acid, stirring the mixture at a set temperature for a first period of time, adding ascorbic acid to the mix and incubate the mixture for a second period of time. The size and shape of the nanostructures are determined by the concentration ratio of the polymer to chloroauric acid and the temperature and incubation time. The concentrations of the polymer and chloroauric acid can be found in the ranges described above. The temperature can be adjusted based on the size and shape of the desired nanostructures, but can be in the range of about 4 °C to about 100 °C. Similarly, the incubation period (i.e., the first time period) can be adjusted based on the desired properties of the nanostructures, but can range from about 15 minutes to one day.
In some embodiments, about 0.1 to 1 part ascorbic acid (e.g., about 1 to 5 M) is added to the mixture after the first incubation period. The second incubation period after adding ascorbic acid can be from about 1 to about 24 hours. Without being limited by theory, adding ascorbic acid provides a substantial increase in the amount of nanostructures produced.
In certain embodiments, the methods further comprise adding to the mixture or altering the mixture with about 1 to about 100 parts of gold chloride (e.g., about 0.001 M to 1 M) or silver nitrate (e.g., about 0.001 M to 1 M) or another metal (for example, noble metal, transition metal, alkali metal or lanthanide). This alteration step can further increase the resonance intensity of the resulting nanostructures. In some embodiments, gold chloride, silver nitrate or other metal is added to the mixture before ascorbic acid is added to the reaction. In other embodiments, gold chloride, silver nitrate or another metal is added to the mixture after adding ascorbic acid. The order of addition of the metal and ascorbic acid can be adjusted to tailor the resulting nanostructures to a desired shape and size.
The present invention is further illustrated by the following examples which should not be considered exhaustive. Those skilled in the art, based on the present description, should note that various changes can be made to the specific embodiments described and still obtain the same or similar result without departing from the spirit and scope of the invention.
All patent and non-patent related documents referenced throughout the description are incorporated herein in their entirety and for all purposes.
7QCP ίη/ΖΖΠΖ/Ε/ΥΙΛΙ
EXAMPLES
EXAMPLE 1
LSPR signal amplification with analytes conjugated to gold nanoparticles
An analyte detection system was prepared by providing a plastic chip on which a gold nanolayer film was placed. Human IgG proteins (100 pg/ml) were immobilized on the gold nanoshell film to create the sensor surface. A control sensor was constructed by immobilizing bovine serum albumin on the gold nanoshell film. The two types of sensor surfaces were placed on an instrument equipped with light-emitting and light-harvesting fibers that direct light toward the gold nanoshell surface and collect light reflected from the surface.
A sample containing free protein A (10 pg/ml) was contacted with the two types of sensor surfaces and changes in the reflectance spectrum were measured. As illustrated in Figure 1, the introduction of free protein A to the sensor containing immobilized human IgG does not produce a significant visible change in the reflectance spectrum of the gold nanolayer film, as measured by a change in the peak wavelength.
The sensor surfaces were regenerated by treatment with 1 mM hydrochloric acid and a sample containing protein A conjugated to colloidal gold nanoparticles (CGC) at two different concentrations (3.5 pg/ml and 0.175 pg/ml) was contacted with sensor surfaces. The change in the reflectance spectrum of the gold nanoshell surface was accentuated when protein A (i.e., target analyte) was conjugated with colloidal gold nanoparticles. Specifically, 3.5 pg/ml protein A-CGC produced a greater variation in peak wavelength than 10 pg/ml unlabeled protein A. See Figure 1, sensor 2. The amplification of the plasmon resonance signal was large enough to make detection of nanogram concentrations of the A-CGC protein possible. See Figure 1, sensor 3. The changes in the reflectance spectrum of the BSA sensor represent the non-specific binding of protein A molecules to the sensor surface and are significantly smaller than the changes induced by the specific binding of protein A molecules to immobilized IgG molecules. .
The results of this initial experiment demonstrate that considerable amplification of changes in localized surface plasmon resonance signals induced by binding events on a metal nanoshell surface can be achieved by coupling the target analyte to colloidal gold nanoparticles. An almost 60-fold improvement in sensitivity is observed with detection of nanogram quantities of analyte.
/qcp Ln/zznz/E/YiAi
EXAMPLE 2 Amplification of LSPR signals in a sandwich assay
This example describes a series of experiments designed to evaluate whether amplification of localized surface plasmon resonance signals could also be achieved with gold nanoparticle conjugates in a sandwich assay format, in which the target analyte is not directly conjugated with gold nanoparticles. A gold nanolayer chip surface was prepared as described in Example 1. C7 antibody against C-reactive protein (CRP) (100 pg/ml) was immobilized on the gold nanolayer film placed on the surface of the chip to create the anti-CRP sensor. The C6 antibody, which recognizes a distinct, non-overlapping CRP epitope, unlike the C7 antibody, was conjugated to colloidal gold nanoparticles (C6-CGC) for some experiments or used in an unlabeled form for other experiments.
In a first series of experiments, a sample containing one of three different concentrations of CRP (1 ng/ml, 10 ng/ml or 100 ng/ml) was incubated with the anti-CRP sensor for 15 to 20 minutes and monitored. changes in the reflectance spectrum of the gold nanolayer. As illustrated in Figure 2, very minimal peak shift was observed upon binding of CRP to the anti-CRP C7 antibody immobilized on the sensor surface. Subsequent exposure of the sensor surface to unlabeled anti-CRP C6 antibody (1 pg/ml) did not result in further significant peak shifts. See Figure 2. Similarly, subsequent exposure of the sensor surface to 3 pg/ml C6-CGC did not produce any additional change in the reflectance spectrum, indicating that the bound CRP molecules were possibly saturated with unlabeled C6 antibody. See Figure 2.
In a second series of experiments, a sample containing one of three different concentrations of CRP (1 ng/ml, 10 ng/ml, or 100 ng/ml) was incubated with the anti-CRP sensor for 15 to 20 minutes. Subsequently, two different concentrations of C6-CGC (1 pg/ml and 3 pg/ml) were introduced and the changes in the reflectance spectrum were measured (Figures 3 and 4A). The results demonstrate that conjugation of anti-CRP C6 antibody with gold nanoparticles amplifies the peak wavelength variation compared to unlabeled C6 antibody. Higher concentrations of C6-CGC produce a dose-dependent variation in the peak wavelength. However, the signal difference between 1 ng/ml and 10 ng/ml was small (Figure 4B).
In a third series of experiments, the effect of analyte incubation time on signal development was evaluated. The anti-CRP sensor was contacted with the sample containing 0 ng/ml, 10 ng/ml or 100 ng/ml CRP and immediately, 3 pg/ml C6CGC was introduced without any analyte incubation time or washing. . As illustrated in Figures 5 and 6,
7QCP ίη/ΖΖΠΖ/Ε/ΥΙΛΙ shorter analyte incubation period results in smaller peak wavelength variations.
The results of these three sets of experiments demonstrate that amplification of LSPR signals can be achieved with gold nanoparticle conjugates in a sandwich assay format. A better signal variation is observed when the detector antibody is labeled with colloidal gold particles compared to the unlabeled antibody, thus making it possible to detect nanogram concentrations of analytes.
EXAMPLE 3
Enhanced Signal Amplification with Gold-Coated Silver Nanostructures
In order to examine whether varying the type of metal used to label the binding partners affected the amplification of LSPR signals, composite metal nanostructures were prepared. Specifically, gold-coated silver nanostructures were prepared as follows. Silver nanostructures were prepared by adding 50.0 mL of deionized H2O, 500.0 pL of trisodium citrate (75 mM), 200 pL of AgNOs (200 mM), and 500.0 pL of H2O2 (27%) while stirring vigorously at room temperature. . Then, a 500 pL aliquot of NaBhU (200 mM) was quickly injected into the aqueous solution, causing a color change to light yellow. Over a period of several minutes, the color continued to change from dark yellow to red to violet, and finally stayed blue. The UV/Vis spectrum determined that the absorbance peak of the solution occurred at 604.5 nm.
A gold coating was added to the silver nanostructures by adding 5.0 mL of the blue solution to a mixture of 50 pL of polyvinylpyrrolidone (PVP molecular weight ~ 10,000, 20% in ethanol) and 50 pL of HAuCU (20 mM ). After 72 hours of incubation, the sample turned dark red and had an absorbance peak at 534.5 nm. The nanoparticles were washed twice by centrifugation at 20,000 rpm for 20 min and resuspended in 2.0 mL deionized H2O. The solution had a deep red color, the absorption peak at 530.3 nm, and a total absorbance of 15.0 OD units.
Conjugation of gold-coated silver nanostructures (Au@AgNPs) with anti-CRP C6 antibody was carried out by adding 600.0 pL of Au@AgNPs and 20.0 pL of anti-CRP C6 antibody (8.0 mg/mL). to 880.0 pL of deionized H2O which brings the final antibody concentration to 17.8 pg/mL/OD. After a 2-h incubation period at 4°C, the sample was centrifuged at 30,000 g for 20 min and resuspended in 1.5 mL of blocking solution containing BSA (10 mg/mL) in PBS. The Au@AgNPs conjugated with anti-CRP C6 antibody were stored at 4 °C until next use.
7QCP ίη/ΖΖΠΖ/Ε/ΥΙΛΙ
The anti-CRP gold nanoshell sensor was prepared as described in Example 2 and had the absorption peak at 530 nm. A control sensor containing the gold nanoshell without any immobilized antibody was also prepared. The sensors were equilibrated with 100 pL of PBS.
100 pL of anti-CRP C6 antibody conjugated to Au@AgNPs diluted to 1.5 OD in PBS was premixed for 1 minute with 1, 10, or 500 pg/mL of CRP antigen. Then, the mixture was contacted with the anti-CRP or control sensor surface and the changes in the reflectance spectrum of the gold nanoshell surface were measured. The results demonstrate that the gold-coated silver nanostructures enhanced the peak wavelength variation induced by the binding of the antibody-CRP complex to the sensor surface (Figure 7). Detection of 1 pg/mL of CRP antigen was possible with the gold-coated silver nanostructures, which is a 1000-fold improvement in sensitivity compared to that obtained with gold nanoparticles. At higher concentrations of antigen, the binding sites are saturated and no further variations occur.
The results of this experiment demonstrate the significantly enhanced amplification of LSPR signals from a metal nanoshell surface achieved when composite nanostructures, such as gold-coated silver nanostructures, are used to label analyte binding partners.
EXAMPLE 4
Synthesis of high optical density nanostructures
The gold nanoparticles were prepared by mixing the following reagents in a final volume of 1 ml in the order indicated: 0.1 ml of 1% PVP-10 (1% w/w), 0.2 ml of 0.1 M gold chloride, 0.1 ml of 5 N NaOH, 0.4 ml of water and 0.2 ml of 1 M ascorbic acid. The reaction mixture was mixed after each addition. Spectroscopic measurements indicated that the reaction was virtually complete after 24 hours at room temperature. This protocol produced spherical gold nanoparticles exhibiting the LSPR peak at around 535 nm and the corresponding optical density of around 80 per ml. Layer formation with additional gold or silver was carried out by adding silver nitrate or gold chloride to the previously formed gold nanoparticles. Excess reagents were removed by centrifugation at 30,000# for 1-2 hours.
In a separate reaction, 0.05 ml of 20% (w/w) PVP was mixed with 0.25 ml of water, 0.1 ml of 5 N NaOH, 0.1 ml of 1 M sodium citrate, 0.5 ml of 0.1 M gold chloride, and 1 ml of 1 M ascorbic acid. This protocol resulted in the immediate formation of colloidal gold /qcp Ln/zznz/E/YiAi particles at an OD of around 90/ml with LSPR peak at ~525 nm. A linear correspondence between the final OD and the gold concentration was observed between 2.5 mM gold and 25 mM gold in the final reaction mixture.
It is understood that the invention described is not limited to the methodology, the 5 protocols and the particular materials that were described, since these may vary. It is also understood that the terminology used herein is only intended to describe particular embodiments and is not intended to limit the scope of the present invention which will be limited only by the appended claims.
Those skilled in the art will recognize or be able to determine various equivalents of specific embodiments of the invention described herein simply through routine experimentation. Such equivalents are intended to be encompassed by the following claims.
Contents10
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Priority claims4
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Numbers
- Publication
- 2022013567
- Application
- 2022013567
Titles2
- Spanish
- AMPLIFICACIÓN DE SEÑAL EN ENSAYOS DE COMPAÑERO DE UNIÓN ESPECÍFICO DE PLASMONES
- English
- SIGNAL AMPLIFICATION IN PLASMON SPECIFIC BINDING PARTNER ASSAYS
Classification
- CPC, 4
- G01N33/553
- G01N33/54373
- B82Y15/00
- G01N33/54393
- IPC, 4
- G01N33 553
- B82Y15 00
- C07K14 00
- C40B40 10