Abaxis, Inc.

Zoetis Services LLC

Vincent Chiang

Rajesh K Mehra

Kenneth P Aron

Jessica Frisz

Asher Krell

Sarah Ann Unser

The present invention relates to nanostructure-binding partner conjugates, as well as reaction mixtures, analyte detection devices, and methods of making and using the conjugates. In particular, the invention provides a method of detecting a target analyte in a sample comprising mixing the sample with a first detection conjugate and a second detection conjugate in solution, wherein the first and second detection conjugates comprise metallic nanostructures coupled to binding partners that are capable of specifically binding to the target analyte if present in the sample to form a complex between the first detection conjugate, the analyte, and the second detection conjugate, wherein a change in an optical signal upon complex formation indicates the presence of the target analyte in the sample.

Solution-based plasmonic specific-binding partner assays using metallic nanostructures

The present invention relates to analyte detection devices and methods of using such devices to detect minute quantities of a target analyte in a sample. In particular, the invention provides a method of detecting a target analyte in a sample comprising mixing the sample with a first detection conjugate and a second detection conjugate in solution, wherein the first and second detection conjugates comprise metallic nanostructures coupled to binding partners that are capable of specifically binding to the target analyte if present in the sample to form a complex between the first detection conjugate, the analyte, and the second detection conjugate, wherein a change in an optical signal upon complex formation indicates the presence of the target analyte in the sample. Methods of preparing nanostructures and nanoalloys, as well as nanostructures and nanoalloys conjugated to binding partners, are also described.

Signal amplification in solution-based plasmonic specific-binding partner assays

The present invention relates to analyte detection devices and methods of using such devices to detect minute quantities of a target analyte in a sample. In particular, the invention provides an analyte detection device comprising a plurality of composite metallic nanostructures conjugated to analyte binding partners and a surface containing a metallic nanolayer on which a plurality of capture molecules is immobilized. Methods of preparing composite nanostructures are also described.

Signal amplification in plasmonic specific-binding partner assays

The present invention discloses methods for detecting the presence of a complex between a first reagent and a second reagent in solution. In particular, the invention provides methods for qualitative or quantitative detection of an analyte or its specific binding partner in complex biological samples. The invention further discloses algorithms using summary rate changes at selected wavelengths in the absorbance spectra of colloidal metal-labeled analytes or specific binding partners to identify intermolecular interactions between the analyte and its binding partner.

Multi-wavelength analyses of sol-particle specific binding assays

The present invention discloses methods of reducing non-specific interactions of interfering species present in a sample in metallic nanoparticle-based assays, thereby increasing the sensitivity of these assays. In particular, the methods entail neutralizing the chemical reactivity of functional groups present in interfering species by addition of a neutralizing agent, such as an alkylating agent or heavy metal ion. The methods are especially useful in assays for the detection of analytes in biological samples. Reagent kits and assay mixtures for the practice of the described methods are also disclosed.

Methods of reducing non-specific interaction in metal nanoparticle assays

Chloride ion and sodium ion determination methods, compositions, and assays are provided which are based on the use of sodium ion as an activator for &agr;-amylase. Chloride ion and sodium ion determination are performed by colorimetry, using measurements of &agr;-amylase activity to indirectly measure the desired ion concentrations. One preferred composition for chloride ion determination comprises &agr;-amylase that is substantially calcium free, sodium ion in higher concentration than the &agr;-amylase, and an &agr;-amylase activity detecting substrate. In the methods, &agr;-amylase is deactivated by a calcium-binding compound, thereby preventing calcium from bonding with the &agr;-amylase. Next, chloride ion and sodium ion stoichiometrically bond with deactivated &agr;-amylase, thereby activating the &agr;-amylase. Chloride ion determination methods are based on using test sample chloride as the limiting factor in &agr;-amylase activation and sodium ion determination methods are based on using test sample sodium as the limiting factor in &agr;-amylase activation.

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San Ramon, CA, United States of America

Vincent Chiang