Abstract: The invention provides compositions (e.g., peptide compositions) useful for the detection of antibodies that bind to Borrelia antigens. The peptide compositions comprise polypeptide sequences comprising variants in the IR6 domain of the Borrelia VlsE protein. The invention also provides devices, methods, and kits comprising such peptide compositions and useful for the detection of antibodies that bind to Borrelia antigens and the diagnosis of Lyme disease.

Abstract: The invention provides compositions (e.g., peptide compositions) useful for the detection of antibodies that bind to Ehrlichia antigens. The peptide compositions comprise polypeptide sequences based on an immunogenic fragment of the Ehrlichia Outer Membrane Protein 1 (OMP-1) protein. The invention also provides devices, methods, and kits comprising such peptide compositions and useful for the detection of antibodies that bind to Ehrlichia antigens and the diagnosis of monocytic ehrlichiosis.

Abstract: 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.

Abstract: The present invention discloses analyte detection devices for detecting one or more analytes present in test samples, especially biological samples. In particular, the devices of the invention are lateral flow assay devices comprising immobilized metal nanoparticle conjugates as the detection means. Methods of using the devices and kits comprising the devices are also described.

Abstract: 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.