Design, Characterization, and Integration of Nanometric Objects with Chip-scale Platforms for Disease Diagnosis

Abstract

Nanomaterials (e.g., metal nanoparticles) are playing increasingly important roles in disease detection. This emergence arises from the need to detect markers and pathogens at ever-lower levels in human and veterinary diagnostics, homeland security, and food and water safely. This paper reviews our recent work using surface enhanced Raman scattering for detection of proteins, viruses, and microorganisms in heterogeneous immunoassays. It describes the assay platform, which consists of an antibody-modified capture substrate and gold nanoparticle-based label. The latter draws on the ability to reproducibly construct gold nanoparticles modified with a monolayer of an intrinsically strong Raman scatterer that is coated with a layer of antibodies. This construct, referred to as an extrinsic Raman label, exploits both the signal enhancement of scatterers when coated on nanometer-sized gold particles and the antigenic binding specificity of the immobilized antibody layer. Issues related to nonspecific adsorption, particle stability, and measurement reproducibility are also discussed.