12 - Development of the immunoassay of antibodies and cytokines on nanobioarray chips

Abstract

Immunoassays have been utilized as a method to detect secreted proteins such as antibodies or cytokines. These soluble proteins in blood or serum allow for clinical diagnostics of diseases ranging from hepatitis, autoimmune disorders, Alzheimer’s disease to cancer. Immunoassays can be homogeneous and heterogeneous, with heterogenous immunoassay (e.g., enzyme-linked immunosorbent assay (ELISA)) being much more common because the unbound proteins are easily washed away from the solid substrate. The need of sample volumes in excess of 10μL in ELISA poses a restriction to the detection of antibodies and cytokines, usually found in low concentrations and low volumes in clinical samples. This necessitates the development of nanolitre-volume liquid handling and high detection sensitivity of low-volume and low-concentration samples. This chapter describes the recent development of the nanobioarray chip technology that will address these needs.