Nanoparticle-based Point of Care Immunoassays for in vitro Biomedical Diagnostics.

In resource-limited settings, the availability of medical practitioners and early diagnostic facilities are inadequate relative to the population size and disease burden. To address cost and delayed time issues in diagnostics, strip-based immunoassays, e.g. dipstick, lateral flow assay (LFA) and microfluidic paper-based analytical devices (microPADs), have emerged as promising alternatives to conventional diagnostic approaches. These assays rely on chromogenic agents to detect disease biomarkers. However, limited specificity and sensitivity have motivated scientists to improve the efficiency of these assays by conjugating chromogenic agents with nanoparticles for enhanced qualitative and quantitative output. Various nanomaterials, which include metallic, magnetic and luminescent nanoparticles, are being used in the fabrication of biosensors to detect and quantify biomolecules and disease biomarkers. This review discusses some of the principles and applications of such nanoparticle-based point of care biosensors in biomedical diagnosis.