Development of Gold Nanorod Lateral Flow Test for Quantitative Multi-analyte Detection

Abstract

Lateral flow tests are widely used in clinical and non-clinical applications for detection of analytes in complex sample matrix. However, a need for multiplex, ultra-sensitive, diagnostic assay providing quantitative results is inevitable. A label-free, multi-analyte lateral flow test strip using gold nanorods is being developed for rapid and simultaneous quantification of disease representing biomarkers in their clinically relevant ranges. Gold nanoparticles exhibit a strong optical extinction at visible and near infrared wavelengths due to localized surface plasmon resonance (SPR). The band can be tuned by increasing the aspect ratio of the nanorod, which is suitable for multiplex biosensing. Monodispersed gold nanorods of various aspect ratios (e.g. 5, 10) were synthesized by seed mediated growth method and characterized using electron microscopy. Biofunctionalization of the nanorods and immobilization of nanorod probes were investigated. The test region in the strip has multiple capture lines embedded with functional biomolecules for quantitative assessment. As a model system, HER2 level in the clinical significant range is assayed for early stage appraisal of breast cancer.