Multiplexed Biomolecular Detection Based on Single Nanoparticles Immobilized on Pneumatically Controlled Microfluidic Chip

A microfluidic chip integrated with pneumatically controlled valves was developed for multiplexed biomolecular detection via localized surface plasmonic resonance (LSPR) of single gold nanorod. The cost-effective microfluidic chip was assembled by polydimethylsiloxane layers and glass substrates with a precisely controlled thickness. The thin and flat microfluidic chip fitted the narrow space of dark-field microscopy and enabled the recording of single-nanoparticle LSPR responses. Aptamer-antigen-antibody sandwiched detection scheme was utilized to enhance the LSPR responses for label-free biomolecular detection. This microfluidic chip successfully demonstrated the multiplexed detection of three independent analytes (PSA, IgE, and thrombin).