On-chip Protein Assays Using Microbead Arrays: an Integrated System for Salivary-based Clinical Diagnostics

A microfluidic device containing arrays of microwells filled with microbead sensors was used to perform protein assays in a saliva sample. Techniques for the fabrication of fully integrated arrays of microwells within polydimethylsiloxane (PDMS) microchannels were demonstrated. Subsequent microwell loading with stochastic arrays of encoded microbeads was performed and the devices were used for multiplexed immunoassays. Low femtomolar limits of detection (LOD) for cytokines indicative of pulmonary inflammation have been demonstrated. Device fabrication and optimization experiments for 900-well microbead array devices demonstrating rapid, highly sensitive protein assays are presented.