Novel sensor-integrated proteome on chip (SPOC) platform with thousands of folded proteins on a 1.5 sq-cm biosensor chip to enable high-throughput real-time label-free screening for kinetic analysis.

Abstract

An automated proteomic platform for producing and screening an array of functional proteins on biosensor surfaces was developed to address the challenges of measuring proteomic interaction kinetics in high throughput (HTP). This technology is termed Sensor-Integrated Proteome On Chip (SPOC) which involves in-situ cell-free protein expression in nano-liter volume wells (nanowells) directly from rapidly customizable arrays of plasmid DNA, facilitating simultaneous capture-purification of up to 2400 unique full-length folded proteins onto a 1.5 sq-cm surface of a single gold biosensor chip. Arrayed SPOC sensors can then be screened by real-time label-free analysis, including surface plasmon resonance (SPR) to generate kinetic affinity, avidity data. Fluorescent and SPR assays were used to demonstrate zero crosstalk between protein spots. The functionality of the SPOC protein array was validated by antibody binding assay, post-translational modification, mutation-mediated differential binding kinetics, and catalytic activity screening on model SPOC protein arrays containing p53, Src, Jun, Fos, HIST1H3A, and SARS-CoV-2 receptor binding domain (RBD) protein variants of interest, among others. Monoclonal antibodies were found to selectively bind their target proteins on the SPOC array. A commercial anti-RBD antibody was used to demonstrate discriminatory binding to numerous SARS-CoV-2 RBD variants of concern with comprehensive kinetic information. With advantages of HTP, flexibility, low-cost, quick turnaround time, and real-time kinetic affinity profiling, the SPOC proteomic platform addresses the challenges of interrogating protein interactions at scale and can be deployed in various research and clinical applications.