Sensing of Proteins in Human Serum using Nanoparticle-Green Fluorescent Protein Conjugates

There is a direct correlation between protein levels and disease states in human serum making it an attractive target for sensors and diagnostics. However this is made challenging because serum features more than 20,000 proteins with an overall protein content of greater than 1 mM. Here we report a hybrid synthetic-biomolecule based sensor that uses green fluorescent protein-nanoparticle arrays to detect proteins at biorelevant concentrations in both buffer and human serum. Distinct and reproducible fluorescence response patterns were obtained from five serum proteins (human serum albumin, immunoglobulin G, transferrin, fibrinogen and α-antitrypsin) in buffer and when spiked into human serum. Using linear discriminant analysis we identified these proteins with an identification accuracy of 100% in buffer and 97% in human serum. The arrays were also able to discriminate between different concentrations of the same protein as well as a mixture of different proteins in human serum.