Detection and identification of proteins using nanoparticle–fluorescent polymer ‘chemical nose’ sensors

A sensor array containing six non-covalent gold nanoparticle-fluorescent polymer conjugates has been created to detect, identify and quantify protein targets. The polymer fluorescence is quenched by gold nanoparticles; the presence of proteins disrupts the nanoparticle-polymer interaction, producing distinct fluorescence response patterns. These patterns are highly repeatable and are characteristic for individual proteins at nanomolar concentrations, and can be quantitatively differentiated by linear discriminant analysis (LDA). Based on a training matrix generated at protein concentrations of an identical ultraviolet absorbance at 280 nm (A280 = 0.005), LDA, combined with ultraviolet measurements, has been successfully used to identify 52 unknown protein samples (seven different proteins) with an accuracy of 94.2%. This work demonstrates the construction of novel nanomaterial-based protein detector arrays with potential applications in medical diagnostics.