Iodide-Responsive Cu–Au Nanoparticle-Based Colorimetric Sensor Array for Protein Discrimination

Here, for the first time, we present a colorimetric sensor array toward sensitive protein discrimination based on a novel strategy of diverse DNA–protein interactions with the performance of iodide-responsive Cu–Au nanoparticles (NPs). Different steric hindrance effects generated from differential interactions of DNA and proteins inhibit the accessibility of iodide to the NP surfaces, generating diverse colorimetric signals as “fingerprints” associated with each specific protein, which is subjected to linear discriminant analysis (LDA), a pluralistic statistic analysis technique for assignment of unknown samples to their suitable categories and data classification, to generate a clustering map. On the basis of the LDA analysis, eight proteins with a concentration of 20 nM in pure aqueous buffer and in real serum samples were successfully discriminated with 100% accuracy.