Targeted protein surface sensors as a tool for analyzing small populations of proteins in biological mixtures.

Optical cross-reactive sensor arrays (the so-called chemical "noses/tongues") have recently been demonstrated as a powerful tool for high-throughput protein detecting and analysis. Nevertheless, applying this technology to biomarker detection is complicated by the difficulty of non-selective sensors to operate in biological mixtures. Herein we demonstrate a step toward circumventing this limitation by using self-assembled fluorescent receptors consisting of two distinct recognition motifs: specific and non-specific. When combined in an array, binding cooperatively between the specific and non-specific protein binders enables the system to discriminate among closely related isoform biomarkers even in the presence of serum proteins or within human urine.