A specific and biocompatible fluorescent sensor based on the hybrid of GFP chromophore and peptide for HSA detection

Abstract

It is still a challenge for clinical diagnostics to design non-toxic and selective sensors for a specific analyte in blood serum, which contains a large number of proteins, small molecules, and ions. Herein, H1, a synthetic hybrid of green fluorescent protein (GFP) chromophore and peptide for human serum albumin (HSA) detection via obvious fluorescence enhancement was reported. The fluorescence response was caused by the non-covalent binding between H1 and the subdomain IIA cavity of HSA, and this specific binding behavior can be confirmed by the decrease of fluorescence intensity of the sole tryptophan residue (Trp-214) located in the same subdomain. H1 showed remarkable sensitivity and selectivity toward HSA without interference from other proteins. A good linear relationship between the fluorescence intensity of H1 and HSA concentration from 0 to 67.0μgmL−1 was obtained with the detection limit reaching as low as 198.6ngL−1. Moreover, H1 was successfully utilized to detect trace HSA in healthy human urine (HU) and human blood serum (HBS), respectively. The resulting H1/HSA system also showed a satisfactory sensing ability toward anionic surfactant sodium dodecyl sulfate (SDS) through decreased fluorescence intensity with the detection limit of 3.48ngL−1.