A novel strategy for rapid real-time chiral discrimination of enantiomers using serum albumin functionalized QCM biosensor

Abstract

A novel and effective method has been developed for chiral discrimination using a quartz crystal microbalance (QCM) biosensor with self-assembled bovine serum albumin (BSA) or human serum albumin (HSA). The successfully constructed QCM chiral biosensors exhibited rapid and real-time enantioselective recognition. The QCM chiral discrimination factor (αQCM) can be calculated through resonance frequency shifts in response to five pairs of enantiomers. Moreover, the interactions between these ten enantiomers and two serum albumins (SA) were investigated in detail by means of ultraviolet–visible (UV–vis) and fluorescence (FL) spectra. The results indicated that the discrimination ability were quite different between BSA and HSA. R,S-1-(3-Methoxyphenyl)ethylamine (R,S-3-MPEA) and R,S-1-(4-methoxyphenyl)ethylamine (R,S-4-MPEA) can be easily differentiated by the BSA sensor, while the selectivity of the HSA sensor for R,S-tetrahydronaphthylamine (R,S-TNA), R,S-2-octanol (R,S-2-OT) and R,S-methyl lactate (R,S-MEL) was higher than that of the BSA sensor. The UV and FL spectra indicated the formation of a complex between SA and enantiomers and strong fluorescence quenching through static quenching mechanism. The in-depth study demonstrated that the calculated UV/FL discrimination factors (αUV and αFL) were consistent with the QCM experimental results (αQCM).