Selective recognition of Histidine enantiomers using novel molecularly imprinted organic transistor sensor

L-Histidine (L-His) is an essential bioactive amino acid, playing a significant role in several biological processes. Therefore, the accurate determination of L-His is of great significance to human health. In this work, a strategy was developed for the chiral detection of L-His using an organic electrochemical transistor (OECT) sensor based on molecularly imprinted polymer (MIP). MIP films were electrodeposited on OECT gate platforms. MIP films designed for specifically recognizing His combined with the amplified function of an OECT yielded highly sensitive and selective OECT biosensor. The properties of the resulting biosensor were characterized by various analytical methods. The results indicated that changes in channel current was proportional to D-His and L-His concentrations from 100 nM to 10 mu M, with the detection limits of 10 nM and 100 nM (S/N > 3), respectively. Furthermore, the highly selective MIP film allowed to differentiate L-His from D-His or D-His from L-His. In terms of selectivity, the tests suggested apparent differences in channel current changes between L-His and D-His and interferences. The applicability of the biosensor for L-His detection in human urine demonstrated this sensor will be ideal transducers for disposable applications in the future.