Layer-by-layer assembly sensitive electrochemical sensor for selectively probing L-histidine based on molecular imprinting sol-gel at functionalized indium tin oxide electrode.

A novel sensitive and selective imprinted electrochemical sensor was successfully constructed for the direct detection of L-histidine by combination of a molecular imprinting film and multi-walled carbon nanotubes (MWNTs). The sensor was fabricated onto an indium tin oxide (ITO) electrode via stepwise modification of MWNTs and a thin film of molecularly imprinted polymers (MIPs) via sol-gel technology. The introduced MWNTs exhibited noticeable enhancement on the sensitivity of the MIPs sensor. Meanwhile, the molecularly imprinted film displayed high sensitivity and excellent selectivity for the target molecule L-histidine. The proposed imprinted sensor was characterized by using scanning electron microscope (SEM) and electrochemical methods involving cyclic voltammetry (CV), differential pulse voltammetry (DPV) and amperometric i-t curve. A linear ranging from 2.0 μmol L(-1) to 1.0 mmol L(-1) for the detection of L-histidine was observed with the detection limit of 5.8×10(-9) mol L(-1) for S/N=3. This imprinted electrochemical sensor was successfully employed to detect L-histidine in human blood serum.