Fabrication of electrochemical biosensor based on layer‐by‐layer multilayers film of poly(3‐aminobenzylamine) for dopamine detection

Abstract

The purpose of this research is to fabricate the poly(3-aminobenzyl amine)/poly(sodium 4-styrenesulfonate) (PABA/PSS) multilayer thin film on fluorine doped tin oxide (FTO)-coated glass substrate through layer-by-layer (LBL) self-assembly method for dopamine (DA) detection. The prepared PABA/PSS thin film was characterized by attenuated total reflection-fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) to study morphologies and properties of thin films. The optimal number of bilayers was assessed based on the results of SEM and cyclic voltammetry (CV) prior to use as a DA biosensor. The electrochemical behaviors of the optimized thin film toward detection of DA in neutral solution were studied using CV and amperometry. It was found that the obtained thin film showed a good sensitivity of 6.92 nA.cm -2.uM-I and a linear range of 0.1-1.0 uM (R2 = 0.99) with low limit of detection of 0.0628 uM, long-term stability and good reproducibility. Moreover, the PABA/PSS thin film also presented excellent selectivity toward DA detection in the presence of ascorbic acid (AA), uric acid (UA) and glucose which are the common biomolecules in human blood and urine.