Molecular Imprinted Poly(2,5-benzimidazole)-Modified VO<sub>2</sub>–CuWO<sub>4</sub> Homotype Heterojunction for Photoelectrochemical Dopamine Sensing
Kheibar Dashtian, Shaaker Hajati, Mehrorang Ghaedi
Abstract
A photoactive molecularly imprinted poly(2,5-benzimidazole)-modified vanadium dioxide–cupric tungstate (VO2–CuWO4) as an efficient photosensitive n–n type-II heterojunction thin film was electrochemically deposited on Ti substrate for the selective and robust photoelectrochemical (PEC) bioanalysis of dopamine (DA). The optical absorption of n-VO2/n-CuWO4 type-II heterojunction was capably broadened toward the visible region, which permitted superior light-harvesting and robust carriers generation, separation, and transfer processes significantly enhancing the anodic photocurrent, as confirmed by a series of PEC analyses. Findings revealed that the as-prepared label-free MIP-PEC sensor can quantitatively monitor DA in a linear range of 1 nM to 200 μM with a detection limit of 0.15 nM. This MIP-PEC sensor showed robust selectivity under conditions with high concentrations of interfering substances, which can be recovered in the real samples of urine, cocoa chocolate, and diluted yogurt, indicating its promising potential applications in biological and food samples. This work not only featured the use of photoelectrically active MIP/VO2–CuWO4 for PEC detection of DA, but also provided a new horizon for the design and implementation of functional polymers/metal oxides heterojunction materials in the field of PEC sensors and biosensors.