In situ surface oxygen vacancy effect synergistic with internal polarization effect in BiFeO₃ for photoelectrochemical detection of T4 DNA ligase

Recently, the field of cathode photoelectrochemistry has advanced significantly, yet there remained a dearth of innovative approaches in signal transmission strategies. This paper introduced a novel concept where the dopamine (DA)-engineered surface vacancy (Ov) effect on BiFeO₃ microspheres synergistically interacted with the intrinsic polarization of the material, leading to a significantly enhanced photocurrent when compared to that of Bi₂O₃ or Fe₂O₃ alone without a built-in electric field. Based on this finding, we proposed a PEC biosensor that leveraged the competitive binding reaction between single-base nucleotides and DA for photocurrent output, wherein the T4 DNA ligase-mediated ligation reaction governed the production of single-base nucleotides. The detection system demonstrated commendable performance for T4 DNA ligase analysis, with a linear detection range spanning from 0.0006 to 10 U/mL. The detection limit was determined to be 0.0001 U/mL. This ligase detection method requires no labeling, was straightforward to operate, and exhibited high sensitivity and excellent selectivity. This study not only elucidates the synergistic effect of in-situ surface Ov effect and the internal polarization effect the ferroelectric material to construct an efficient PEC sensing mechanism, but also introduces a new method for measuring T4 DNA ligase.