In situ surface oxygen vacancy effect synergistic with internal polarization effect in BiFeO 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 BiFeO microspheres synergistically interacted with the intrinsic polarization of the material, leading to a significantly enhanced photocurrent when compared to that of BiO or FeO 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.