Photoelectrochemical aptasensor driven by visible-light based on BiFeO3@TiO2 heterostructure for microcystin-LR detection

Herein, a simple and effective visible-light driven photoelectrochemical (PEC) aptasensor was designed using BiFeO 3 @TiO 2 nanocomposites for accurate and rapid detection of microcystin-LR (MC-LR). This composite was obtained by coupling p-type BiFeO 3 nanoparticles with n-type TiO 2 nanosphere to constructed a p-n heterojunction. This p-n heterojunction not only could narrow the band-gap of TiO 2 from 3.14 eV down to 2.14 eV of BiFeO 3 @TiO 2 , resulting in superior utilization of visible light. More importantly, it also could accelerate charge separation/transfer leading to enhanced photoelectrochemical (PEC) performance of BiFeO 3 @TiO 2 . Based on these excellent optoelectronic performances of BiFeO 3 @TiO 2 composite, a PEC aptasensor with “turning on” signal mechanism was constructed by aminated aptamer as a biorecognition probe. The constructed PEC aptasensor performed gratifying analytical property toward MC-LR with a low detection limit of 0.016 pM (S/N = 3) and a wide detection range (5.0 × 10 −5  ∼ 2.5 × 10 2 nM). This PEC aptasensor possessed promising potential application value for its precise selective and ultrasensitive for MC-LR in practical analysis.