Photoelectrochemical immunosensor for DNA hydroxymethylation based on PTCA-sensitized perovskite Bi4TaO8Cl

DNA hydroxymethylation is an important epigenetic modification, which plays crucial roles in many biological processes, such as gene expression and cell differentiation. Herein, a novel photoelectrochemical immunosensor was built for detecting 5-hydroxymethylcytosine (5hmC), where the perovskite Bi 4 TaO 8 Cl sensitized by 3,4,9,10-perylenetetracarboxylicacid (PTCA) was implemented as photoactive material, anti-5hmC antibody was served as target recognition reagent, ZrO 2 was used for connecting more modifications, and ferrocene was adopted as signal amplification unit. The prepared nanomaterials of Bi 4 TaO 8 Cl, PTCA and ZrO 2 were well characterized. The possible mechanism for the improved PEC response of Bi 4 TaO 8 Cl sensitized by PTCA was investigated carefully, indicated that the matched energy band facilitated the migration of photogenerated electron. In addition, the possible mechanism for signal amplification caused by ferrocene was investigated, showing that ferrocene acted as electron donor to accelerate electron transfer. Under the optimal condition, the biosensor manifested wide detection range from 0.02 to 100 nM with the low detection limit of 5.2 pM (S/N = 3). Moreover, the applicability of the biosensor was demonstrated by investigating the effect of heavy metal Cd 2+ and perfluorooctanoic acid on 5hmC content in the leaves and roots of wheat seedlings, as well as the effect of ALV-J on 5hmC content in chicken serum.