Enhanced photoactivity of Bi2S3 nanoflowers by CS-AgBr and CeO2: Application in photoelectrochemical biosensor for the effect of antibiotics on N6-methyladenosine in rice tissues

Abstract

• The CS-AgBr greatly improves the photoelectric activity of Bi 2 S 3 . • N 6 -methyladenosine-5′-triphosphate was specifically recognized and detected by PEC biosensor. • The photocurrent response is enhanced by the band matching of Bi 2 S 3 /CS-AgBr/CeO 2 . • The effect of three antibiotics on m 6 ATP expression in rice seedlings was investigated. CS-AgBr and octahedral CeO 2 greatly enhanced the photoactivity of Bi 2 S 3 nanoflowers due to the Bi 2 S 3 can form an energy band match with CS-AgBr and CeO 2 , which can accelerate electron transfer and reduce photogenerated electron-hole pair recombination. Thus, CeO 2 /CS-AgBr/Bi 2 S 3 exhibits good photoelectrochemical (PEC) response. With this as a basis, a novel PEC immunosensor was intended for N 6 -methyladenosine-5′-triphosphate (m 6 ATP) detection, in which m 6 ATP antibody was applied as the recognition unit for m 6 ATP, Bi 2 S 3 /CS-AgBr was utilized towards the photoactive material, and CeO 2 was employed as the signal amplification unit. m 6 ATP antibody was firstly captured on CPBA/CS-AgBr/Bi 2 S 3 /ITO surface through the covalent reaction between the boronic acid group of 4-carboxyphenylboronic acid (CPBA) and the o-diol structure of m 6 ATP antibody. Then, m 6 ATP was specifically recognized based on the specific immune reaction between the antigen and the antibody. Finally, signaling amplification unit of CeO 2 achieved signal enhancement through the capture of the phosphate group of m 6 ATP. Under optimal conditions, the PEC biosensor exhibited a wide linear range of 0.001–150 nM and a low detection limit of 0.48 pM (3σ). The suitability was assessed by investigating the results of the effect of antibiotics on the m 6 A levels in total RNA of rice root and leaf tissues. The results indicated that all of the three antibiotics (tobramycin, amoxicillin and chloramphenicol) inhibited the expression of m 6 ATP within 1, 4 and 7 days of cultivation.