title: A Cathodic "Signal-off" Photoelectrochemical Aptasensor for Ultrasensitive and Selective Detection of Oxytetracycline.
abstract: A novel cathodic "signal-off" strategy was proposed for photoelectrochemical (PEC) aptasensing of oxytetracycline (OTC). The PEC sensor was constructed by employing a p-type semiconductor BiOI doped with graphene (G) as photoactive species and OTC-binding aptamer as a recognition element. The morphological structure and crystalline phases of obtained BiOI-G nanocomposites were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The UV-visible absorption spectroscopic analysis indicated that doping of BiOI with graphene improved the absorption of materials in the visible light region. Moreover, graphene could facilitate the electron transfer of BiOI modified electrode. As a result, the cathodic photocurrent response of BiOI under visible light irradiation was significantly promoted when a suitable amount of graphene was doped. When amine-functionalized OTC-binding aptamer was immobilized on the BiOI-G modified electrode, a cathodic PEC aptasensor was fabricated, which exhibited a declined photocurrent response to OTC. Under the optimized conditions, the photocurrent response of aptamer/BiOI-G/FTO was linearly proportional to the concentration of OTC ranging from 4.0 to 150 nM, with a detection limit (3S/N) of 0.9 nM. This novel PEC sensing strategy demonstrated an ultrasensitive method for OTC detection with high selectivity and good stability.
authors.affiliation: Key Laboratory for Large-Format Battery Materials and System (Ministry of Education), School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology , Luoyu Road 1037, Wuhan 430074, P.R. China.
authors.forename: Kai
authors.initials: K
authors.lastname: Yan
authors.affiliation: Key Laboratory for Large-Format Battery Materials and System (Ministry of Education), School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology , Luoyu Road 1037, Wuhan 430074, P.R. China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Key Laboratory for Large-Format Battery Materials and System (Ministry of Education), School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology , Luoyu Road 1037, Wuhan 430074, P.R. China.
authors.forename: Yaohua
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Key Laboratory for Large-Format Battery Materials and System (Ministry of Education), School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology , Luoyu Road 1037, Wuhan 430074, P.R. China.
authors.forename: Jingdong
authors.initials: J
authors.lastname: Zhang
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques; D055664:Electrochemical Techniques / Q000295:instrumentation; D004566:Electrodes; D006108:Graphite / Q000737:chemistry; D010118:Oxytetracycline / Q000032:analysis*; D010316:Particle Size; D055668:Photochemical Processes; D013499:Surface Properties
chemical_list: D052157:Aptamers, Nucleotide; D006108:Graphite; D010118:Oxytetracycline