| Antibiotics abuse poses serious threat to human health and pollutes the ecological environment.Therefore,it is very necessary to develop a simple,sensitive and rapid method for detection antibiotics.Photoelectrochemical(PEC)biosensors detection has the advantages of simple instrument,fast analysis speed and high sensitivity,among them,designing PEC functional nanomaterials with high photoelectric conversion efficiency and good biocompatibility is key procedure for fabricating high performance of PEC biosensors.The bismuth materials have low photoelectric consversion efficiency,which limit its application in the field of PEC sensing.Carbon-based materials can be used to improve the photoelectric activity of semiconductor materials due to their physicochemical properties,good biocompatibility and good electrical conductivity.Thus,this thesis designed and prepared a series of superior performance bismuth/carbon based photoelectric functional nanomaterials,and introduced specific recognition aptamer as bio-identification components to fabricate PEC platform to achieve sensitive detection of several antibiotics.The specific research contents are as follows:1?The p-type BiFeO3 nanoparticles were modified to n-type ultrathin carbon nitride nanosheets(utg-C3N4)by simple electrostatic adsorption method to obtain p-n heterojunction BiFeO3/utg-C3N4 photoelectric functional nanomaterials.The PEC performance analysis indicated that the photocurrent of BiFeO3/utg-C3N4 is 7 times that of BiFeO3 nanoparticles under visible light excitation,and the band gap of BiFeO3 reduced from 2.20 eV to 2.04 eV,which improves the absorption efficiency of visible light of functional nanomaterials.Further,the aptamer that specifically recognizes ampicillin(AMP)was modified on BiFeO3/utg-C3N4,and a visible light-driven,highly selective and highly sensitive detection of AMP PEC aptasensor was successfully constructed.The prepared PEC aptasensor exhibits excellent analytical performance with a wide linear range of 1×10=112 to 1x10-6 mol L-1,and the detection limit is as low as 3.3x10-13 mol L-1(S/N = 3),and successfully applied for the detection of AMP in milk.2?BiPO4 nanorod-modified three-dimensional nitrogen doped graphene hydrogel(BiPO4/3DNGH)photoelectric functional nanomaterials were prepared by a simple one-step hydrothermal method.The PEC performance analysis shows that the absorption of BiPO4/3DNGH has been extended to the visible light region compared with BiPO4 nanorods,and the band gap of BiPO4/3DNGH(2.10 eV)is much lower than the band gap of pure BiPO4(3.85 eV).Under visible light irradiation,the photocurrent signal of the prepared BiP04/3DNGH is significantly higher than that of BiPO4.Further,a tetracycline(Tc)aptamer was used as a biometric element,and an"on-off-on'PEC aptasensor for Tc detection was successfully constructed.Under optimized conditions,the proposed PEC aptasensor exhibits a wide line range(1xl0-100x10-6 mol L-1)and a low detection limit of 3.3x10-11 mol L-1(S/N = 3).This sensor can be applied for the detection of Tc in milk.3?Bi2MoO6/BNG photoelectric functional nanomaterials with oxygen vacancies were prepared by a simple and gentle one-pot solvothermal method to modify Bi2MoO6 nanoparticles onto boron and nitrogen co-doped graphene(BNG)nanosheets.PEC performance analysis show that the presence of oxygen vacancy can help to expand the absorption range,accelerate charge transfer,and improve the PEC performance of Bi2MoO6/BNG,which is 11.6 times the higher than that of Bi2MoO6.Furthermore,the aptamer of lincomycin(LIN)was fixed into Bi2MoO6/BNG photoelectric functional nanomaterials,and a PEC aptasensor with high efficiency for detecting LIN was successfully constructed.The proposed PEC aptasensor has excellent analytical performance for LIN,with a wide linear response of 1x10-11 to 1x10-6 mol L-1 and a low detection limit of 3.7x10-12 mol L-1(S/N = 3),which can be used for the detection of LIN in milk. |
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