Research On Photoelectrochemical Biosensing Properties Based On Nano Zinc Oxide Composited Materials

Cancer,as the three dead killers,has become the main cause of death,morbidity and mortality are rising,which are huge threat to public health.Cancer is not equal to death,Early detection of cancer for clinical diagnosis and treatment is very important,it is difficult to carry out early and accurate detection by the general detection methods.Photoelectrochemical bioanalysis can be used to rapidly and accurately determine low concentration of protein,nucleic acid and other cancer-related biological substances.In addition,photoelectrochemical bioanalysis use optical signals as excitation signals to get photocurrent,which has the advantages of optical and electrochemical detection and can achieve high sensitivity detection of tumor markers.ZnO is a third generation wide band gap semiconductor material with excellent thermal,chemical property,low density,good biocompatibility and photochemical stability.ZnO nanomaterials exhibit excellent development prospects in photoelectrochemical bioanalysis.On the other hand,the nano-zinc oxide electrode has low utilization of light,zinc oxide can only absorb ultraviolet light and photogenerated electron-hole is easy recombination,which is disadvantaged to the preparation of high sensitivity sensor,we utilized nano-Zinc oxide composite electrode material to prepare photoelectrochemical biosensor with excellent sensing properties.On that basis,taking advantage of rare earth ions with deep penetration depth,large stokes displacement,low background noise and low toxicity,etc.,the 980 nm laser was used to excite the rare earth material,producing ultraviolet light and visible light,which excite the nanocomposite electrode material,avoiding the influence of using ultraviolet light in the photoelectrochemical biology detection system.In this paper,we use photoelectrochemical methods for highly sensitive rapid detection the of tumor markers,based on zinc oxide nanocomposites photoelectrodes.We prepared the nano-zinc oxide electrode with three-dimensional macroporous by template method.The nano-zinc oxide thin film electrode was prepared by pulse laser deposition.Then,the nano zinc oxide electrode were compound with the narrow band gap semiconductor material?Ag₂S,Cd S?,ZnO/ Ag₂ S composite electrode and ZnO/Cd S composite electrode were fabricated successfully.The composite structure electrodes expanded the scope of light absorption to long wavelength,meanwhile,an effective matching of energy levels of electrodes materials are beneficial to accelerate charge separation and suppress photo-generated carriers recombination.So the photoelectrochemical biosensor with low cost,high sensitivity,low detection limit,wide detection range,good stability and specificity was prepared for detection of alpha fetoprotein?AFP?under different light sources.?1?First,a three-dimensional ordered macroporous nano-zinc oxide electrode was fabricated on the FTO glass by colloidal crystal template method,then small size and uniformly dispersed Ag₂ S NPs were prepared using the Successive Ionic Layer Adsorption And Reaction?SILAR?method,which were adsorbed on ZnO IOs surface and frame work,nonenzymatic FTO/ZnO/Ag₂ S composited electrodes for photoelectrochemical detection of low concentration AFP with high sensitivity were prepared,under Xenon lamp irradiation.The composited electrode biosensor range from 0.05 ng/m L to 200 ng/m L with a low detection limit of 8 pg/ml.?2?NaYF₄: Yb,Tm,ZnO,Cd S were deposition on the FTO glass substrate by pulse laser deposition?PLD?one by one,the FTO/NaYF₄:Yb,Tm/ZnO/Cd S composite thin film electrodes were prepared,high sensitivity detection for AFP was achieved under 980 nm irradiation.The linear range was 0.01 ng / m L-200 ng / m L and the detection limit was 5 pg / m L.The zinc oxide material electrode was compounded with narrow bandgap nanomaterials that can improve the utilization of light and suppress the recombination of carriers,gaining high sensitivity of the sensor.We have studied the properties of two kinds of structured zinc oxide composite electrodes using different light sources for detection tumor markers alpha-fetoprotein.Compared with ZnO thin film electrode prepared by PLD,the three-dimensional macroporous ZnO composited electrode shows a higher,faster photoelectric response and better sensitivity.The introduction of rare earth ions of FTO/NaYF₄:Yb,Tm/ZnO/Cd S composited electrode.ZnO / Cd S can maximize the use of rare earth upconversion luminescence,under the 980 nm laser excitation.The photoelectrochemical system for detection of AFP has wider linear range,lower detection limit,and it shows a better application prospects for the future of photoelectrochemical biological applications and detection in vivo.