Biofuel Cell Based On Photoelectric Effect And Their Application In Chemical Sensor

Biofuel cell?BFC?can generate signals by redox reaction or photoelectric conversion without external power supply.The excess energy can be stored,simplifies the preparation process of the sensor,reduces the testing cost,and facilitates the miniaturization and integration of the sensor.In addition,BFC also have the advantages of high efficiency,no pollution,wide range of fuel sources,mild reaction conditions,simple operation,easy control and maintenance,good biocompatibility,suitable for biological macromolecules and DNA chemical sensing analysis.Photoelectrochemical?PEC?technology based on the photoelectric effect using light as the excitation signal,detect the optical current generated by the photoelectric effect,excitation signal and detection signal separation can significantly reduce the background noise,causing it has a very high sensitivity and suitable for chemical sensing.Microfluidic paper-based analytical devices??-PADs?is one of the most promising analytical equipment in point-of-care testing,which is cheap,simple and don't require complicated peripherals,can be used as a truly one-time,portable analysis.In this paper,the introduction of PEC technology into BFC is committed to the design of simple,inexpensive,portable,self-powered ?-PADs chemical sensor,specifically carried out the following aspects of the work:1.The highly ordered single-crystal TiO₂ nanorod arrays were grown on the FTO chip by simple hydrothermal method,CdS quantum dots?QDs?were coupled to the TiO₂ nanorod arrays to form CdS@TiO₂ sensitized structure,broaden the absorption spectrum of the range,improve the utilization of light energy,and enhance the intensity of the optical current.Using the specific DNA hybridization reaction between the target DNA and capture hairpin DNA-CdS probe to induce the conformational conversion of the hairpin DNA-CdS probe,the hairpin was opened,forcing the CdS QDs away from the TiO₂ nanorod array and destroying the sensitized effect between CdS QDs and TiO₂ nanorods array,resulting the quenching of the photocurrent.In this way,the ultra-sensitive and specific detection of target DNA is realized,which opens an alternative avenue for photoelectrochemical signal transduction.2.A three-dimensional?3D??-PADs based on hollow channel was designed and fabricated.Compared with the paper channel,the hollow channel can greatly improve theflow rate of the fluid in the channel,save the analysis time and improve the detection efficiency.In addition,the Ag nanoparticles?NPs?-graphene?Ag-G?nanocomposites was used for functionalization of paper electrodes,greatly enhance the conductivity of paper electrodes.In this paper,a glucose/oxygen BFC was constructed.In biocathode,nanoporous PtNi was synthesized by chemical etching method,and the reduction of oxygen was achieved by the synergistic catalysis of nanoporous PtNi and bilirubin oxidase?BOD?.In bioanode,carcino embryonie antigen?CEA?-Au NPs-glucose dehydrogenase?GDH?bioconjugate?CEA-Au-GDH?was used as an anode catalyst to oxidize glucose.With the competitive immune reaction between CEA and CEA-Au-GDH,a BFC competitive immune sensor was constructed,achieved self-powered,ultra-sensitive point-of-care testing without external energy.3.Introducing PEC technology into BFC,in bioanode,the internal hollow and surface porous WO₃ microspheres were prepared by a simple hydrothermal reaction.A "signal quenching" photoelectric BFC DNA sensor was constructed with the sensitized effect between CdS QDs and TiO₂ nanorods array and the configuration changes of capture hairpin DNA-CdS probe induced by target DNA,achieved the target DNA self-powered,ultra-sensitive,specific detection.In biocathode,the introduction of a large surface area,excellent catalytic ability and long-term stability porous Pt-Pd flower-like nanoparticles,effectively achieved the catalytic reduction of oxygen.The 3D hollow channel ?-PADs integrated paper-based super capacitor could automatic storage and release electron generated by photoelectric BFC.Then use the multimeter to detect the instantaneous amplification of the photocurrent,abandoned the complex electrochemical workstation,fully realized the photoelectric BFC self-powered and portable.In this paper,the "signal quenching" photoelectric BFC DNA sensor has a wide linear detection range?10 aM-100 pM?for the target DNA,the detection limit is as low as 3.7 aM,provided a good detection platform for home and wild environment sensitive and accurate chemical sensing.