Construction Of Flexible Self-powered Sensor And Application In Hormone Analysis

Enzymatic biofuel cells(EBFCs)can directly utilize biofuels widely found in nature,converting chemical energy into electrical energy under the catalysis of biological enzymes.They had been widely used in self-powered biosensors,wearable devices,and implantable power supplies.Compared with traditional fuel cells,EBFCs had many advantages,such as extensive fuel sources,environmental friendliness,and mild reaction conditions.The self-powered biosensor platform based on EBFCs had attracted researchers’ widespread attention due to its unique advantages such as no additional power supply,small size,simple equipment,and strong anti-interference ability.This paper constructed a self-powered sensing platform for the detection of hormone molecules.However,the self-powered sensing platform was still limited by the output performance and stability issues of EBFCs,which were mainly affected by the interactive interference of the anion two-stage reaction,high internal resistance of the battery,and poor stability of biological enzymes.In this paper,an anode sandwich amplification strategy was introduced to improve the accuracy of detection and avoid false positive results;a novel self-powered sensor based on EBFCs with long lifetime and good stability was constructed using enzyme mimicking nanomaterials and biological enzymes to construct a dual enzyme system.The specific research contents were as follows:Part One.Construction of a flexible self-powered sensor based on an enzymatic biofuel cell and its application in the determination of phthalate hormonesA self-powered sensing platform with a combination of biofuel cells(BFCs)and aptamer,without membrane and mediator,was developed to detect dibutyl phthalate(DBP).The GOD/Bi3Ti2O8F/CNT-rGO was used as the bioanode,and an AptNH2/AuNPs/CNTs-rGO was used as the cathode.The electrons generated by the oxidation of glucose by glucose oxidase on the bioanode were transferred to the biocathode,where O2 was reduced to H2O,resulting in a higher power output for the battery.When the target DBP was present,the aptamer(Apt)fixed on the biocathode captured the DBP through specific recognition,forming an Apt@DBP compound.The complex caused an increase in the steric resistance of the cathode surface,which greatly hindered the electron transfer between O2 and the cathode surface.Thus,the output power and open circuit voltage of the EBFC dropped sharply.This self-powered aptasensor could achieve ultra sensitive detection of DBP,with a wide detection range(10.00 fM-1.00 nM)and a lower detection limit(1.99 fM),which was superior to the reported detection methods.The self-powered sensing platform constructed in this work required no external power supply,was simple to construct,and was easy to miniaturize.It had unique advantages of good selectivity and high sensitivity.Meanwhile,by simply replacing the aptamer or antibody corresponding to other analytes,it was expected to be used in basic biochemical research,clinical diagnosis and environmental monitoring.Part Two.Construction of a signal-on flexible self-powered sensor and its application in estrogen detectionA signal-on self-powered biosensing platform based on EBFCs was constructed to detect estradiol.The CNTs-rGO flexible electrode was used as the battery substrate,and a bioanode was constructed based on GOD.A novel estradiol self-powered sensor was constructed with Apt.The GOD/Bi3Ti2O8F@AuNPs/Apt2/E2/Aptl/CTNs-rGO was used as the bioanode,whlie CNTs-rGO was uesd as the cathode.The electrons generated by the oxidation of glucose catalyzed by GOD on the bioanode were transferred to the biocathode,where O2 was reduced on the cathode.In the presence of estradiol,Apt2 assembled on the Apt2/GOD/Bi3Ti2O8F@AuNPs bioconjugate captured estradiol by specific recognition,and immobilized the bioconjugate on the anode.Thus,this promoted the electron transfer between glucose and the anode surface,which caused an increase in the output power and open circuit potential of the EBFC.The linear range of the self-powered sensor were 10.00-1000 pM and 0.10 nM-1.00 μM,and the detection limit was down to 3.80 pM,which was successfully applied to the detection of commercially available estradiol drugs.Part Three.Construction of a sandwich self-powered biosensor based on Cu-MOF and its application in estrogen detectionThe PVA-TA/CNTs-rGO(PTCR)flexible electrode was prepared by vacuum filtration.Based on the PTCR electrode,a flexible self-powered sensor was successfully prepared and applied to the sensitive and selective detection of estradiol.The sensing platform used GOD/Cu-MOF@AuNPs/Apt2/E2/Aptl/AuNPs/PTCR as the bioanode,while the PTCR was used as the cathode.Glucose was as the fuel to construct a sandwich-type self-powered sensor based on Cu-MOF mimetic enzyme.The Cu-MOF could increase the loading of GOD and increase the electron transfer rate between the redox center of GOD and the electrode surface.Meanwhile,the MOF had good catalytic performance for H2O2 under neutral conditions,and combined with GOD to form a dual enzyme system,which further improved the performance of EBFCs.In the presence of estradiol,the aptamer on the bioconjugate specifically recognized estradiol and was immobilized on the anode to form a sandwich structure of Apt 1-E2-Apt2.The electrons generated by the oxidation of the glucose catalyzed by GOD on the anode were transferred to the biocathode,and O2 was reduced on the cathode,which increased the output power and open circuit potential of the EBFC.The sandwich-type self-powered sensor based on Cu-MOF showed a linear range from 1.00 pM-1.00 nM,and a detection limit was down to 0.12 pM.The low-cost,reliable and portable self-powered flexible sensor was of great significance for the development of promising implantable portable field detection sensor equipment.