Enzyme Biofuel Cell Based Novel Self-Powered Biosensing Analysis And Energy Storage

Enzyme biofuel cell(EBFC)is a green energy conversion device that employs enzyme as catalyst;it can directly convert the chemical energy in the biological fluid into electric energy.Since EBFC can directly generate energy in the biological system,thus,aside from functioning as energy source for implantable and portable biomedical devices,EBFC has been developed into self-powered biosensor(EBFC-SPB),which draws a great deal of attentions due to its vital features of obviating the external power sources,offering the potential of miniaturization and on-site analysis.However,the development of EBFC-SPB still has the following three key problems:low energy output of EBFC,resulting in unsatisfactory sensitivity of EBFC-SPB;multi-target quantitative analysis has not yet been achieved;traditional EBFC-SPB still serves as a basic analytical detection tool.Solving the above problems is the key to developing a novel self-powered sensing mode,and therefore improving the practical application value of EBFC-SPB.In addition,in mild environment,compared with abiotic catalysts,the bioenzyme catalysts and biological organic molecules that commonly used in EBFC systems exhibit more efficient redox chemical activities.However,the application of such bioenzymes and biological organic molecules is still limited to the field of fuel cells.Lithium-ion batteries have become the dominant energy source for electronic products,but the drawbacks in the safety,environmental friendliness,and performance need to be overcome urgently.In view of the above features of biological enzymes and organic biomolecules,we believe that they have considerable application prospects in eliminating the obstacles preventing the development of lithium ion batteries.In this contribution,we have explored the novel electrode materials with high electrochemical activity and high specific surface area for developing high energy density EBFC;orginally desiged a high-throughput EBFC-SPB systems;and expanded the application of EBFC-SPB to the field of theranostic.In addition,we have also developed green and efficient lithium-air battery via combining biocatalysis with energy storage.The main research works are as follows:1.Nitrogen-doped hollow carbon nanospheres for high-energy-density biofuel cells and self-powered sensing of microRNA-21 and microRNA-141:Nitrogen-doped mesoporous carbon nanomaterials have been recognized as the ideal electrode materials for constructing high performance EBFC due to their excellent electrical conductivity and high electrochemical activity.However,the smaller pores of existing mesoporous materials are detrimental to the entry of biological enzymes,resulting in low enzyme loading.In addition,EBFC-SPBs have been regarded as the most promising portable biosensors with online-detection capacity in recent years due to the features of energy saving and easy miniaturization.However,only single target can be detected via the existing EBFC-SPBs,greatly hampering their practical application in actual sample analysis.In order to solve the above problems,we fabricated nitrogen-doped hollow carbon nanospheres with large pores(pNHCSs)via a green microwave-assisted hydrothermal method(MWHM).Due to their three-dimensional structure and the incorporation of nitrogen,the pNHCS-functionalized electrode not only efficiently enriched the load of enzyme but also significantly facilitated DET rate.Thus,the pNHCS-based EBFCs exhibited an outstanding power output.Then,based on a dual-fuel-driven EBFC,we developed an innovative self-powered biosensor to sense two kinds of cancer-related microRNAs,miR-21 and miR-141,at the same time.In addition,the sensor exhibits excellent detection sensitivity.2.A glucose/O2 fuel cell-based self-powered biosensor for probing a drug delivery model with self-diagnosis and self-evaluation:Cancer is the greatest threat to human health.Theranostic nanoplatform that can achieve accurate therapy has been proven to be one of the most effective ways to conquer cancer.Herein,a high-performance glucose/O2 fuel cell was constructed,and a diagnosis-induced drug delivery mode and a therapeutic evaluation-sensing mode were designed at the anode and cathode electrodes,respectively,realizing a self-powered sensing system with triple cascade functions-"diagnosis-therapy-evaluation”.Specifically,the leukemia cells(K562 cells)were selected as model tumor cells,and the circulating microRNA-125a(miR-125a)was employed as a corresponding biomarker.The self-powered sensing system with self-diagnostic and self-evaluation functions(DDM-SDSE)was constructed via immobilizing targeting drug nanocarrier on the anode of fuel cell through specific partial complementation(PDS)of DNA,and modifying cathode with apopotic cell aptamers(PSp).Once the DDM-SDSE was exposed to a K562 cells-contained system,the power density of the system(Pmax)increased to a high level as the miR-125a could competitively hybridize with the PDS and simultaneously actuate the release of targeting drug nanocarrier from anode,alleviating the block effect.Such increasement in the Pmax worked as the diagnosis signal for cancer risk assessment.Synchronously,the released drug nanocarrier could internalize into K562 leukemia cells to induce the apoptosis of K562 cells,fulfilling therapeutic tasks.As the stable exposure of phosphatidylserine on the extracellular leaflet of the plasma membrane,the apoptotic K562 cells can be captured by the PSp modified cathode.Therefore,the Pmax of the DDM-SDSE eventually displays a dramatic time-dependent decrease due to the gradually increased block effect on the reduction of oxygen caused by the continuous capture of apoptotic K562 cells from the given system.Such time-dependent decrease in Pmax served as the signal to real-time evaluate the therapeutic effect and to further build the unbiased apoptotic kinetic model.Overall,based on above-proposed strategies,the SPB has been successfully integrated with theranostic nanoplatform to realize a DDM-SDSE,which can serve as a "diagnosis-therapy-evaluation" tool.This work lays the foundation for the realization of economic individualized medicine.3.Superior efficient rechargeable lithium-air battery via a bifunctional biological Laccase:We originally presented an enzyme catalytic Lithium-Air battery employing laccase from Trametes versicolor(LacTv)as bifunctional biocatalyst.For aqueous Lithium-Air battery,the pH of electrolyte intrinsically changes during discharge/charge processes because water molecules are involved in the reactions at the air electrode.Our study revealed that the electrocatalytic cycle of LacTv was in fact synergistically matched with the intrinsically pH change of battery during discharge/charge cycle.In the rechargeable aqueous Li-Air battery,LacTv catalyzed discharge reaction(ORR)during battery power output.Upon continuous discharging,the pH of electrolyte changed to neutral,at this point the battery was switched to charge process in which LacTv catalyzing charge reaction(OER).During charge process,the pH of electrolyte could return to initial value,LacTv restored the initial ORR activity and achieved a reversible cycle of bifunctional catalysis.LacTv showed catalytic activity and stability far exceeding that of the bench mark Pt/C.The battery offered superior voltage efficiency(discharge voltage:?3.75 V)with a very low round-trip overpotential of?0.24 V and yielded a high capacity of 16.5 Ah g-1 at current density of 100 mA g-1,Additionally,our results revealed the intrinsic pH change of the battery during discharge/charge can in situ regulate the reversible transformation of the corresponding ORR/OER catalysis of LacTv for better serving the battery.