| The preparation and application of one-dimensional micro-nano-fiber materials have been one of the research hotspots in recent years.Biotechnology provides an effective means for the preparation of one-dimensional materials with special micro-nano-structures.Bacterial cellulose?BC?materials with nano-scale can be prepared by microbial culture.Due to its excellent mechanical properties and biocompatibility,as well as high transparency,facile modification and other excellent physical/chemical properties,BC has broad application prospects in different fields.By regulating the growing environment of BC and combining“self-assembly”method,3D BC based nanocomposites with controllable morphologies can be constructed.Furthermore,by optimizing the surface functional structure,the interfacial properties of BC nanomaterials can be regulated.Thus,the applications of BC in photoelectricity,biomedical material,sensor,energy storage and other fields can be expanded.Recently,biosensors have been widely used in environmental prosecution,blood glucose detection and food supervision due to their advantages such as low cost,easy to manufacture,high efficiency,rapidity,high sensitivity and portability.However,most biosensors are still dependent on external energy,which greatly restricts the wide application and development of biosensors.In order to achieve real-time,rapid and portable detection,it is of great significance to build low-cost and miniaturized self-powered sensors for analysis and detection.Also,in order to solve the disadvantages of lacking in biocompatibility,low analytical sensitivity and uncontrollable detection range of biosensor,the design and development of a kind of flexible electrode material with excellent mechanical properties and biocompatibility to construct self-powered biosensor has become one of the hot-spots in current research.Especially for the growth of the BC controlled environment and 3D nanonetwork structure,excellent mechanical properties,good biocompatibility,large surface area,high flexible and abundant functional groups and other characteristics,it provides an excellent microenvironment and active site for bio-enzyme and functional nanomaterials.Therefore,BC is an excellent carrier for the construction of flexible electrode materials in biosensors.Carbon nanotubes?CNTs?have been widely used in the sensor field due to their advantages of good conductivity and large specific surface area.In this paper,the new enzyme biofuel cell?EBFC?technology combined with biological means and advantages of one-dimensional nanocarbon,carboxylated multiwalled carbon nanotubes?c-MWCNTs?,is utilized to design and manufacture simple,cheap and portable self-powered biosensor.Here,some new self-powered biosensors are developed and applied to glucose detection.Meanwhile,because the stability and activity of enzyme are easily affected by factors such as acidity and alkalinity,temperature and dissolved oxygen in the microenvironment,it is easy to lose its activity,the design and development of a new type of non-enzymatic sensor has become a research hot-spot.Among them,zero-dimensional carbon quantum dots?CQDs?,as a new type of fluorescence carbon nanomaterials,is also a member of the nanocarbon family.Due to its advantages of good light stability,non-toxicity and low cost et.al,it has been widely used in chemical analysis and biosensing,cell imaging and biomarkers and other fields.This paper also combines the advantages of biotechnology and zero-dimensional carbon point to design and develop a new type of non-enzyme intelligent response membrane sensor and apply it to the detection of heavy metal ions.The main research is as follows:?1?BC/c-MWCNTs flexible electrodes were prepared by using BC and c-MWCNTs as carriers and conductive materials,respectively.Then,laccase?Lac?and glucose oxidase?GOx?were used to prepare enzyme immobilized biocathode and bioanode.Subsequently,the flexible BC based glucose/O2 enzyme biofuel cell?EBFC?was constructed for the first time.Electrochemical tests showed that c-MWCNTs promoted the direct electron transfer?DET?of the enzyme and realized the transfer of electrons from the active center of Lac to the electrode surface.Meanwhile,the prepared glucose/O2 EBFC has a good output power(55.0?W·cm-3),a wide detection range?0-20 mM?and an acceptable detection limit?0.267 mM?for glucose.?2?In order to improve the detection range of glucose,BC/c-MWCNTs nanocomposites were successfully prepared by biological self-assembly method.Meanwhile,Lac and GOx were crosslinked by glutaaldehyde to prepare biocathode and bioanode,and then the glucose/O2 EBFC was constructed.Electrochemical tests showed that the maximum output voltage of glucose/O2 EBFC was 0.62 V,with acceptable power density(32.98?W·cm-3),wide detection range?0-30 mM?and low detection limit?0.209 mM?.As-prepared BC/c-MWCNTs electrode is an excellent biosensor electrode material,and the sensor has the potential to be used in glucose detection.?3?In order to further improve the sensitivity of glucose detection,controlled deposition of gold nanoparticles?AuNPs?on the surface of BC/c-MWCNTs nanocomposites was used to obtain BC/c-MWCNTs/AuNPs flexible electrodes.Lac and GOx were respectively immobilized on the flexible electrode in combination with the electrostatic self-assembly method to obtain the enzyme immobilized biocathode and bioanode,and BC flexible glucose/O2 self-powered biosensor was constructed.By selecting different target factors and simulating the coexistence of target factors in human blood,single factor and multiple factor tests were carried out.The experimental results showed that the self-powered biosensor has good anti-interference and high selectivity.Meanwhile,the constructed glucose/O2self-powered biosensor has a high output power density(345.14?W·cm-3),a wide detection range?0-50 mM?and a low detection limit?2.874×10-33 mM?towards glucose.It is mainly attributed to the excellent physical and chemical properties of c-MWCNTs and AuNPs,which realize the synergistic effect between them and better promote the direct electron transfer of enzymes and the transfer of electrons from the active center of enzyme protein molecules to the surface of electrodes.BC/c-MWCNTs/AuNPs as flexible electrode has potential application in self-powered biosensor,which lays a theoretical basis and technical support for the detection of human blood glucose.?4?Nitrogen-doped carbon quantum dots?N-CQDs?were prepared by one-step hydrothermal method with citric acid?CA?and ethylenediamine?EDA?as carbon and nitrogen sources,respectively.The optical properties of N-CQDs were also extended to BC/N-CQDs films by biological self-assembly method.The prepared BC/N-CQDs films has good selectivity for metal ions and good detection range?0-600?M?and low detection limit?84 nM?for Fe3+.Meanwhile,it has been successfully applied to the actual water sample detection.this non-enzymatic sensor can be used as a potential fluorescence detection membrane material.?5?To further study the universality and reusability of bio-assembled non-enzymatic response membrane.In this paper,reduced graphene quantum dots?N-GOQDs?with good water solubility and stable optical properties were introduced to conduct biological self-assembly with BC.The results of experiments and analysis verified that BC/N-GOQDs nanocomposite membrane can be used as a metal ion fluorescence detection membrane.Meanwhile,the BC/N-GOQDs fluorescence response membrane has good reusability by using Fe3+and EDTA to act on the sample system alternately.Combined with the“self-assembly”method,3D BC intelligent response membrane with controllable morphology can be constructed. |
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