| The study of direct electrochemistry of protein played an important role tohuman. In this paper, surfactants, new quaternary ammonium salts and copolymerhydrogel have been used as the protein immobilization materials to modify electrodesurface. And we discussed that the direct electrochemistry and electrocatalysis ofprotein in these modified electrodes. It is significant for us to understand themechanism of the direct electron transfer and to fabricate the unmediated biosensors.Due to the special structure of surfactant, which could be adsorb on two differentpolarities, surfactant with high surface active and well biocompatibility have beenutilized to entrap protein and facilitate the direct electron transfer between theelectroactive center of protein and the electrode without disturbing the structure ofprotein. In this paper, a series of surfactant with different ethylene oxide (PEO) unitlengths modified electrode have been used to entrap protein, we can find out theoptimum ratio between the surfactant and protein, and we also could work out theoptimum ethylene oxide (PEO) unit lengths of surfactant on the electrode. From thediscussion above, it demonstrated that the surfactant with different ethylene oxide(PEO) unit lengths modified electrodes not only provided a favorable microenvironmentto keep the bioactivity of Hb but also exhibited high electrocatalytic performance tohydrogen peroxide with fast response, and excellent stability. We also investigated theeffect of solution pH on the potential of chitosan/Hb/AEO3/GC, chitosan/Hb/AEO23/GC and chitosan/Hb/AEO9/GC modified electrodes.With the fast improving standard of life, the demand of antimicrobial material isincreasing."Quaternary ammonium polymers"were used as a typical kind ofantimicrobial material, its chemical stability, low toxity, thermal stability made its application in biotechnology, pharmaceutical and agriculture. Above all, the antimicrobialagent is a kind of potential materials in the future.Based on dimethylaminothyl methacrymethacrylate (DMAEMA), bromoethane,hexyl bromide, decyl bromide and bromododecane, we synthesized the quaternaryammonium salt with different side chain lengths, and their structure was verified byFT-IR spectra and elemental analysis respectively. UV-vis spectra was used to provethe secondary of protein structure was not disturbed in the new quaternary ammoniumsalt complex films, the quaternary ammonium salt modified electrode could realizethe direct electrochemistry of protein on GC electrode, which implied that this kind ofmaterial provide a friendly environment for protein, also represented the material isbiocompatibility. Based on the electrochemical data, we can draw the conclusion thatwith the increasing of side chain length of quaternary ammonium salt, once it achievean optimum chain length, the amount of immobilization of protein could reach amaximum. We also investigate the electrocatalysis of H2O2on the three modifiedelectrode. From the medical point of view, it is the first time for us to utilize thisquaternary ammonium salt material to cure the candida albican and aspergilusfumigates and receive a good antimicrobial effect. From the discussion above,quaternary ammonium salt is a promising material in antimicrobial agent and directprotein electrochemistry.Hydrogels have always be popular for their extreme hydrophilicity, biocompatibility,low toxicity, which made it widely applied in agriculture, forest, biochemistry andmedical areas. Hydrogel were sorted by pH, temperature, ionic strength, electric fieldsensitive hydrogel and so on. Nowadays, some polymer hydrogel were used toimmoblize protein and realized the direct electron transfer beween the proten andelectrode.It is the first time for us to report AA-PEGMA copolymer gel to entrap protein.The result from CD and UV-vis spectra demonstrated that the native structure of Hbwas well preserved after immobiliation in the AA-PEGMA copolymer films, nodisturbing. The AA-PEGMA copolymer films not only could realize electrochemistryof protein, but also exhibited electrochemical catalytic of H2O2, due to the material possess some merits, such as the hydrophilic properties and electrical conductivity.SEM illustrated that there must be some special effect between copolymer andproteins. We investigate the electrochemical and the electrocatalytic chemistry ofAA-PEGMA copolymer films and studied the stability and reproductivity ofChitiosan/Hb/AA-PEGMA copolymer/GC electrode, the results suggested that theAA-PEGMA copolymer composite film was a suitable matrix for the immobilized Hbto maintain its activity. The research may open a new opportunity for designing novelthird generation of biosensors.Poor mechanical properties have inhabited the further application of hydrogel, inthis paper, we synthesis the hydrophobic association hydrogels (HA-gels) based onAEO-AC, AM, SDS and water, which was prepared through micellar copolymerizationof a small amount of AEO-AC as hydrophobic association monomer. FTIR spectrumdemonstrated that AEO-AC was successfully synthesized. In this paper, weinvestigate the mechanical properties and the swelling properties of HA-gels withaltering the content of SDS and hydrophobic monomer AEO-AC.Above all, it is the first time for us to explore the different ethylene oxide (PEO)unit lengths of nonionic surfactant, the different chain length of quaternary ammoniumsalts and AA-PEGMA copolymer as the immobilization materials to entrap proteinand do the research of the electrochemistry of Hb. For hydrophobic hydrogel, weconcentrate on the research of swelling properties and mechanical properties ofHA-gels with altering SDS and AEO-AC. The results were not only supply us tounderstand the mechanism direct electron transfer of protein, but also provide us adeeply insight about the mechanical and swelling properties of AEO-AC typehydrophobic association hydrogel.
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