乙醇脱氢酶在聚苯胺-聚丙烯酸修饰电极上的固定及表征

Immobilization and characterization of alcohol dehydrogenase on polyaniline-polyacrylic acid modified electrode

采用循环伏安法在铂电极上于0．5mol／L苯胺-2．5mol／LHCI-15％（质量分数）聚丙烯酸的水溶液中制备聚丙烯酸掺杂的聚苯胺膜；并在0．25mol／L磷酸氢二钠-柠檬酸缓冲溶液（pH=7）中测试掺杂后的聚苯胺膜的电化学性能，聚苯胺-聚丙烯酸（PAn-PAA）复合膜修饰电极在电位为-0．2～0．4V时出现1对稳定的氧化还原峰，与PAn修饰电极相比，它在此中性缓冲溶液中具有更好的导电性和电化学活性，可用作固定酶的载体和酶催化反应的电子传递媒介。实验中采用两步法将乙醇脱氢酶（ADH）固定至PAn-PAA复合膜中，用循环伏安（CV）、交流阻抗（EIS）和扫描电镜（SEM）等方法对固定乙醇脱氢酶前后膜的性能进行表征。结果表明ADH已固定至复合膜中。

Polyaniline-polyacrylic acid （PAn-PAA） composite film was electrochemically deposited on Pt electrode in the solution containing 0.5 mol/L aniline, 2.5 mol/L HC1, 15% poly（acrylic acid） by cyclic voltammetry. And the electrochemical properties of this composite film were tested in 0.25 mol/L disodium hydrogen phosphate-citric acid buffer at pH= 7. The resulting PAnPAA composite film has one stable redox peak in the range of -0.2 - 0.4 V, and shows better conductivity and electroactivity in comparison with PAn modified electrode. And it can be used as carrier for enzyme immobilization and mediator for enzyme-catalyzed reaction. Alcohol dehydrogenase （ADH） was immobilized on the PAn-PAA composite film by a two-step method. PAn-PAA composite film and PAn-PAA-ADH film were tested by means of cyclic voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy. The results indicate that ADH is assuredly immobilized on PAA-PAn composite film.