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底液pH值对{HECE/AA}n-Mb薄膜电化学性质的影响

发表时间:2011-04-15  浏览量:1363  下载量:438
全部作者: 胡洋,胡乃非,刘红云
作者单位: 北京师范大学化学学院
摘 要: 血红素蛋白质肌红蛋白(myoglobin, Mb)能够被吸入到由羟乙基乙氧基纤维素季铵盐(HECE)和褐藻酸(AA)构筑的{HECE/AA}n层层组装薄膜中,形成吸入型蛋白质薄膜{HECE/AA}n-Mb。该薄膜中电活性Mb的表面浓度随底液pH值的增加而显著降低。电活性小分子探针(cyclic voltammetry, CV)实验和电化学阻抗谱(electrochemical impedance spectroscopy, EIS)实验表明,{HECE/AA}n-Mb薄膜对于溶液中的对离子的通透性随pH值增加而明显降低。对于以“电子跳跃”为主要电子转移机理的{HECE/AA}n-Mb薄膜而言,溶液中对离子进出薄膜可能是Mb发生直接电子转移的制约因素,因此测试溶液的pH值变化直接影响了薄膜的通透性,而薄膜通透性的变化又影响了对离子在薄膜中的传输,从而影响了Mb的直接电化学。
关 键 词: 电化学分析;肌红蛋白;吸入;层层组装;直接电化学;pH值
Title: Influence of pH of testing solutions on electrochemical activity of {HECE/AA}n-Mb films
Author: HU Yang, HU Naifei, LIU Hongyun
Organization: College of Chemistry, Beijing Normal University
Abstract: The {HECE/AA}n-Mb films was fabricated by loading heme protein myoglobin (Mb) into {HECE/AA}n layer-by-layer films, where HECE is quaternized hydroxyethyl cellulose ethoxylate and AA is sodium alginate. The fraction of electroactive Mb among the total Mb loaded into the {HECE/AA}n-Mb films decreases remarkably as the pH of testing solution increases. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) experiments with small electroactive probe demonstrates that the permeability of {HECE/AA}n-Mb films toward small counterions in solution decreases remarkably as the pH of testing solution increases. The transportation of counterions from external solution phase into film phase and/or from film phase to solution phase may become a limiting factor for Mb exchanging electrons with the underlying PG electrodes since the Mb molecules in the films take electron-hopping or electron self-exchange mechanism in electron transfer. The pH of testing solution would influence the porosity or permeability of the films, and the mobility of counterions with the film phase depends on the porosity or permeability of the films, so the pH of testing solution would greatly influence the electrochemical activity of Mb in the films.
Key words: electrochemical analysis; myoglobin; absorption; layer-by-layer assembly; direct electrochemistry; pH value
发表期数: 2011年4月第7期
引用格式: 胡洋,胡乃非,刘红云. 底液pH值对{HECE/AA}n-Mb薄膜电化学性质的影响[J]. 中国科技论文在线精品论文,2011,4(7):619-626.
 
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