Long tethers binding redox centers to polymer backbones enhance electron transport in enzyme "wiring" hydrogels
Long tethers binding redox centers to polymer backbones enhance electron transport in enzyme "wiring" hydrogels
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DOI：
10.1021/ja029510e
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发表时间：
2003-04-23
影响因子：
15
通讯作者：
Heller, A
中科院分区：
文献类型：
--
作者：
Mao, F;Mano, N;Heller, A
描述了具有（5.8 +/-0.5）X 10（-6）cm（2）s（-1）的表观电子扩散系数（D-app）的氧化还原水凝胶。相对于先前研究的氧化还原水凝胶，D-app的数量级增加是由于氧化还原中心通过13个原子间隔臂束缚到交联的氧化还原聚合物主链的主链。长而灵活的系链允许氧化还原中心从大体积元素中扫过电子，并有效地收集葡萄糖氧化酶的电子。间隔臂使得来自葡萄糖氧化酶的电子的收集如此有效，以致于葡萄糖已经在相对于Ag/AgCl的-0.36V（在pH 7.2下酶的FAD/FADH（2）中心的氧化还原电势的可逆电势）下被电氧化。在-0.1 V（Ag/AgCl）的电位下，极限电流密度达到1.15 mA cm（-2）。该聚合物的新型氧化还原中心是三-二烷基化的N，N-双咪唑Os 2 +/3+络合物。其氧化还原电位为-0.195 V（Ag/AgCl），相对于其2，2 '-联吡啶类似物Os（bpy）（2+/3+）为0.8 V。
A redox hydrogel with an apparent electron diffusion coefficient (D-app) of (5.8 +/- 0.5) x 10(-6) cm(2) s(-1) is described. The order of magnitude increase in D-app relative to previously studied redox hydrogels results from the tethering of redox centers to the backbone of the cross-linked redox polymer backbone through 13 atom spacer arms. The long and flexible tethers allow the redox centers to sweep electrons from large-volume elements and to collect electrons of glucose oxidase efficiently. The spacer arms make the collection of electrons from glucose oxidase so efficient that glucose is electrooxidized already at -0.36 V versus Ag/AgCl, the reversible potential of the redox potential of the FAD/FADH(2) centers of the enzyme at pH 7.2. The limiting current density of 1.15 mA cm(-2) is reached at a potential as low as -0.1 V versus Ag/AgCl. The novel redox center of the polymer is a tris-dialkylated N,/\r-biimidazole Os2+/3+ complex. Its redox potential, -0.195 V versus Ag/AgCl, is 0.8 V reducing relative to that of Os(bpy)(2+/3+), its 2,2'-bipyridine analogue.