In vivo CH3(CH2)11SAu SAM electrodes in the beating heart:: In situ analytical studies relevant to pacemakers and interstitial biosensors

被引:17
作者
Chou, HA
Zavitz, DH
Ovadia, M
机构
[1] Univ Illinois, Dept Pediat, Chicago, IL 60612 USA
[2] Childrens Hosp, Christ Med Ctr, Heart Inst Children Hope, Oak Lawn, IL 60453 USA
[3] Univ Illinois, Dept Chem, Chicago, IL 60612 USA
关键词
self-assembled monolayers (SAM); biosensors; biocompatibility; cardiac pacemakers; SAM degradation; neutron activation analysis (NAA); impedance spectroscopy;
D O I
10.1016/S0956-5663(02)00116-1
中图分类号
Q6 [生物物理学];
学科分类号
071011 ;
摘要
To study in vivo modification of the SAM equivalent circuit when a highly ordered SAM is used as a bioelectrode, dodecanethiolate SAM -Au intramuscular electrodes were studied in living rat heart in a challenging in situ perfused rat model by impedance spectroscopy, cyclic voltammetry, and neutron activation analysis (NAA). The SAM layer experienced disintegration in vivo biological system, as NAA detected the presence of An atoms that had leached into the surrounding living tissue. Therefore, the underlying Au surface became exposed during biological implant. Study by impedance spectroscopy, however, revealed perfect capacitive behavior for the SAM, similar to in vitro behavior. Electrodes showed a pure capacitive Nyquist plot with 86.1-89.4degrees near-vertical line segments as the equivalent circuit locus, as for a parallel plate capacitor. Impedance magnitude varied linearly with 1/omega excluding diffusionally limited ionic charge transport. There was no diffusional conductive element Z(winfinity) or spatially confined Warburg impedance ZD. The effect of in vivo exposure of a highly ordered SAM is a 'sealing over' effect of new defects by the binding of proteinaceous or lipid species in the biological milieu, a fact of significance for SAM electrodes used either as pacemaker electrodes or as a platform for in vivo biosensors. (C) 2002 Elsevier Science B.V. All rights reserved.
引用
收藏
页码:11 / 21
页数:11
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