Engineered nanometric architectures or conductive matrices for efficient electron coupling

The overall objective of this program is to develop an effective means for integrating enzymes onto an electrode in order to improve electron transfer and enzyme loading and stability. The approach is based on conformably coating a layer of functional polymer onto an arrayed multi-walled carbon nanotube (MWCNT) electrode. The immobilized enzymes will be further covalently encapsulated by a hydrogel mesh. This approach is significant because of a) high enzyme loading (the amount of immobilized enzymes will be around 100-fold higher than other means); b) efficient electron transfer (the electrical communication will be facilitated by a reduced distance between enzyme and electrode); and c) improved stability. This combination is very unique and has not been achieved to date. Owing to the high biocompatibility of hydrogel and related shielding effect, the immobilized enzymes are expected to have an extended lifetime more than 45 days (the maximum lifetime reported so far). Thus, this technique will meet the military need to power modest-power demand devices that require mW to W for extended periods of time. BENEFIT: This program will develop an effective means for integrating enzymes onto an electrode. This will enable the military to have a practical enzyme-based biological fuel cell in the future. The commercial applications include implantable biological fuel cell, high sensitive sensor, and portable power supplies etc.