© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Adv. Mater. 2010, XX, 1–5 1 www.advmat.de www.MaterialsViews.com COMMUNICATION wileyonlinelibrary.com By Caofeng Pan, Ying Fang, Hui Wu, Mashkoor Ahmad, Zhixiang Luo, Qiang Li, Jianbo Xie, Xinxu Yan, Lihua Wu, Zhong Lin Wang, and Jing Zhu* Generating Electricity from Biofluid with a Nanowire-Based Biofuel Cell for Self-Powered Nanodevices [∗] Dr. C. F. Pan, Dr. H. Wu, A. Mashkoor, Z. X. Luo, J. B. Xie, X. X. Yan, Dr. L. H. Wu, Prof. J. Zhu Beijing National Center for Electron Microscopy Laboratory of Advanced Materials State Key Laboratory of New Ceramics and Fine Processing Department of Material Science and Engineering Tsinghua University Beijing 100084 (PR China) The National Center for Nanoscience and Technology (NCNST) of China Beijing 100080 (PR China) E-mail: jzhu@mail.tsinghua.edu.cn Prof. Y. Fang, Q. Li The National Center for Nanoscience and Technology (NCNST) of China Beijing 100080 (PR China) Prof. Z. L. Wang School Materials Science and Engineering Georgia Institute of Technology Atlanta Georgia 30332–0245 (USA) DOI: 10.1002/adma.201002519 The goal of nanotechnology is to build nanodevices that are intelligent, multifunctional, exceptionally small, extremely sen- sitive and have low power consumption. When the nanodevice is required for applications such as in vivo biomedical sen- sors, a nanoscale power source is required. Although a battery or energy storage unit is a choice for powering nanodevices, harvesting energy from the environment is an essential solu- tion for building a “self-powered” nanodevice/nanosystem, [1,2] which is an integration of nanodevice(s) and nano-enabled energy scavenging technologies. [3] Previously, nanogenerators (NGs) have been demonstrated that can convert mechanical energy of low (order of Hz) and high (around 50 kHz) fre- quencies into electricity by means of piezoelectric zinc oxide nanowires (NWs). [4–6] A single silicon NW-based heterostruc- ture has been used to fabricate solar cells that are effective for driving an NW-based pH sensor or logic gate. [2] Still, the most abundant energy available in biosystems is chemical and biochemical energy, such as glucose. In this paper, we report an NW-based biofuel cell (NBFC) based on a single proton conductive polymer NW for converting chemical energy from biofluids, such as glucose/blood, into electricity, using glucose oxidase (GOx) and laccase as catalyst. The glucose is supplied from the biofluid and the NW serves as the proton conductor. Although the electrolyte solution is a choice for transferring proton, it is essential to develop a proton conductive NW in some cases, such as the case in Figure S3c (see Section III of the Supporting Information (SI)), in which the anode and cathode solution are separated. A net current is generated due to the chemical potential difference between the anode and cathode as a result of the respective chemical reactions at those electrodes. The NBFC of a single NW generates an output power as high as 0.5–3 μW, and has been integrated with NW-based pH, glucose or photon sensors for performing self-powered sensing. This study shows the feasibility of building self-powered nanodevices for biological sciences, environmental monitoring, defense technology and even per- sonal electronics. Our nano biofuel cell is based on an electrochemical process of converting glucose into gluconolactone ( Figure 1a ). GOx and laccase are used as catalysts at the anode and cathode, respectively. GOx is an enzyme that catalyses the oxi- dation of β- D-glucose by molecular oxygen. However, in the absence of mediating small molecules, the well-defined direct electrochemical action of GOx systems is rendered extremely difficult, as its active center-flavin adenine dinucleotide (FAD) is deeply embedded within a protective protein shell. GOx immobilized on the surface of carbon nanotubes (CNTs) was reported to have a direct electron transfer and retain its Figure 1. Design of a single Nafion/poly(vinyl pyrrolidone) compound nanowire (NPNW)-based biofuel cell. a) The NW lies on a substrate (of any kind), with both ends tightly bonded to the substrate and outlet inter- connects. GOx and laccase are used as catalysts in the anode and cathode region, respectively. b) The NBFC is immersed into a biofuel solution, two chemical reactions occur in the anode and cathode regions, creating a corresponding chemical potential drop along the NW, which drives the flow of protons in the NW and electrons through the external load.