Generating electricity from biofluid with a nanowire-based biofuel cell for self-powered nanodevices.

The goal of nanotechnology is to build nanodevices that are intelligent, multifunctional, exceptionally small, extremely sensitive and have low power consumption. When the nanodevice is required for applications such as in vivo biomedical sensors, 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 solution 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) frequencies into electricity by means of piezoelectric zinc oxide nanowires (NWs). [ 4–6 ] A single silicon NW-based heterostructure 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 biofl uids, such as glucose/blood, into electricity, using glucose oxidase (GOx) and laccase as catalyst. The glucose is supplied from the biofl uid 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