In situ energy harvesting is a major limitation for the development of implantable biomedical digital devices. Considerable efforts have been made to improve Glucose/O2 Enzymatic Biofuel Cells (EBFCs), able to generate electrical power in the physiological environment, in order to match the demands of biomedical electronics [1]. A key advance was the development of redox hydrogels. They permit efficient connection of high amounts of oxidoreductases to electrodes, leading to easily miniaturizable BFCs with power densities in the range of 100 μW.cm-2 suitable for application [2]. However, their open circuit potentials still fall below the requirements of conventional electronics. On the other hand, the power and voltage demands have decreased thanks to tremendous progress in low-power electronics [3], rendering devices compatible with the performance of EBFCs.

Here we demonstrate that common data processing functions such as binary counting can be powered by a glucose/O2 micro-EBFC directly integrated on an Application Specific Integrated Circuit (ASIC) at the die level. An EBFC based on Glucose Oxidase and Bilirubin Oxidase hydrogels immobilized on 400 μm diameter electrodes was designed on the Si chip of the 4-bit ripple-counter. The system could be continuously powered during several hours from a single 50 μL droplet of aerated 5mM glucose solution.

1] S. Cosnier, A. Le Goff, M. Holzinger, Electrochem. Comm., 2014, 38, 19-23.

[2] N. Mano, F. Mao, A. Heller, JACS, 2003, 125, 6588-6594.

[3] A. Chandrakasan, N. Verma, D.C. Daly, Annual Rev. Biomed. Eng., 2008, 10, 247-274.