Recent progress and continuing challenges in bio-fuel cells. Part I: enzymatic cells.

Recent developments in bio-fuel cell technology are reviewed. A general introduction to bio-fuel cells, including their operating principles and applications, is provided. New materials and methods for the immobilisation of enzymes and mediators on electrodes, including the use of nanostructured electrodes are considered. Fuel, mediator and enzyme materials (anode and cathode), as well as cell configurations are discussed. A detailed summary of recently developed enzymatic fuel cell systems, including performance measurements, is conveniently provided in tabular form. The current scientific and engineering challenges involved in developing practical bio-fuel cell systems are described, with particular emphasis on a fundamental understanding of the reaction environment, the performance and stability requirements, modularity and scalability. In a companion review (Part II), new developments in microbial fuel cell technologies are reviewed in the context of fuel sources, electron transfer mechanisms, anode materials and enhanced O(2) reduction.