Solubilized Enzymatic Fuel Cell (SEFC) for Quasi-Continuous Operation Exploiting Carbohydrate Block Copolymer Glyconanoparticle Mediators

Enzymatic biofuel cells are ecofriendly power sources that can deliver μW–mW outputs from renewable substrates, but their stability is a major issue owing to enzyme fragility. The vast majority of reported biofuel cells can only generate power continuously for relatively short periods of time. Here we report a novel “solubilized enzymatic fuel cell (SEFC)” concept for continuous long-term operation. Avoiding surface immobilization techniques allows biocatalytic activity to be easily restored or replenished. The biofuel cell exploits freely diffusing enzymes and β-cyclodextrin-coated glyconanoparticles with entrapped quinone and thiazoline redox mediators, for mediated glucose and oxygen conversion. The cell was designed with permselective membranes to enable substrate and proton diffusion while trapping the enzymes and glyconanoparticles in separate compartments. The SEFC exhibited a peak power loss of only 26.3% after 7 days of continuous charge–discharge cycling at 50 μA; thus, SEFCs may be envisaged to power lab-on-a-chip devices for periods of several weeks.