A Single Layer Glucose Fuel Cell Intended as Power Supplying Coating for Medical Implants

Abstract

We present a novel type of abiotically catalysed implantable glucose fuel cell with anode and cathode placed side by side, using a Raney‐platinum glucose oxidation anode with high tolerance towards oxygen. In contrast to conventional assembly designs used for implantable glucose fuel cells, no permeable cathode mounted in front of the anode to effect oxygen depletion is required. At 2.2 ± 0.1 μW cm–2 the single layer fuel cell exhibits only half the maximum power density of the conventional fuel cell, which solely stems from the doubled total fuel cell area demand. Nevertheless, the novel single layer design is advantageous in terms of simplified fabrication and reduced overall thickness, facilitating implementation of the fuel cell as a power supplying coating directly on the surface of medical implants. Furthermore, the single layer design offers an attractive possibility to diminish the reduction of power density by limited oxygen mass transfer to the cathode by increasing the cathode to anode area proportion. With doubled cathode area proportion a by 36% higher power density can be reached. To calculate the optimum cathode to anode area proportions, we introduced an analytical model based on the experimentally determined polarisation resistances of the individual electrodes.

Abiotic (Nonenzymatic) Implantable Biofuel Cells

“…The more recent concept of the single-layer fuel cell (Figure 14.4c) exploits the fact that the sensitivity of a platinum electrode toward oxygen or glucose can be controlled by the porosity and specific surface area of the electrode, as shown schematically in Figure 14.5 [74,75]. In the case of a relatively thick porous platinum electrode with a large interior surface area, oxygen is fully consumed in the outer region of the pores by either (i) electroreduction to water or (ii) direct chemical reaction with glucose on the catalytically active surface.…”

“…Consequently, the overall electrode potential is dominated by the redox potential of oxygen reduction. Using platinum electrodes with different porosity and specific surface area a fully platinum-based fuel cell with anode and cathode placed next to each other can be realized [74]. This design obviates the need for an elaborate stacking of the individual electrodes and offers a high degree of freedom in terms of integrating the fuel cell together with the implantable device.…”

“…Since the size of anode and cathode can be freely adjusted to counterbalance electrode polarization, the geometric footprint of the device can be optimized. The power density of their optimized single-layer fuel cell is thus only 34% lower compared to a fuel cell built from the same electrodes but in stacked assembly [74].…”

Thin film nanoporous electrodes for the selective catalysis of oxygen in abiotically catalysed micro glucose fuel cells

“…Obtaining an adequate efficiency of the fuel cell acquires the use of both a glucose selective anode as well as an oxygen selective cathode. Considering the latter, common catalyst material such as platinum (Pt) or Raney-Pt alloy offers both good catalytic properties towards DO reduction and glucose oxidation [20,22,23], and is therefore not a perfect material if both analytes are present. Activated carbon may represent an alternative but has a lower overall catalytic activity compared to the RaneyPt alloy in the presence of glucose [24,25].…”

Nanostructured Inorganic Materials at Work in Electrochemical Sensing and Biofuel Cells

“…Various strategies for enzymatic electrode elaboration have been developed by different groups leading to efficient performances in vitro [30,[175][176][177][178][179][180][181] (from 1 to over 1000 µW·cm -2 ) and in those implanted in living organisms [124,[182][183][184][185][186][187][188]. Aiming to provide larger specific surface areas and a higher density of surface active sites, different methods have been developed to substitute one of the electrodes, mostly the anode, with an abiotic one, leading to the concept of the hybrid biofuel cell (hBFC) [180,[189][190][191], and in some cases, all the electrodes are substituted by abiotic catalysts [174,181,[192][193][194][195][196].…”