Current Response Enhancement According to the Doping Anion’s Nature in Redox Polyelectrolyte─Enzyme Assemblies

CORIA-ORIUNDO, LUCY L.; HERRERA, SANTIAGO E.; MÉNDEZ DE LEO, LUCILA P.; BATTAGLINI, FERNANDO

ACS Applied Polymer Materials

ACS Publications

Lugar: washington DC; Año: 2022 vol. 4 p. 7759 - 7769

2637-6105

High-power density output in enzymatic fuel cells is a key feature to reduce the size of self-powered implantable medical devices. Electron transfer mediated through redox polyelectrolytes allows the transport of electrons from enzymes away from the electrode improving the current output. It is known that doping ions in polyelectrolytes introduce relevant characteristics in the generation of assemblies regarding mass adsorption and stiffness. In this work, binary 1:1 sodium salts (NaX; X = F-, Cl-, Br-, NO3-, ClO4-) were studied as doping ions of two redox polyelectrolytes (osmium based branched polyethyleneimine and osmium based linear polyallylamine) to improve the adsorption and electron transfer process in glucose oxidase/redox polyelectrolyte assemblies. Cyclic voltammetry, Quartz crystal microbalance with dissipation (QCM-D), Polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) and Atomic force microscopy (AFM) were used to understand the growing mechanism of these films and their performance. Ion hydrophobicity plays a key role, being bromide the one that generates the greater absorption and the best electron transfer efficiency for both redox polyelectrolytes. Branched polyethyleneimine doped with bromide was the best combination for the construction of bioanodes. Applied on an O2-glucose enzymatic fuel cell yields a power density output of 2.5 mW cm-2 achieving state-of-the-art performance.