LAUSR

This pioneering study contains the fabrication of a novel concept of direct-electron-transfer (DET) bio-nanoink for a mediator-free and oxygen-insensitive glucose sensing. The DET bio-nanoink is composed of glycan chain-rich flavin adenine dinucleotide (FAD)-dependent glucose dehydrogenase (GDH), single-walled carbon nanotubes (SWCNTs), and surfactant sodium cholate in aqueous solution. We discovered FAD-GDH genes in various fungi and characterized the enzymatic properties of the recombinant enzymes produced by Pichia pastoris as a host. Glycan-chain-rich Aspergillus terreus var. aureus FAD-GDH is screened and is the most suitable for the bio-nanoink compared to conventional FAD-GDHs from Aspergillus species in terms of chemical stability and activity. The amperometric biosensor is fabricated with piezoelectric inkjet printing, where the small fraction (several pL) of the bio-nanoink can be erupted without clogging of the nozzle. The biosensor with the bio-nanoink showed a large (1 mA cm–2 at +0.6 V 48 mM...