3.5.1 Selective ion sensors based on ionophore-modified graphene field-effect transistors

Kenzo Maehashi, Yasuyuki Sofue, Shogo Okamoto, Yusuhide Ohno, Koichi Inoue & Kazuhiko Matsmoto
Selective potassium (K) ion sensors were fabricated by modifying graphene field-effect transistors (FETs) with valinomycin, a selective K ionophore. The valinomycin-modified graphene FETs demonstrated highly sensitive, selective electrical detection of K ions in electrolytes. The K ions bound to the valinomycin in the graphene channel and affected the electrical potential of the channel. The transfer curves were shifted in a negative direction as the K ion concentration increased, indicating that K ions in solution were...