Direct measurement of K⁺ ion efflux from neuronal cells using a graphene-based ion sensitive field effect transistor

A graphene-based ion sensitive field effect transistor (GISFET) has been developed and investigated in terms of its ion sensing performance. The GISFET sensor was found to demonstrate a high detection sensitivity enabling direct measurement of K⁺ ion efflux from live cells. The sensing performance of the GISFET was directly compared to that of a commercial Si ISFET and very similar detection results were obtained, highlighting the promise of the GISFET sensor for ion-sensing applications. Additionally, fabrication of a GISFET array containing 25 devices using a CMOS compatible photolithographic process was demonstrated, which resulted in good uniformity across the array and high ion sensing properties of the devices, underlining their application potential for simultaneous multi-well testing with small sample volume.