Aptasensors based on graphene field-effect transistors for arsenite detection

All-electronic chemical sensors based on field-effect transistors (FETs) hold tremendous promise for rapid and sensitive detection of arsenic in groundwater. Their sensitivity, however, is fundamentally limited by a chemical gating mechanism where target ion charges are directly measured. We have developed a highly sensitive aptasensor, based on scalable graphene FETs, which relies on the conformational change of the negatively charged aptamer upon arsenite binding, offering a wide analytical range, from 0.05 to 1000 ppb, and with a 0.02 ppb detection limit. Circular dichroism spectroscopy studies confirmed the conformational change of the aptamer, and molecular dynamic studies further validated that arsenite had bound with the hairpin loop of the aptamer. This work provides a highly accurate chemical sensing platform for rapid detection of arsenic in drinking water.