Attomolar Detection of ssDNA Without Amplification and Capture of Long Target Sequences With Graphene Biosensors

Graphene-based biosensors can be produced in a scalable manner at reasonable cost, and they show significant promise for sensitive detection of small molecules and biomarkers such as proteins, single strand nucleic acids, and drug targets. Here, we describe an approach that enables a limit of detection of 1 aM for a ssDNA target without amplification. We also show that a sensor based on a short (20mer) probe complementary to a portion of a longer (100mer) target provides enhanced sensitivity and saturation signal level. Finally, we show that graphene-based DNA biosensors can be repeatedly recycled with consistent sensor responses by melting off bound target strands. These results show the potential utility of this technology in nucleic acid detection for disease diagnostics.