Graphite oxide electrical sensors are able to distinguish single nucleotide polymorphisms in physiological buffers

Abstract

Atomically flat materials based on graphene present unique opportunities for new technologies and are expected to standardize in near future for their properties based on size, shape and number of atomic layers. On the thicker end of the spectrum, graphite oxides (GrO) present a unique set of material properties in the family of graphene-based 2D materials. In this work, an optimized chemical sourcing and bottom-up nanofabrication approach is utilized for scalable fabrication of a highly sensitive field-effect based biodetector platform, deployable in concentrated liquid medium. GrO based biodetectors displaying very low variations in device-to-device sensor characteristics, were deployed for label-free detection of DNA concentrations from 5 pM to 5 nM in physiological buffer. Furthermore, charge-transport behaviour of GrO devices in electrochemical gate configuration was compared with that of the state-of-the-art graphene based devices. A comparative model for GrO-electrolyte interface is discussed based on the recent developments in this field and elucidate the role surface functional layers play in influencing the field-effect and biosensor performance of GrO based devices. The biodetector platform demonstrated here was able to distinguish analyte DNA strands (20 base pairs) with mismatched nucleotide sequences (containing 1 and 2 base-pair mismatches) from complementary DNA strands. Based on these findings, GrO may serve as cheap and scalable alternative to realize rapid and point-of-care medical diagnostic solutions for screening of diseases related to single nucleotide polymorphisms.