ACS applied materials & interfaces 2017 09 06() doi 10.1021/acsami.7b12103
Solid-state nanopores within graphene-based materials are on the brink of fundamentally changing the sensing of desired bio-analytes through ion trafficking across nanoporous membranes. Here, we report on a two-electrode electrochemical biosensor comprised of a graphene oxide-polycarbonate track-etched nanosieve platform for the rapid and sensitive detection of the Human Immunodeficiency Virus Type 1 (HIV-1) envelope glycoprotein ectodomain (gp140MS). We have covalently linked an engineered high-affinity one-domain soluble CD4 fused to a human domain targeting HIV-1 coreceptor binding site and ferrocene (Fc) (2Dm2m) to the nanosieve platform. An exponential decrease in the ionic current resulted from a partial blockade of the nanosieve due to the specific interactions of gp140MS with the 2Dm2m protein, which was immobilized on the nanosieve platform by bio-linkage as a function of applied voltages of 0.1-2.0 volts. There was no change in current when a non-specific antigen bovine serum albumin was tested under identical conditions. This platform had high sensitivity, and when the receptor-binding phenomenon was tested to identify the minimum concentration of target analyte the lowest detection limit was as short as 8.3 fM, and with sensitivity and response times of 0.87 mA-mM-1cm-1 and 12 s, respectively. In addition to this remarkable sensitivity, our nano-biorecognition platform has the advantage of superior stability due to the few layered graphene oxide laminates. It also exhibits exceptional biomolecule binding and higher reusability, sustainability and ease of fabrication in a soft mechanism. Real samples of HIV positive and negative patients were successfully tested to confirm the virus by the developed platform. To the best of our knowledge, this is the first time prosperous pervious remembrance surface has been employed in a nano-biosensing application. In light of the recent great trend of using graphene-based nanopore surfaces created by sophisticated ion-beam methods in sensing and sequencing, this hybrid-surface nanolayer fabricated by the simple vacuum filtration of a few layered graphene oxide laminates may serve as a good alternative in terms of ease of fabrication without expensive instrumental prerequisites.