Reduced graphene-oxide transducers for biosensing applications beyond the Debye-screening limit.

Biosens Bioelectron

Institute of Materials in Electrical Engineering 1, RWTH Aachen University, Aachen, Germany; Department of Informatics and Microsystem Technology, University of Applied Sciences Kaiserslautern, Zweibrücken, Germany. Electronic address:

Published: April 2019

In the field of label-free biosensing, various transducer materials and strategies are under investigation to overcome the Debye-screening limitation of charged biomolecules. We demonstrate an in-line, impedimetric aptasensor with reduced graphene-oxide (rGO) thin films as transducers to detect prostate specific antigens (PSA) in a physiological buffer solution. Unlike classical electrochemical impedance spectroscopy (EIS), this direct, label-free and fully-electronic biosensor approach does not need any redox markers. As specific capture molecules, short anti-PSA aptamers ensured a close binding of the target molecules to the transducer surfaces. Results showed a limit of detection smaller than 33 pM of PSA and a wide detection range from 0.033 to 330 nM fully covering the clinically relevant range of PSA (0.115-0.290 nM). This promising performance can be attributed to the bipolar electronic transport characteristics of the ultra-thin rGO layers similar to pristine graphene. The attachment of target biomolecules to the films changes the resistance of the rGO thin films. Such an in-line EIS configuration with rGO thin films opens promising prospects for biosensing beyond the Debye-screening limitation, which is a major challenge for conventional semiconductor field-effect devices towards clinical applications.

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Source
http://dx.doi.org/10.1016/j.bios.2018.09.045DOI Listing

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