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Biofouling-Resilient Nanoporous Gold Electrodes for DNA Sensing
journal contribution
posted on 2015-09-01, 00:00 authored by Pallavi Daggumati, Zimple Matharu, Ling Wang, Erkin SekerElectrochemical
nucleic acid sensors are promising tools for point-of-care
diagnostic platforms with their facile integration with electronics
and scalability. However, nucleic acid detection in complex biological
fluids is challenging as biomolecules nonspecifically adsorb on the
electrode surface and adversely affect the sensor performance by obscuring
the transport of analytes and redox species to the electrode. We report
that nanoporous gold (np-Au) electrodes, prepared by a microfabrication-compatible
self-assembly process and functionalized with DNA probes, enabled
detection of target DNA molecules (10–200 nM) in physiologically
relevant complex media (bovine serum albumin and fetal bovine serum).
In contrast, the sensor performance was compromised for planar gold
electrodes in the same conditions. Hybridization efficiency decreased
by 10% for np-Au with coarser pores revealing a pore-size dependence
of sensor performance in biofouling conditions. This nanostructure-dependent
functionality in complex media suggests that the pores with the optimal
size and geometry act as sieves for blocking the biomolecules from
inhibiting the surfaces within the porous volume while allowing the
transport of nucleic acid analytes and redox molecules.