posted on 2024-02-19, 06:44authored byAmanda
J. Ritz, Olivia M. Stuehr, Danté N. Comer, Robert A. Lazenby
Nanostructuring of gold surfaces
to enhance electroactive surface
area has proven to significantly enhance the performance of electrochemical
aptamer-based (E-AB) sensors, particularly for electrodes on the microscale.
Unlike for sensors fabricated on polished gold surfaces, predicting
the behavior of E-AB sensors on surfaces with varied gold morphologies
becomes more intricate due to the effects of surface roughness and
the shapes and sizes of surface features on supporting a self-assembled
monolayer. In this study, we explored the impact of gold morphology
characteristics on sensor performance, evaluating parameters such
as signal change in response to the addition of the target analyte,
aptamer probe packing density, and continuous sensing ability. Our
findings reveal that surface area enhancement can either enhance or
diminish sensor performance for gold nanostructured E-AB sensors,
contingent upon the surface morphology. In particular, our results
indicate that the aptamer packing density and target analyte signal
change results are heavily dependent on gold nanostructure size and
features. Sensing surfaces with larger nanoparticle diameters, which
were prepared using electrodeposition at a constant potential, had
a reduced aptamer packing density and exhibited diminished sensor
performance. However, the equivalent packing density of polished electrodes
did not yield the equivalent signal change. Other surfaces that were
prepared using pulsed waveform electrodeposition achieved optimal
signal change with a deposition time, tdep, of 120 s, and increased deposition time with enhanced electroactive
surface area resulted in minimized signal changes and more rapid sensor
degradation. By investigating sensing surfaces with varied morphologies,
we have demonstrated that enhancing the electroactive surface does
not always enhance the signal change of the sensor, and aptamer packing
density alone does not dictate observed signal change trends. We anticipate
that understanding how electrodeposition techniques enhance or diminish
sensor performance will pave the way for further exploration of nanostructure-aptamer
relationships, contributing to the future development of optimized,
miniaturized electrochemical aptamer-based sensors for continuous,
in vivo sensing.