We report the design and fabrication of two “signal-on” electrochemical DNA (E-DNA) sensors on gold nanostars-modified gold disk electrodes. The signaling mechanism of the sensor is based on target binding-induced change in the conformation and flexibility of the thiolated and methylene blue-modified DNA probe. In this new sensor design, the DNA probes are attached on the gold nanostars instead of the gold disk electrode. Two DNA probes, each with a different oligothymine spacer (T10 and T14), were used in this study. Alternating current voltammetry was used for both sensor characterization and target interrogation. Similar to the sensors fabricated on gold disk electrodes, the new sensors also behaved as “signal-on” sensors at high AC frequencies. Despite the lower % signal enhancement, the two new sensors fabricated on gold nanostars-modified electrodes were functional and capable of differentiating between the non- complementary and full complementary target DNA. The sensors were also successfully regenerated using sodium dodecyl sulfate. Future work includes the evaluation of DNA probes with different spacer sequences, with the goal of identifying a sequence best suited for this sensor architecture. With further characterization and optimization, these sensors could find applications in hybrid electrochemical and surface-enhanced Raman spectroscopy (EC-SERS) detection of DNA sequences relevant to cancer diagnosis.

“Signal-on” electrochemical DNA sensors fabricated on electrostatically assisted surface assembly of gold nanostars

255th National Meeting (2018)

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