Poly‐5‐amino‐1,3,4‐thiadiazole‐2‐thiol Modified Disposable Sensors for the Electrochemical Monitoring of Sequence‐Selective DNA Hybridization

ABSTRACT A disposable pencil graphite electrode (PGE) was coated with a poly‐amino‐1,3,4‐thiadiazole‐2‐thiol (p‐AMT) film generated by the electropolymerization of AMT using cyclic voltammetry (CV). This polymeric layer was subsequently used as a platform for anchoring thiolated HBV‐DNA probes through thiol–disulfide interactions. The aim of the study was to develop a highly sensitive, selective, and repeatable biosensor for DNA hybridization. Surface alterations following the electrode modification were examined via scanning electron microscopy, confirming successful film formation. Immobilization efficiency on the p‐AMT modified electrode was compared to that on an unmodified PGE, revealing approximately a 2.4‐fold enhancement in the adenine oxidation response. The sensor achieved a detection limit of 56.5 nM (351 ppb). Selectivity was evaluated by comparing responses to the complementary target, a single‐base mismatched sequence, and a non‐complementary sequence. The findings confirmed the strong preference of the sensor toward the fully complementary DNA strand.