Synthesis of Thin‐Layered Molybdenum Disulfide‐Based Polyaniline Nanointerfaces for Enhanced Direct Electrochemical DNA Detection

The low electronic conductivity limits the application of molybdenum disulfide (MoS 2 ) in electrochemical sensing field, let alone the label‐free and self‐signal amplification DNA sensing. Aiming at this problem, a novel polyaniline‐molybdenum disulfide (PANI‐MoS 2 ) nanocomposite through a facile oxidation polymerization aniline monomer on the thin‐layer MoS 2 matrix is prepared, which is preobtained via a simple ultrasonic exfoliation method. It is generally appreciated that conducting polymers, e.g., polyaniline (PANI), can work as a direct transducer based on themselves‐signal without any label or indicator. Moreover, MoS 2 not only serves as an excellent conductive skeleton provided a high electrolytic accessible surface area for redox‐active PANI, but also supports a direct path for electron transfer. Therefore, the hybrid of PANI and MoS 2 exhibits superior electrochemical performance to pure PANI and MoS 2 , and can be considered as a superior candidate for direct and label‐free electrochemical DNA sensing. A series of experiments are performed to investigate the effect of synthetic conditions (component, dosage of MoS 2 , and reaction time) on probe DNA (pDNA) immobilization and hybridization adopting the PANI self‐signal as the measure signal. The results show that the dosage of MoS 2 has a more influence on pDNA immobilization and hybridization.