Electrochemical Cloth-Based DNA Sensors (ECDSs): A New Class of Electrochemical Gene Sensors.

Electrochemical (EC) sensors have been widely developed for DNA detection, but they are seldom used in a simple, economic, and efficient manner. In this work, for the first time, EC cloth-based DNA sensors (ECDSs) are developed as a new class of EC DNA sensors, without the need for cumbersome chip fabrication and high-cost peripheral facilities. Carbon ink- and solid wax-based screen printing were used to produce ultracheap sensing devices (the cost of one sensor is estimated to be $0.045). Also, a CdTe QDs/MWCNTs nanocomposite (CdTe-MWCNTs) was applied to modify the sensing interface to obtain a stronger EC signal. Specifically, the newly developed double linear hybridization chain reaction (DL-HCR) greatly amplified the EC signal, relative to the conventional linear HCR. Under optimized conditions, target DNA (TD) samples (75-bp DNA fragments prepared via PCR amplification) were determined in a range from 20 fM to 5 nM, with a detection limit of 8.74 fM and relative standard deviations of 2.04% and 4.75% for intra- and inter-assays at 50 pM TD, respectively. Additionally, the ECDSs had an acceptable storage stability and high selectivity. Importantly, the ECDSs, coupled with simple enzyme digestion, could detect genomic DNA from Listeria monocytogenes (L. monocytogenes), and a detection limit of 0.039 ng/μL was obtained. When coupled with enzyme digestion and PCR amplification, the ECDSs could determine L. monocytogenes in milk samples, with detection limits of approximately 1.64 × 104 and 11 CFU/mL. These results demonstrate that the method offers a broad prospect for cost-effective, reliable, and highly sensitive gene-sensing applications.