Electrochemical Cloth-Based DNA Sensors (ECDSs): A New Class\nof Electrochemical Gene Sensors

Abstract

Electrochemical\n(EC) sensors have been widely developed for DNA\ndetection, but they are seldom used in a simple, economic, and efficient\nmanner. In this work, for the first time, EC cloth-based DNA sensors\n(ECDSs) are developed as a new class of EC DNA sensors, without the\nneed for cumbersome chip fabrication and high-cost peripheral facilities.\nCarbon ink- and solid wax-based screen printing were used to produce\nultracheap sensing devices (the cost of one sensor is estimated to\nbe $0.045). Also, a CdTe QDs/MWCNTs nanocomposite (CdTe-MWCNTs) was\napplied to modify the sensing interface to obtain a stronger EC signal.\nSpecifically, the newly developed double linear hybridization chain\nreaction (DL-HCR) greatly amplified the EC signal, relative to the\nconventional linear HCR. Under optimized conditions, target DNA (TD)\nsamples (75-bp DNA fragments prepared via PCR amplification) were\ndetermined in a range from 20 fM to 5 nM, with a detection limit of\n8.74 fM and relative standard deviations of 2.04% and 4.75% for intra-\nand inter-assays at 50 pM TD, respectively. Additionally, the ECDSs\nhad an acceptable storage stability and high selectivity. Importantly,\nthe ECDSs, coupled with simple enzyme digestion, could detect genomic\nDNA from Listeria monocytogenes (L. monocytogenes), and a detection limit of 0.039\nng/μL was obtained. When coupled with enzyme digestion and PCR\namplification, the ECDSs could determine L. monocytogenes in milk samples, with detection limits of approximately 1.64 ×\n10⁴ and 11 CFU/mL. These results demonstrate that the method\noffers a broad prospect for cost-effective, reliable, and highly sensitive\ngene-sensing applications.