Development of ultrasensitive and selective MoS2/SWCNT/au modified electrochemical DNA biosensor for Salmonella detection

Salmonella is a gram-negative bacterium responsible for food contamination, threatening public health. It has the potential to contaminate not only food but also water and soil. Since poultry is a particularly at-risk group, bacteria can potentially cause a global food crisis by disrupting food supply and logistics. Since total prevention of bacterial contamination is not possible, the detection process emerges as a vital process. However, established "gold standard" techniques require expensive tools and trained personnel to perform the procedures. In this study, Salmonella bacterial DNA in contaminated water samples, such as physiological saline was detected by utilizing the MoS2/SWCNT modified and gold electrodeposited biosensor platform. Thiol-functionalized and methylene blue-tethered DNA capture probes specifically designed for Salmonella bacterial DNA were used as the bio-recognition element. The biosensor was subjected to sensitivity and selectivity tests and used for the detection of genomic DNA of Salmonella. The MoS2/SWCNT modified biosensor reached a limit of detection of 0.262 aM and a limit of quantification of 0.861 aM for reference DNA sequences while differentiating 2-base and 4-base mismatch DNA sequences from the complementary DNA sequences and detecting up to 10 fg/mu L (1.81 copy/mu L) with a limit of detection 1.14 fg/mu L for genomic DNA.