Detection of pathogenic microorganisms using biosensor based on multi-walled carbon nanotubes dispersed in DNA solution

► Multi-walled carbon nanotubes was directly dispersed in DNA solution. ► DNA sensor used to detect Escherichia coli O157:H7 bacteria. ► Detection limit as low as 1 nM. ► The sensitivity of the DNA sensor reached approximately 0.19 nM/mV. ► The DNA sensor can respond well to 120 min of sonication time, a pH value of 9, and 20 μM of DNA sequence concentration.