Development of chemiresistive sensor made of carbon nanotube to detect E. coli

Abstract

Rapid detection of bacteria is crucial to control the increasing number of outbreaks and food recalls. The current detection method relies on a lab based bacterial culture that takes several hours to few days to test the samples. Here, we demonstrate a facile and rapid fabrication of a chemiresistive sensor using multiwalled carbon nanotubes (MWCNTs) for detecting E. coli bacteria. MWCNTs functionalized with magnetic nanoparticles, act as the transduction element and magnetically assisted printing is used to obtain a thin conducting strip. The sensing strip is functionalized with specific antibodies for target bacteria. E. coli K12 is chosen as the target bacteria and Bacillus subtilis as the negative control. Specific binding between antibody and bacteria is investigated by measuring the change in the resistance of the strip. The change in resistance is proportional to the increasing concentration of bacteria present in the sample. A response time of ~ 2 minutes can be attributed to the sensor. The detection limit with whole cell is in the range of 105 cells/ml, whereas with the cell lysates, the limit of detection improves to 103 cells/ml.