Rapid Detection for Salmonella typhimurium by Conventional Resistive Temperature Sensor Based on Photothermal Effect of Carboxylated Graphene Oxide

Photothermal effect of nanomaterial has been applied to the establishment of rapid detection method such as test strip. Previously, the detector for the photothermal test strip method mainly was a bulky thermal imaging camera or an infrared-sensing temperature sensor of which the detection data obtained is unstable due to its susceptibility to environmental changes. Herein, a resistive temperature sensor which is more stable and less susceptible to external environment was adopted. A test strip was used to detect Salmonella enterica Typhimurium ( Salmonella typhimurium ). The carboxylated graphene oxides (GOs), which have a more excellent photothermal effect, labeled with anti- Salmonella typhimurium antibodies, were used as a nanomarker to produce thermal signal. Subsequently, temperature variation signal (ΔT) generated by carboxylated GOs exposed to 808 nm laser was detected by conventional resistive temperature sensor directly. Under optimal conditions, a standard curve of ΔT with respect to the different numbers of Salmonella typhimurium was established, the detection limit was 10 4 CFU·mL -1 and the detection time was 20 min. The proposed detection method with high sensitivity, specificity, and efficiency can be used as a novel and on-site screening technology to detect Salmonella typhimurium in food, environmental, or clinical samples.