Nanotechnology-based biosensor for the detection of harmful pathogens in potable water

We report and discuss our first efforts devoted to realizing an innovative and miniaturized nanotechnology-based biosensor capable of real-time detect and quantify the presence of harmful pathogens dispersed in potable water. Gold nanorods, selected for their colorimetric sensitivity to the refractive index change, are functionalized, via the electrostatic linking method, with anti-Escherichia coli (E.coli) antibody. Selective recognition experiments are performed by utilizing a physiological solution containing different E.coli concentrations, thus exploiting the interaction between E.coli surface antigens and the anti-E.coli antibody. The system is characterized in terms of morphological, optical, and spectroscopic properties. Results reveal an excellent capability to discriminate small changes in the E.coli concentration in a range from 10 to 102 CFU/mL.