- We have fabricated a surface enhanced Raman spectroscopy (SERS) based nanobiosensor for very specific detection of E. coli up to the concentration levels of single bacterium. The sensor was fabricated on nanosculptured thin films (nSTFs) of Ag over Si substrate. The height, porosity and other features of the nSTF were optimized for the maximum enhancement in our previous studies [1, 2]. T4- bacteriophages were immobilized on the surface of the nSTF by using 4-aminothiophenol (4-ATP) and glutaraldehyde as a cross-linker. Further, the sensor chip was incubated in bovine serum albumin solution to block the sites available for nonspecific binding. The sample solutions of varying concentrations of two strains of E. coli (RFM443 (E. coli B) and XLMRF (E. coli μX)] and 3 other gram negative bacteria C. violaceum (CV026), P. dentrificans and P. aeruginosa were prepared for the characterization of the sensor probe. The bacteria other than E. coli B were used for control experiments to demonstrate the specificity of the sensor.