Microspot with integrated wells (MSIW) for the detection of E. coli

There is an increasing problem in getting quality water for developing countries. Water system is contaminated and without proper treatment, it has been consumed as drinking water. It is a big problem for health. Escherichia coli (E.coli) is the main cause for the contamination of water and illness in people. Early detection of E.coli presence in the drinking water followed by subsequent treatment for elimination of E.coli can solve this problem. The present work developed a new method for detecting E.coli in contaminated water using microspot with integrated wells (MSIW). The method involves the fabrication of MSIW, coating the MSIW with enzyme substrates such as 4-MUG substrate (4-Methylumbelliferyl-b-D-glucuronide, trihydrate) and Red-Gal substrate(6-Chloro-3-indolyl-β-D-galactoside) in proper medium and dispensing the contaminated water into MSIW. GlucuronidaseA (gusA) gene in E.coli encodes the beta-D-Glucuronidase (GUS) to hydrolyze the substrate 4-MUG enzymatically which leads to the generation of the fluorigenic compound 4-MU. β-galactosidase enzyme in E.coli produces red color when it reacts with Red-Gal substrate. Using portable optical readers, average color/fluorescence intensity emitting by MSIW is measured and quantified. Comparing obtained intensity values with calibrated intensity values, the level of contamination can be predicted for early warnings.