Fabrication and integration of PDMS-glass based microfluidic with optical absorbance measurement device for coliform bacteria detection

The detection of coliform bacteria which contain the disease-causing microorganism is a useful indication for water contamination. Currently, the emerging of technology in molecular biology research and industry is in demand for portable and miniaturized system. This paper demonstrates the development and integration of microfluidic and optical absorbance measurement device for portable coliform bacteria detection. The microfluidic device was fabricated with glass and polydimethylsiloxane (PDMS) material using photolithography, replica molding (soft lithography), and oxygen plasma bonding techniques. Then, the optical absorbance measurement device for coliform bacteria detection was developed using 470 nm blue light emitting diode (LED), photo detector, ARDUINO microcontroller, liquid crystal display (LCD), and mechanical elements. The coliform bacteria suspension sample was inserted into the microfluidic device and the presence of coliform bacteria was analyzed using the developed optical absorbance measurement device. The absorbance measurement from the prototype and colony number of the coliform bacteria samples were collected and analyzed. The final analysis had indicated that the developed prototype was able to detect the coliform bacteria in suspension at the lowest detection of 17,200 CFU/ml.