Paper based E-Coli Sensor
In this paper, we developed an affordable paper-based sensor for water quality detection that provides a visible
change in color on detecting bacteria. It is made of a nitrocellulose membrane coated with chemicals including: 1) Lysozyme
which lyses bacteria present in sample, 2) DNA probes binds with the DNA of the lysed bacteria, 3) Gold nanoparticles that
are used as a detector. The chemicals are coated on the nitrocellulose membrane using electro spinning coating method. The
binding of the DNA probes to the E. coli DNA results in the formation of complexes. These complexes cause the
aggregation of gold nanoparticles that, in turn, causes the color to change from red to blue, providing a visual indication of
bacteria being present. We then showed that combining these components with gold nanoparticles followed by exposure to
an E. coli contaminated water sample (concentrations tested—106 and 108 cells/mL) resulted in a dramatic color change.
Overall, this device represents a novel low-cost method for long term detection of bacteria in a water supply and other
Keywords - Water Quality, Electro spinning Coatings, Gold Nanoparticles, Nitrocellulose.