Chemical Sciences

The technology offers rapid and sensitive colorimetric detection of pathogens in water based onmetal nanoparticle-enzyme interaction.The intensity of color development depends upon the amount of bacterial contamination present in water sample. This novel field-friendly innovation provides instant visible color change seen via naked-eye with a sensitivity of 103 cells.mL-1. The technique involves a polymer or bioreceptor coated silver nanoparticles combining catalytic activity of an enzyme that produces a colored end-point readout signal. The salient feature of the bioassay includes the co-presence of enzyme inhibitor and bioreceptor simultaneously on the surface of nanoparticles. If water is contaminated, the nanobioprobe gets entangled with microbe and enzyme is rendered free in solution consequently its catalytic activity produces pink color. On the other hand if water is microbe-free, the nanobioprobe inhibits the activity of enzyme producing yellow color. The dual activity of nanobioprobe has been demonstrated by three versions of the bioassay that are reproducible and are IPR protected.