A Novel Device and Method for Assay of Bacterial Chemotaxis Towards Chemoattractants

Capillary assemblies and microfluidic devices used for bacterial chemotaxis assays have certain inherent limitations. This opens opportunities for innovation in the area. The present study describes an innovative economical device called chemotaxis plate and also a method to use this device for chemotaxis assay. Two type cultures, Pseudomonas putida MCC 2989 and Bacillus subtilis MCC 2049, chemotactic to L-aspartate, were used to validate the new device and establish the protocol for assay. 100 to 1000 fold higher number of cells were recovered in presence of chemoattractant as compared to control (p < 0.05). This novel assay technique showed 100% sensitivity and 99.21% specificity for chemotaxis assay of Pseudomonas putida MCC 2989 towards 3 mM L-aspartate over 50 min assay time. The device was also used to isolate bacteria chemotactic to caffeine directly from environmental samples. Very high chemotaxis response indices were reported for the first-time using chemotaxis plate.