Detecting and differentiating escherichia coli strain TOP10 using optical crystals

Abstract

We report a method for detecting Escherichia coli using a nematic liquid crystal (LC), 4-cyano-4′-pentylbiphenyl (5CB). Among three E. coli strains tested, TOP10 strain grown on agar plates induces a homeotropic orientation of LCs whereas DH5a and JM109 strains do not. This results in a clear distinction in the optical appearance of LCs as either uniformly dark or bright under polarised light. The LC-based method provides a simple, rapid and low-cost method of identifying E. coli strains. © 2010 Taylor & Francis.