Imaging of bacteria using chromonic liquid crystals

ABSTRACT

We explored adsorption isotherms of Escherichia coli (E.coli) and Salmonella over the poly-L-lysine (PLL) coated glass surface. The detection of the adsorbed bacteria was explored using 14 wt% di-sodium-chromo-glycate (DSCG) solution in water and 5CB. The textures of the optical cells made up of LCs and the adsorbed bacteria over PLL-coated glass substrate were obtained by using a polarized microscope in the transmission mode under crossed polars. We found that DSCG solution exhibits a dark spot on the adsorbed E.coli and Salmonella. In contrast to DSCG solution, 5CB did not show any dark spot.

Keywords:

• DSCG
• E. coli
• Lyotropic liquid crystal
• Polarized microscopy
• Salmonella
• Thermotropic liquid crystal

Acknowledgment

Authors would like to thank Professor V. Perumal of School of Biological Science, Indian Institute of Technology Delhi for providing bacteria used for these studies.