Elucidation of Cell Killing Mechanism by Comparative Analysis of Photoreactions on Different Types of Bacteria

作者：Swetha S; Singh Maheshwari Kumari; Minchitha K U; Balakrishna R Geetha^*

来源：Photochemistry and Photobiology, 2012, 88(2): 414-422.

DOI：10.1111/j.1751-1097.2011.01057.x

The mechanism of biocidal action of nano titania on Escherichia coli and Staphylococcus aureus has been evaluated by various biochemical techniques like lipid peroxidation, hydrolysis of orthonitrophenol beta-d-galactopyranoside, estimation of proteinamino acid and bacterial nucleic acids leakage into solution, in addition to morphology studies by electron microscopy (TEM and SEM) and K+ ion leakage by inductively coupled plasma optical emission spectrometry. The active anatase phase of nano titania has been synthesized by sol-gel and pulverization techniques to obtain particle sizes averaging around 11 nm. The nano semiconductor with a bandgap of 3.2 eV responds well to the UV source to liberate reactive oxygen species (ROS). Gram negative bacteria easily succumb to the ROS at a faster rate than gram-positive bacteria with an observable difference in the mode of attack. The use of analytical techniques revealed the release of peroxidized lipid (26 nmol mL-1) and protein content (370 mu g mL-1) with a K+ ion concentration of 22 000 ppb on complete destruction of E. coli.

• 出版日期2012-4