Abstract
Ecotoxicity of PSL nanoparticles with various functional groups to Escherichia coli KP7600 strain was investigated using Colony Count method. As a result, it was found that the only positively-charged PSL nanoparticles lead to expression of the death of bacterial cells. The confocal observation of the bacterial cells after 1 h of exposure to the positively-charged PSL nanoparticles with amino acid groups dispersed in the NaCl aqueous solution showed that the surface of dead cells were almost entirely covered with the nanoparticles. In addition, the uptake of nanoparticles inside the bacterial cells was not observed regardless of the cell viability. It was supposed that the adhesion of positively-charged nanoparticles onto the surface of bacterial cells due to the electrostatic attractive force causes a decrease in the liquidity of the cell membrane, and the inhibition of metabolism through the cell membrane lead to the death of bacterial cells.
