(542f) Salt Effects on Synthetic Cationic Antimicrobial Polymer-Cell Interactions
AIChE Annual Meeting
2024
2024 AIChE Annual Meeting
Materials Engineering and Sciences Division
Charged and Ion-Containing Polymers III: Membranes and Other Applications
Wednesday, October 30, 2024 - 1:45pm to 2:00pm
Polymer adsorption onto cells were studied with a fluorescently tagged polyelectrolyte, polydiallyldimethyl ammonium chloride (PDADMAC). Adsorption of the polymer onto bacterial cells (E. coli, S. aureus, and P. aeruginosa) was observed in a parallel-plate flow chamber via fluorescence microscopy. The polymer was flowed over cells adhered to the flow chamber window along with SYTOX blue, a stain indicating cell permeabilization, which is often correlated with cell death. Time-lapse video was analyzed to measure the adsorption of PDADMAC and the permeability for each cell.
Both PDADMAC antimicrobial activity and adsorption decreased with increasing NaCl concentration, as well as adsorption capacity. Above 0.15 M NaCl, PDADMAC adsorbed, but did not kill the cells but it did prevent further growth, essentially acting as a bacteriostat. When PDADMAC was washed from the cell surface, the cells resumed growth, showing that the bacteriostatic effect is reversible under certain conditions. When PDADAMAC coverage on the cell was too high, cells undergo a morphological change where they shrink, and cannot regrow even when PDADMAC is removed. These morphological changes are absent when the NaCl concentration is high.