Carbon nanotube-assisted capturing of bacterial pathogens

Abstract

This study explored the use of co-polymer poly(propionylethyleneimine-co-ethyleneimine (PPEI-EI) functionalized multi-walled carbon nanotubes (MWNTs) as a coating material on filters for capturing of bacterial pathogens from aqueous solutions. Polycarbonate membranes with pore sizes of 1.2 and 3.0 μm were coated with different PPEI-EI-MWNTs and cross-linked PPEI-EI-MWNTs samples at various coating densities, and then evaluated for capturing of E. coli cells at flow rates of 0.25 and 0.5 mL min⁻¹. With a good combination of PPEI-EI-MWNTs sample, coating density, appropriate filter pore size and flow rate, a capture efficiency of higher than 4 log (up to 6 log or larger) of bacterial cells was achieved. The filters coated with the cross-linked PPEI-EI-MWNTs were unexpectedly less efficient than those with the other PPEI-EI-MWNTs samples, likely due to the poorer dispersibility of the cross-linked sample and consequently the less homogeneous coating on filters. The results of this study demonstrated the feasibility of PPEI-EI-MWNTs as a coating material on filters for highly effective capturing of bacterial pathogens, and also presented both challenges and opportunities for further investigations in controlling the coating material synthesis to improve performance in capturing bacterial cells.