Hyperbranched polymer nanofibrous membrane grafted with silver nanoparticles for dual antifouling and antibacterial properties against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa

摘要

In this study, a series of Ag-loaded hyperbranched polyethyleneimine/polyethersulfone (HPEI/PES) nanofibrous membranes were prepared via electrospinning. Hyperbranched polyethyleneimine was used as a dispersant and capping agent by the chelation of Ag ions by its internal imine groups and due to its highly branched structure. The nanofibrous membranes were characterised using scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), pure water flux and contact angle measurements. The SEM images revealed smooth, dense and uniform nanofibres with average diameters ranging from 107.8 +/- 46.2 to 145.9 +/- 49.9 nm. Spherical AgNPs with an average diameter of 6.4 +/- 2.3 nm were observed. Characterisation using XRD coupled with selected area electron diffraction (SAED) confirmed that the AgNPs were crystalline with a peak corresponding to the (111) crystal lattice. The modified nanofibrous membranes displayed a high pure water flux of up to 630.14 +/- 10.25 L/m(2).h. The modified nanofibrous membranes displayed excellent antibacterial properties against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa achieving an inhibition of growth rate (I-R) >= 99%. It was also found that the modified nanofibrous membranes prevented the attachment and colonisation of the three bacterial species. The antifouling characteristics of the nanofibrous membranes were assessed by filtration of bovine serum albumin (BSA), a model foulant. An increased flux recovery ratio for the modified nanofibrous membranes (68.43-86.71%) was observed as compared to that of the pristine PES membrane (51.8%), showing that fouling resistance and bacterial growth inhibition could be improved simultaneously by integrating antifouling and antibacterial properties.