Antimicrobial nano-fibrous membranes developed from electrospun polyacrylonitrile nanofibers

In this study, polyacrylonitrile (PAN) nano-fibrous membranes with fiber diameters of ∼450 nm were prepared by the technique of electrospinning; amidoxime nano-fibrous membranes were then prepared through treatment of PAN nano-fibrous membranes in hydroxylamine (NH2OH) aqueous solution. The –CN groups on the surface of PAN nanofibers reacted with NH2OH molecules and led to the formation of –C(NH2)N–OH groups, which were used for coordination of Ag+ ions. Subsequently, the coordinated Ag+ ions were converted into silver nanoparticles (AgNP) with sizes being tens of nanometers. Morphologies, structures, and antimicrobial efficacies (against Staphylococcus aureus and Escherichia coli) of the membranes of electrospun PAN (ESPAN) nanofibers, ESPAN surface functionalized with amidoxime groups (ASFPAN), ASFPAN coordinated with silver ions (ASFPAN–Ag+), and ASFPAN attached with silver nanoparticles (ASFPAN–AgNP) were investigated. The study revealed that, with treatment of ESPAN membranes in 1 M NH2OH aqueous solution for 5 min, the resulting ASFPAN membranes became antimicrobial without distinguishable morphological variations; further treatment of ASFPAN membranes in 0.1 M AgNO3 aqueous solution for 1 h and the subsequent treatment in 0.01 M KBr aqueous solution for 2 h followed by photo-decomposition made the respective membranes of ASFPAN–Ag+ and ASFPAN–AgNP highly antimicrobial, which were capable of killing the tested microorganisms in 30 min. The water permeability test indicated that these membranes possessed adequate transport properties for filtration applications. This study demonstrated a convenient and cost-effective approach to develop antimicrobial nano-fibrous membranes that are particularly useful for the filtration of water and/or air.

Research highlights▶ Antimicrobial nano-fibrous membranes were developed from electrospun polyacrylonitrile nanofibers. ▶ The combination of amidoxime functional groups with silver ions/nanoparticles into one system is an effective strategy to achieve dual and/or synergetic effects on antimicrobial efficacy. ▶ This study demonstrated a convenient and cost-effective approach to develop antimicrobial nano-fibrous membranes that would be particularly suitable for the filtration of water and/or air.