Constructing antibacterial surfaces with alkali treatment on polyethylene terephthalate nanofibers

Abstract

Polyethylene terephthalate (PET) can prevent bacteria from adhesion by repelling the bacteria with its negatively charged surface. However, it is commonly believed that it does not have the ability to directly inactivate bacteria. Surprisingly, we have found that alkali-treated PET nanofibers, which are also negatively charged due to the carboxyl end groups, can have remarkable antibacterial properties (antibacterial rate (AR) at 89% and 75%, against S.aureus and E.coli, respectively). We find that alkali-treatment has brought increased carboxyl end groups to the surface, making the surface more negatively charged. The positively charged cetyltrimethylammonium ions (CTA+) that are used as catalysts for the alkali-treatment can form stable electrical double layers (EDL) with the carboxyl groups near the fiber surfaces, and the enriched CTA+ in EDL can efficiently inactivate the bacteria. Based on these, an effective heavy-metal free antibacterial fiber has been developed by loading iron-phthalocyanine to the nanofibers. This phthalocyanine-empowered antibacterial fiber can inactivate bacteria under dark conditions (99% AR) by the surface CTA+ and the generated weak reactive oxygen species.