Constructing antibacterial surfaces with alkali treatment on polyethylene terephthalate nanofibers

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.

Automated summary

Polyethylene terephthalate (PET) with its negatively charged surface repels bacteria but lacks direct antibacterial activity. Alkali-treated PET nanofibers, also negatively charged due to carboxyl groups, surprisingly exhibit remarkable antibacterial properties (89% and 75% antibacterial rate against S.aureus and E.coli, respectively). The increased carboxyl groups on the fiber surface induced by alkali-treatment attract positively charged cetyltrimethylammonium ions (CTA+), which can efficiently inactivate the bacteria by forming stable electrical double layers (EDL). An effective heavy-metal free antibacterial fiber has been developed by loading iron-phthalocyanine to the nanofibers, which can inactivate bacteria under dark conditions by utilizing surface CTA+ and weak reactive oxygen species.