Metal-organic framework- and graphene quantum dot-incorporated nanofibers as dual stimuli-responsive platforms for day/night antibacterial bio-protection

Development of advanced antibacterial nanomaterials is important to prevent pathogenic microbial contami-nation and achieve bioprotection. Herein, we developed dual-stimuli-responsive nanoplatforms with efficient antibacterial activity based on electrospun polycaprolactone/hydroxypropyltrimethylammonium chloride chi-tosan (PQ) nanofiber membranes (NFMs) incorporated with naringenin-loaded zeolitic imidazolate framework-8 (NAR@ZIF-8) and graphene quantum dots (GQDs). These NFM nanoplatforms could simultaneously be used as smart pH-responsive controlled-release and photocatalytic systems. NAR was encapsulated in the microporous structure of the ZIF-8 channel, with a loading capacity of 22.57%. NAR@ZIF-8-and GQD-incorporated PQ (PQZG) nanofibers exhibited enhanced thermal stability and mechanical properties. The release kinetics and microstructure of the nanocarriers demonstrated that the acid-sensitive cleavable crystal structure of ZIF-8 resulted in the pH-responsive release of NAR from PQZG NFMs. Moreover, the presence of GQDs significantly enhanced the photoinduced reactive oxygen species (ROS) generation by NFMs. pH-triggered NAR release and photoinduced ROS generation improved the antibacterial efficacy of PQZG NFMs, forming the synergetic chemical-photodynamic strategies of the dual stimuli-responsive nanoplatforms. Additionally, cytotoxicity ex-periments revealed that the PQZG NFMs were non-toxic and had good biocompatibility. Therefore, the designed composite nanomaterials combined with the two antibacterial strategies can aid in the development of biosafe nanofibrous membranes for antibacterial or multifunctional bio-protection.

Automated summary

In this study, we developed a smart nanoplatform that is responsive to pH and light, using nanofiber membrane structure incorporated with PQ, ZIF-8, and GQDs to achieve efficient antibacterial activity. The synergistic effect of NAR and photoinduced ROS improved the antibacterial efficacy of the nanofiber membranes, which also showed non-toxicity and good biocompatibility.