Abstract:

Objective In order to address the clinical challenges of increasing antibiotic resistance and the growing demand for precise antibacterial strategies in infected wound treatment, an intelligent dressing with high antibacterial efficacy and low resistance risk was developed. By integrating photothermal therapy (PTT) with controlled drug release technology, a photothermally responsive antibacterial nanofiber membrane was constructed. Near-infrared (NIR) light was utilized to trigger localized hyperthermia and synergistic drug release, achieving efficient antibacterial action while minimizing damage to healthy tissues.

Method The polyacrylonitrile-Prussian blue/lactic acid/ciprofloxacin (PAN-PB/LA/CIP) nanofiber membrane was prepared by electrospinning PAN with PB, LA, and CIP. A three-factor and three-level orthogonal experiment was adopted to optimize spinning parameters (concentration, voltage, distance). Morphology and photothermal properties were analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and thermal imaging, while drug release profiles were obtained by measuring cumulative release rates. Antibacterial activity against S.aureus and E.coli with/without NIR irradiation was tested. Cytotoxicity was assessed via CCK-8.

Results The optimum electrospinning process parameters for preparing PAN-PB/LA/CIP fiber film were determined by three-factor and three-level orthogonal experiment, which are 14% spinning solution concentration, 15 cm receiving distance and 16 kV voltage. The fiber membrane prepared under these conditions showed a uniform structure, the average fiber diameter was stable at 270 nm without obvious beading phenomenon, and good air permeability. The SEM and FT-IR characterization results revealed that the average particle size of the prepared PB nanoparticles was (137.5±24.6) nm, which was consistent with the document. FT-IR analysis confirmed that all components of PAN-PB/LA/CIP fiber membrane were successfully prepared, PB, CIP, and PAN were physically mixed with each other and LA with chemical bonding reaction, ensuring the functional stability and better quality of the material. The fiber membrane showed good photothermal synergistic antibacterial properties: under the near-infrared light irradiation of 0.5 W/cm², the fiber membrane temperature rapidly rose to 48.5 ℃ within 20 min and remained stable, which was significantly better than the pure PAN fiber membrane in the control group (the temperature rose by only 1.9 ℃), and had good photothermal activity. The photothermal conversion performance of the fiber membrane remained stable after three light cycles. When triggered by near-infrared light, the drug release behavior of the fiber membrane changed significantly, and the cumulative drug release at 24 h and 72 h reached 12.15% and 17.83%, respectively, compared to the non-light group (4.95% and 5.67%), indicating that the increase rate was more than three times, and the drug release rate was significantly accelerated and that the photothermal therapy dominated by the fiber membrane can significantly improve the therapeutic efficiency. The results of antibacterial experiment further confirmed its excellent antibacterial performance: under near-infrared light irradiation, the clearance rate of PAN-PB/LA/CIP fiber membrane against S.aureus and E.coli reached 100%. Multiple comparison results demonstrated that the incorporation of CIP significantly enhanced the antibacterial efficacy of the fiber membrane against both S.aureus and E.coli, with a statistically significant difference (P<0.05) between the NIR-irradiated group and the control group. The PAN-PB/LA/CIP nanofiber membrane, which combines photothermal and antibacterial effects, exhibited outstanding antibacterial performance under NIR irradiation. Moreover, cytotoxicity assessment (cell viability > 90%) confirmed its excellent biocompatibility.

Conclusion A photothermally responsive PAN-PB/LA/CIP composite antibacterial dressing was successfully developed, which achieves synergistic antibacterial action through localized hyperthermia and controlled drug release. Optimized spinning parameters ensured structural stability and air permeability. NIR-triggered heating (48.5 ℃) combined with rapid drug release significantly enhanced antibacterial efficiency (100% clearance) while avoiding thermal damage to tissues. The dressing demonstrates potential for constructing antibacterial microenvironments in infected wounds, providing a foundation for self-adaptive wound treatment systems.In the future, it is necessary to further optimize the ratio of materials, explore in vivo experiments and long-term biocompatibility, and promote its clinical development.

Key words: antibacterial dressing, photothermal response, electrospinning, phase change material, drug controlled release, nanofiber membrane, smart dressing