关键词: 纳米纤维素, N-异丙基丙烯酰胺, 温度响应性, 溶液-凝胶转变, 抗菌性能

Abstract:

Objective The conventional wound dressings have limitations including difficulty in conforming to irregular wound surfaces due to fixed shapes, inability to intelligently respond to wound conditions, and potential for secondary injury during dressing changes. In order to address these limitations, a multifunctional hydrogel dressing was engineered to intelligently respond to wound conditions while maintaining excellent biocompatibility, thereby enhancing the management of chronic and complex wounds.

Method Aldehyde-functionalized cellulose nanofiber (DACNF) and carboxymethyl chitosan (CMCS) were selected as matrix materials. By introducing thermosensitive polymer segments of poly(N-isopropyl-acrylamide) (PNIPAm), a composite thermosensitive hydrogel system was constructed. The multi-level structure and functional properties of this hydrogel were systematically characterized using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC).

Results This composite hydrogel exhibits a uniform and continuous three-dimensional porous structure with a pore size distribution ranging from 20 μm to 80 μm. This structure facilitates efficient transport of water, nutrients, and drug molecules. Swelling property tests revealed that the material achieved a water absorption swelling rate of 1 415.4% within 8 h, demonstrating exceptional liquid absorption capacity. This enables effective management of wound exudate, preventing local maceration while maintaining an optimally moist healing environment. Regarding antibacterial property, it exhibited over 99.9% inhibition rates against both Staphylococcus aureus and Escherichia coli, indicating significant broad-spectrum antibacterial effects on preventing wound infections. Additionally, this hydrogel demonstrated reversible thermoresponsive behavior, with a gel-to-solution transition temperature of approximately 34 ℃. At room temperature (25 ℃), it existed as a flowable solution capable of seamlessly covering irregular wound surfaces. Upon contact with skin (approximately 37 ℃), it rapidly transformed into a stable gel state within 300 s, firmly adhering to and protecting the wound. During dressing changes, localized cooling reversed it back to a sol state, enabling painless, non-invasive dressing replacement and significantly reducing patient discomfort.

Conclusion A novel hydrogel dressing with rapid thermosensitive responsiveness, high fluid absorption capacity, and potent antimicrobial properties has been successfully developed. Its outstanding biocompatibility, intelligent response characteristics, and reversible adhesion functionality demonstrate significant application potential in chronic wound care, extensive burn treatment, pressure ulcer management, and the repair of other irregular wound surfaces. This hydrogel not only overcomes multiple inherent drawbacks of conventional dressings but also provides novel material design strategies and practical foundations for developing next-generation smart wound management products.

Key words: nanocellulose, N-isopropylacrylamide, temperature responsiveness, solution-gel transition, antibacterial property