关键词: 纳米纤维素, 季铵化改性, 聚乙烯醇, 气凝胶, 伤口敷料

Abstract:

Objective The primary objective of this research was to conceptualize, design, and fabricate a novel antibacterial wound dressing engineered to integrate multiple critical functionalities essential for modern wound management. These include superior exudate absorption, adequate air and moisture vapor permeability (breathability), significant mechanical durability under stress, and sustained, broad-spectrum antimicrobial efficacy. Driven by the escalating challenges of wound infections and the limitations of conventional passive dressings, this work addresses the pressing clinical demand for intelligent, multifunctional biomaterials that can actively combat microbial colonization while concurrently fostering a moist, protective, and pro-healing environment. To achieve this, the study specifically investigates the development and characterization of a lightweight, elastic composite aerogel. This advanced material is synthesized through the synergistic combination of cationically modified nanofibrillated cellulose (EP-CNF), which provides inherent antimicrobial activity and structural reinforcement, with poly(vinyl alcohol) (PVA), contributing to enhanced flexibility and gel-forming properties. The innovative fabrication process yields a three-dimensional network structure characterized by ultra-high porosity, interconnecting pores, and remarkable flexibility. This unique architecture is fundamentally designed to not only manage wound fluids effectively and allow gaseous exchange but also to serve as a protective barrier and a potential carrier for therapeutic agents. Consequently, the developed EP-CNF/PVA composite aerogel demonstrates exceptional potential as a high-performance, multifunctional platform for next-generation advanced wound care applications.

Method In this study, nanofibrillated cellulose (CNF) was first subjected to cationic modification using 2,3-epoxypropyltrimethylammonium chloride (EPTMAC) to graft quaternary ammonium groups onto its polymeric chains, yielding cationically functionalized CNF (designated as EP-CNF). Subsequently, EP-CNF was blended with poly(vinyl alcohol) (PVA) at systematically varied volume ratios through a solution-based mixing process to achieve homogeneous dispersion and interfacial integration between the two components. The resulting mixtures were then processed using a unidirectional freezing technique, followed by freeze-drying, to fabricate lightweight and hierarchical porous EP-CNF/PVA composite aerogels. The three-dimensional network structure, formed under controlled freezing conditions, endowed the aerogels with aligned porosity and structural integrity. The aerogels were comprehensively characterized in terms of their microstructure, physical properties, liquid absorption capacity, air permeability, mechanical performance under compressive stress, and antibacterial activity against common wound pathogens. Special emphasis was placed on understanding how the volume ratio of EP-CNF to PVA influenced the material's functional performance, thereby evaluating their suitability as advanced wound dressing materials with tunable properties.

Results The composite aerogels exhibited an interconnected three-dimensional porous network structure. The sample with an EP-CNF to PVA mass ratio of 5∶5 showed optimal comprehensive performance, with a porosity of 90.17%, water absorption capacity of 991.15% of its own weight, water vapor transmission rate of 2 337.21 g/(m²·d), and compressive stiffness of 97.45 kPa. These properties indicate excellent liquid uptake, moisture permeability, and mechanical resilience suitable for wound dressing applications. Moreover, the material demonstrated significant antibacterial activity against both Staphylococcus aureus and Escherichia coli, with inhibition rates of 99.53% and 88.54%, respectively.

Conclusion The EP-CNF/PVA composite aerogel developed in this study successfully integrates several critical wound-dressing properties—including high porosity, outstanding liquid absorption capacity, favorable breathability, mechanical robustness, and efficient antibacterial performance—into a single, lightweight material system. Structural and functional analyses confirm that the cationic modification of cellulose via quaternary ammonium groups plays a decisive role in imparting strong and sustained antimicrobial activity against both Gram-positive and Gram-negative bacteria. Concurrently, the directional freezing process effectively creates an aligned, hierarchical pore structure, which not only enhances mechanical resilience under compression but also facilitates rapid fluid uptake and uniform vapor transmission, thereby maintaining a moist yet breathable wound microenvironment. The synergistic combination of these engineered features positions this aerogel as a highly promising candidate for advanced wound care applications. To translate this potential into clinically viable solutions, further comprehensive investigations are essential. Future work should systematically evaluate in vivo biocompatibility, biodegradation behavior, and the material's direct influence on wound healing dynamics, such as epithelial regeneration and inflammatory response.

Key words: nanocellulose, quaternization modification, poly(vinyl alcohol), aerogel, wound dressing