Aramid Nanofiber/Gelatin Composite Hydrogels With Strengthened Nodal Connectivity Revealed by Graph Theory

Hydrogels derived from biomacromolecules offer excellent biocompatibility for biomedical applications, yet their limited mechanical strength often restricts broader use. Aramid nanofibers (ANFs) have emerged as high-performance building blocks for nanocomposites, but the influence of their surface states on nodal connectivity and reinforcement efficiency remains insufficiently understood. In this work, we utilize ANFs as a fibrous scaffold to construct composite hydrogels with gelatin. Gelatin coats ANF surfaces through interfacial hydrogen bonding, promoting inter-fiber connections, as confirmed by graph-theoretical analysis of average nodal connectivity. The resulting composite hydrogels can be further cross-linked with tannic acid to form a hierarchical network with markedly enhanced strength and modulus. The incorporation of tannic acid also enables in situ formation of monodisperse silver nanoparticles, imparting antimicrobial functionality. Moreover, the hydrogels exhibit sustained tannic-acid release while maintaining mechanical integrity. This synergistic integration of synthetic ANFs with natural biomolecules provides a robust platform for developing multifunctional hydrogels for biomedical applications. Highlights Exceptional mechanical performance due to strengthened fibrous network. Surface-controlled connectivity elucidated through graph theory analysis. Multifunctionality with strong potential for biomedical applications.