Design, Characterization, and Electrospinning of Hyaluronic Acid Bioconjugated for Biomedical Applications

Hyaluronic acid (HA) is a naturally occurring polysaccharide widely used in biomedical applications due to its excellent biocompatibility and its key biological role in tissue regeneration and wound healing. However, its high hydrophilicity, limited mechanical stability, and poor processability represent major challenges for its processing by electrospinning for the fabrication of nanofibrous scaffolds. Therefore, chemical modification presents an effective strategy to tailor the physicochemical properties of HA while preserving its biological relevance. In this thesis, a systematic and modular chemical approach for the functionalization of hyaluronic acid was developed using carbodiimide-mediated coupling. Structurally diverse amino acids and bioactive peptide motifs were covalently introduced along the HA backbone under mild aqueous conditions. The resulting HA bioconjugates were characterized by NMR and ATR-FTIR spectroscopy, confirming successful bioconjugation while preserving the integrity of the polysaccharide backbone, with a substitution degree depending on both the molecular structure of the substituents and the conjugation strategy. Selected HA derivatives were subsequently processed into nanofibrous scaffolds by electrospinning. To overcome the intrinsic limitations of HA processability, polyvinylpyrrolidone was employed in combination with HA, and both single-layer and asymmetric bilayer architectures were developed by combining hydrophilic HA-based layers with a poly(D,L-lactic acid) support. The resulting scaffolds exhibited continuous fibrous morphologies and tunable surface properties. Scaffold surface properties were investigated by contact angle measurements, which demonstrated that surface wettability was governed by scaffold architecture and surface chemistry. Raman spectroscopy, supported by multivariate analysis, enabled the discrimination between non- functionalized and functionalized HA-based systems. Importantly, UV sterilization was shown to be effective without inducing detectable chemical modifications. Preliminary biological evaluation highlighted the influence of surface hydration and stability on cell–material interactions, underscoring the need to balance bioactivity and structural robustness. Overall, this work provides a versatile platform for the controlled chemical modification of hyaluronic acid and its integration into electrospun scaffold systems, offering design principles for the development of HA-based biomaterials for wound-healing applications.