Physicochemical and biomedical evaluation of bisabolol oil-loaded polysaccharide- based hydrogel systems

Abstract

The complex biological process of wound healing is frequently interfered with by infection, dehydration, and restricted cell proliferation. Biocompatibility, infection control, andawet environment are all necessary. Natural biopolymers with the capacity to formsignificant stablehydrogel matrices are chitosan (CS) and cellulose nanofibers (CNF), which are recognizedfor their biocompatibility and biodegradability. Strong anti-inflammatory and antibacterial properties have been discovered for α-bisabolol (BIS), a naturally occurring sesquiterpenealcohol. This enables it as a promising option for wound treatment. This study investigates theeffect of adding varying proportions of α-bisabolol oil in a chitosan/cellulose nanofiber-basedhydrogel precursor and its hydrogel form. Rheological properties were measured in CS/CNF- bisabolol oil suspensions in the liquid state, prior to gelation, to investigate oil incorporationeffects on flow behavior and network interactions. Rheological tests revealed that all formulations exhibited shear-thinning, non-Newtonian behavior, with viscoelastic gel-likecharacteristics. α-Bisabolol-enriched chitosan/cellulose nanofiber hybrid hydrogels wereformulated using the freeze-casting method. Varying concentrations of α-bisabolol oil wereincorporated, which were stabilized by Tween 80. The surface morphology was examinedusingscanning electron microscopy. Raman spectroscopy confirmed the structural and chemical interactions in the hydrogels. A moisture retention test revealed that bisabolol-enrichedhydrogels retained up to 97% of their hydration and could absorb water up to 10 times their original weight. The optimal water vapor transition rate was obtained at B1 (0.1 mLbisabolol) with a value of 68.9 g/m²·h. The in vitro degradation test showed the best degradationrateof 31% at B3 (0.3 mL bisabolol) after 21 days. The formulated hydrogels showed inhibitoryzones, and the largest inhibitory zones were found at B2 (0.2 mL bisabolol) (10.1 mm) against S. aureus and B3 (0.3 mL bisabolol) (10.5 mm) against P. aeruginosa. The ChorioallantoicMembrane (CAM) experiment verified the formulations' angiogenic and biocompatiblepotentials, showing increased vascularization without any signs of embryotoxicity across a14- day incubation period. These results imply that CS/CNF hydrogels with α-bisabolol oil arepromising candidates for wound dressings, which can promote skin tissue regeneration.