Cellulose Hydrogels Derived from Pineapple Bagasse for Potential Dental Applications: Chlorhexidine-Loaded Hydrogels with Antibacterial and Cytocompatible Properties

Pineapple fibers were used as a sustainable raw material to isolate native cellulose from alkaline–acid treatment. The cellulose fibers were regenerated into transparent and flexible cellulose hydrogels using the lithium chloride/N,N-dimethylacetamide (LiCl/DMAc) solvent system, followed by a phase-inversion process of the cellulose solution under ethanol vapor. Chlorhexidine was incorporated into the hydrogels to provide antibacterial properties. The concentration of chlorhexidine ranged from 0.1 to 0.8 wt%. The prepared hydrogels showed better early onset cytocompatibility than the cell culture dish used as a control. For the evaluation of antibacterial properties, strains of <i>Streptococcus mutans</i>, <i>Streptococcus sanguis</i>, and <i>Streptococcus anginosus</i> were used. The results indicated antibacterial activity at all chlorhexidine concentrations tested, with the area of bacterial inhibition increasing with increasing bactericidal content in the hydrogel films. Adding bactericide into cellulose films did not compromise their early onset cytocompatibility in the first 72 h. The study suggests that adding chlorhexidine provides the hydrogel films with antibacterial properties, potentially expanding their applications in dentistry.