SYNTHESIS OF POLYVINYL ALCOHOL POLYETHYLENE GLYCOL HYDROGEL REINFORCED WITH NANOCELLULOSE FROM EMPTY FRUIT BUNCH

Abstract

Hydrogel's advantageous traits have led to increasing interest, indicating its promising potential as a wound dressing. Due to their biocompatibility, substantial water content, and customizable structural properties, hydrogels are an excellent choice for enhancing wound healing. This study successfully created a wound dressing hydrogel by combining polyvinyl alcohol (PVA) and polyethylene glycol (PEG) with glycerin, strengthening it with cellulose nanofibers (CNFs), and infusing it with lemongrass essential oil (LG) through the freeze-thaw process. Modifying the composition or adding materials can address drawbacks of PVA-based hydrogels such as susceptibility to mechanical deformation, rapid water loss leading to dehydration, and absence of antibacterial capabilities. Improving the hydrogel's characteristics, like flexibility and water retention capacity, was achieved by blending PEG and glycerin within the polymeric structure of the PVA hydrogel. The optimization study via the central composite design (CCD) approach identified the ideal concentrations of glycerin and PEG, in conjunction with the response surface methodology (RSM), to maximize moisture retention capability (MRC) in the hydrogel. With 4% (w/v) glycerin and 6% (w/v) PEG concentrations, the PVA-PEG/gly hydrogel achieved an optimal MRC of 46.82 ± 0.54%, a porosity of 42.17 ± 0.94%, a swelling capacity of 143.24 ± 1.66%, and a gel fraction of 58.06 ± 1.65%. Furthermore, cellulose nanofibers (CNFs) served as effective reinforcing agents by integrating with PVA-based hydrogels, contributing to improved mechanical strength, stability, and overall efficiency by enhancing the hydrogels' structure. Through the deep eutectic solvent (DES) technique, CNFs were isolated from empty fruit bunches (EFB) in conjunction with the ultrasonication technique. The influence of DES processing parameters—reaction time (60-120 min), extraction temperature (70-90°C), and molar ratio (HBA: HBD of 1:1-1:3)—on CNF yield was assessed using the CCD approach within the RSM. After a 90-minute reaction, a maximum CNF yield of 69.00 ± 2.57% was attained at 90°C, using a DES (HBA: HBD) molar ratio of 1:2. The CNFs obtained showed a crystallinity of 80.5% and had a nano-scale size, with an average diameter of 24.10 ± 3.20 nm. Besides integrating CNFs to enhance mechanical strength, the inclusion of lemongrass essential oil (LG) into the PVA-PEG/gly hydrogel boosts its inherent antibacterial properties. Different concentrations of lemongrass essential oil (LG) and cellulose nanofibers (CNF) were tested on the PVA-PEG/gly-CNF-LG hydrogel in another optimization study to assess their influence on the hydrogel's moisture retention capability (MRC) characteristic. The peak MRC of 37.82 ± 0.54% was achieved by the composition with 3% (v/v) LG and 3.5% (w/v) CNF. The PVA-PEG/gly-CNF-LG hydrogel displayed notable features: 47.51 ± 0.53% porosity, 176.89 ± 1.56% swelling capacity, 1.44 MPa tensile strength, and 78.89 ± 0.42% gel fraction. Furthermore, it exhibited robust antibacterial activity, as indicated by the presence of distinct zones of inhibition when tested on Bacillus subtilis and Staphylococcus aureus. The formulated PVA-PEG/gly-CNF-LG hydrogel demonstrated exceptional physical, mechanical, and antibacterial characteristics, rendering it suitable for wound dressing applications.