Synthesis and biological applications of nanocomposite hydrogels based on the methacrylation of hydroxypropyl methylcellulose and lignin loaded with alpha-pinene.

Oral conditions, such as recurrent aphthous stomatitis, are chronic inflammatory disorders that significantly affect the life quality. This study aims to develop a novel buccal mucoadhesive based on methacrylate hydroxypropyl methylcellulose (M-HPMC) and methacrylate lignin (M-SLS) encapsulated with nanostructured lipid carriers (NLCs) for controlled release of alpha-pinene (α-pinene). NLCs with particle sizes of 152 ± 3 nm were prepared by using stearic acid and oleic acid as solid and liquid lipids, respectively. Following the successful synthesis of M-HPMC and M-SLS, various concentrations of α-pinene loaded NLCs (0, 18, 38, and 50 wt%) were encapsulated in M-HPMC/M-SLS hydrogel. It was demonstrated that the physiological and mechanical performances of hydrogels were changed, depending on the NLC content. Remarkably, the incorporation of 18 wt% NLC improved the compressive strength (143 ± 14 kPa) and toughness (17 ± 1 kJ/m) of M-HPMC/M-SLS hydrogel. This nanocomposite hydrogel considerably decreased dissipated energy from 1.64 kJ/m to 0.99 kJ/m, after a five-cycle compression test. The nanocomposite hydrogel exhibited controlled α-pinene release for up to 96 h which could significantly improve the antioxidant activity of M-HPMC/M-SLS matrix. Moreover, the reinforcing M-HPMC/M-SLS hydrogel with α-pinene-loaded NLCs resulted in increased adhesive strength (113.5 ± 7.5 kPa) to bovine buccal mucosa and cytocompatibility in contact with fibroblasts.