Development of photocrosslinked methylcellulose hydrogels for soft tissue reconstruction

A variety of materials have been used as fillers for soft tissue augmentation. In this study, methylcellulose (MC), a water-soluble derivative of the polysaccharide cellulose, was modified with functional methacrylate groups and photocrosslinked to produce hydrogels for potential application in plastic and reconstructive surgery. Purified macromer (5% theoretical modification, 2.3% actual) was resuspended in 0.05 wt.% of the photoinitiator, 2-methyl-1-[4-(hydroxyethoxy)phenyl]-2-methyl-1-propanone, cast into custom molds, and exposed to long-wavelength UV light for 10 min to form gels. Photocrosslinked MC hydrogels at varying weight/volume percentages displayed equilibrium weight swelling ratios (wet weight/dry weight) and elastic moduli of 30 ± 3 to 17 ± 2 and 8.48 ± 0.25 kPa to 23.21 ± 1.55 kPa, respectively, demonstrating the formation of stable gels with tunable properties. Human dermal fibroblasts grown in the presence of MC hydrogels in vitro exhibited no significant changes in cell viability after 5 days of co-culture, indicating that the materials are non-cytotoxic. Higher weight percentage MC hydrogels (6%) implanted subcutaneously in CD-1 mice maintained their integrity and original dimensions after 80 days in vivo, eliciting a mild inflammatory response with no observed inflammatory exudate, minimal vascular infiltration and thin translucent fibrous capsule formation of approximately 50 μm in thickness. Taken together, the material and biological properties of photocrosslinked MC hydrogels suggest that they may be of use in soft tissue reconstruction.