Injectable redox-polymerized methylcellulose hydrogels as potential soft tissue filler materials

There is a significant clinical need for long-lasting, injectable materials for soft tissue reconstruction. Methylcellulose (MC) is an FDA-approved polysaccharide derivative of cellulose that is inexpensive, renewable, and biocompatible, and may serve as an alternative to existing synthetic and natural fillers. In this study, MC was modified with functional methacrylate groups and polymerized using a redox-initiation system to produce hydrogels with tunable properties. By varying the percent methacrylation and macromer concentration, the equilibrium moduli of the hydrogels were found to range between 1.29 ± 0.46 and 12.8 ± 2.94 kPa, on par with human adipose tissue, and also displayed an inverse relationship to the swelling properties. Rheological analyses determined gelation onset and completion to be in accordance with the ISO standard for injectable materials. Cellulase enzymatic treatment resulted in complete degradation of the hydrogels by 48 h, presenting the possibility of minimally invasive removal of the materials in the event of malposition or host reaction. In addition, co-culture experiments with human dermal fibroblasts showed the gels to be cytocompatible based on DNA measurements and Live/Dead staining. Taken together, these redox-polymerized MC hydrogels may be of use for a wide range of clinical indications requiring soft tissue augmentation.