Injectable and biodegradable sugar beet pectin/gelatin hydrogels for biomedical applications.

Injectable hydrogels have advantages over pre-formed hydrogels in biomedical applications. In our previous study, we showed usefulness of sugar beet pectin (SBP) as an injectable gel material. However, the in vivo biodegradability of the gels was low because animals lack suitable hydrolytic enzymes of SBP. In this study we developed SBP-based injectable gels with higher in vivo biodegradability than the previous SBP gels by incorporating biodegradable gelatin into the latter. An aqueous solution with dissolved SBP and gelatin rapidly (< 1 min) formed gels through a horseradish peroxidase-catalyzed oxidative coupling reaction between feruloyl moieties on the SBP molecules and phenolic moieties on the gelatin molecules. Gelation time and mechanical properties of the gels were tunable by adjusting the polymer concentrations. The gels containing doxorubicin, an anti-cancer drug, successfully suppressed the growth of a solid tumor created by subcutaneous injection of mouse melanoma B16F1 cells into nude mice. These results indicate that injectable and biodegradable SBP/gelatin gels are useful in biomedical applications.