Synthetic polymers composed or metabolites endogenous to the mammalian organism are designed. The design is based on the monomer xylitol, which possesses a wide range of physical properties that are biologically relevant. Xylitol-based hydrogels and elastomers are biocompatible in vitro and in vivo, compared to the prevalent synthetic polymer poly (L-lactic-co-glycolic acid) (PLGA). It furthermore provides a platform to tune mechanical properties, degradation profiles, and cell attachment.