Recent developments in cyclic acetal biomaterials for tissue engineering applications.

At an ever increasing pace, synthetic biomaterials are being developed with specific functionalities for tissue engineering applications. These biomaterials possess properties including biocompatibility, mechanical strength, and degradation as well as functionalities such as specific cell adhesion and directed cell migration. However, synthetic polymers are often not completely biologically inert and may non-specifically react with the surrounding in vivo environment. An example of this reactivity is the release of acidic degradation products from hydrolytically degradable polymers based upon an ester moiety. In order to address this concern, a novel class of biomaterials based upon a cyclic acetal unit has been developed. Scaffolds suitable for the replacement of both hard and soft tissues have been successfully fabricated from cyclic acetals and a detailed characterization of scaffold properties has been performed. Cyclic acetal based biomaterials have also been used to repair bone defects and promote bone growth, displaying a minimal inflammatory response. This review will discuss the most recent research of current biomaterials and cyclic acetals, and particularly focus on the tissue engineering applications of these materials. Finally, this review will also briefly discuss polyacetals and polyketals for drug delivery applications.