Injectable biomaterials, including hydrogels and nanoparticles, are under intense evaluation in the development of therapeutic strategies that deliver biologics.  Acetalated dextran has recently been used as the basis for a novel vaccine and has been employed to develop and deliver therapeutic compounds in response to heart injury.  This ground-breaking study sought to demonstrate that biomaterials could be employed to facilitate healing at the site of injury in the heart.  In this study, the strategy was to deliver, via sustained release, therapeutic compounds that promote healing - without repeated therapeutic intervention. Other materials including  poly(lactic-co-glycolic acid) (PLGA) have been evaluated for delivery in cardiac applications. However, these delivery systems include inherent limitations such as an acidic microenvironment for biologically-based cargoes and necessarily have the potential to disrupt proper therapeutic function of the delivered biologic.  Ac-Dex is currently under evaluation for the delivery of a number of biologically-based compounds - with applications including vaccines, cardiac intervention and restoration, inflammation, and others.