Biodegradable polymers such as polyesters and polycarbonates formed by ring-opening polymerizations, including poly-( -caprolactone), poly(p-dioxanone), poly(trimethylene carbonate), and most notably poly(glycolic acid) and poly(lactic acid), have met wide acceptance for medical uses as a consequence of their low toxicity, degradation properties, and ease of synthesis. [1][2][3][4] As medical device materials, biodegradable polymers do not require removal after implantation, thereby eliminating a second surgical procedure; furthermore, the chronic immune response often associated with permanently implanted synthetic materials is reduced or eliminated as the macromolecules degrade after performing their intended function. These polymers are used in medical applications in various roles including sutures, staples, and stent coatings, as orthopedic cell scaffolds, and as micro-and nanoparticles for drug delivery applications. [5][6][7][8] When a polymer does not meet the requirements for an intended application, two monomers are often copolymerized or two or more polymers are blended with each other to alter properties such as degradation rate, flexibility, and strength. A representative example is Vicryl, a commercially available poly(lactide-co-glycolide) suture produced by Ethicon. In general, these aforementioned polymers are distinctly limited by the range of properties attainable and lack of chemical side groups for further functionalization, potentially hindering the development and synthesis of more tailored materials.In recent years, a number of new polymers have been introduced to address the need for functionalizable materials. These include linear polyesters based on amino acids, 9,10 sugars, 11,12 or modified hydroxy acids, 13,14 linear polycarbonates based on sugars, 12 glycerol, 15 and dihydroxyacetone, 16 modified trimethylene carbonate monomers, 17,18 and others. 19 Polyester dendrimers composed of glycerol and lactic or succinic acids have also been reported. 20 Poly( -caprolactone) is one polymer that has been used widely in a variety of medical devices. Currently, poly( -caprolactone) is incorporated in materials for tissue scaffolding including bone, 21 blood vessels, 22 and nerves, 23 as well as drug delivery systems 24 and suture materials, 25 but it is limited by a lack of functional side groups. An advantage of using poly( -caprolactone) is because of its slow degradation rate which does not create acidic microenvironments like poly(glycolic acid) and poly(lactic acid). 26 Herein we report new copolymers based on 6-hydroxyhexanoic acid and glycerol which contain pendant side chains with varying common reactive groups. The utility of these
