Biodegradable poly(diol citrate) nanocomposite elastomers for soft tissue engineering

At present, synthetic biodegradable polymers commonly used for scaffolds in tissue engineering have a limited range of mechanical properties. This limitation is a challenge to in vivo tissue engineering, as the cell-scaffold construct is expected to maintain or restore normal tissue biomechanics during new tissue formation. Herein we report the synthesis and characterization of biodegradable elastomeric nanocomposite materials whose mechanical properties can be tailored to meet the requirements of soft tissue engineering applications. The nanocomposite consists of a nanofibrous poly(l-lactic acid) (PLLA) nanophase and an elastomeric poly(diol citrate) macrophase. Incorporation of a PLLA nanophase provides reinforcement to the poly(diol citrate) as demonstrated by an increase in tensile strength, modulus, and elongation at break with minimal permanent deformation. The mechanical properties of the nanocomposite were altered with the concentration of PLLA, choice of poly(diol citrate), and polymerization conditions. More importantly, the tensile mechanical properties compare favorably to those of human cartilage, ligament, and blood vessel. Furthermore, the compressive modulus is very similar to those of human and bovine articular cartilage. These results suggest that poly(diol citrate) nanocomposite elastomers are promising candidate biomaterials for soft tissue engineering.