The nanofibrous architecture of poly(L-lactic acid)-based functional copolymers.
It remains a challenge to synthesize functional materials that can develop advanced scaffolding architectures for tissue engineering. In this study, a series of biodegradable amphiphilic poly(hydroxyalkyl (meth)acrylate)-graft-poly(l-lactic acid) (PHAA-g-PLLA) copolymers have been synthesized and fabricated into nano-fibrous scaffolds. These copolymers can be further functionalized, are more hydrophilic, and have faster degradation rates than the PLLA homopolymer, which are advantageous for certain tissue engineering applications. First, PLLA-based macromonomers were prepared by using functional hydroxyalkyl (meth)acrylates (HAA) as initiators. The PHAA-g-PLLA copolymers were then synthesized using free radical copolymerization of PLLA-based macromonomers and HAA. Nano-fibrous architecture was created using a thermally induced phase separation technique from these functional PHAA-g-PLLA copolymers. The nano-fibrous structure mimics the architecture of natural collagen matrix at the nanometer scale. The effects of the macromonomer composition, copolymer composition, blending ratio, and solvent selection on nano-scale structures were studied. In general, the nano-fibrous structure was created when the amount of HAA in the macromonomer was low. By increasing the amount of HAA in the macromonomer, microspheres with nano-fibrous surfaces were obtained. Further increasing the amount of HAA led to the creation of microspheres with leaf-like surfaces. These PLLA-based materials had much faster degradation rates than the PLLA, and could be completely degraded from several weeks to a few months depending on their composition and molecular weight. Furthermore, the PHAA-g-PLLA copolymers possess functional hydroxyl groups, which can be used to couple with bioactive molecules to control cell-material interactions. Therefore, these biodegradable functional copolymers have the design flexibility to fabricate various biomimetic materials for tissue engineering applications.
Liu
Xiaohua
X
Department of Biologic and Materials Sciences, University of Michigan, 1011 North University Ave, Ann Arbor, MI 48109-1078, USA.
Ma
Peter X
PX
D019245:Compressive Strength; D005663:Furans / Q000737:chemistry; D019344:Lactic Acid / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D057139:Nanofibers / Q000737:chemistry* / Q000648:ultrastructure; D011091:Polyesters; D011102:Polyhydroxyethyl Methacrylate / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
D005663:Furans; D011091:Polyesters; D011108:Polymers; D012997:Solvents; D011102:Polyhydroxyethyl Methacrylate; D019344:Lactic Acid; C018674:tetrahydrofuran; C033616:poly(lactide)