(122a) Synthesis and Characterization of Degradable Nanoparticles for Controlled Delivery of Growth Factors for Bone Regeneration
Customizable poly(lactic acid)-b-poly(ethylene glycol) dimethacrylate crosslinking agents were synthesized through a ring opening polymerization reaction, and were subsequently incorporated into poly(methacrylate-co-methacrylic acid) nanoparticles. To achieve a range of degradation profiles, the PLA and PEG chain length in the crosslinker was varied. The crosslinked, co-polymeric nanoparticles were synthesized using UV-initiated free radical emulsion polymerization. Fourier-transform infrared spectroscopy was used to confirm the composition of the resulting nanoparticles and dynamic light scattering and electrophoretic light scattering were used to assess the particle size and zeta potential, respectively. Nuclear magnetic resonance spectroscopy was used to study the influence of polymer composition on degradation kinetics. The particle loading capacity and release profiles were analyzed using chymotrypsin as a model for bone morphogenetic protein-2, a widely studied growth factor for bone regeneration. Ultimately, our work shows that variation of nanoparticle degradation rates can control the release rate of growth factors and provide sustained delivery within a therapeutic timeframe for bone regeneration. In addition, our system shows promise for the potential to sequentially deliver multiple growth factors with physiologically relevant profiles.
The work was supported in part by a grant from the National Institutes of Health (R01 EB022025).