Impact of Polymer Architecture on PCL-DA/PLLA Semi-IPN Properties
Abstract
Cranio-maxillofacial (CMF) bone defects are most commonly treated with autografts despite their many limitations. Namely, the rigid autografts are difficult to shape and fit into complex defect geometries, resulting in poor osseointegration and healing. To address this issue, the Grunlan group has proposed a “self-fitting” CMF bone tissue scaffold based on a thermoresponsive shape memory polymer (SMP). Upon exposure to warm saline (T>55°C), the SMP scaffold becomes malleable and can be easily press-fitted into complex shaped defects. The SMP scaffolds are based on a linear poly(ɛ-caprolactone) diacrylate (PCL-DA) network, where interconnected pores are introduced via solvent casting particulate leaching (SCPL) fabrication. Recently, linear poly(L-lactic acid) (PLLA) was incorporated into the PCL-DA network as a semi-interpenetrating network (semi-IPN), and was shown to both enhance modulus and to accelerate degradation toward matching the rate of bone neotissue formation. The PCL-DA:PLLA semi-IPN’s unique properties were thought to be linked to phase separation, or polymer miscibility. Since star polymers are known to have different hydrodynamic volumes and interactions than their linear counterparts, the aim of this work explored the effects of changing from a linear to star architecture in a semi-IPN. Star substitution into nonporous films yielded further tunable properties, particularly in terms of accelerated degradation profiles, as well as mechanical and shape memory characteristics, with polymer miscibility as a main contributor.
Subject
shape memory polymerscaffold
PCL
PLLA
degradation
cranio-maxillofacial
thermoresponsive
defects
bone
Citation
McKinzey, Kelly (2020). Impact of Polymer Architecture on PCL-DA/PLLA Semi-IPN Properties. Undergraduate Research Scholars Program. Available electronically from https : / /hdl .handle .net /1969 .1 /194468.