Self-Fitting Craniomaxillofacial (CMF) Bone Scaffolds with Tunable Properties
| dc.contributor.advisor | Grunlan, Melissa A | |
| dc.contributor.committeeMember | Maitland, Duncan J | |
| dc.contributor.committeeMember | Alge , Daniel L | |
| dc.contributor.committeeMember | Saunders, W. Brian | |
| dc.creator | Pfau, Michaela R | |
| dc.date.accessioned | 2023-12-20T19:53:22Z | |
| dc.date.available | 2023-12-20T19:53:22Z | |
| dc.date.created | 2021-05 | |
| dc.date.issued | 2021-05-04 | |
| dc.date.submitted | May 2021 | |
| dc.date.updated | 2023-12-20T19:53:23Z | |
| dc.description.abstract | The use of self-fitting scaffolds based on thermoresponsive shape memory polymers (SMPs) offers a potential solution to treat craniomaxillofacial (CMF) bone defects via regenerative healing. Porous SMP scaffolds were previously prepared by Grunlan and coworkers with poly(ε-caprolactone)-diacrylate (PCL-DA, Mn ~10 kg/mol). In this present work, the in vivo healing potential of PCL-DA self-fitting scaffolds was assessed using a rabbit calvarial defect model. The scaffolds did not impede bone tissue formation, and further showed successful peripheral tissue integration, both histologically and by push-out testing, when compared to a PEEK implant. PCL-DA self-fitting scaffolds are limited by a slow degradation rate as well as a high transition temperature (Ttrans = Tm,PCL ~55 ºC) required for press-fitting. To accelerate degradation, a semi-interpenetrating (semi-IPN) scaffold composition was previously prepared with PCL-DA and poly(L-lactic acid) (PLLA, Mn ~ 15 kg/mol) (75/25 wt%). Herein, osteogenesis of human mesenchymal stem cells (hMSCs) in vitro was assessed for PCL-DA versus PCL-DA/PLLA semi-IPN scaffolds, both with and without a bioactive polydopamine (PD) coating. PD-coated scaffolds promoted hydroxyapatite (HAp) mineralization and the PD-coated PCL-DA/PLLA semi-IPN scaffolds exhibited enhanced osteogenic differentiation versus the PD-coated PCL-DA scaffolds. The accelerated degradation of PCL-DA/PLLA semi-IPNs was explored by substituting PLA-based thermoplastic polymers of varying molecular weight (Mn), crystallinity, and hydrophilicity. Degradation rates under base-catalyzed and neutral, non-catalyzed conditions were correlated to annealing temperature and phase separation. To lower the SMP scaffold’s Ttrans, macromers with 4-arm star architecture were substituted into the PCL-DA/PLLA semi-IPN design. This resulted in a reduced Ttrans (Tm,star-PCL ~45 °C) for improved tissue safety during implantation, as well as a reduced macromer solution viscosity that was shown to improve fabrication of larger scaffolds via SCPL. Lastly, PCL-DA-based SMP scaffolds were prepared as co-networks with poly(propylene fumarate) (PPF). Low Mn PCL and poly(D,L-lactic acid) (PDLLA) were used as macroinitiators to prepare compatibilized diblock PPF copolymers: PPF-PCL and PPF-PDLLA. These afforded facile incorporation into PCL-DA networks over analogous PPF homopolymers. These scaffolds uniquely exhibited tunable hydration while retaining mechanical properties throughout a 4-month non-catalyzed degradation study. | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.uri | https://hdl.handle.net/1969.1/200824 | |
| dc.language.iso | en | |
| dc.subject | Shape Memory Polymers (SMPs) | |
| dc.subject | Tissue Engineering (TE) | |
| dc.title | Self-Fitting Craniomaxillofacial (CMF) Bone Scaffolds with Tunable Properties | |
| dc.type | Thesis | |
| dc.type.material | text | |
| local.etdauthor.orcid | 0000-0001-9518-5471 | |
| thesis.degree.department | Biomedical Engineering | |
| thesis.degree.discipline | Biomedical Engineering | |
| thesis.degree.grantor | Texas A&M University | |
| thesis.degree.level | Doctoral | |
| thesis.degree.name | Doctor of Philosophy |
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