Search bioRxiv⌕ Search

Biology subjects

Hollister, S.

Publications and source records attributed to Hollister, S..

2 recordsLinked to original sources

Generative design approach to combine architected Voronoi foams with porous collagen scaffolds to create a tunable composite biomaterial

Regenerative biomaterials for musculoskeletal defects must address multi-scale mechanical challenges. We are developing biomaterials for craniomaxillofacial bone defects that are often large and irregularly shaped. These require close conformal contact between implant and defect margins to aid healing. While we have identified a mineralized collagen scaffold that promotes mesenchymal stem cell osteogenic differentiation in vitro and bone formation in vivo, its mechanical performance is insufficient for surgical translation. We report a generative design approach to create scaffold-mesh composites by embedding a macro-scale polymeric Voronoi mesh into the mineralized collagen scaffold. The mechanics of architected foam reinforced composites are defined by a rigorous predictive moduli equation. We show biphasic composites localize strain during loading. Further, planar and 3D mesh-scaffold composites can be rapidly shaped to aid conformal fitting. Voronoi-based composites overcome traditional porosity-mechanics relationship limits while enabling rapid shaping of regenerative implants to conformally fit complex defects unique for individual patients.

bioengineering↗

Tissue Engineered Vascularized Patient-Specific Temporomandibular Joint Reconstruction in a Yucatan Pig Model

PurposePediatric temporomandibular joint (TMJ) reconstruction occurs as a result of acquired, developmental, and/or congenital conditions. Current pediatric reconstruction options are limited. The aim of this project was to develop a proof of principle porcine model for a load bearing, customized 3-dimensional (3D) printed and BMP2-coated scaffold implanted in a pedicled (temporal) flap as a regenerative approach to pediatric TMJ mandibular condyle reconstruction. Materials and MethodsScaffolds were custom designed and 3D printed based on porcine computed tomography and absorbed with BMP2. Two operations occured: (1) implantation of scaffold in temporalis muscle to establish vascularity, and six weeks later, (2) unilateral condylectomy and rotation of the vascularized scaffold (with preservation of superficial temporal artery) onto mandibular ramus defect and secured with titanium screws. At 6 months post-implantation, the pigs were sacrified. The experimental side (muscle-scaffold) and the control side (unoperated condyle) were individually harvested at 6 months and evaluated by clinical, mechanical, radiographic, and qualitative/histologic methods. ResultsScaffolds maintained physical properties similar in appearance to unoperated condyles. The vascularized scaffolds had bone formation at edges and adjacent to scaffold-bone interface. New bone was visible in scaffold. Condyle height on the reconstructed side was 68% and 78% of the control side. Reconstructed condyle stiffness was between 20% and 45% of the control side. ConclusionIn our porcine model, customized 3D printed TMJ scaffolds impregnanted with BMP2 and implanted in and pedicled on temporalis muscle has the ability to (1) reconstruct a TMJ defect model, (2) maintain appropriate condylar height and upper airway diameter, and (3) generate new bone, without impacting functional outcomes.

bioengineering↗