Abstract
A major drawback of nanocomposite scaffolds in bone tissue engineering is dimensional shrinkage after the fabrication process. Shrinkage yields gaps between the scaffold and host bone in the defect site and eventually causes failure in osteointegration by micromovement. The present study was conducted using titanium (Ti) mesh and Gelfoam® to prevent radial and axial micromovement, respectively. A critical-sized defect (CSD) was created in the center of the calvarium of Sprague Dawley rats to implant porous polydopamine-laced hydroxyapatite collagen calcium silicate (HCCS-PDA), a novel nanocomposite scaffold. Gelfoam® was applied around the edge of the defect, and then the HCCS-PDA scaffold was inserted in the defect area. Ti mesh was placed between the periosteum and skin right, above the inserted scaffold site. There were two test groups, with a fixture (Gelfoam® and Ti mesh) and without a fixture, each group contained five animals. The rats were sacrificed after three months post-operation. The explanted calvaria underwent micro-CT scanning and a push-out test to quantify osteointegration and mechanical strength between the scaffold and host bone. Histological analysis of undecalcified bone was performed by grinding resin infiltrated calvaria blocks to prepare 10 μm slices. Osteointegration was higher in the group with fixation than without fixation. Movement of the HCCS-PDA scaffold in the gap resulted in diminished osteointegration. With fixation, the movement was inhibited and osteointegration became prominent. Here we present a successful method of preventing axial and radial movement of scaffolds using Gelfoam® and Ti mesh. Applying this fixture, we expect that an HCCS-PDA scaffold can repair CSD more effectively.
Highlights
The tissue engineering (TE) of bone regeneration can enhance the field of plastic, reconstruction, and orthopedic surgery by repairing large bone defects rapidly and efficiently
TE bone regeneration is performed by implanting scaffolds seeded with stem cells into the defect site in order to repair with newly formed bone
The brittle characteristic does not allow the scaffold to be cut or trimmed, which would damage the scaffold structure. These limitations usually cause the gap between the scaffold and host calvarial bone to allow micromovement or dislodgement of the scaffold in the critical-sized defect (CSD)
Summary
The tissue engineering (TE) of bone regeneration can enhance the field of plastic, reconstruction, and orthopedic surgery by repairing large bone defects rapidly and efficiently. Recent 3D printing technology further broadened the application of the nanocomposite materials on scaffold fabrication by controlling the internal environments such as pore size, porosity, and pore distribution. This 3D porous nanocomposite scaffold is most commonly tested for its osteogenic potential in surgeries using animal models. Ceramic or nanocomposite scaffolds have a major limitation: They shrink during the fabrication process This shrinkage creates a space between the host bone and the scaffold, allowing the scaffold to move freely and uncontrollably. This causes instability or micromovement of the scaffold during the experiment, and such movement critically hinders the ability of bone to regenerate
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