The healing of bone defects by cell-free and stem cell-seeded 3D-printed PLA tissue-engineered scaffolds

Abstract

In this paper, the in-vivo healing of critical-sized bony defects by cell-free and stem cell-seeded 3D-printed PLA scaffolds was studied in rat calvaria bone. The scaffolds were implanted in the provided defect sites and histological analysis was conducted after 8 and 12 weeks. The results showed that both cell-free and stem cell-seeded scaffolds exhibited superb healing compared with the empty defect controls, and new bone and connective tissues were formed in the healing site after 8 and 12 weeks, postoperatively. The higher filled area, bone formation and bone maturation were observed after 12 weeks, particularly for PLA + Cell scaffolds.

Application of bioactive metal ions in the treatment of bone defects

“…PLA is a widely used biodegradable material with good biocompatibility and relatively low cost, and it has great application potential in the biomedical field. 199 At present, a variety of PLA-based products, such as surgical sutures, medical dressings, and microcapsule materials, have been approved by the US Food and Drug Administration for clinical application. 200 In terms of bone repair materials, PLA has the shortcomings of poor biological activity and single function, which is difficult to meet the different requirements of clinical application.…”

Bioactive Scaffolds as a Promising Alternative for Enhancing Critical-Size Bone Defect Regeneration in the Craniomaxillofacial Region

“…In another study, autologous BM-MSCs seeded on β-TCP scaffolds displayed osteoinductive effects in rabbit mandibular CSDs, supporting their role as a source of osteoinductive signals in vivo . Similarly, allogeneic BM-MSCs seeded on 3D-printed PLA scaffolds and grafted into rat calvarial CSDs stimulated bone healing and neovascularization …”

“…233 Similarly, allogeneic BM-MSCs seeded on 3D-printed PLA scaffolds and grafted into rat calvarial CSDs stimulated bone healing and neovascularization. 54 Regarding clinical trials, human BM-MSCs (hBM-MSCs) secretome adsorbed on porous β-TCP scaffolds and grafted during maxillary sinus floor elevation surgeries displayed strong osteoinductive properties. 234 Additionally, autologous BM-MSCs seeded on BCP granules and grafted subperiosteally in severely resorbed mandibular alveolar ridges promoted bone growth, effectively augmenting alveolar ridge height, allowing the placement of dental implants.…”

“…Some relevant examples of scaffolds made solely with synthetic polymers and evaluated in vivo are (a) 3D-printed PCL scaffolds with kagome structure implanted into rabbit cranial CSDs demonstrated superior osteoconductive and mechanical properties compared to grid-structured PCL scaffolds; (b) 3D-printed and apatite-coated PLA scaffolds loaded with rhBMP-2, accelerated bone regrowth after implantation into rat calvarial CSDs; (c) polydopamine (pDA)-coated PLA scaffolds to which nanoparticles containing plasmids coding for VEGF were bound, were implanted into rat calvarial CSDs, enhancing significantly bone regeneration; (d) 3D-printed PLA scaffolds, acellular or seeded with MSCs, were grafted into rat cranial CSDs promoting bone regrowth and tissue neovascularization; and (e) polycarbonate/ceramic scaffolds containing human cells were grafted into rabbit mandibular CSDs promoting bone healing …”

“…Most use composite materials that include at least one synthetic polymer blended with natural polymers, DBM, metals, oxides, and carbon-based materials to improve their properties for the fabrication of scaffolds. 21 Some relevant examples of scaffolds made solely with synthetic polymers and evaluated in vivo are (a) 3D-printed PCL scaffolds with kagome structure implanted into rabbit cranial CSDs demonstrated superior osteoconductive and mechanical properties compared to grid-structured PCL scaffolds; 51 (b) 3D-printed and apatite-coated PLA scaffolds loaded with rhBMP-2, accelerated bone regrowth after implantation into rat calvarial CSDs; 52 (c) polydopamine (pDA)-coated PLA scaffolds to which nanoparticles containing plasmids coding for VEGF were bound, were implanted into rat calvarial CSDs, enhancing significantly bone regeneration; 53 (d) 3D-printed PLA scaffolds, acellular or seeded with MSCs, were grafted into rat cranial CSDs promoting bone regrowth and tissue neovascularization; 54 and (e) polycarbonate/ ceramic scaffolds containing human cells were grafted into rabbit mandibular CSDs promoting bone healing. 55 The synthetic polymers polyether ether ketone (PEEK), poly(methyl methacrylate) (PMMA), and porous high-density polyethylene (pHDPE) 56 have been widely used to treat large cranial defects, specifically for brain protection and shape restoration instead of promoting bone regeneration because they are osteoconductive but not osteoinductive.…”