Injectable, Hierarchically Degraded Bioactive Scaffold for Bone Regeneration

Biomimetic Mineralized 3D-Printed Polycaprolactone Scaffold Induced by Self-Adaptive Nanotopology to Accelerate Bone Regeneration

Three-dimensional (3D)-printed biodegradable polymer scaffolds are at the forefront of personalized constructs for bone tissue engineering. However, it remains challenging to create a biological microenvironment for bone growth. Herein, we developed a novel yet feasible approach to facilitate biomimetic mineralization via self-adaptive nanotopography, which overcomes difficulties in the surface biofunctionalization of 3D-printed polycaprolactone (PCL) scaffolds. The building blocks of self-adaptive nanotopography were PCL lamellae that formed on the 3D-printed PCL scaffold via surface-directed epitaxial crystallization and acted as a linker to nucleate and generate hydroxyapatite crystals. Accordingly, a uniform and robust mineralized layer was immobilized throughout the scaffolds, which strongly bound to the strands and had no effect on the mechanical properties of the scaffolds. In vitro cell culture experiments revealed that the resulting scaffold was biocompatible and enhanced the proliferation and osteogenic differentiation of mouse embryolous osteoblast cells. Furthermore, we demonstrated that the resulting scaffold showed a strong capability to accelerate in vivo bone regeneration using a rabbit bone defect model. This study provides valuable opportunities to enhance the application of 3D-printed scaffolds in bone repair, paving the way for translation to other orthopedic implants.

Advancements in alveolar bone grafting and ridge preservation: a narrative review on materials, techniques, and clinical outcomes

This narrative review systematically explores the progression of materials and techniques in alveolar ridge preservation (ARP). We commence by delineating the evolution from traditional ARP methods to cutting-edge alternatives, including platelet-rich fibrin, injectable bone repair materials, and hydrogel systems. Critical examination of various studies reveals these innovative approaches not only accelerate bone healing but also significantly improve patient-reported outcomes, such as satisfaction, pain perception, and overall quality of life. Emphasis is placed on the correlation between advanced ARP techniques and enhanced patient comfort and clinical efficacy, underscoring their transformative potential in dental implantology. Highlighting the effectiveness of ARP, the implant survival rate over a span of 5 to 7 years was high, showcasing the reliability and success of these methods. Further, patients expressed high aesthetic satisfaction with the soft tissue outcome, evidenced by an average visual analog scale (VAS) score of 94. This positive aesthetic appraisal is linked to the clinical health of implants, potentially due to the employment of tooth-supported surgical guides. The economic analysis reveals a varied cost range for bone graft substitutes ($46.2 to $140) and socket sealing materials ($12 to $189), with a noteworthy correlation between the investment in barrier membranes and the diminished horizontal and vertical ridge resorption. This suggests that membrane usage significantly contributes to preserving ridge dimensions, offering a cost-effective strategy for enhancing ARP outcomes. In conclusion, this review illuminates the significant advancements in ARP, highlighting the shift towards innovative materials and techniques that not only promise enhanced bone regeneration and reduced healing times but also improve patient satisfaction and aesthetic outcomes. The documented high implant survival rate and the beneficial economic implications of membrane use further validate the effectiveness of contemporary ARP strategies, paving the way for their broader adoption in dental implantology.

Methacrylated gelatin and platelet-rich plasma based hydrogels promote regeneration of critical-sized bone defects

Physiological repair of large-sized bone defects requires instructive scaffolds with appropriate mechanical properties, biocompatibility, biodegradability, vasculogenic ability and osteo-inductivity. The objective of this study was to fabricate in situ injectable hydrogels using platelet-rich plasma (PRP)-loaded gelatin methacrylate (GM) and employ them for the regeneration of large-sized bone defects. We performed various biological assays as well as assessed the mechanical properties of GM@PRP hydrogels alongside evaluating the release kinetics of growth factors (GFs) from hydrogels. The GM@PRP hydrogels manifested sufficient mechanical properties to support the filling of the tissue defects. For biofunction assay, the GM@PRP hydrogels significantly improved cell migration and angiogenesis. Especially, transcriptome RNA sequencing of human umbilical vein endothelial cells and bone marrow-derived stem cells were performed to delineate vascularization and biomineralization abilities of GM@PRP hydrogels. The GM@PRP hydrogels were subcutaneously implanted in rats for up to 4 weeks for preliminary biocompatibility followed by their transplantation into a tibial defect model for up to 8 weeks in rats. Tibial defects treated with GM@PRP hydrogels manifested significant bone regeneration as well as angiogenesis, biomineralization, and collagen deposition. Based on the biocompatibility and biological function of GM@PRP hydrogels, a new strategy is provided for the regenerative repair of large-size bone defects.

Sequential deacetylation/self-gelling chitin hydrogels and scaffolds functionalized with fucoidan for enhanced BMP-2 loading and sustained release

Bone morphogenetic protein 2 (BMP-2) is a potent osteoinductive factor that promotes bone formation. A major obstacle to the clinical application of BMP-2 is its inherent instability and complications caused by its rapid release from implants. Chitin based materials have excellent biocompatibility and mechanical properties, making them ideal for bone tissue engineering applications. In this study, a simple and easy method was developed to spontaneously form deacetylated β-chitin (DAC-β-chitin) gels at room temperature through a sequential deacetylation/self-gelation process. The structural transformation of β-chitin to DAC-β-chitin leads to the formation of self-gelling DAC-β-chitin, from which hydrogels and scaffolds were prepared. Gelatin (GLT) accelerated the self-gelation of DAC-β-chitin and increased the pore size and porosity of the DAC-β-chitin scaffold. The DAC-β-chitin scaffolds were then functionalized with a BMP-2-binding sulfate polysaccharide, fucoidan (FD). Compared with β-chitin scaffolds, FD-functionalized DAC-β-chitin scaffolds showed higher BMP-2 loading capacity and more sustainable release of BMP-2, and thus had better osteogenic activity for bone regeneration.

Advances and Prospects in Materials for Craniofacial Bone Reconstruction

The craniofacial region is composed of 23 bones, which provide crucial function in keeping the normal position of brain and eyeballs, aesthetics of the craniofacial complex, facial movements, and visual function. Given the complex geometry and architecture, craniofacial bone defects not only affect the normal craniofacial structure but also may result in severe craniofacial dysfunction. Therefore, the exploration of rapid, precise, and effective reconstruction of craniofacial bone defects is urgent. Recently, developments in advanced bone tissue engineering bring new hope for the ideal reconstruction of the craniofacial bone defects. This report, presenting a first-time comprehensive review of recent advances of biomaterials in craniofacial bone tissue engineering, overviews the modification of traditional biomaterials and development of advanced biomaterials applying to craniofacial reconstruction. Challenges and perspectives of biomaterial development in craniofacial fields are discussed in the end.