Study on proanthocyanidins crosslinked collagen membrane for guided bone tissue regeneration

Proanthocyanidin surface preconditioning of dental pulp stem cell spheroids enhances dimensional stability and biomineralization in vitro

AIM

Lack of adequate mechanical strength and progressive shrinkage over time remain challenges in scaffold-free microtissue-based dental pulp regeneration. Surface collagen cross-linking holds the promise to enhance the mechanical stability of microtissue constructs and trigger biological regulations. In this study, we proposed a novel strategy for surface preconditioning microtissues using a natural collagen cross-linker, proanthocyanidin (PA). We evaluated its effects on cell viability, tissue integrity, and biomineralization of dental pulp stem cell (DPSCs)-derived 3D cell spheroids.

METHODOLOGY

Microtissue and macrotissue spheroids were fabricated from DPSCs and incubated with PA solution for surface collagen cross-linking. Microtissue viability was examined by live/dead staining and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, with transverse dimension change monitored. Microtissue surface stiffness was measured by an atomic force microscope (AFM). PA-preconditioned microtissues and macrotissues were cultured under basal or osteogenic conditions. Immunofluorescence staining of PA-preconditioned microtissues was performed to detect dentin sialophosphoprotein (DSPP) and F-actin expressions. PA-preconditioned macrotissues were subjected to histological analysis, including haematoxylin-eosin (HE), alizarin red, and Masson trichrome staining. Immunohistochemistry staining was used to detect alkaline phosphatase (ALP) and dentin matrix acidic phosphoprotein 1 (DMP-1) expressions.

RESULTS

PA preconditioning had no adverse effects on microtissue spheroid viability and increased surface stiffness. It reduced dimensional shrinkage for over 7 days in microtissues and induced a larger transverse-section area in the macrotissue. PA preconditioning enhanced collagen formation, mineralized nodule formation, and elevated ALP and DMP-1 expressions in macrotissues. Additionally, PA preconditioning induced higher F-actin and DSPP expression in microtissues, while inhibition of F-actin activity by cytochalasin B attenuated PA-induced dimensional change and DSPP upregulation.

CONCLUSION

PA surface preconditioning of DPSCs spheroids demonstrates excellent biocompatibility while effectively enhancing tissue structure stability and promoting biomineralization. This strategy strengthens tissue integrity in DPSC-derived spheroids and amplifies osteogenic differentiation potential, advancing scaffold-free tissue engineering applications in regenerative dentistry.

Personalized PLGA/BCL Scaffold with Hierarchical Porous Structure Resembling Periosteum-Bone Complex Enables Efficient Repair of Bone Defect

Using bone regeneration scaffolds to repair craniomaxillofacial bone defects is a promising strategy. However, most bone regeneration scaffolds still exist some issues such as a lack of barrier structure, inability to precisely match bone defects, and necessity to incorporate biological components to enhance efficacy. Herein, inspired by a periosteum-bone complex, a class of multifunctional hierarchical porous poly(lactic-co-glycolic acid)/baicalein scaffolds is facilely prepared by the union of personalized negative mold technique and phase separation strategy and demonstrated to precisely fit intricate bone defect cavity. The dense up-surface of the scaffold can prevent soft tissue cell penetration, while the loose bottom-surface can promote protein adsorption, cell adhesion, and cell infiltration. The interior macropores of the scaffold and the loaded baicalein can synergistically promote cell differentiation, angiogenesis, and osteogenesis. These findings can open an appealing avenue for the development of personalized multifunctional hierarchical materials for bone repair.

Barrier Membranes for Guided Bone Regeneration (GBR): A Focus on Recent Advances in Collagen Membranes

Guided bone regeneration (GBR) has become a clinically standard modality for the treatment of localized jawbone defects. Barrier membranes play an important role in this process by preventing soft tissue invasion outgoing from the mucosa and creating an underlying space to support bone growth. Different membrane types provide different biological mechanisms due to their different origins, preparation methods and structures. Among them, collagen membranes have attracted great interest due to their excellent biological properties and desired bone regeneration results to non-absorbable membranes even without a second surgery for removal. This work provides a comparative summary of common barrier membranes used in GBR, focusing on recent advances in collagen membranes and their biological mechanisms. In conclusion, the review article highlights the biological and regenerative properties of currently available barrier membranes with a particular focus on bioresorbable collagen-based materials. In addition, the advantages and disadvantages of these biomaterials are highlighted, and possible improvements for future material developments are summarized.

Traditional Chinese medicine promotes bone regeneration in bone tissue engineering

Bone tissue engineering (BTE) is a promising method for the repair of difficult-to-heal bone tissue damage by providing three-dimensional structures for cell attachment, proliferation, and differentiation. Traditional Chinese medicine (TCM) has been introduced as an effective global medical program by the World Health Organization, comprising intricate components, and promoting bone regeneration by regulating multiple mechanisms and targets. This study outlines the potential therapeutic capabilities of TCM combined with BTE in bone regeneration. The effective active components promoting bone regeneration can be generally divided into flavonoids, alkaloids, glycosides, terpenoids, and polyphenols, among others. The chemical structures of the monomers, their sources, efficacy, and mechanisms are described. We summarize the use of compounds and medicinal parts of TCM to stimulate bone regeneration. Finally, the limitations and prospects of applying TCM in BTE are introduced, providing a direction for further development of novel and potential TCM.