Differently Charged P (VDF-TrFE) Membranes Influence Osteogenesis Through Differential Immunomodulatory Function of Macrophages

A biomaterial-mediated immune response is a critical factor to determine the cell fate as well as the tissue-regenerative outcome. Although piezoelectric-membranes have attracted considerable interest in the field of guided bone regeneration thanks to their biomimetic electroactivity, the influence of their different surface-charge polarities on the immune-osteogenic microenvironment remains obscure. The present study aimed at investigating the interaction between piezoelectric poly (vinylidene fluoridetrifluoroethylene) [P (VDF-TrFE)] membranes with different surface polarities (negative or positive) and macrophage response, as well as their subsequent influence on osteogenesis from an immunomodulating perspective. Specifically, the morphology, wettability, crystal phase, piezoelectric performance, and surface potential of the synthetic P (VDF-TrFE) samples were systematically characterized. In addition, RAW 264.7 macrophages were seeded onto differently charged P (VDF-TrFE) surfaces, and the culture supernatants were used to supplement cultures of rat bone marrow mesenchymal stem cells (rBMSCs) on the corresponding P (VDF-TrFE) surfaces. Our results revealed that oppositely charged surfaces had different abilities in modulating the macrophage-immune-osteogenic microenvironment. Negatively charged P (VDF-TrFE), characterized by the highest macrophage elongation effect, induced a switch in the phenotype of macrophages from M0 (inactivated) to M2 (anti-inflammatory), thus promoting the osteogenic differentiation of rBMSCs by releasing anti-inflammatory cytokine IL-10. Interestingly, positively charged P (VDF-TrFE) possessed pro-inflammatory properties to induce an M1 (pro-inflammatory) macrophage-dominated reaction, without compromising the subsequent osteogenesis as expected. In conclusion, these findings highlighted the distinct modulatory effect of piezoelectric-P (VDF-TrFE) membranes on the macrophage phenotype, inflammatory reaction, and consequent immune-osteogenic microenvironment depending on their surface-charge polarity. This study provides significant insight into the design of effective immunoregulatory materials for the guided bone regeneration application.

Periodontal Bifunctional Biomaterials: Progress and Perspectives

Periodontitis is a chronic infectious disease that destroys periodontal supportive tissues and eventually causes tooth loss. It is attributed to microbial and immune factors. The goal of periodontal therapy is to achieve complete alveolar bone regeneration while keeping inflammation well-controlled. To reach this goal, many single or composite biomaterials that produce antibacterial and osteogenic effects on periodontal tissues have been developed, which are called bifunctional biomaterials. In this review, we summarize recent progress in periodontal bifunctional biomaterials including bioactive agents, guided tissue regeneration/guided bone regeneration (GTR/GBR) membranes, tissue engineering scaffolds and drug delivery systems and provide novel perspectives. In conclusion, composite biomaterials have been greatly developed and they should be chosen with care due to the risk of selection bias and the lack of evaluation of the validity of the included studies.

Modified Synthesis and Physicochemical Characterization of a Bioglass-Based Composite for Guided Bone Regeneration

Objectives. Bioglass composites and polymers are materials of great interest for the medical and dental areas due to their properties, combining the bioactivity of ceramic materials and the mechanical properties of polymers. The purpose of the present study was to develop and to characterize the physicochemical and morphological properties an experimental bioglass-based ternary composite composed associated with sodium carboxymethylcellulose (Na-CMC) and polyvinyl alcohol (PVA). The compatibility of functional groups with bioglass was previously evaluated. The composite was then synthesized and evaluated in terms of morphology, elemental composition, compressive strength, porosity, and bioactivity. Materials and Methods. The bioglass was previously synthesized using a sol-gel route and characterized using FTIR analysis to identify the functional groups. The bone graft composite was then synthesized associating the bioglass with PVA, surfactant Triton X, and Na-CMC. The composite was then morphologically characterized using SEM/EDS. The porosity of the composite was analyzed using µCT, which also provided the composite compression strength. The composite was then evaluated in terms of its bioactivity using SEM/EDS analyses after immersion in SBF for 12, 24, 48, and 72 h. Results. FTIR analysis confirmed, among other components, the presence of Si–O–Ca and Si–O–Si bonds, compatible with bioglass. SEM analysis exhibited a composite with a porous structure without spikes. The elemental mapping confirmed the presence of Si, Ca, and P in the composite. µCT analysis demonstrated a porous structure with 42.67% of open pores and an average compression strength of 124.7 MPa. It has also demonstrated ionic changes in the composite surface after immersion in SBF, with increasing detection of Ca and P as a function of time, highlighting its chemical bioactivity. Conclusions. It can be concluded that the proposed bioglass-based composite presents a three-dimensional, well-structured, chemically bioactive porous structure, mechanically resistant for being reinforced with polymeric phases, with promising results as a synthetic bone graft, which makes it suitable for guided bone regeneration.