A Synthetic Biodegradable Polymer Membrane for Guided Bone Regeneration in Bone Defect

Guided bone regeneration (GBR) technique is most commonly used to treat alveolar bone defect. Polylactic acid (PLA) attracts much attention to utilize as a GBR membrane because it has relatively high mechanical strength and biodegradability. However, randomized controlled trials of PLA as a GBR membrane in animals were rare. The aim of this work is to observe the efficacy of polylactic acid membrane in guiding bone regeneration in Beagle canine alveolar bone defect restoration and to compare efficacy with the collagen membrane, providing an experimental basis for further clinical use of the polylactic acid membrane. The tests of physical and chemical properties showed that the PLA membrane has well mechanical strength to maintenance the space for the new bone, and has proper aperture for the attachment of osteoblasts. Through X-ray and histopathological examination of the different time points, the bone grafting material covered with PLA membrane can form similar mature bone compared to collagen membrane ones. Meanwhile, biodegradable speed of the PLA membrane was slower. Thus, this study showed that polylactic acid membrane as synthetic biodegradable polymer was reliably effective in guiding bone regeneration of alveolar bone defects, showed the favorable osteogenic capability and forecasts well applications in bone augmentation.

Preparation and characterization of a novel composite membrane of natural silk fiber/nano-hydroxyapatite/chitosan for guided bone tissue regeneration

Natural silk fiber (SF) was introduced into the chitosan/nano-hydroxyapatite (CS/n-HA) system to fabricate a novel guided bone tissue regeneration (GBR) membrane. The effect of different treatment methods (degummed, un-degummed, or dissolved SF) and different contents of SF on the properties of the CS/n-HA composite membrane was investigated. Results demonstrated that the degummed SF/CS/n-HA composite membrane with a weight ratio of 2:6:2 possessed the highest mechanical strength, where SF supported the composite membrane as a skeleton frame in the form of primeval state, while the un-degummed SF and dissolved SF had weaker reinforce effect due to the poor interface or poor interaction between SF and CS, and the dissolved SF/CS/n-HA composite membrane displayed the fastest degradation. However, the three SF could all improve the cell biocompatibility of the CS/n-HA composite membrane. Conclusively, the study revealed that degummed SF could in situ reinforce the CS/n-HA composite membrane with a simple and green processing method, which would provide an important guidance significant to develop a novel GBR membrane.

Nanofibrous asymmetric collagen/curcumin membrane containing aspirin-loaded PLGA nanoparticles for guided bone regeneration

The goal of the current study was to develop an asymmetric guided bone regeneration (GBR) membrane benefiting from curcumin and aspirin. The membrane was prepared using electrospinning technique and then was physic-chemically characterized by the conventional methods. The release profile of aspirin from the prepared membrane was also measured by ultraviolet spectrophotometry. Also, the antibacterial activities of the membrane was evaluated. We also assessed the in vitro effects of the prepared membrane on the biocompatibility and osteogenic differentiation of dental pulp stem cells (DPSCs), and evaluated in vivo bone regeneration using the prepared membrane in the defects created in both sides of the dog’s jaw by histology. The results from the characterization specified that the membrane was successfully prepared with monodispersed nanosized fibers, uniform network shaped morphology, negative surface charge and sustained release platform for aspirin. The membrane also showed antimicrobial effects against all tested bacteria. The presence of curcumin and aspirin in the asymmetric membrane enhanced osteogenic potential at both transcriptional and translational levels. The results of the animal test showed that the test area was completely filled with new bone after just 28 days, while the commercial membrane area remained empty. There was also a soft tissue layer above the new bone area in the test side. We suggested that the prepared membrane in this work could be used as a GBR membrane to keep soft tissue from occupying bone defects in GBR surgeries. Besides, the surgeries can be benefited from antibacterial activities and bone healing effects of this novel GBR membrane while, simultaneously, promoting bone regeneration.

Development of FGF-2-loaded electrospun waterborne polyurethane fibrous membranes for bone regeneration

Guided bone regeneration (GBR) membrane has been used to improve functional outcomes for periodontal regeneration. However, few studies have focused on the biomimetic membrane mimicking the vascularization of the periodontal membrane. This study aimed to fabricate waterborne polyurethane (WPU) fibrous membranes loaded fibroblast growth factor-2 (FGF-2) via emulsion electrospinning, which can promote regeneration of periodontal tissue via the vascularization of the biomimetic GBR membrane. A biodegradable WPU was synthesized by using lysine and dimethylpropionic acid as chain extenders according to the rule of green chemical synthesis technology. The WPU fibers with FGF-2 was fabricated via emulsion electrospinning. The results confirmed that controlled properties of the fibrous membrane had been achieved with controlled degradation, suitable mechanical properties and sustained release of the factor. The immunohistochemical expression of angiogenic-related factors was positive, meaning that FGF-2 loaded in fibers can significantly promote cell vascularization. The fiber scaffold loaded FGF-2 has the potential to be used as a functional GBR membrane to promote the formation of extraosseous blood vessels during periodontal repairing.

Lithographically-Fabricated HA-Incorporated PCL Nanopatterned Patch for Tissue Engineering

Inspired by the aligned extracellular matrix and bioceramics in human bone tissue, we investigated the relative contributions of nanotopography and equine bone powders (EBPs) with human dental pulp stem cells (DPSCs) to the osteogenesis. Both nanotopography and EBPs independently promoted the osteogenesis of DPSCs, osteogenesis was further promoted by the two factors in combination, indicating the importance of synergistic design factor of guided bone regeneration (GBR) membrane. The osteogenesis of DPSCs was affected by the polycaprolactone-based nanotopography of parallel nanogrooves as well as EBPs coating. Interestingly, both nanopattern and EBPs affected the DPSCs morphologies; nanopattern led to cell elongation and EBPs led to cell spreading and clustering. Analysis of the DPSCs-substrate interaction, DPSCs-EBPs interaction suggests that the combined environment of both factors play a crucial role in mediating osteogenic phenotype. This simple method to achieve a suitable environment for osteogenesis via nanotopography and EBPs coating modulation may be regarded as a promising technique for GBR/GTR membranes, which widely used dental and maxillofacial surgery applications.

ID: 1058 Effective bone formation through BMP-2-immobilized highly porous GBR membrane

Sound healing of large bone defects is critical challenges in most of clinical fields. In general healing process of bone regeneration, the rapid infiltration of connective tissue, whereas relatively slow bone regeneration in bone defect leads to the incomplete bone formation. To solve this drawback, guide bone regeneration (GBR) membrane which could prevent rapid infiltration of connective tissue into bone defect, thus GBR membrane is feasible for compact bone regeneration in clinical fields. In recent, the most researchers believed that bioactive molecules-grafted GBR membranes may enhance the bone regeneration. To allow graft of bioactive molecules from porous membrane, chemically modified scaffolds are commonly used. This modification leads to sufficient interaction with active sites of bioactive molecules to stable the immobilization of bioactive molecules in the body. However it is hard to apply to clinical applications because of the toxicity of chemical residue used for the modification. In this study, we developed a GBR membrane with leaf-stacked structure which can allow sustained release of bone morphogenetic protein-2 (BMP-2) without any additional modification. The morphology, mechanical property, BMP-2 release profile, osteogenic differentiation of human periosteum-derived cells, and new bone formation efficiency of the BMP-2-loaded GBR membrane compared with commercial product were investigated.