Guided tissue regeneration with use of β-TCP/chitosan composite membrane

Fabrication and properties evaluation of chitosan/BaTiO3 composite membranes for the periodontitis treatment

Periodontitis gradually damages the hard and soft tissues surrounding the tooth, leading to tooth loss. In recent years, the use of biomaterials in periodontitis treatment has expanded, including gels, nanoparticles, microparticles, fibers, and membranes. Among these, membranes have more clinical applications. Due to the ability of the piezoelectric material to regenerate damaged tissues, the aim of this study was to create piezoelectric composite membranes. To achieve this, Barium titanate powder (BaTiO3 powder)-a piezoelectric substance-was synthesized using the hydrothermal method and analyzed with X-ray diffraction (XRD) and Field emission scanning electron microscopy (FESEM). Four types of membranes were fabricated using solvent casting method: three composite membranes with chitosan matrix and BaTiO3 fillers (at 3%, 6%, and 9% weight), and one chitosan membrane without BaTiO3. The microstructure of the membrane surfaces, agglomeration of BaTiO3 in membranes, and hydrophilicity, antibacterial, and electrical properties of the membrane were also investigated. The results indicated that membranes containing 3 and 6% BaTiO3 had suitable surface structure for the periodontitis treatment. Agglomeration of BaTiO3 particles was higher in the membrane containing 9% BaTiO3. The large amount of BaTiO3 improved the antibacterial properties of the membranes. Additionally, the membranes containing BaTiO3 had high electrical properties, especially those with 3% and 6% BaTiO3. Therefore, composite membranes containing BaTiO3, especially membranes containing 6% BaTiO3, are more favorable options than those without BaTiO3 for periodontitis treatment.

Multifunctional Scaffolds Based on Emulsion and Coaxial Electrospinning Incorporation of Hydroxyapatite for Bone Tissue Regeneration

Tissue engineering is nowadays a powerful tool to restore damaged tissues and recover their normal functionality. Advantages over other current methods are well established, although a continuous evolution is still necessary to improve the final performance and the range of applications. Trends are nowadays focused on the development of multifunctional scaffolds with hierarchical structures and the capability to render a sustained delivery of bioactive molecules under an appropriate stimulus. Nanocomposites incorporating hydroxyapatite nanoparticles (HAp NPs) have a predominant role in bone tissue regeneration due to their high capacity to enhance osteoinduction, osteoconduction, and osteointegration, as well as their encapsulation efficiency and protection capability of bioactive agents. Selection of appropriated polymeric matrices is fundamental and consequently great efforts have been invested to increase the range of properties of available materials through copolymerization, blending, or combining structures constituted by different materials. Scaffolds can be obtained from different processes that differ in characteristics, such as texture or porosity. Probably, electrospinning has the greater relevance, since the obtained nanofiber membranes have a great similarity with the extracellular matrix and, in addition, they can easily incorporate functional and bioactive compounds. Coaxial and emulsion electrospinning processes appear ideal to generate complex systems able to incorporate highly different agents. The present review is mainly focused on the recent works performed with Hap-loaded scaffolds having at least one structural layer composed of core/shell nanofibers.

A novel γ-PGA composite gellan membrane containing glycerol for guided bone regeneration

An ideal barrier membrane design should incorporate the function of a delivery vehicle for transporting drugs and osteoinductive factors to where the body is under inflammation. In the present study, a functional hydrogel-based barrier membrane is fabricated using calcium-form poly-γ-glutamic acid (γ-PGA) and glycerol blending into gellan gum. The concentration of the calcium-form poly-γ-glutamic acid (γ-PGA) and the glycerol ratio are studied for improving practicability in easy-handling and expanding the coverage area. Gellan gum-based membranes with uniformly distributed calcium aggregates are not only successfully manufactured but also providing excellent characteristics for protein adsorption, bioactivity, and bone cell maturation. Our composite gellan gum-based membranes were tested including to their morphology, mechanical properties, swelling behavior, protein adsorption, drug diffusion, and lysozyme degradation. The biocompatibility, proliferation, and osteoblastic response of membranes were examined by osteoblast-like (MG63) cells. Our results indicate that adequate physical cross-linking with γ-PGA improves the original mechanical properties and delays degradation. Growing glycerol ratio not only enhances the elongation at break and diffusion rate, but it also changes the tensile strength and the remaining weight. In vitro biocompatibility tests, an adequate ratio of γ-PGA modification significantly enhances the proliferation, the secretion of alkaline phosphatase (ALP) and mineralization. However, worth noting is the glycerol-modified membrane cannot bear a close resemblance with the non-glycerol group in the high level of osteoblastic response. In general, these tunable materials with biocompatibility, biodegradability, and positive osteoblastic responses were poised to be possible candidates for bone defect repair.

Guided bone regeneration activity of different calcium phosphate/chitosan hybrid membranes

To fulfill the properties of membrane for guided bone tissue regeneration, chitosan (CS) and calcium phosphates were blended to produce porous hybrid membranes by lyophilization. We synthesized three different calcium phosphates: calcium deficient hydroxyapatite (CDHA), biphasic calcium phosphate (BCP) and β‑tricalcium phosphate (TCP) by a reverse emulsion method followed by calcination, and compared their efficacy on bone regeneration. The CDHA/CS, BCP/CS, and TCP/CS membranes had an interconnected pore structure with porosity of 91-95% and pore size of 102-147 μm. These hybrid membranes could promote the permeability and adhesiveness to bone cells as demonstrated by in-vitro cell culture of primary osteoblast. Particularly, the CDHA/CS and BCP/CS could further increase the cell attachment and differentiation, whereas the BCP/CS and TCP/CS could enhance cell proliferation. Finally, these hybrid membranes were assessed for guided bone regeneration in the critical-size calvarial bone defects created in SD rats. Histological and histomorphometric analyses revealed that the BCP/CS membrane had the most effective bone regeneration compared to the other two hybrid membranes. At three-week post-surgery, the BCP/CS membrane could enhance new bone generation up to 57% of the original bone defect area. The BCP/CS membrane thus has the potential to be applied for guided bone regeneration.

Smart Carriers and Nanohealers: A Nanomedical Insight on Natural Polymers

Biodegradable polymers are popularly being used in an increasing number of fields in the past few decades. The popularity and favorability of these materials are due to their remarkable properties, enabling a wide range of applications and market requirements to be met. Polymer biodegradable systems are a promising arena of research for targeted and site-specific controlled drug delivery, for developing artificial limbs, 3D porous scaffolds for cellular regeneration or tissue engineering and biosensing applications. Several natural polymers have been identified, blended, functionalized and applied for designing nanoscaffolds and drug carriers as a prerequisite for enumerable bionano technological applications. Apart from these, natural polymers have been well studied and are widely used in material science and industrial fields. The present review explains the prominent features of commonly used natural polymers (polysaccharides and proteins) in various nanomedical applications and reveals the current status of the polymer research in bionanotechnology and science sectors.

Preparation and Bioactivity Properties of a Novel Composite Membrane of Fructose Mediatedβ-Tricalcium Pyrophosphate/(Polyethylene Glycol/Chitosan) for Guided Tissue Regeneration

A novel composite membrane ofβ-tricalcium pyrophosphate (β-TCP) and fructose- (F-) mediated chitosan/poly(ethylene glycol) (CS/PEG) was prepared by thermally induced phase separation technique. The prepared composite membranes were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The mechanical property, swelling, degradation, and cytotoxicity of the composite membranes were evaluated in vitro with respect to its potential for use as biodegradable guided tissue regeneration (GTR) membrane. In vitro degradation tests showed the composite membrane with a controllable degradation rate when changing theβ-TCP content. The incorporation ofβ-TCP granules also caused a significant enhancement of tensile strength. Whenβ-TCP content is controlled to 50 wt%, homogeneous composite membranes with well mechanical property and enzymatic degradation rate can be obtained. Cytotoxicity assay demonstrates that the composite membranes were nontoxic and had very good cell compatibility. Most importantly, the release of calcium ions and glucosamine from the composite membranes was proved to increase the cell proliferation of NIH3T3. The results of this study have indicated that this novel F-β-TCP/CS/PEG composite can be a suitable material for GTR applications.

Novel biomimetic thermosensitive β-tricalcium phosphate/chitosan-based hydrogels for bone tissue engineering

Among the less invasive surgical procedures for tissue engineering application, injectable in situ gelling systems have gained great attention. In this contest, this article is aimed to realize thermosensitive chitosan-based hydrogels, crosslinked with β-glycerophosphate and reinforced via physical interactions with β-tricalcium phosphate. The kinetics of sol-gel transition and the composite hydrogel properties were investigated by rheological analysis. The hydrogels were also characterized by Fourier transform infrared study, X-ray diffraction, scanning electron microscopy, transmission electron microscopy analysis, and thermal and biological studies. The hydrogels exhibit a gel-phase transition at body temperature, and a three-dimensional network with typical rheological properties of a strong gel. The presence of the inorganic phase, made up of nanocrystals, provides a structure with chemico-physical composition that mimics natural bone tissue, favoring cellular activity. These findings suggest the potential of the materials as promising candidates for hard tissue regeneration.

CHITOSAN IN APPLICATIONS OF BIOMEDICAL DEVICES

Chitosan is a natural polysaccharide with great potential for biomedical applications due to its biocompatibility, biodegradable capability, and nontoxicity. Various techniques used for preparing chitosan microspheres/membranes and evaluations of these fabrications have also been reviewed. The hydrophilicity of chitosan provides unique characteristics of hydrogel formation with the acidic media and may entrap the drug content inside of the matrix for controlled release. In order to improve upon the scope of preparation of chitosan microspheres, we had successfully employed and incorporated a high-voltage system into the direct pumping injection process. The wide range of drug release profiles could be attributed to the surface characteristics, porosities, and various structures of chitosan microspheres upon treatment with Na5P3O10/NaOH solutions of various volume ratios. We also demonstrated that with the addition of chitosan/β-TCP microspheres as a constituent into the PMMA cement significantly decreases the curing peak temperature and increases the setting time. The excellent gelforming property of chitosan offers another biomedical application in membrane separation fields. Chitosan membranes were prepared by a thermal induced phase separation method, following treatment with nontoxic NaOH gelating and Na5P3O10, Na2SO3 crosslinking agents. In order to further improve the mechanical strength and biocompatibility and to expand the potential of chitosan GTR membranes in periodontal applications, various chitosan membranes incorporating with negatively charged alginate, bioactive tricalcium phosphate, and platelet rich plasma, respectively, were also prepared and characterized. Moreover, we had also utilized chitosan, which with good blood-clotting, cheap, and easy preparation characteristics, as the raw material to prepare rapid clotting wound dressing and tooth plug.