Comparative Evaluation of Mathematical Model and In Vivo Study of Calcium Phosphate Bone Grafts.

One of the key factors of the interaction 'osteoplastic material-organism' is the state of the implant surface. Taking into account the fact that the equilibrium in regeneration conditions is reached only after the reparative histogenesis process is completed, the implant surface is constantly modified. This work is devoted to the numerical description of the dynamic bilateral material-medium interaction under close to physiological conditions, as well as to the assessment of the comparability of the model with and experimental results.

Meso-Macroporous Hydroxyapatite Powders Synthesized in Polyvinyl Alcohol or Polyvinylpyrrolidone Media.

Mesoporous hydroxyapatite (HA) is widely used in various applications, such as the biomedical field, as a catalytic, as a sensor, and many others. The aim of this work was to obtain HA powders by means of chemical precipitation in a medium containing a polymer-polyvinyl alcohol or polyvinylpyrrolidone (PVP)-with concentrations ranging from 0 to 10%. The HA powders were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, atomic emission spectroscopy with inductively coupled plasma, electron paramagnetic resonance, scanning electron microscopy (SEM), and transmission electron microscopy (TEM).

Low-Temperature Calcium Phosphate Ceramics Can Modulate Monocytes and Macrophages Inflammatory Response In Vitro.

Creating bioactive materials for bone tissue regeneration and augmentation remains a pertinent challenge. One of the most promising and rapidly advancing approaches involves the use of low-temperature ceramics that closely mimic the natural composition of the extracellular matrix of native bone tissue, such as Hydroxyapatite (HAp) and its phase precursors (Dicalcium Phosphate Dihydrate-DCPD, Octacalcium Phosphate-OCP, etc.).

Composite Remineralization of Bone-Collagen Matrices by Low-Temperature Ceramics and Serum Albumin: A New Approach to the Creation of Highly Effective Osteoplastic Materials.

This study examined the effectiveness of coating demineralized bone matrix (DBM) with amorphous calcium phosphate (DBM + CaP), as well as a composite of DBM, calcium phosphate, and serum albumin (DBM + CaP + BSA). The intact structure of DBM promotes the transformation of amorphous calcium phosphate (CaP) into dicalcium phosphate dihydrate (DCPD) with a characteristic plate shape and particle size of 5-35 µm. The inclusion of BSA in the coating resulted in a better and more uniform distribution of CaP on the surface of DBM trabeculae.

Peculiarities of charge compensation in lithium-doped hydroxyapatite.

Hydroxyapatite (HA) remains one of the most popular materials for various biomedical applications and its fields of application have been expanding. Lithium (Li) is a promising candidate for modifying the biological behavior of HA. Li is present in trace amounts in the human body as an alkaline and bioelectric material.

Development of Nonwoven Fibrous Materials Based on Poly-3-Hydroxybutyrate with a High Content of α-Tricalcium Phosphate.

α-tricalcium (α-TCP) phosphate is widely used as an osteoinductive biocompatible material, serving as an alternative to synthetic porous bone materials. The objective of this study is to obtain a highly filled fibrous nonwoven material composed of poly-3-hydroxybutyrate (PHB) and α-TCP and to investigate the morphology, structure, and properties of the composite obtained by the electrospinning method (ES). The addition of α-TCP had a significant effect on the supramolecular structure of the material, allowing it to control the crystallinity of the material, which was accompanied by changes in mechanical properties, FTIR spectra, and XRD curves.

Functionalization of Octacalcium Phosphate Bone Graft with Cisplatin and Zoledronic Acid: Physicochemical and Bioactive Properties.

Bones are the fourth most frequent site of metastasis from malignant tumors, including breast cancer, prostate cancer, melanoma, etc. The bioavailability of bone tissue for chemotherapy drugs is extremely low. This requires a search for new approaches of targeted drug delivery to the tumor growth zone after surgery treatment.

Zn-Doped Calcium Magnesium Phosphate Bone Cement Based on Struvite and Its Antibacterial Properties.

The development of magnesium calcium phosphate bone cements (MCPCs) has garnered substantial attention. MCPCs are bioactive and biodegradable and have appropriate mechanical and antimicrobial properties for use in reconstructive surgery. In this study, the cement powders based on a (Ca + Mg)/P = 2 system doped with Zn at 0.

Osteogenesis Enhancement with 3D Printed Gene-Activated Sodium Alginate Scaffolds.

Natural and synthetic hydrogel scaffolds containing bioactive components are increasingly used in solving various tissue engineering problems. The encapsulation of DNA-encoding osteogenic growth factors with transfecting agents (e.g.

Biomimetic Remineralized Three-Dimensional Collagen Bone Matrices with an Enhanced Osteostimulating Effect.

Bone grafts with a high potential for osseointegration, capable of providing a complete and effective regeneration of bone tissue, remain an urgent and unresolved issue. The presented work proposes an approach to develop composite biomimetic bone material for reconstructive surgery by deposition (remineralization) on the surface of high-purity, demineralized bone collagen matrix calcium phosphate layers. Histological and elemental analysis have shown reproduction of the bone tissue matrix architectonics, and a high-purity degree of the obtained collagen scaffolds; the cell culture and confocal microscopy have demonstrated a high biocompatibility of the materials obtained.

Effects of Various Ripening Media on the Mesoporous Structure and Morphology of Hydroxyapatite Powders.

Mesoporous hydroxyapatite (HA) materials demonstrate advantages as catalysts and as support systems for catalysis, as adsorbent materials for removing contamination from soil and water, and as nanocarriers of functional agents for bone-related therapies. The present research demonstrates the possibility of the enlargement of the Brunauer-Emmett-Teller specific surface area (SSA), pore volume, and average pore diameter via changing the synthesis medium and ripening the material in the mother solution after the precipitation processes have been completed. HA powders were investigated via chemical analysis, X-ray diffraction analysis, Fourier-transform IR spectroscopy, transmission electron microscopy (TEM), and scanning (SEM) electron microscopy.

3D Printed Gene-Activated Sodium Alginate Hydrogel Scaffolds.

Gene therapy is one of the most promising approaches in regenerative medicine to restore damaged tissues of various types. However, the ability to control the dose of bioactive molecules in the injection site can be challenging. The combination of genetic constructs, bioresorbable material, and the 3D printing technique can help to overcome these difficulties and not only serve as a microenvironment for cell infiltration but also provide localized gene release in a more sustainable way to induce effective cell differentiation.

Octacalcium Phosphate for Bone Tissue Engineering: Synthesis, Modification, and In Vitro Biocompatibility Assessment.

Octacalcium phosphate (OCP, CaH(PO)·5HO) is known to be a possible precursor of biological hydroxyapatite formation of organic bone tissue. OCP has higher biocompatibility and osseointegration rate compared to other calcium phosphates. In this work, the synthesis of low-temperature calcium phosphate compounds and substituted forms of those at physiological temperatures is shown.

Study of Electron-Nuclear Interactions in Doped Calcium Phosphates by Various Pulsed EPR Spectroscopy Techniques.

Substituted calcium phosphates (CaPs) are vital materials for the treatment of bone diseases and repairing and replacement of defects in human hard tissues. In this paper, we present some applications of the rarely used pulsed electron paramagnetic resonance (EPR) and hyperfine interaction spectroscopy approaches [namely, electron spin-echo envelope modulation (ESEEM) and electron-electron double-resonance detected nuclear magnetic resonance (EDNMR)] to investigate synthetic CaPs (hydroxyapatite, tricalcium, and octacalcium phosphate) doped with various cations (Li, Na, Mn, Cu, Fe, and Ba). These resonance techniques provide reliable tools to obtain unique information about the presence and localization of impurity centers and values of hyperfine and quadrupole tensors.

Mesoporous Iron(III)-Doped Hydroxyapatite Nanopowders Obtained via Iron Oxalate.

Mesoporous hydroxyapatite (HA) and iron(III)-doped HA (Fe-HA) are attractive materials for biomedical, catalytic, and environmental applications. In the present study, the nanopowders of HA and Fe-HA with a specific surface area up to 194.5 m/g were synthesized by a simple precipitation route using iron oxalate as a source of Fe cations.

Study of Octacalcium Phosphate Behavior in Different Model Solutions.

Octacalcium phosphate (OCP), a new-generation bone substitute material, is a considered precursor of the biological bone apatite. The two-layered structure of OCP contains the apatitic and hydrated layers and is intensively involved in ion-exchange surface reactions, which results in OCP hydrolysis to hydroxyapatite and adsorption of ions or molecular groups presented in the environment. During various procedures, such as biomaterial solubility, additive release studies, or the functionalization technique, several model solutions are applied.

Bringing a Gene-Activated Bone Substitute Into Clinical Practice: From Bench to Bedside.

Bone grafting and reconstruction are still challenging in clinical practice because of the limitations of bone autografts and the drawbacks of currently approved bone substitutes. We thus developed a gene-activated bone substitute based on octacalcium phosphate and naked plasmid DNA carrying the vascular endothelial growth factor gene. This advanced combined therapy medicinal product had no cytotoxic effects , slightly decreased bone marrow mesenchymal stromal cell (MSC) doubling time, and was characterized by a prolonged level of gene construct delivery in a luciferase bioimaging assay.

Sodium alginate-based composites as a collagen substitute for skin bioengineering.

The skin is a combination of two different types of tissue-epithelial and connective (mesenchymal). The outer protective layer of the skin, the epidermis, consists of multiple layers of keratinocytes residing on the basement membrane that separates them from the underlying dermis, which consists of a well-vascularized fibrous extracellular matrix seeded mainly by fibroblasts and mesenchymal stromal cells. These skin features suggest that the development of a fibroblast-friendly porous scaffold covered with a flat dense sheath mimicking the basement membrane, and sufficient to support keratinocyte attachment, would be a reasonable approach in the generation of clinically-relevant skin substitutes useful for reconstructive dermatology and burn treatment.

Scaffold-free, Label-free, and Nozzle-free Magnetic Levitational Bioassembler for Rapid Formative Biofabrication of 3D Tissues and Organs.

Scaffolding is the conceptual framework of conventional tissue engineering. Over the past decade, scaffold-free approaches as a potential alternative to classic scaffold-based methods have emerged, and scaffold-free magnetic levitational tissue engineering (magnetic force-based tissue engineering [Mag-TE]) is a type of this novel tissue engineering strategy. However, Mag-TE is often based on the use of potentially toxic magnetic nanoparticles.

3D Printed Gene-activated Octacalcium Phosphate Implants for Large Bone Defects Engineering.

The aim of the study was the development of three-dimensional (3D) printed gene-activated implants based on octacalcium phosphate (OCP) and plasmid DNA encoding . The first objective of the present work involved design and fabrication of gene-activated bone substitutes based on the OCP and plasmid DNA with gene using 3D printing approach of ceramic constructs, providing the control of its architectonics compliance to the initial digital models. X-ray diffraction, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and compressive strength analyses were applied to investigate the chemical composition, microstructure, and mechanical properties of the experimental samples.

The Influence of Co Additive on the Sintering, Mechanical Properties, Cytocompatibility, and Digital Light Processing Based Stereolithography of 3Y-TZP-5AlO Ceramics.

Nanocrystalline 3 mol% yttria-tetragonal zirconia polycrystal (3Y-TZP) ceramic powder containing 5 wt.% AlO with 64 m/g specific area was synthesized through precipitation method. Different amounts of Co (0-3 mol%) were introduced into synthesized powders, and ceramic materials were obtained by heat treatment in the air for 2 h at 1350-1550 °C.

Fabrication of calcium phosphate 3D scaffolds for bone repair using magnetic levitational assembly.

The calcium phosphate particles can be used as building blocks for fabrication of 3D scaffolds intended for bone tissue engineering. This work presents for the first time a rapid creation of 3D scaffolds using magnetic levitation of calcium phosphate particles. Namely, tricalcium phosphate particles of equal size and certain porosity are used, which undergo the process of recrystallization after magnetic levitational assembly of the scaffold to ensure stitching of the scaffold.

Influence of Al on the Structure and in Vitro Behavior of Hydroxyapatite Nanopowders.

Nanopowders of aluminum-substituted (0-20 mol %) hydroxyapatite (HA) with the average size of 40-60 nm were synthesized by the precipitation method from nitrate solutions. A series of samples were studied by various analytical tools to elucidate the peculiarities of Al introduction. Electron paramagnetic resonance and pulsed electron-nuclear double resonance data demonstrate that incorporation of Al resulted in a decrease in the concentration of impurity carbonate anions and lead to an increase in the number of protons in the distant environment of the impurity nitrogen species.

Three-Dimensional Reconstruction of Erythrocytes Using the Novel Method For Corrective Realignment of the Transmission Electron Microscopy Cross-Section Images.

The detailed kinetics study of erythrocyte deformability is useful for the early diagnosis of blood diseases and for monitoring the blood rheology. Present solutions for a three-dimensional (3D) reconstruction of erythrocytes has a limited potential. This study aimed to use erythrocyte transmission electron images (ETIs) to evaluate the morphological relationship between adjacent ETIs and generate erythrocytes 3D model.

Fibrinogen-modified sodium alginate as a scaffold material for skin tissue engineering.

In search for a new pro-angiogenic scaffold material suitable for skin bioengineering and grafting therapy, we have fabricated a number of composite sodium alginate (AG)-fibrinogen (FG) sponge scaffolds using the freeze-drying approach. Thrombin was added to drive FG/fibrin conversion, while ε-aminocapronic acid (εAc) was used as antifibrinolytic component. The slow rates of scaffold biodegradation were achieved by using Ca and Mg cations as cross-linking agents.