In Situ Synthesis and Characterizations of a Strontium-Substituted Dicalcium Phosphate Anhydrous/Hydroxyapatite Biphasic Whisker and Its Properties Evaluation.

Dicalcium phosphate anhydrous (DCPA) presents good biomineralization ability, the strontium element is known for superior bone affinity, and a whisker possesses good mechanical strength; all these are beneficial for improving the drawbacks of hydroxyapatite (HAP) like weaker mechanical properties, poor biomineralization, and slower degradation/absorption. Therefore, a homogeneous precipitation was adopted to synthesize Sr-substituted and DCPA and HAP coexisting whiskers. The composition, structure, and morphology based on urea dosage and substitution content were characterized, and the roles of DCPA, Sr, and whisker shape were investigated.

Fabrication of quantum dot-immobilized YO microspheres with effective photoluminescence for cancer radioembolization therapy.

Microspheres composed of Y-containing materials are effective agents for cancer radioembolization therapy using β-rays. The distribution and dynamics of these microspheres in tissues can be easily determined by providing the microspheres with an imaging function. In addition, the use of quantum dots will enable the detection of microspheres at the individual particle level with high sensitivity.

Preparation and characterizations of antibacterial poly(methyl methacrylate) bone cement via copolymerization with a quaternary ammonium monomer of dimethylaminotriclosan methacrylate.

Poly (methyl methacrylate) (PMMA) bone cement relies on the loaded antibiotic to realize the antibacterial purpose. But the exothermic behavior during setting often makes temperature-sensitive antibiotics inactivated. It is necessary to develop new material candidates to replace antibiotics.

Enhancement of apatite formation on Ti-50Zr alloy in simulated body environment.

Ti-50Zr alloy is 2.5 times as strong as pure Ti and has a lower Young's modulus, making it a useful material for repairing bone and teeth. However, Ti-50Zr alloy has a limited ability to bond with bone in vivo.

In vitro and in vivo pharmacological profile of OPC-61815, a water-soluble phosphate ester pro-drug of tolvaptan.

Tolvaptan is an orally active vasopressin V receptor antagonist and used for the treatment of volume overload in some disease as an aquaretic. Tolvaptan sodium phosphate (OPC-61815) is a pro-drug of tolvaptan that was designed to improve water solubility and enable intravenous use. The conversion of OPC-61815 to tolvaptan was evaluated for in vitro and in vivo pharmacokinetic studies.

Preparation of bioactive and antibacterial PMMA-based bone cement by modification with quaternary ammonium and alkoxysilane.

Bone cement based on poly(methyl methacrylate) (PMMA) powder and methyl methacrylate (MMA) liquid is a very popular biomaterial used for the fixation of artificial joints. However, there is a risk of this cement loosening from bone because of a lack of bone-bonding bioactivity. Apatite formation in the body environment is a prerequisite for cement bioactivity.

Fabrication and properties of alginate/calcium phosphate hybrid beads: A comparative study.

Background: Microbeads for bone repair have been widely studied because they can be conveniently used in clinical applications.

Objective: This study concerns the preparation, physical properties and in vitro characterisation of different types of alginate/calcium phosphate (CaP) ceramic microbeads, which were designed for use as drug delivery systems and bone-regeneration matrices.

Methods: Hybrid microbeads were successfully prepared from sodium alginate and various CaP, namely 𝛼-tricalcium phosphate, 𝛽-tricalcium phosphate and hydroxyapatite using the liquid droplet method.

Effect of Calcium Acetate Content on Apatite-Forming Ability and Mechanical Property of PMMA Bone Cement Modified with Quaternary Ammonium.

Polymethyl methacrylate (PMMA)-based bone cement is a popular biomaterial used for fixation of artificial joints. A next-generation bone cement having bone-bonding ability, i.e.

Compositional dependence of the apatite formation ability of Ti-Zr alloys designed for hard tissue reconstruction.

Ti-Zr alloys are expected to be novel biomaterials with low stress shielding owing to their lower Young's moduli than pure Ti. The drawback of metallic biomaterials is that their bone-bonding abilities are relatively low. NaOH and heat treatments have been performed to provide Ti-50Zr with apatite-forming ability in the body environment, which is essential for bone bonding.

Setting behavior, apatite-forming ability, mechanical strength of polymethylmethacrylate bone cement through bioactivity modification of phosphate functional groups combined with Ca ions.

Bioactivity modification helps polymethylmethacrylate (PMMA) bone cement to reinforce its interfacial adhesion to bone tissues through the chemical bonding of apatite. Since Si-OH groups combined with Ca ions have succeeded in inducing apatite formation, more combinations of functional groups and active ions are being explored. In this study, Bis[2-(methacryloyloxy)ethyl] phosphate (B2meP) containing phosphate (=POH) groups and Ca(CHCOO) supplying Ca ion were adopted to investigate the feasibility of equipping PMMA bone cement with apatite-forming ability , more effects under designed contents on setting behavior, injectability, contact angle, cytotoxicity and mechanical strength were also investigated.

Structural control of magnetite nanoparticles for hyperthermia by modification with organic polymers: effect of molecular weight.

Hyperthermia treatment using appropriate magnetic materials in an alternating magnetic field to generate heat has been recently proposed as a low-invasive cancer treatment method. Magnetite (FeO) nanoparticles are expected to be an appropriate type of magnetic thermal seed for this purpose, and the addition of organic substances during the synthesis process has been studied for controlling particle size and improving biological functions. However, the role of the properties of the organic polymer chosen as the modifier in the physical properties of the thermal seed has not yet been comprehensively revealed.

Cytocompatible and Antibacterial Properties of Chitosan-Siloxane Hybrid Spheres.

Microporous spheres in a hybrid system consisting of chitosan and γ-glycidoxypropyltrimethoxysilane (GPTMS) have advantages in a range of applications, e.g., as vehicles for cell transplantation and soft tissue defect filling materials, because of their excellent cytocompatibility with various cells.

In situ synthesis of magnetic iron oxide nanoparticles in chitosan hydrogels as a reaction field: Effect of cross-linking density.

Magnetic iron oxides such as magnetite and γ-hematite have attracted considerable attention as thermoseeds for hyperthermia treatment because of their ability to generate heat under an alternating magnetic field. Control of the particle size and their combination with biocompatible polymers are expected to be beneficial for optimization of the nanoparticles. These processes can be accomplished through the synthesis of magnetite in gels, as the network structure of the polymer gel can control the grain growth of the magnetite.

In vitro apatite mineralization and heat generation of magnetite-reduced graphene oxide nanocomposites for hyperthermia treatment.

Nanocomposites of magnetite (FeO) and reduced graphene oxide (rGO) generate heat under an alternating magnetic field and therefore have potential applications as thermoseeds for cancer hyperthermia treatment. However, the properties of such nanocomposites as biomaterials have not been sufficiently well characterized. In this study, the osteoconductivity of FeO-rGO nanocomposites of various compositions was evaluated in vitro in terms of their apatite-forming ability in simulated body fluid (SBF).

Structural Effects of Sulfur-Containing Functional Groups on Apatite Formation on Ca-Modified Copolymers in a Simulated Body Environment.

Chemical modification with specific functional groups has been the conventional method to develop bone-bonding bioactive organic-inorganic hybrids. These materials are attractive as bone substitutes because they are flexible and have a Young's modulus similar to natural bone. Immobilization of sulfonic acid groups (-SOH) onto the polymer chain is expected to produce such hybrids because these groups induce apatite formation in a simulated body fluid (SBF) and enhance the activity of osteoblast-like cells.

Structural effects of phosphate groups on apatite formation in a copolymer modified with Ca in a simulated body fluid.

Organic-inorganic composites are novel bone substitutes that can ameliorate the mismatch of Young's moduli between natural bone and implanted ceramics. Phosphate groups contribute to the formation of apatite in a simulated body fluid (SBF) and the adhesion of osteoblast-like cells. Therefore, modification of a polymer with these functional groups is expected to enhance the ability of the organic-inorganic composite to bond with bone.

Development of hafnium metal and titanium-hafnium alloys having apatite-forming ability by chemical surface modification.

Hafnium (Hf) has attracted considerable attention as a component of biomedical titanium (Ti) alloys with low Young's moduli and/or shape-memory functionalities, because its cytotoxicity is as low as that of Ti. The drawback of metals is that their bone-bonding ability is generally low. It is known that apatite formation in the body is a prerequisite for bone-bonding.

Effect of metallographic structure and machining process on the apatite-forming ability of sodium hydroxide- and heat-treated titanium.

Although titanium (Ti) is clinically used for hard tissue reconstruction, it has low bone-bonding ability, i.e. bioactivity.

Preparation of chitosan-hydroxyapatite composite mono-fiber using coagulation method and their mechanical properties.

Autograft has been carried out for anterior cruciate ligament (ACL) reconstruction surgery. However, it has negative aspect because patients lose their healthy ligaments from other part. We focus on a chitosan-hydroxyapatite (HAp) composite fiber as a scaffold of ligament regeneration.

Characterization and degradation study of chitosan-siloxane hybrid microspheres synthesized using a microfluidic approach.

Chitosan microspheres can address challenges associated with poor bioavailability or unsustained drug release when used as drug delivery systems thanks to their mucoadhesiveness, which allows the drug dosage to be retained in the gastrointestinal track for extended periods. Chitosan-3-glycidoxypropyltrimethoxysilane-β-glycerophosphate (chitosan-GPTMS-β-GP) hybrid microspheres were synthetized through sol-gel processing using a microfluidic approach. Microspheres with uniform spherical shapes and sizes of approximately 650μm were obtained.

Enhanced biosafety of silica coated gadolinium based nanoparticles.

One of the most important and novel approaches of biomedical engineering is the development of new, effective and non-invasive medical diagnosis abilities, and treatments that have such requirements as advanced technologies for tumor imaging. Gadolinium (Gd) compounds can be used as MRI contrast agents, however the release of Gd ions presents some adverse side effects such as renal failure, pancreatitis or local necrosis. The main aim of the work was the development and optimization of Gadolinium based nanoparticles coated with silica to be used as bioimaging agent.

Bioactive carbon-PEEK composites prepared by chemical surface treatment.

Polyetheretherketone (PEEK) has attracted much attention as an artificial intervertebral spacer for spinal reconstruction. Furthermore, PEEK plastic reinforced with carbon fiber has twice the bending strength of pure PEEK. However, the PEEK-based materials do not show ability for direct bone bonding, i.

Apatite-forming ability of vinylphosphonic acid-based copolymer in simulated body fluid: effects of phosphate group content.

Phosphate groups on materials surfaces are known to contribute to apatite formation upon exposure of the materials in simulated body fluid and improved affinity of the materials for osteoblast-like cells. Typically, polymers containing phosphate groups are organic matrices consisting of apatite-polymer composites prepared by biomimetic process using simulated body fluid. Ca(2+) incorporation into the polymer accelerates apatite formation in simulated body fluid owing because of increase in the supersaturation degree, with respect to apatite in simulated body fluid, owing to Ca(2+) release from the polymer.

Fibronectin adsorption on osteoconductive hydroxyapatite and non-osteoconductive α-alumina.

The osteoconductivity mechanism of hydroxyapatite (HAp) has not been elucidated. It is hypothesized that specific proteins adsorb on HAp, promoting its osteoconductivity. To verify this hypothesis, we compared the adsorption behavior of fibronectin (Fn) on HAp powder and on α-alumina (α-Al2O3) powder, a material with no osteoconductivity.