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This paper presents a novel cheminformatics approach for the design and synthesis of hydroxyapatite/collagen nanocomposites, which have potential biomedical applications in tissue engineering, drug delivery, and orthopedic and dental implants. The nanocomposites are synthesized by the co-precipitation method with different ratios of hydroxyapatite and collagen. Their mechanical, biological, and degradation properties are analyzed using various experimental and computational techniques. Attenuated total reflection–Fourier-transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction unveil the low crystallinity and nanoscale particle size of hydroxyapatite (22.62 nm) and hydroxyapatite/collagen composites (14.81 nm). These findings are substantiated by scanning electron microscopy with energy-dispersive X-ray spectroscopy, confirming the Ca/P ratio between 1.65 and 1.53 and attesting to the formation of non-stoichiometric apatites in all samples, further validated by molecular simulation. The antimicrobial activity of the nanocomposites is evaluated in vitro against several bacterial and fungal strains, demonstrating their medical potential. Additionally, in silico analyses are performed to predict the absorption, distribution, metabolism, and excretion properties and the bioavailability of the collagen samples. This study paves the way for the development of novel biomaterials using chemoinformatics tools and methods, facilitating the optimization of design and synthesis parameters, as well as the prediction of biological outcomes. Future research directions should encompass the investigation of in vivo biocompatibility and bioactivity of the nanocomposites, while exploring further applications and functionalities of these innovative materials. [ABSTRACT FROM AUTHOR]

Poly(glycerol sebacate) (PGS) is a novel polymeric material intended for applications in tissue engineering (TE). This study involves synthesizing the PGS prepolymer (pPGS) and subsequent manufacturing of porous PGS-based scaffolds with an addition of hydroxyapatite (HAp) by means of thermally induced phase separation followed by thermal cross-linking and salt-leaching (TIPS-TCL-SL). The study aims to investigate the effect of the apatite filler content on properties and morphology of porous PGS/HAp scaffolds. The emphasis is put on the mechanical behavior of the material characterized by means of compression tests and dynamic thermal mechanical analysis (DMTA). In addition to the reference polymer scaffold, the composites with filler contents of 10, 20 and 30 wt% have been examined. Our research revealed that the HAp content does not affect the mechanical properties in a directly proportional manner. The 30 wt% addition of HAp resulted in frayed structure and decrease in the mechanical parameters in comparison to other tested specimens. On the other hand, an addition of 10% did not sufficiently boost the properties. Therefore, a 20% addition of HAp was concluded to have superior mechanical properties in comparison to other analyzed specimens. A similar relationship results from the DMTA studies. Moreover, the strain sweep and frequency sweep tests confirmed the stability of the mechanical parameters in various conditions, as well as the elastomeric nature of the materials. Finally, the material did not exhibit cytotoxicity against standard L929 fibroblasts and cells readily populated the scaffolds. [Display omitted] [ABSTRACT FROM AUTHOR]

In situ facile synthesis and the characterization of nanohydroxyapatite/chitosan (nHAP/CS) biocomposites were investigated for examining their potential applications in orthopedic implant technology. Firstly, the bare nHAP, europium-doped hydroxyapatite (Eu-nHAP), yttrium-doped hydroxyapatite (Y-nHAP), and Eu- and Y-codoped hydroxyapatite (Eu,Y-nHAP) nanoparticles were synthesized by the wet precipitation technique using biowaste-eggshell-derived calcium oxide powders. Then, through ultrasonication using the nanohydroxyapatite/chitosan mixtures (molar ratio = 1:2), the nHAP/CS, Eu-nHAP/CS, Y-nHAP/CS, and Eu,Y-nHAP/CS biocomposites were fabricated. Among them, Eu,Y-nHAP/CS showed higher cell viability (94.9%), higher solubility (pH = 7.6 after 21 days), and greater antibacterial activity than those of the other composites. In addition, Eu,Y-nHAP/CS exhibited improved mechanical properties compared with the other composites. For example, the nanoindentation test displayed the Eu,Y-nHAP/CS-coated 316L stainless steel implant to possess a higher Young's modulus value (9.24 GPa) and greater hardness value (300.71 MPa) than those of the others. The results indicate that the biomass-eggshell-derived Eu,Y-doped nHAP is of good use for orthopedic implant applications. [ABSTRACT FROM AUTHOR]

This study aimed to develop injectable chitosan oligosaccharide (COS) and bovine hydroxyapatite (BHA) hybrid biocomposites, and characterise their physiochemical properties for use as a dental pulp-capping material. The COS powder was prepared from chitosan through hydrolytic reactions and then dissolved in 0.2% acetic acid to create a solution. BHA was obtained from waste bovine bone and milled to form a powder. The BHA powder was incorporated with the COS solution at different proportions to create the COS–BHA hybrid biocomposite. Zirconium oxide (ZrO2) powder was included in the blend as a radiopacifier. The composite was characterised to evaluate its physiochemical properties, radiopacity, setting time, solubility, and pH. Fourier-transform infrared spectroscopic analysis of the COS–BHA biocomposite shows the characteristic peaks of COS and hydroxyapatite. Compositional analysis via ICP-MS and SEM-EDX shows the predominant elements present to be the constituents of COS, BHA, and ZrO2. The hybrid biocomposite demonstrated an average setting time of 1 h and 10 min and a pH value of 10. The biocomposite demonstrated solubility when placed in a physiological solution. Radiographically, the set hybrid biocomposite appears to be more radiopaque than the commercial mineral trioxide aggregate (MTA). The developed COS-BHA hybrid biocomposite demonstrated good potential as a pulp-capping agent exhibiting high pH, with a greater radiopacity and reduced setting time compared to MTA. Solubility of the biocomposite may be addressed in future studies with the incorporation of a cross-linking agent. However, further in vitro and in vivo studies are necessary to evaluate its clinical feasibility. [ABSTRACT FROM AUTHOR]

In the last few decades, hydroxyapatite (HA) has become one of the most highly prized biominerals in the biomedical industry for orthopedic and dental applications. The focus of this research was to synthesize biomimetic HA from Tridax procumbens (TP) leaf extract and investigate their antibiofilm properties. The HA was made using the sol-gel method and the HA-TP biocomposite was made by precipitation method. The d.nm size of HA and HA-TP biocomposite was determined as 193.28 and 258.14 d.nm, respectively. The zeta potential of HA and HA-TP biocomposite was determined as -21.2 and -18.3 mV, respectively, and found highly stable. The FTIR study revealed that phytochemicals of TP were successfully impregnated into HA-TP biocomposite. The HA and HA-TP biocomposite were found spherical and agglomerated from SEM analysis. In HR-TEM analysis, the average diameter of the HA and HA-TP biocomposite were 16.57 - 64.22 nm and 51.71 - 138.68 nm, respectively. According to the EDX analysis, HA is primarily composed of calcium, oxygen, and phosphate, whereas, HA-TP biocomposite is primarily composed of calcium, phosphate, oxygen, and carbon. In the antioxidant assay, the IC50 value (concentration required to scavenge 50% of free radicals) of HA-TP biocomposite was determined as 156.69 ± 14.02 and 180.21 ± 12.84 µg/mL in DPPH and ABTS free radical scavenging assays, respectively. The MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration) of assynthesized HA-TP biocomposite against Staphylococcus aureus - ATCC 13565 and Escherichia coli - MTCC 41 were observed as 181.09 ± 21.47 and 317.30 ± 41.03, and 157.59 ± 32.18 and 264.03 ± 21.58 µg/mL, respectively. The assynthesized HA-TP biocomposite has detrimentally affected the biofilm formation of both the tested bacteria S. aureus - ATCC 13565 and E. coli -- MTCC 41. The study concluded that the as-synthesized HA-TP biocomposite could be highly helpful in the biomedical field for alleviating oxidative-stress-related disorders and inhibiting microbial biofilm formation. [ABSTRACT FROM AUTHOR]

This study intends to analyze the properties and potential applications of a novel composite coating composed of poly (methyl methacrylate) (PMMA) and silver-doped hydroxyapatite (HAPAg) produced from waste eggshells, which was dip-coated onto Ti6Al4V substrates. Medical implants frequently made of the titanium alloy Ti6Al4V can benefit greatly from surface coatings in terms of biocompatibility and performance. In order to add antibacterial and osteoconductive characteristics, silver-doped hydroxyapatite nanoparticles were dispersed within a PMMA matrix to create the PMMA/HAPAg composite coating. The coated samples report an average contact angle (CA) between 70 and 750 and total surface free energy (SFE) between 35 and 50 mJ/m2, which signifies its improved wettability. The 7.03% change in hydrophilicity was observed between PMMA/H0 (75.270 ± 1.690) and PMMA/H20 (700 ± 1.440) coated samples. The increase in adhesion strength and coating thickness with the increase in HAPAg reinforcement was observed. The surface morphology of the defective zones was examined using scanning electron microscopy (SEM), and information on the elemental composition of synthesized was obtained using Inductively Coupled Plasma Mass Spectroscopy (ICPMS), Fourier Transform Infrared spectroscopy (FTIR) and X-ray diffractogram (XRD). Atomic force microscopy (AFM) reveals the surface roughness; root mean square roughness, roughness profile, skewness and kurtosis of the coated samples. The contact angle reports the hydrophilicity and SFE. Finally, the results conclude that the composite coating had a consistent distribution of HAPAg nanoparticles incorporated within the PMMA matrix. The minimal presence of Ag ions on the surface indicates the coating's potential antibacterial properties, and it is highly recommended for dental applications. [Display omitted] [ABSTRACT FROM AUTHOR]

The current treatment of osteomyelitis includes systemic antibiotic therapy and a debridement procedure of the formed biofilm and necrotic tissue. Moreover, cements and three-dimensional scaffolds are used both for the delivery of therapeutic agents and as fillers for bone defects. The aim of our research was to test, on cellular cultures, the biocompatibility of a previously synthesized microporous biocomposite containing hydroxyapatite and a collagen matrix including a therapeutic agent (ciprofloxacin and gentamicin). The scaffold was obtained by direct mineralization namely co-precipitation of hydroxyapatite on a collagen matrix. [ABSTRACT FROM AUTHOR]

The key challenge in tissue engineering is to develop structures with sufficient characteristics that will replicate the natural extracellular matrix (ECM) to promote tissue regeneration. Copper and manganese minerals substituted hydroxyapatite (CuMn-HA)/chitosan (CTS)–polyvinyl pyrrolidone (PVD) were fabricated by sol–gel and solvent casting techniques, respectively. Fabricated biocomposites have been identified by the use of Fourier transform infrared (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) for the analysis of functional groups, crystalline phases and surface morphology. The XRD and FTIR spectra of the biocomposite revealed the existence of functional groups and crystalline phases in the biocomposites. The SEM images revealed biocomposite and inclusion of CuMn-HA in rough morphology. Physicochemical characteristics such as swelling and compressive strength have been examined in the preparation of biocomposite materials. Biocomposites (10, 20, 30 wt% of CuMn-HA biocomposite) exhibited great material characteristics where 30% displayed the minimum swelling and a compressive property of 71 MPa was tested. It displayed the highest inhibition zone towards bacteria population and was also found to be blood-compatible with a haemolytic value of only about 2.5% relative to other compounds. Finally, in-vitro cell cultures were performed in biocomposite scaffolds to determine the effects of CuMn-HA on the proliferation of osteoblast cells, resulting in biocomposites contrast to pristine PVD/CTS. [ABSTRACT FROM AUTHOR]

The biocompatibility of orthopaedic implants and their effects on fracture healing have key roles for success. In this study, it was aimed to investigate the effects of a novel biocomposite consisting of hydroxyapatite (HA), hexagonal boron nitride (h-BN), chitosan (Cs), and type 1 collagen (Ct1) on biocompatibility and fracture healing in rats. A total of 60 adult male Wistar rats weighing 300-500 g were used in the study. The rats were randomly divided into 2 groups named A (uncoated/control) and B (biocomposite coated). Biocomposite (HA/h-BN/Cs/Ct1) coated and uncoated stainless-steel implants were used as intramedullary pins. Groups A and B were divided into subgroups of A1 and B1 (15th day), A2 and B2 (30th day), A3 and B3 (45th day) according to the date of euthanasia. Clinical, radiographic, haematological, biochemical, and histopathological findings were evaluated by pairwise comparisons. The findings were consistent and similar. No statistically significant difference was found for a finding disturbing the biocompatibility. Histopathological examinations showed that coating biomaterials did not resorb over the course of 15, 30, and 45 days. It is thus revealed that the content is biocompatible. However, it has been concluded that it is necessary to increase the physical strength of the coating surface against sterilization and surgical procedures. As a result, based on the interpretations of the clinical, radiographic, haematological, biochemical, and histopathological findings, the biocompatibility of HA/h-BN/Cs/Ct1 biocomposite materials has been revealed. [ABSTRACT FROM AUTHOR]

Nano-hydroxyapatite (nHA) based polymer biocomposites have been widely used in biomedical industry because of biocompatibility and improved mechanical properties. The goal of this study was to produce ultra high molecular weight (UHMW) polyethylene/nHA composite via heat-assisted friction stir processing and to investigate the effects of process parameters on composite’s microstructure and tensile characteristics. The process parameters include rotational speed (ω), feed rate (f), volume fraction of nHA (v), and shoulder temperature (T). ANOVA was performed to identify the significant process parameters. Moreover, empirical models for tensile properties were developed and validated. Microscopic analysis revealed that the process parameters substantially affect the dispersion of reinforcing particles, formation of defects, and mixing of materials. Low levels of ω and T and high levels of f and v lead to defects (agglomeration of reinforcing particles, voids, and channels). Five percent volume of nHA with medium levels of other process parameters resulted in better material mixing, minimum defects, and better mechanical properties (10% increase in strength with only 1% reduction in percent elongation, relative to the parent material). [ABSTRACT FROM AUTHOR]

In the present study, we aimed at fabricating an osteoinductive biocomposite scaffold using keratin obtained from human hair, jellyfish collagen and eggshell-derived nano-sized spherical hydroxyapatite (nHA) for bone tissue engineering applications. Keratin, collagen and nHA were characterized with the modified Lowry method, free-sulfhydryl groups and hydroxyproline content analysis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR) and thermal gravimetric analysis (TGA) which confirmed the success of the extraction and/or isolation processes. Human adipose mesenchymal stem cells (hAMSCs) were isolated and the cell surface markers were characterized via flow cytometry analysis in addition to multilineage differentiation capacity. The undifferentiated hAMSCs were highly positive for CD29, CD44, CD73, CD90 and CD105, but were not seen to express hematopoietic cell surface markers such as CD14, CD34 and CD45. The cells were successfully directed towards osteogenic, chondrogenic and adipogenic lineages in vitro . The microarchitecture of the scaffolds and cell attachment were evaluated using scanning electron microscopy (SEM). The cell viability on the scaffolds was assessed by the MTT assay which revealed no evidence of cytotoxicity. The osteogenic differentiation of hAMSCs on the scaffolds was determined histologically using alizarin red S, osteopontin and osteonectin stainings. Early osteogenic differentiation markers of hAMSCs were significantly expressed on the collagen-keratin-nHA scaffolds. In conclusion, it is believed that collagen-keratin-nHA osteoinductive biocomposite scaffolds have the potential of being used in bone tissue engineering. [ABSTRACT FROM AUTHOR]

In order to prepare sophisticated biomaterials using a biomimetic approach, a deeper understanding of biomineralization is needed. Of particular importance is the control and regulation of the mineralization process. In this study, a novel bilayer rate-controlling model was designed to investigate the factors potentially influencing mineralization. In the absence of a rate-controlling layer, nano-scale hydroxyapatite (HA) crystallites exhibited a spherical morphology, whereas, in the presence of a rate-controlling layer, HA crystallites were homogeneously dispersed and spindle-like in structure. The mineralization rate had a significant effect on controlling the morphology of crystals. Furthermore, in vitro tests demonstrated that the reaction layer containing spindle-like HA crystallites possessed superior biological properties. These results suggest that a slow mineralization rate is required for controlling the morphology of inorganic crystallites, and consumption by the rate-controlling layer ensured that the ammonia concentration remained low. This study demonstrates that a biomimetic approach can be used to prepare novel biomaterials containing HA crystallites that have different morphologies and biological properties. [ABSTRACT FROM AUTHOR]

The present study evaluated a new concept of combined scaffolds as a promising bone replacement material for patients with a bone tumour or bone metastasis. The scaffolds were composed of hydroxyapatite doped with selenium ions and a biodegradable polymer (linear or branched), and contained an active substance-bisphosphonate. For this purpose, a series of biodegradable polyesters were synthesized through a ring-opening polymerization of ε-caprolactone or D,L-lactide in the presence of 2-hydroxyethyl methacrylate (HEMA) or hyperbranched 2,2-bis(hydroxymethyl)propionic acid polyester-16-hydroxyl (bis-MPA) initiators, substances often used in the synthesis of medical materials. The polymers were obtained with a high yield and a number-average molecular weight up to 45,300 (g/mol). The combined scaffolds were then manufactured by a direct compression of pre-synthesized hydroxyapatite doped with selenite or selenate ions, obtained polymer and pamidronate as a model drug. It was found that the kinetic release of the drug from the scaffolds tested in vitro under physiological conditions is strongly dependent on the physicochemical properties and average molecular weight of the polymers. Furthermore, there was good correlation with the hydrolytic biodegradation results of the scaffolds fabricated without drug. The preliminary findings suggest that the fabricated combined scaffolds could be effectively used for the sustained delivery of bioactive molecules at bone defect sites. [ABSTRACT FROM AUTHOR]

This work presents a novel composite hydrogel consisting of silk fibroin (SF) and nanohydroxyapatite (nanoHA) prepared by a new and innovative method using ethanol as gelling agent capable of forming hydrogels in few minutes. The properties of the composite material, such as the microstructure as well as the chemical and physical properties were studied. Moreover in␣vitro studies of osteoblastic citocompatibility were performed. The microporosity and macroporosity obtained combined with interconnected porous structure and a uniform dispersion of nanoHA particles throughout the fibroin matrix makes composite hydrogel suitable for bone regeneration. The compression modulus of composite hydrogels was increased as the nanoHA concentration increased from 10 to 15 wt.% and the water uptake ability of these materials decreased with the incorporation of nanoHA. The metabolic and alkaline phosphatase activities of osteoblastic cells were improved with the incorporation of nanoHA in the SF matrix providing a more promising material for bone tissue engineering. [ABSTRACT FROM AUTHOR]

[Display omitted] • nHAp/PLDLLA composites with wt.% ratio: 10/90 and 20/80 were prepared by an-extrusion process. • Structural properties of the filler and polymeric blends were characterized in detail. • Mechanical results and density values were reported as close to human bone. • Contact angle analysis showed a favored growth of tissue on the biocomposite containing 10 wt% nHAp. • The PLDLLA-based composite can be an excellent candidate for bone reconstruction implants. A novel, bone-reconstruction dedicated polymeric-nanohydroxyapatite material has been prepared for 3D-printed implant. The composites of poly(L-lactide- co -D,L-lactide) (PLDLLA) and nanosized hydroxyapatite were prepared by a co-rotating twin-screw extrusion. Structural properties of the filler and polymeric blends were characterized by XRD (X-ray Powder Diffraction), SEM (Scanning Electron Microscopy), and EDS mapping (energy dispersive spectroscopy), FT-IR (Fourier-transformed infrared spectroscopy), and NMR (Nuclear Magnetic Resonance) technics. Molar masses of the composites at various preparation steps were also investigated. The structural studies and thermogravimetric analysis proved a successful preparation of the nanohydroxyapatite and its nanocomposites. Mechanical results in conjunction with density values, reported as close to human bone, evidenced usability of this novel material for internal bone fixation implant. Contact angle analysis showed favored growth of tissue on the biocomposite containing 10 wt% of the filler. The PLDLLA-based composite can be an excellent candidate for bone reconstruction implants due to their superior mechanical properties, bioactivity, and complete resorbability. [ABSTRACT FROM AUTHOR]

Abstract: Nanotechnology has enabled the engineering of nanostructured materials to meet current challenges in bone replacement therapies. Biocomposite nanofibrous scaffolds of poly(l-lactic acid)-co-poly(ɛ-caprolactone), gelatin and hydroxyapatite (HA) were fabricated by combining the electrospinning and electrospraying techniques in order to create a better osteophilic environment for the growth and mineralization of osteoblasts. Electrospraying of HA nanoparticles on electrospun nanofibers helped to attain rough surface morphology ideal for cell attachment and proliferation and also achieve improved mechanical properties than HA blended nanofibers. Nanofibrous scaffolds showed high pore size and porosity up to 90% with fiber diameter in the range of 200–700nm. Nanofibrous scaffolds were characterized for their functional groups and chemical structure by FTIR and XRD analysis. Studies on cell–scaffold interaction were carried out by culturing human fetal osteoblast cells (hFOB) on both HA blended and sprayed PLACL/Gel scaffolds and assessing their growth, proliferation, mineralization and enzyme activity. The results of MTS, ALP, SEM and ARS studies confirmed, not only did HA sprayed biocomposite scaffolds showed better cell proliferation but also enhanced mineralization and alkaline phosphatase activity (ALP) proving that electrospraying in combination with electrospinning produced superior and more suitable biocomposite nanofibrous scaffolds for bone tissue regeneration. [Copyright &y& Elsevier]

Abstract: Biocomposites of hydroxyapatite, HAp, in conjunction with various binders including poly(vinyl alcohol), PVA, and collagen have the potential of serving in various tissue engineering applications, such as in bone repair and reconstruction tasks, especially if the nanoparticles of hydroxyapatite are used. Here, hydroxyapatite nanoparticles (n-HAp) were synthesized at the ultimate size range of 10–50nm and then incorporated into PVA or in situ synthesized in collagen/PVA. The biocomposites of HAp with PVA exhibited relatively high elasticity (as revealed by the linear viscoelastic material functions, characterized upon small-amplitude oscillatory shear) especially upon cryogenic treatment. The incorporation of the collagen into the PVA/HAp biocomposite provided internal porosity to the biocomposite with the pores in the 50–100nm range for collagen/HAp and 50–500nm for the collagen/HAp/PVA. [Copyright &y& Elsevier]

A new kind of tissue engineering scaffold materials of needle-like nano-hydroxyapatite (n-HA) and polyamide (PA) biocomposite is prepared by co-solution, co-precipitation method and water treatment under normal atmospheric pressure. The n-HA crystals uniformly distribute in the composite with a crystal size of 10–20 nm in diameter by 70–90 nm in length. The n-HA/PA composite has good homogeneity, high n-HA content (65 wt%), and high bioactivity. Strong molecule interactions and chemical bondings are present between the n-HA and PA in the composite, which are verified by IR, XPS and XRD. The composite has excellent mechanical properties close to the natural bone. The porous 3-D scaffold is made by injection foaming method, which has not only macropores, but also micropores on the walls of macropores. The porosity is 80% and the average macropore diameter is about 300 μm of the composite.The n-HA/PA composite can be used for tissue engineering and bone repair or substitute. [Copyright &y& Elsevier]

Different biomaterials have been used as scaffolds for bone tissue engineering. Here we characterize a biomaterial composed of sintered (1100°C) and powdered hydroxyapatite (HA) and type I collagen (Coll), both of bovine origin, designed for osteoconductive and osteoinductive scaffolds. Coll/HA proportions were 1/2.6 and 1/1 (wet weight), and particles sizes varied from 200 to 400 μm. Vv (volume density) and Sv (surface to volume density) for the HA particles in the composite ranged from 0.48±0.06 to 0.55±0.02 and 5.090±0.545 to 6.366±0.289 μm−1, respectively. Due to the relatively small changes in Vv and Sv, a macroporosity could be characterized for the biocomposite. X-ray diffraction and infrared spectroscopy showed that the sintered bone was composed essentially of HA with minimum additional groups such as surface calcium hydroxide, surface and crystal water, free carbon dioxide and possibly brushite. Mass spectrometry detected carbonates at A and B sites of HA, and weakly bound to the structure. Human osteoblasts adhered and spread on both the HA particle surface and the collagen fibers, which seemed to guide cells between adjacent particles. The biocomposite studied has several characteristics considered as ideal for its use as a scaffold for osteoconduction and osteoinduction. [Copyright &y& Elsevier]

Traditionally, hydroxyapatite was used as a coating material on titanium substrate by various techniques. In the present work, a biocomposite was successfully fabricated from hydroxyapatite and titanium powders by powder metallurgy method. Bioactivity of the composite in a simulated body fluid (SBF) was investigated. Main crystal phases of the as-fabricated composite are found to be Ti2O, CaTiO3, CaO, α-Ti and a TiP-like phase. When the composite is immersed in the simulated body fluid for a certain time, a poor-crystallized, calcium-deficient, carbonate-containing apatite film will form on the surface of the composite. The time required to induce apatite nucleation is within 2 h. In addition, the apatite is also incorporated with a little magnesium and chlorine element. It is found that Ti2O has the ability to induce the formation of bone-like apatite in the SBF. And a dissolve of the CaO phase could also provide favorable conditions for the apatite formation, by forming open pores on the surface of the composite and increasing the degree of supersaturation of the SBF with respect to the apatite. [Copyright &y& Elsevier]

• Functionalized nHAp was obtained using arginine or polyethylenimine. • Resulted nanoparticles were comparatively characterized relative to used modifiers. • Linear polyethylenimine coated hydroxyapatite had the best DNA binding ability. • Use of LPEI functionalized nHAp in biocomposites recipe had a strengthening effect. • The 3D constructs demonstrated rapid self–recovery and fatigue resistant behavior. Functionalized nano-hydroxyapatite (nHAp) was obtained by wet chemical technique, using arginine (Arg) or polyethylenimine (branched-bPEI, or linear-LPEI) as cationic modifiers and dispersing agents. TEM, FT-IR, SEM, DLS and WAXD characterization results showed that the prepared nanoparticles possessed needle- or plate-like morphologies and Arg and PEI were successfully grafted onto nHAp. LPEI functionalized nHAp exhibited a good similitude with biological apatite and the best DNA binding ability. In addition, the incorporation of nHAp/LPEI nanoparticles within collagen/dimethylsilanediol hyaluronate-based porous matrices pointed out a significant improvement of the compressive modulus of biocomposites: up to a six-fold increase, compared with the polymer matrix without fillers. Moreover, the composite sponges revealed high toughness during five consecutive compression tests without any permanent deformation and cracks. Therefore, nHAp/LPEI nanoparticles could be considered promising materials for biomedical applications, like gene carrier or reinforcement filler with strong interfacial adhesion in biocomposites for bone engineering. [ABSTRACT FROM AUTHOR]

This paper proposes the development of a biomimetic composite based on naturally derived biomaterials. This freeze-dried scaffold contains a microwave-synthesized form of biomimetic hydroxyapatite (HAp), using the interwoven hierarchical structure of eggshell membrane (ESM) as bio-template. The bone regeneration capacity of the scaffold is enhanced with the help of added tricalcium phosphate from bovine Bone ash (BA). With the addition of Gelatin (Gel) and Chitosan (CS) as organic matrix, the obtained composite is characterized by the ability to stimulate the cellular response and might accelerate the bone healing process. Structural characterization of the synthesized HAp (ESM) confirms the presence of both hydroxyapatite and monetite phases, in accordance with the spectroscopy results on the ESM before and after the microwave thermal treatment (the presence of phosphate group). Morphology studies on all individual components and final scaffold, highlight their morphology and porous structure, characteristics that influence the biocompatibility of the scaffold. Porosity, swelling rate and the in vitro cytotoxicity assays performed on amniotic fluid stem cells (AFSC), demonstrate the effective biocompatibility of the obtained materials. The experimental results presented in this paper highlight an original biocomposite scaffold obtained from naturally derived materials, in a nontoxic manner. [ABSTRACT FROM AUTHOR]

Type I collagen and nanocrystalline-substituted hydroxyapatite are the major components of a natural composite—bone tissue. Both of these materials also play a significant role in orthopedic surgery and implantology; however, their separate uses are limited; apatite is quite fragile, while collagen's mechanical strength is very poor. Therefore, in biomaterial engineering, a combination of collagen and hydroxyapatite is used, which provides good mechanical properties with high biocompatibility and osteoinduction. In addition, the porous structure of the composites enables their use not only as bone defect fillers, but also as a drug release system providing controlled release of drugs directly to the bone. This feature makes biomimetic collagen–apatite composites a subject of research in many scientific centers. The review focuses on summarizing studies on biological activity, tested in vitro and in vivo. [ABSTRACT FROM AUTHOR]

Healing of large bone defects requires implants or scaffolds that provide structural guidance for cell growth, differentiation, and vascularization. In the present work, an agarose-hydroxyapatite composite scaffold was developed that acts not only as a 3D matrix, but also as a release system. Hydroxyapatite (HA) was incorporated into the agarose gels in situ in various ratios by a simple procedure consisting of precipitation, cooling, washing, and drying. The resulting gels were characterized regarding composition, porosity, mechanical properties, and biocompatibility. A pure phase of carbonated HA was identified in the scaffolds, which had pore sizes of up to several hundred micrometers. Mechanical testing revealed elastic moduli of up to 2.8 MPa for lyophilized composites. MTT testing on Lw35human mesenchymal stem cells (hMSCs) and osteosarcoma MG-63 cells proved the biocompatibility of the scaffolds. Furthermore, scaffolds were loaded with model drug compounds for guided hMSC differentiation. Different release kinetic models were evaluated for adenosine 5′-triphosphate (ATP) and suramin, and data showed a sustained release behavior over four days. [ABSTRACT FROM AUTHOR]