Indirect Contact Methods Research Articles

Preparation and Characterization of Photo-Cross-Linkable Methacrylated Silk Fibroin and Methacrylated Hyaluronic Acid Composite Hydrogels.

Composite biomaterials with excellent biocompatibility and biodegradability are crucial in tissue engineering. In this work, a composite protein and polysaccharide photo-cross-linkable hydrogel was prepared using silk fibroin methacrylate (SFMA) and hyaluronic acid methacrylate (HAMA). SFMA was obtained by the methacrylation of degummed SF with glycidyl methacrylate (GMA), while HA was methacrylated by 2-aminoethyl methacrylate hydrochloride (AEMA). We investigated the effect of the addition of 1 wt % HAMA to 5, 10, and 20 wt % SFMA, which resulted in an increase in both static and cycling mechanical strengths. All composite hydrogels gelled under UV light in <30 s, allowing for rapid stabilization and stiffness increases. The biocompatibility of the hydrogels was confirmed by direct and indirect contact methods and by evaluation against the NIH3T3 and MC3T3 cell lines with a live-dead assay by confocal imaging. The range of obtained mechanical properties from developed composite and UV-cross-linkable hydrogels sets the basis as possible future biomaterials for various biomedical applications.

Toxicological Assessment of Biodegradable Poli-ε-Caprolactone Polymer Composite Materials Containing Hydroxyapatite, Bioglass, and Chitosan as Potential Biomaterials for Bone Regeneration Scaffolds.

Polycaprolactone (PCL) is a biodegradable polyester that might be used in tissue engineering to obtain scaffolds for bone reconstruction using 3D-printing technologies. New material compositions based on PCL, with improved physicochemical properties and excellent biocompatibility, would improve its applicability in bone regeneration. The aim of this study was to assess the potential toxic effects of PCL-based composite materials containing 5% hydroxyapatite (PCL/SHAP), 5% bioglass (PCL/BIO), or 5% chitosan (PCL/CH) on MG-63 human fibroblast-like cells in vitro. Material tests were carried out using X-ray diffraction, differential thermal analysis/thermal gravimetry, BET specific surface analysis, and scanning electron microscopy. The effect of the biomaterials on the MG-63 cells was then assessed based on toxicity tests using indirect and direct contact methods. The analysis showed that the tested biomaterials did not significantly affect cell morphology, viability, proliferation, or migration. We concluded that biodegradable PCL-based scaffolds may be suitable for tissue scaffold production, and the addition of bioglass improves the growth of cultured cells.

Rare Earth Extraction from Phosphogypsum by Aspergillus niger Culture Broth.

The extraction of rare earth elements (REEs) from phosphogypsum (PG) is of great significance for the effective utilization of rare earth resources and enhancing the resource value of PG waste residues. This study used Aspergillus niger (A. niger) fungal culture filtrate as a leaching agent to investigate the behavior of extracting REEs from PG through direct and indirect contact methods. According to the ICP-MS results, direct leaching at a temperature of 30 °C, shaking speed of 150 rpm, and a solid-liquid ratio of 2:1, achieved an extraction rate of 74% for REEs, with the main elements being yttrium (Y), lanthanum (La), cerium (Ce), and neodymium (Nd). Under the same conditions, the extraction rate of REEs from phosphogypsum using an A. niger culture filtrate was 63.3% higher than that using the simulated organic acid-mixed solution prepared with the main organic acid components in the A. niger leachate. Moreover, the morphological changes observed in A. niger before and after leaching further suggest the direct involvement of A. niger's metabolic process in the extraction of REEs. When compared to using organic acids, A. niger culture filtrate exhibits higher leaching efficiency for extracting REEs from PG. Additionally, using A. niger culture filtrate is a more environmentally friendly method with the potential for industrial-scale applications than using inorganic acids for the leaching of REEs from PG.

Larvicidal activity of Stemona collinsiae root extract against Musca domestica and Chrysomya megacephala

Musca domestica and Chrysomya megacephala, considered synanthropic insects, are medically important flies, as they transmit vector-borne diseases to humans and animals. In Thailand, Stemona (Stemonaceae) plants have been traditionally used as insecticides. This study was designed to determine the larvicidal activity of S. collinsiae root extract against M. domestica and C. megacephala larvae. A 70% ethanol crude extract from S. collinsiae roots was tested against the third-instar larvae of both species using direct and indirect contact methods. The development and mortality rates of the insects were observed, and the LC values were calculated. The extract caused irregular development in both species, shown as segmental puparia that could not emerge as adult flies. The LC50 values of the extract against M. domestica tested by direct and indirect contact methods were 0.0064 ± 0.0005 mg/larva and 0.0165 ± 0.0002 mg/cm2/larva, respectively. In the case of C. megacephala, the LC50 value determined by the indirect contact method was 1.0500 ± 0.0001 mg/cm2/larva. The ethanolic root extract of S. collinsiae was able to kill the larvae of both species after dermal administration. It is of interest to develop S. collinsiae root extract as a natural fly control biopesticide.

Study on Factors Affecting Hemolytic Properties of Cyanoacrylate Glues for Surgical Use

This study aims to discuss the factors affecting the hemolytic properties of α-cyanoacrylate glues for surgical use. The results showed that the different extractions, test methods, pH value, rapid solidification and the extract ratio were the main factors affecting the hemolytic properties. The choose of PBS as the extraction for haemolysis test maybe was more suitable than physiological saline. It was recommended that using both direct contact methods and indirect contact methods should be more comprehensive for hemolytic evaluation.

Synthesis and physical properties of LaNiO2 crystals

Infinite-layer (IL) nickelates are an emerging family of superconductors whose similarities and differences to cuprate superconductors are under intense debate. To date, the IL phase of nickelates can only be reached via topotactic oxygen reduction of the perovskite phase, using H$_2$ gas or reducing agents such as CaH$_2$. While the topotactic reduction method has been widely employed on thin film and polycrystalline powder samples, the reduction of La$_{1-x}$Ca$_x$NiO$_3$ single-crystals with lateral dimensions up to 150 $\mu$m was achieved only recently, using an indirect contact method with CaH$_2$. Here we report the topotactic transformation of much larger LaNiO$_3$ crystals with lateral dimensions of more than one millimeter, via direct contact with CaH$_2$. We characterize the crystalline, magnetic, and electronic properties of the obtained IL LaNiO$_{2}$ crystals by powder and single-crystal x-ray diffraction (XRD), magnetometry, electrical transport, and x-ray photoelectron spectroscopy (XPS) measurements. The amount of incorporated topotactic hydrogen due to the reduction process is determined by a gas extraction method. In addition, we investigate the evolution of the lattice parameters under hydrostatic pressure up to 12 GPa, using high-resolution synchrotron XRD. Furthermore, we provide a direct comparison of several physical properties of the LaNiO$_{2}$ crystals to their powder and thin film counterparts.

In situ synthesis of silver or selenium nanoparticles on cationized cellulose fabrics for antimicrobial application

In this study, we developed a method to prepare inorganic nanoparticles in situ on the surface of cationized cellulose using a rapid microwave-assisted synthesis. Selenium nanoparticles (SeNPs) were employed as a novel type of antimicrobial agent and, using the same method, silver nanoparticles (AgNPs) were also prepared. The results demonstrated that both SeNPs and AgNPs of about 100 nm in size were generated on the cationized cellulose fabrics. The antibacterial tests revealed that the presence of SeNPs clearly improved the antibacterial performance of cationized cellulose in a similar way as AgNPs. The functionalised fabrics demonstrated strong antibacterial activity when assessed using the challenge test method, even after repeated washing. Microscopic investigations revealed that the bacterial cells were visually damaged through contact with the functionalised fabrics. Furthermore, the functionalised fabrics showed low cytotoxicity towards human cells when tested in vitro using an indirect contact method. In conclusion, this study provides a new approach to prepare cationic cellulose fabrics functionalised with Se or Ag nanoparticles, which exhibit excellent antimicrobial performance, low cytotoxicity and good laundry durability. We have demonstrated that SeNPs can be a good alternative to AgNPs and the functionalised fabrics have great potential to serve as an anti-infective material.

Production of titanium powder by metallothermic reduction of TiO2 in cold pressed pellets

In order to produce low-cost titanium (Ti) with high productivity, fundamental studies on producing metallic Ti from titanium dioxide (TiO2) in the cold pressed pellets were conducted by metallothermic reduction with an indirect contact method. This paper focuses on discussing the mechanism of the reduction process and the relationships of RM (a revised reduction index) with reduction temperature, reduction time, and mole ratio of TiO2 to CaCl2 ( $${n_{{\rm{Ti}}{{\rm{O}}_2}}}/{n_{{\rm{CaC}}{{\rm{l}}_2}}}$$ ) in the pellets. The results show that metallic Ti was obtained from the reduction of TiO2 in the pellets by calcium (Ca) vapor; pellets were reduced homogenously and Ca vapor diffused into the porous pellets by Knudsen diffusion or the mixing diffusion of molecular diffusion and Knudsen diffusion at 1273 K; RM increased with the increases of temperature and reduction time and was 96.34% when TRedu=1273 K, tRedu=6 h, and $${n_{{\rm{Ti}}{{\rm{O}}_2}}}/{n_{{\rm{CaC}}{{\rm{l}}_2}}} = 4$$ ; the reasonable nTiO2/nCaCl2 value is 3–5 for the pellets with enough strength and high RM.

Gallium‐ and Cerium‐Doped Phosphate Glasses with Antibacterial Properties for Medical Applications

Novel cerium‐ (Ce) and gallium (Ga)‐doped phosphate glasses (PGs) are successfully obtained by the peroxidation method. The new glasses are characterized using Fourier‐transform infrared spectroscopy (FTIR), Raman spectroscopy, X‐ray diffraction, inductively coupled plasma‐optical emission spectroscopy (ICP‐OES), and pH measurements. A strong correlation between glass properties and their composition is found. The incorporation of Ga/Ce in the glass structure is confirmed by peak shifts in Raman and FTIR spectra. Degradation tests conducted in water confirm the soluble character of the PGs and reveal the influence of Ga and Ce on the degradation rate. Ga‐doped glasses are found to be less soluble than Ce‐doped ones (43%, 33%, 21%, and 16% of dry mass remained after 7 weeks for 7Ga, 5Ga, 5Ce, and 7Ce, respectively). Biological evaluation using ST‐2 cells shows adequate cell response with a cell viability of 80% measured using the indirect contact method depending on the composition. The cell viability decreases with an increase in Ga content and increases with Ce content. The antibacterial character of Ga/Ce‐doped PGs is confirmed by turbidity measurements against Escherichia coli and Staphylococcus carnosus. The novel Ce/Ga‐doped PGs exhibiting antibacterial properties and biocompatibility reported here are interesting for tissue engineering and wound healing applications.

Cytotoxicity Evaluation of The Bioresorbable and Titanium Plates/Screws Used in Maxillofacial Surgery on Gingival Fibroblasts and Human Mesenchymal Bone Marrow Stem Cells.

Objective Bioresorbable and titanium plates/screws are considered as a standard treatment for fixation of the bone segments of craniofacial area and paying attention to their biocompatibility is an important issue along with other aspects of application. The purpose of the study was to evaluate the cell viability of two types of plate and screw used in maxillofacial surgeries in contact with gingival fibroblasts and bone marrow stem cells. Materials and Methods In this experimental study after extraction and cultivation of cells from healthy human gingival tissue and alveolar bone of jaw, cytotoxicity of device was evaluated. In direct contact method, samples had near vicinity contact with the both cell lines and in indirect contact method, by-products released, like ions, from samples after 8 weeks were used to assess cytotoxicity. Then cytotoxicity was evaluated on the 2nd, 4th and 6th day with MTS tests and microscopy. The data were analyzed by one-way ANOVA and independent t tests. Results There was a statistically significant difference between the German plate and screw and all the samples studied on day 6 (P<0.05). Furthermore, a statistically significant difference was observed between both metal samples and both bio-absorbable samples on day 6 and both cell lines (P<0.05). Comparisons between the two groups with each other for both cell lines on the 6th day were statistically significant (P<0.05). ConclusionOur results suggest that that cytotoxicity of biomaterial, from different brands, were not similar and some of the biomaterial showed lower degree of toxicity compared to others and specialist using these products showed be aware of this differences. Our investigation indicates more biocompatibility of bioresorbable plates and screws compared to titanium. In addition our results suggest that biomaterials were not completely neutral.

Preliminary Study on Development of 3D Free-Form Surface Reconstruction System Using a Webcam Imaging Technique

Reverse engineering faces challenges when it comes to data extraction using indirect contact method. There are 3D scanners capable of extracting data from distance more than a few meters away without contacting the objects but yet limited to same space range only. Although synchronizing the 3D scanners from another place can enable long distance data extraction, synchronizing devices over long distance can lead to other issues such as lagging. Moreover, the uses of 3D scanners usually involve quite long consumption time regardless of same space range or long distance range application. To overcome these issues, this study introduces a 3D surface reconstruction system by including a webcam imaging technique to produce a 3D point cloud, which is the same as that produced by a 3D scanner, and thus, eliminate the use of a 3D scanner. Through webcam imaging, image data can be transferred over the Internet and can be shared instantly even in different locations. Hence, webcam imaging is an alternative to using a 3D scanner. This system will continuously generate 3D free-form surfaces to resemble the surface profile of physical objects. Acquiring data until the surface fitting process will take less time compared with using a combination of 3D scanner and CAD software. In addition, results produced from the webcam imaging technique are compared with conventional results from a 3D scanner.

Bioleaching behaviors of silicon and metals in electrolytic manganese residue using silicate bacteria

Electrolytic manganese residue (EMR) is a kind of solid waste generated along with the production of electrolytic manganese, with a high content of quartz and metals. The former can be used as silicon fertilizer for crops after activation, while the latter may cause harm to surrounding environment due to their toxicity. The aim of this study was to investigate the effects of bacterial on the activation of silicon and fixation of heavy metals in EMR by using microbe-mineral direct contact and indirect contact methods. Mixed cultures of Bacillus mucilaginosus (BM) and Bacillus circulans (BC) were used to achieve activation of silicon in EMR, and the leaching concentration of Mn, Co and Ni and their chemical forms in the leaching residue were also investigated. The results show that the microbe-mineral direct contact method has better performance for the activation of silicon in EMR with the available silicon in the leaching solution up to 163.27 mg L−1 than the indirect contact method. The metals (Mn, Co and Ni) remaining in the residue mainly exist as the stable state after bioleaching, with lower leaching concentration after bioleaching of 20 d. And the effect of silicon bacteria on activation of silicon and the fixation mechanism of metals including the effect of silicate and silicate bacteria is confirmed, and it is verified by the identification of metabolites and the analysis of chemical reaction process. This study investigates the treatment of EMR by using mixed silicate bacteria, and reveals the mechanisms of bacteria on the activation of silicon and fixaion of heavy metals in EMR. The bioleaching method not only provides silicon source for soil but also can realize the reclamation of EMR.

Antibacterial efficiency of cellulose-based fibers covered with ZnO and Al2O3 by Atomic Layer Deposition

Covering the natural fibers with metal oxides enhances the antibacterial properties of textiles. The efficiency of the nanostructured layer is determined by its thickness, uniformity, configuration and adherence to the flexible substrate. Conformal coatings with ZnO and Al2O3 of cotton and viscose fabrics were achieved by Atomic Layer Deposition (ALD) at low temperature. Morphological examination conducted by Scanning Electron Microscopy (SEM) displayed the surface functionalization, elemental mapping provided by Energy Dispersive X-ray Spectroscopy (EDS) illustrated the uniform distribution of Zn and Al oxides, and the chemical structure stability was demonstrated by Fourier Transform Infrared Spectrometry (FTIR). The inhibition of Escherichia coli and Staphylococcus aureus evaluated after 18 h of incubation disclosed very good antibacterial properties of the organic-inorganic composites, with emphasis on viscose coated with metal oxides. In vitro cytotoxic studies developed through direct and indirect contact methods, highlighted the non-toxic effects of Al2O3 on human fibroblasts and keratinocytes.

The Antimicrobial Efficacy of Hypoxia Mimicking Cobalt Oxide Doped Phosphate-Based Glasses against Clinically Relevant Gram Positive, Gram Negative Bacteria and a Fungal Strain.

Bioactive phosphate glasses are of considerable interest for a range of soft and hard tissue engineering applications. The glasses are degradable and can release biologically important ions in a controlled manner. The glasses can also potentially be used as an antimicrobial delivery system. In the given study, novel cobalt-doped phosphate-based glasses, (P2O5)50(Na2O)20(CaO)30-x(CoO)x where 0 ≤ x (mol %) ≤ 10, were manufactured and characterized. As the cobalt oxide concentration increased, the rate of dissolution was observed to decrease. The antimicrobial potential of the glasses was studied using direct and indirect contact methods against both Escherichia coli (NCTC 10538) Staphylococcus aureus (ATCC 6538) and Candida albicans (ATCC 76615). The results showed strong, time dependent, and strain specific antimicrobial activity of the glasses against microorganisms when in direct contact. Antimicrobial activity (R) ≥ 2 was observed within 2 h against Escherichia coli, whereas a similar effect was achieved in 6 h against Staphylococcus aureus and Candida albicans. However, when in indirect contact, the dissolution products from the bioactive glasses failed to show an antimicrobial effect. Following direct exposure to the glasses for 7 days, osteoblast-like SAOS-2 cells showed a 5-fold increase in VEGF mRNA while THP-1 monocytic cells showed a 4-fold increase in VEGF mRNA expression when exposed to 10% CoO-doped glass compared with the cobalt free control glass. Endothelial cells stimulated with conditioned medium taken from cell cultures of THP-1 monocytes exposed to 10% CoO doped glass showed clear tubelike structure (blood vessel) formation after 4 h.

Alginate/poly(amidoamine) injectable hybrid hydrogel for cell delivery.

A covalently cross-linked injectable hybrid hydrogel, namely, alginate/poly(amidoamine) (PAMAM), with the objective of cell delivery was innovatively designed and synthesized using tetra-amino-functional PAMAM dendrimer as the cross-linker. With the increase in percentage of PAMAM cross-linker, the pore size and swelling ratio of hydrogels were in the range of 57 ± 18 μm to 88 ± 25 μm and 110 ± 16 to 157 ± 20, respectively. The study of attachment and proliferation of MC3T3-E1 pre-osteoblasts using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay through indirect and direct contact methods indicated a continuous increase in metabolically active live cells with time, implying non-cytotoxicity of the synthesized hydrogel. The live-dead assay showed >95% of live cells for alginate/PAMAM hydrogels, suggesting viability of the encapsulated cells. When the percentage of PAMAM cross-linker in alginate/PAMAM hydrogel was increased from 5 to 25, the percentage degradation rate decreased from 1.1 to 0.29%/day. Given that the poly(ethylene glycol) is commonly used cross-linker for hydrogel syntheses, we compared the behavior with poly(ethylene glycol). The incorporation of poly(ethylene glycol) in alginate/PAMAM hydrogel reduced the activity of MC3T3-E1 cells and their viability compared to the alginate/PAMAM hydrogels. The protonation of amino groups in alginate/PAMAM injectables under physiological conditions led to the formation of cationic hydrogels. These cationic hydrogels showed enhanced cell encapsulation and attachment ability because of electrostatic interaction with negatively charged cell surface as determined by cell adhesion and extensions from scanning electron microscope and vinculin assay and ability of in situ calcium phosphate mineralization. These observations point toward the potential use as an injectable scaffold for cell delivery and tissue engineering applications.

Tribocorrosion and cytotoxicity of FeB-Fe2B layers on AISI 316 L steel

New results about the tribocorrosion resistance and cytotoxicity of FeB-Fe2B layer developed by the powder-pack boriding process on the surface of AISI 316 L steel are presented in this work. Initially, the tribocorrosion tests in the borided AISI 316 L steel and the untreated material (AISI 316 L steel) were performed in Hank's solution, using a ball-on-flat configuration, which was connected with a three electrode-chemical cell. The sliding tests, in the presence or absence of corrosion, were performed under 20N normal force using an alumina ball as a counter body. For the overall experimental conditions, the material loss for each material was estimated according to the ASTM G119 procedure. Further, the in vitro cytocompatibility of FeB-Fe2B layer on AISI 316 L steel and the untreated material was evaluated by the indirect contact method, in which cell lines of immortalized human fibroblast (CHON-002) and normal renal epithelium of Cercopithecus aethiops (Vero) were used.The results showed that the presence of FeB-Fe2B layer on the AISI 316 L steel improves the tribocorrosion resistance 1.5 times than that of the untreated material, with a presence of a wear-corrosion degradation mechanism in contrast with a wear-dominated regime for the untreated material. Finally, the cytotoxicity tests revealed satisfactory properties in terms of effects on survival and proliferative activity of human fibroblasts and Vero cells on the surface of the borided AISI 316 L steel.

Comparison between direct contact and extract exposure methods for PFO cytotoxicity evaluation

A series of recent acute blindness cases following non–complicated retinal detachment surgery caused the release of several health alerts in Spain. The blindness was attributed to certain lots of perfluoro-octane (PFO; a volatile and transient medical device). Similar cases have been reported in other countries. This has raised questions regarding the validity of cytotoxicity test methods currently used to certify the safety of PFO lots. The tests were performed according to the International Organization for Standardization (ISO) norms, using the extract dilution method or the indirect contact method as applied to L929 cells, a line derived from mouse fibroblasts. The limitations of those methods have been resolved in this study by proposing a new cytotoxicity test method for volatile substances. The new method requires direct contact of the tested substance with cells that are similar to those exposed to the substance in the clinical setting. This approach includes a few new technical steps that are crucial for detecting cytotoxicity. Our new method detected toxic PFO lots that corresponded to the lots producing clinical blindness, which previous methods failed to detect. The study suggests applying this new method to avoid occurrence of such cases of blindness.

Accelerated Degradation Behavior and Cytocompatibility of Pure Iron Treated with Sandblasting.

Fe-based materials are of interest for use in biodegradable implants. However, their corrosion rate in the biological environment may be too slow for the targeted applications. In this work, sandblasting is applied as a successful surface treatment for increasing the degradation rate of pure iron in simulated body fluid. Two sandblasting surfaces with different roughness present various surface morphologies but similar degradation products. Electrochemistry tests revealed that sandblasted samples have a higher corrosion rate compared to that of bare iron, and even more noteworthy, the degradation rate of sandblasted samples remains significantly higher during long-term immersion tests. On the basis of our experimental results, the most plausible reasons behind the fast degradation rate are the special properties of sandblasted surfaces, including the change of surface composition (for the early stage), high roughness (occluded surface sites), and high density of dislocations. Furthermore, the cytocompatibility was studied on sandblasting surfaces using human osteoblast-like cells (MG-63) by indirect and direct contact methods. Results revealed that sandblasting treatment brings no adverse effect to the growth of MG-63 cells. This work demonstrates the significant potential of sandblasting for controlling the degradation behavior of iron-based materials for biomedical applications.

Changes in expression of cartilaginous genes during chondrogenesis of Wharton's jelly mesenchymal stem cells on three-dimensional biodegradable poly(L-lactide-co-glycolide) scaffolds.

BackgroundIn cartilage tissue regeneration, it is important to develop biodegradable scaffolds that provide a structural and logistic template for three-dimensional cultures of chondrocytes. In this study, we evaluated changes in expression of cartilaginous genes during in vitro chondrogenic differentiation of WJ-MSCs on PLGA scaffolds.MethodsThe biocompatibility of the PLGA material was investigated using WJ-MSCs by direct and indirect contact methods according to the ISO 10993–5 standard. PLGA scaffolds were fabricated by the solvent casting/salt-leaching technique. We analyzed expression of chondrogenic genes of WJ-MSCs after a 21-day culture.ResultsThe results showed the biocompatibility of PLGA and confirmed the usefulness of PLGA as material for fabrication of 3D scaffolds that can be applied for WJ-MSC culture. The in vitro penetration and colonization of the scaffolds by WJ-MSCs were assessed by confocal microscopy. The increase in cell number demonstrated that scaffolds made of PLGA copolymers enabled WJ-MSC proliferation. The obtained data showed that as a result of chondrogenesis of WJ-MSCs on the PLGA scaffold the expression of the key markers collagen type II and aggrecan was increased.ConclusionsThe observed changes in transcriptional activity of cartilaginous genes suggest that the PLGA scaffolds may be applied for WJ-MSC differentiation. This primary study suggests that chondrogenic capacity of WJ-MSCs cultured on the PLGA scaffolds can be useful for cell therapy of cartilage.

Magnesium-calcium/hydroxyapatite (Mg-Ca/HA) composites with enhanced bone differentiation properties for orthopedic applications

Mg-1Ca/HA composites were produced by blending magnesium-calcium (1wt%) (Mg-1Ca) alloys with 5, 10 and 15wt% of hydroxyapatite (HA). Morphology, elemental and phase composition of Mg-1Ca/HA composites were examined. Biocompatibility assessments were also performed using an indirect contact method by culturing human adipose mesenchymal stem cells (hASCs) in the extracts of Mg-1Ca alloy, Mg-1Ca/HA composites and Dulbecco's modified eagle's medium. Mg-1Ca/HA composites could promote cell proliferation and at the same time, enhanced collagen type I (COL I) and osteocalcin (OCN) expressions of hASCs. Among the Mg-1Ca/HA composites, 10wt% of HA is the optimum amount to be added into Mg-1Ca alloy for enhanced bioactivity, thus emerging as a potential biomaterial for orthopedic fixation.