Development of a composite based on hydroxyapatite and magnesium and zinc‐containing sol–gel-derived bioactive glass for bone substitute applications

Carbon Dots Derived from Curcumae Radix and Their Heartprotective Effect

Background

Acute myocardial infarction (AMI) is a common cardiovascular disease in clinic. Currently, there is no specific treatment for AMI. Carbon dots (CDs) have been reported to show excellent biological activities, which hold promise for the development of novel nanomedicines for the treatment of cardiovascular diseases.

Methods

In this study, we firstly prepared CDs from the natural herb Curcumae Radix Carbonisata (CRC-CDs) by a green, simple calcination method. The aim of this study is to investigate the cardioprotective effect and mechanism of CRC-CDs on isoproterenol (ISO) -induced myocardial infarction (MI) in rats.

Results

The results showed that pretreatment with CRC-CDs significantly reduced serum levels of cardiac enzymes (CK-MB, LDH, AST) and lipids (TC, TG, LDL) and reduced st-segment elevation and myocardial infarct size on the ECG in AMI rats. Importantly, cardiac ejection fraction (EF) and shortening fraction (FS) were markedly elevated, as was ATPase activity. In addition, CRC-CDs could significantly increase the levels of superoxide dismutase (SOD), reduced glutathione (GSH), catalase (CAT), and reduce the levels of malondialdehyde (MDA) and reactive oxygen species (ROS) in myocardial tissue, thereby exerting cardioprotective effect by enhancing the antioxidant capacity of myocardial tissue. Moreover, the TUNEL staining image showed that positive apoptotic cells were markedly declined after CRC-CDs treatment, which indicate that CRC-CDs could inhibit cardiomyocyte apoptosis. Importantly, The protective effect of CRC-CDs on H2O2 -pretreated H9c2 cells was also verified in vitro.

Conclusion

Taken together, CRC-CDs has the potential for clinical application as an anti-myocardial ischemia drug candidate, which not only provides evidence for further broadening the biological application of cardiovascular diseases, but also offers potential hope for the application of nanomedicine to treat intractable diseases.

Regulation of the antibiotic elution profile from tricalcium phosphate bone cement by addition of bioactive glass

This work aimed at tailoring of different properties of antibacterial drug delivery Ca-phosphate cements by incorporation of bioactive glass (BG). The cements were prepared from beta-tricalcium phosphate cement (β-TCP) and BG based on 50 SiO2-20 CaO-15 Na2O-7 B2O3-4 P2O5-4 Al2O3 wt% with different percentages of BG [5, 10, 15, and 20% (w/w)]. The composite cements were characterized by XRD, FTIR, and TEM. Moreover, in vitro bioactivity and biodegradation were evaluated in the simulated body fluid (SBF) at 37 °C. In addition, physical properties and mechanical strength were determined. Also, the effect of glass addition on the drug release profile was examined using gentamicin. Finally, the antimicrobial activity was studied against Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumonia bacteria, one unicellular fungal strain (Candida albicans), and one multicellular fungal strain (Mucor racemosus). The results showed that after soaking in SBF, the compression strength values ranged from 14 to 36 MPa, the bulk densities and porosities were within 1.35 to 1.49 g/cm3 and 51.3 to 44.71%, respectively. Furthermore, gentamicin was released in a sustained manner, and BG decreased the released drug amount from ~ 80% (in pure β-TCP) to 47-53% in the composite cements. A drug release profile that is sustained by all samples was achieved. The antimicrobial test showed good activity of gentamicin-conjugated cements against bacteria and fungi used in this study. Additionally, cytotoxicity results proved that all samples were safe on MG-63 cells up to 50 µg/mL with no more than 7-12% dead cells. From the view of the physico-mechanical properties, bioactivity, biodegradation, and drug release rate, 20BG/β-TCP sample was nominated for practical bone grafting material, where it showed appropriate setting time and a relatively high mechanical strength suitable for cancellous bone.

Effects of cerium-doped bioactive glass incorporation on an alginate/gelatin scaffold for bone tissue engineering: In vitro characterizations

Bioactive glasses (BGs) have been extensively employed in treating bone defects due to their capacity to bond and integrate with hard and soft tissues. To promote their characteristics, BGs are doped with therapeutic inorganic ions; Among these, Cerium (Ce) is of special attention because of its material and biological properties. This study aimed to investigate the effects of the addition of Ce to BG on the physicochemical and biological properties of the alginate/gelatin (Alg-Gel) scaffold compared with a similar scaffold that only contains BG45S5. The scaffolds were characterized for their biocompatibility using human bone marrow-derived mesenchymal stem cells (hBM-MSCs) by MTT analysis. The osteogenic differentiation of hBM-MSCs cultured on the scaffolds was assessed by evaluating the alkaline phosphatase (ALP) activity and the expression of osteogenic-related genes. Scanning electron microscopy of the prepared scaffolds showed an interconnected porous structure with an average diameter of 212-272 μm. The Young's modulus of the scaffolds significantly increased from 13 ± 0.82 MPa for Alg-Gel to 91 ± 1.76 MPa for Alg-Gel-BG/Ce. Ce doping improved the osteogenic differentiation of hBM-MSCs and ALP secretion compared to the other samples, even without adding an osteogenic differentiation medium. The obtained results demonstrated the biocompatibility and osteo-inductive potentials of the Alg-Gel-BG/Ce scaffold for bone tissue engineering.

Effect of Ce-doped bioactive glass/collagen/chitosan nanocomposite scaffolds on the cell morphology and proliferation of rabbit’s bone marrow mesenchymal stem cells-derived osteogenic cells

Background

Cerium-containing materials have wide applications in the biomedical field, because of the mimetic catalytic activities of cerium. The study aims to deeply estimate the biocompatibility of different scaffolds based on Ce-doped nanobioactive glass, collagen, and chitosan using the first passage of rabbit bone marrow mesenchymal stem cells (BM-MSCs) directed to osteogenic lineage by direct and indirect approach. One percentage of glass filler was used (30 wt. %) in the scaffold, while the percentage of CeO₂ in the glass was ranged from 0 to 10 mol. %. Cytotoxicity was evaluated by monitoring of cell morphological changes and reduction in cell proliferation activity of BMMSCs maintained under osteogenic condition using proliferation assays, MTT assay for the direct contact of cells/scaffolds twice in a week, trypan blue and hemocytometer cell counting for indirect contact of cells/scaffolds extracts at day 7. Cell behaviors growth, morphology characteristics were monitored daily under a microscope and cell counting were conducted after 1 week of the incubation of the cells with the extracts of the four composite scaffolds in the osteogenic medium at the end of the week.

Results

Showed that at 24 h after direct contact with composite scaffold, all scaffolds showed proliferation of cells > 50% and increased in cell density on day 7. The scaffold of the highest percentage of CeO₂ in bioactive glass nanoparticles (sample CL/CH/C10) showed the lowest inhibition of cell proliferation (< 25%) at day 7. Moreover, the indirect cell viability test showed that all extracts from the four composite scaffolds did not demonstrate a toxic effect on the cells (inhibition value < 25%).

Conclusion

The addition of CeO₂ to the glass composition improved the biocompatibility of the composite scaffold for the proliferation of rabbit bone marrow mesenchymal stem cells directed to osteogenic lineage.

Supplementary Information

The online version contains supplementary material available at 10.1186/s43141-022-00302-x.

S. N. SN, Lakshmipathy M, Sagadevan S, Mohammad F, Al-Lohedan HA, Paiman S, Oh WC. Nanoformulations of core–shell type hydroxyapatite-coated gum acacia with enhanced bioactivity and controlled drug delivery for biomedical applications

In this work, nanospherical hydroxyapatite (HAP) was prepared that has combined properties of controlled drug delivery, biocompatibility, and antibacterial activity to have applications in the biomedical sector.

Polymeric scaffolds for dental pulp tissue engineering: A review

OBJECTIVES

The purpose of this review is to describe recent developments in pulp tissue engineering using scaffolds and/or stem cells. It is crucial to understand how this approach can revitalize damaged dentin-pulp tissue. Widespread scaffold materials, both natural and synthetic, and their fabrication methods, and stem-progenitor cells with the potential of pulp regeneration will be discussed.

DATA AND SOURCES

A review of literature was conducted through online databases, including MEDLINE by using the PubMed search engine, Scopus, and the Cochrane Library.

STUDY SELECTION

Studies were selected based on relevance, with a preference given to recent research, particularly from the past decade.

CONCLUSIONS

The use of biomaterial scaffolds and stem cells can be safe and potent for the regeneration of pulp tissue and re-establishment of tooth vitality. Natural and synthetic polymers have distinct advantages and limitations and in vitro and in vivo testing have produced positive results for cell attachment, proliferation, and angiogenesis. The type of biomaterial used for scaffold fabrication also facilitates stem cell differentiation into odontoblasts and the resulting biochemistry of tissue repair for each polymer and cell type was discussed. Multiple methods of scaffold design exist for pulp tissue engineering, which demonstrates the variability in tissue engineering applications in endodontics. This review explains the potential of evidence-based tissue engineering strategies and outcomes in pulp regeneration.

Drug Leaching Properties of Vancomycin Loaded Mesoporous Hydroxyapatite as Bone Substitutes

Infections after bone reconstructive surgery become an authentic therapeutic and economic issue when it comes to a modern health care system. In general; infected bone defects are regarded as contraindications for bone grafting. Since the pathogens develop a biofilm on the inner surface of the bone; local delivery of antibiotics becomes more important. The present work focuses on the synthesis of Mesoporous Hydroxyapatite (MPHAP) loaded with drug Vancomycin (Van) and to investigate its loading and leaching ability in phosphate buffer solution (PBS), to be used for post-operative infections. The effect of pore size on MPHAP was analyzed using different fatty acids as organic modifiers. The impacts of various fatty acids chain length on the morphology and pore size were studied. A simple impregnation technique with optimized conditions ensured a high antibiotic loading (up to 0.476 + 0.0135 mg/mL), with a complete in vitro release obtained within 50 h.

Magnesium matrix nanocomposites for orthopedic applications: A review from mechanical, corrosion, and biological perspectives

Magnesium (Mg) and some of its alloys have attracted extensive interests for biomedical applications as they exhibit biodegradability and low elastic modulus that is closer to natural bones than the currently used metallic implant materials such as titanium (Ti) and its alloys, stainless steels, and cobalt-chromium (Co-Cr) alloys. However, the rapid degradation of Mg alloys and loss of their mechanical integrity before sufficient bone healing impede their clinical application. Our literature review shows that magnesium matrix nanocomposites (MMNCs) reinforced with nanoparticles possess enhanced strength, high corrosion resistance, and good biocompatibility. This article provides a detailed analysis of the effects of nanoparticle reinforcements on the mechanical properties, corrosion behavior, and biocompatibility of MMNCs as promising biodegradable implant materials. The governing equations to quantitatively predict the mechanical properties and underlying synergistic strengthening mechanisms in MMNCs are elucidated. The potential, recent advances, challenges and future research directions in relation to nanoparticles reinforced MMNCs are highlighted. STATEMENT OF SIGNIFICANCE: Critically reviewing magnesium metal matrix nanocomposites (MMNCs) for the biomedical application. Clear definitions of strengthening mechanisms using reinforcement particle in the magnesium matrix, as there were controversial in governing equations of strengthening parameters. Providing better understanding of the effect of particle size, volume fraction, interfacial bonding, and uniform dispersion of reinforcement particles on MMNCs.

Development of magnesium implants by application of conjoint-based quality function deployment

Biodegradable magnesium-based implants are the subject of a great deal of research for different orthopedic and vascular applications. The targeted design and properties depend on the specific medical function and location in the body. Development of the biomaterial requires a comprehensive understanding of the biological interaction between the implant and the host tissue, as well as of the behavior in the physiological environment in vivo. Research into and the development of innovative magnesium implants entails interdisciplinary research efforts and communication between materials science, bioscience, and medical experts. The present study provides a transparent planning and communication tool for market-oriented implant development processes. The objective was to identify medical needs at an early stage of the development process and to quantify the importance of the engineering characteristics of different research fields that cater to specific implant requirements. The method is demonstrated by the performance of a survey-based conjoint analysis, which was integrated into a quality function deployment approach. Twenty-seven medical professionals and 29 biomaterial scientists assessed the importance of identified medical requirements, whereby the control of mechanical integrity and degradation along with nontoxicity and nonimmunogenicity showed the highest number of preferences. The evaluation of implant options by 31 experts indicated that the engineering characteristic with the highest importance was the condition and sterilization of the surface. These values can be used to set priorities in strategic decisions. Research trials can be aligned to medical preferences, ensuring high product quality and an effective development process. This is the first paper to report on the application of conjoint-based quality function deployment in biomaterial research.

Bioactive glass (45S5)-based 3D scaffolds coated with magnesium and zinc-loaded hydroxyapatite nanoparticles for tissue engineering applications

Bioactive glass (BG)-based scaffolds of 45S5 composition covered with hydroxyapatite nanoparticles loaded with Mg²⁺, Zn²⁺ and, both Mg²⁺ and Zn²⁺ ions, were developed and tested as materials for tissue engineering applications. The scaffolds were prepared by the foam replica technique and mono- and bi-metal loaded and unloaded hydroxyapatite nanoparticles (HA, Zn-HA, Mg-HA and Mg-Zn-HA) were obtained by an adaptation of the wet chemical deposition method. Coating of BG with these nanoparticles was performed by dip-coating to obtain HA-BG, Zn-HA-BG, Mg-HA-BG and Mg-Zn-HA-BG scaffolds. As predictor of the bone bonding ability of the produced scaffolds, in this study we investigated the formation of an apatite layer on the scaffold surfaces in the presence of simulated body fluid. The cytotoxicity and osteogenic properties of the materials in vitro was evaluated using human osteoblast-like MG-63 cell cultures. The mineralization assay following Kokubo's protocol indicated that bi-metal loaded Mg-Zn-HA-BG scaffolds exhibited higher/faster bioactivity than mono-metal loaded scaffolds while mineralization of HA-BG, Zn-HA-BG and Mg-HA-BG was similar to that of uncoated scaffolds. Moreover, an increase of proliferation of MG-63 cells after 48 h and 7 days was measured by BrdU assays for Mg-Zn-HA-BG scaffolds. In agreement with these results, SEM images confirmed increased interaction between these scaffolds and cells, in comparison to that observed for mono-metal-loaded HA-coated scaffolds. Altogether, the obtained results suggest that nanocrystalline Mg-Zn-HA coatings enhance the biological performance of standard scaffolds of 45S5 BG composition. Thus these novel ion doped HA coated scaffolds are attractive systems for bone tissue engineering.

In vitro drug release behavior of Ce-doped nano-bioactive glass carriers under oxidative stress

Ce-containing bioactive glasses are known to decrease reactive oxygen activities inside the body. That is because of their excellent catalytic activities which come from the fast interchange of Ce³⁺/Ce⁴⁺ oxidation states. This research was mainly aimed at preparing new Ce-doped nano-bioactive glasses based on 60SiO₂-(10-x)B₂O₃-25CaO-5P₂O₅-xCeO₂, in mole% (x = 0 and 5 mol%) as multifunctional bone fillings. Moreover, the glasses were used as a delivery system for ciprofloxacin to intensely solve the bone infection complications. Nevertheless, there were no previous works studied of the nature immersing solution effect on the drug release behavior from Ce-doped nano-bioactive glass carriers. Therefore, phosphate-free and phosphate-containing buffer solutions with/without superoxide species (H₂O₂) were used to investigate the efficacy of this drug delivery system in different environment. The results showed that Ce addition enhanced the formation of apatite layer and cell viability. Moreover, the percentage of released drug was apparently affected by the glass composition and nature of soaking fluid, specifically, in the media containing superoxide species (H₂O₂). In conclusion, the prepared Ce-doped glass nanoparticles illustrated multifunctional bone filling material, but when it intended to be utilized as a drug delivery system, the nature of surrounding medium have to be taken into consideration.

GPTMS-Modified Bredigite/PHBV Nanofibrous Bone Scaffolds with Enhanced Mechanical and Biological Properties

Bioceramic nanoparticles with high specific surface area often tend to agglomerate in the polymer matrix, which results in undesirable mechanical properties of the composites and poor cell spreading and attachment. In the present work, bredigite (BR) nanoparticles were modified with an organosilane coupling agent, 3-glycidoxypropyltrimethoxysilane (GPTMS), to enhance its dispersibility in the polymer matrix. The polyhydroxybutyrate-co-hydroxyvaletare (PHBV) nanofibrous scaffolds containing either bredigite or GPTMS-modified bredigite (G-BR) nanoparticles were fabricated using electrospinning technique and characterized using scanning electron microscopy, transmission electron microscopy, and tensile strength. Results demonstrated that modification of bredigite was effective in enhancing nanoparticle dispersion in the PHBV matrix. PHBV/G-BR scaffold showed improved mechanical properties compared to PHBV and PHBV/BR, especially at the higher concentration of nanoparticles. In vitro bioactivity assay performed in the simulated body fluid (SBF) indicated that composite PHBV scaffolds were able to induce the formation of apatite deposits after incubation in SBF. From the results of in vitro biological assay, it is concluded that the synergetic effect of BR and GPTMS provided an enhanced hFob cells attachment and proliferation. The developed PHBV/G-BR nanofibrous scaffolds may be considered for application in bone tissue engineering.

Evaluation of the in vitro biodegradation and biological behavior of poly(lactic-co-glycolic acid)/nano-fluorhydroxyapatite composite microsphere-sintered scaffold for bone tissue engineering

The objective of this research was to study the degradation and biological characteristics of the three-dimensional porous composite scaffold made of poly(lactic- co-glycolic acid)/nano-fluorhydroxyapatite microsphere using sintering method for potential bone tissue engineering. Our previous experimental results demonstrated that poly(lactic- co-glycolic acid)/nano-fluorhydroxyapatite composite scaffold with a ratio of 4:1 sintered at 90ºC for 2 h has the greatest mechanical properties and a proper pore structure for bone repair applications. The weight loss percentage of both poly(lactic- co-glycolic acid)/nano-fluorhydroxyapatite and poly(lactic- co-glycolic acid) scaffolds demonstrated a monotonic trend with increasing degradation time, that is, the incorporation of nano-fluorhydroxyapatite into polymeric scaffold could lead to weight loss in comparison with that of pure poly(lactic- co-glycolic acid). The pH change for composite scaffolds showed that there was a slight decrease until 2 weeks after immersion in simulated body fluid, followed by a significant increase in the pH of simulated body fluid without a scaffold at the end of immersion time. The mechanical properties of composite scaffold were higher than that of poly(lactic- co-glycolic acid) scaffold at total time of incubation in simulated body fluid; however, it should be noted that the incorporation of nano-fluorhydroxyapatite into composite scaffold leads to decline in the relatively significant mechanical strength and modulus during hydrolytic degradation. In addition, MTT assay and alkaline phosphatase activity results defined that a general trend of increasing cell viability was seen for poly(lactic- co-glycolic acid)/nano-fluorhydroxyapatite scaffold sintered by time when compared to control group. Eventually, experimental results exhibited poly(lactic- co-glycolic acid)/nano-fluorhydroxyapatite microsphere-sintered scaffold is a promising scaffold for bone repair.

Design of magnesium alloys with controllable degradation for biomedical implants: From bulk to surface

The combination of high strength, light weight, and natural biodegradability renders magnesium (Mg)-based alloys promising in orthopedic implants and cardiovascular stents. Being metallic materials, Mg and Mg alloys made for scaffolds provide the necessary mechanical support for tissue healing and cell growth in the early stage, while natural degradation and reabsorption by surrounding tissues in the later stage make an unnecessarily follow-up removal surgery. However, uncontrolled degradation may collapse the scaffolds resulting in premature implant failure, and there has been much research in controlling the degradation rates of Mg alloys. This paper reviews recent progress in the design of novel Mg alloys, surface modification and corrosion mechanisms under different conditions, and describes the effects of the structure, composition, and surface conditions on the degradation behavior in vitro and in vivo.

STATEMENT OF SIGNIFICANCE

Owing to their unique mechanical properties, biodegradability, biocompatibility, Mg based biomaterials are becoming the most promising substitutes for tissue regeneration for impaired bone, vascular and other tissues because these scaffolds can provide not only ideal space for the growth and differentiation of seeded cells but also enough strength before the formation of normal tissues. The most important is that these scaffolds can be fully degraded after tissue regeneration, which can satisfy the increasing demand for better biomedical devices and functional tissue engineering biomaterials in the world. However, the rapid degradation rate of these scaffolds restricts the wide application in clinic. This paper reviews recent progress on how to control the degrdation rate based on the relevant corrosion mechanisms through the design of porous structure, phase structure, grains, and amorphous structure as well as surface modification, which will be beneficial to the better understanding and functional design of Mg-based scaffolds for wide clinical applications in tissue reconstruction in near futures.

Ca3(PO4)2 precipitated layering of an in situ hybridized PVA/Ca2O4Si nanofibrous antibacterial wound dressing

The aim of this study was to develop an in situ hybridized poly(vinyl alcohol)/calcium silicate (PVA/Ca2OSi) nanofibrous antibacterial wound dressing with calcium phosphate [Ca3(PO4)2] surface precipitation for enhanced bioactivity. This was achieved by hybridizing the antibacterial ions Zn(2+) and/or Ag(+) in a Ca2O4Si composite. The hybridization effect on the thermal behavior, physicochemical, morphological, and physicomechanical properties of the nanofibers was studied using Differential Scanning calorimetric (DSC), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Textural Analysis, respectively. In vitro bioactivity, biodegradation and pH variations of the nanofiber composite were evaluated in Simulated Body Fluid (SBF). The antibacterial activity was assessed against Staphylococcus aureus and Pseudomonas aeruginosa. Hybridization of Zn(2+) and/or Ag(+) into the PVA/Ca2O4Si nanofiber composite was confirmed by DSC, XRD and FTIR. The thickness of the nanofibers was dependent on the presence of Zn(2+) and Ag(+) as confirmed by SEM. The nanofibers displayed enhanced tensile strength (19-115.73MPa) compared to native PVA. Zn(2+) and/or Ag(+) hybridized nanofibers showed relatively enhanced in vitro bioactivity, biodegradation (90%) and antibacterial activity compared with the native PVA/Ca2O4Si nanofiber composite. Results of this study has shown that the PVA/Ca2O4Si composite hybridized with both Zn(2+) and Ag(+) may be promising as an antibacterial wound dressing with a nanofibrous archetype with enhanced bioactivity.

Hard tissue regeneration using bone substitutes: an update on innovations in materials

Bone is a unique organ composed of mineralized hard tissue, unlike any other body part. The unique manner in which bone can constantly undergo self-remodeling has created interesting clinical approaches to the healing of damaged bone. Healing of large bone defects is achieved using implant materials that gradually integrate with the body after healing is completed. Such strategies require a multidisciplinary approach by material scientists, biological scientists, and clinicians. Development of materials for bone healing and exploration of the interactions thereof with the body are active research areas. In this review, we explore ongoing developments in the creation of materials for regenerating hard tissues.

The effect of silica sols on electrodeposited zinc coatings for sintered NdFeB

We developed an in situ method to prepare silica particle-containing zinc coatings on NdFeB.

Mechanical properties and in vitro cellular behavior of zinc-containing nano-bioactive glass doped biphasic calcium phosphate bone substitutes

In the present study, different amounts (0.5-5 wt%) of a sol gel-derived zinc-containing nano-bioactive glass (NBG-Zn) powder were added to biphasic calcium phosphate (BCP). The mixtures were sintered at 1,100-1,300 °C and physical characteristics, mechanical properties, phase composition and morphology of them were studied. The samples were also soaked in human blood plasma for 15 days to evaluate variations in their surface morphologies. Rat calvarium-derived osteoblastic cells were seeded on tops of various samples and cell adhesion, proliferation, and alkaline phosphatase activity were evaluated at different culturing periods. The maximum bending strength (62 MPa) was obtained for BCP containing 0.5 wt% NBG-Zn at temperature 1,200 °C. This value was approximately 80% higher than that of pure BCP. The bending strength failed when both sintering temperature and amount of added NBG-Zn increased. At 1,100 °C, NBG-Zn additive did not change the phase composition of BCP. At temperatures 1,200 and 1,300 °C, both alpha-tricalcium calcium phosphate (α-TCP) and beta-tricalcium phosphate (β-TCP and) phases were detected. However, adding higher amount of NBG-Zn to BCP resulted in elevation of β-TCP at 1,200 °C and progression of α-TCP at 1,300 °C. Based on the microscopic observations, adding 0.5 wt% NBG-Zn to BCP led to disappearance of grain boundaries, reduction of micropores and formation of a monolithic microstructure. No calcium phosphate precipitation was observed on sample surfaces after soaking in blood plasma, but some pores were produced by phase dissolution. The size and volume of these pores were directly proportional to NBG-Zn content. Based on the cell studies, both BCP and NBG-Zn-added BCP samples supported attachment and proliferation of osteoblasts, but higher alkaline phosphatase enzyme was synthesized within the cells cultured on NBG-Zn-added BCP. Overall, biphasic calcium phosphate materials with improved mechanical and biological properties can be produced by using small quantity of zinc-containing bioactive glass particles.

A novel green template assisted synthesis of hydroxyapatite nanorods and their spectral characterization

Hydroxyapatite [HAP, Ca10(PO4)6(OH)2] is the main inorganic component of bone material and is widely used in various biomedical applications due to its excellent bioactivity and biocompatibility. In this paper we have reported the synthesis of hydroxyapatite nanorods by green template method using the extracts of three different natural sources which contain tartaric acid and also from commercially available one. The extracts of banana, grape and tamarind are taken as the sources of tartaric acid. The as-synthesized samples were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX). Also the antibacterial activity of HAP with different concentrations against two pathogen bacteria strains Escherichia coli (E. coli) and Klebsiella (Gram-negative bacteria) were tested. The results show that the particles of all the samples are of nanosized and pure. The crystallinity decreases as changing the sources of tartaric acid from commercial to natural one and also changing the natural sources from banana to tamarind extracts. The formation of nanorods are found in all the samples but the nanorods with uniform size distribution can be obtained only by using the tamarind extract as the source of tartaric acid. Moreover, the as-synthesised HAP nanorods derived from natural sources exhibited a strong antibacterial activity against both E. coli and Klebsiella at a concentration of 100 μl. The HAP nanorods synthesized by this method can act as a potential candidate for various biomedical applications.