Displaying publications 41 - 60 of 131 in total

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  1. Hydroxapatite and tricalcium phosphate prepared by precipitation method
    Cik Rohaida CH, Idris B, Mohd Reusmaazran Y, Rusnah M, Fadzley Izwan AM
    Med J Malaysia, 2004 May;59 Suppl B:156-7.
    PMID: 15468865
    A mixture with different compositions of HA and TCP were synthesize in this work by precipitation method using Ca(NO3)2 4H2 and (NH4)2HPO4 as the starting materials. A mixture with HA and TCP phases in different ratios were produced. The powders were sintered from 1000 degrees C to 1250 degrees C. The phase compositions of the mixtures were then studied via XRD. This work shows that the pH value determines the different phase compositions of the HA-TCP mixture. Chemical analyses were carried out by FTIR. The microstructure was observed under SEM.
    Matched MeSH terms: Durapatite/analysis; Durapatite/chemical synthesis*
  2. Characterization of nickel-doped biphasic calcium phosphate/graphene nanoplatelet composites for biomedical application
    Baradaran S, Moghaddam E, Nasiri-Tabrizi B, Basirun WJ, Mehrali M, Sookhakian M, et al.
    Mater Sci Eng C Mater Biol Appl, 2015 Apr;49:656-668.
    PMID: 25686995 DOI: 10.1016/j.msec.2015.01.050
    The effect of the addition of an ionic dopant to calcium phosphates for biomedical applications requires specific research due to the essential roles played in such processes. In the present study, the mechanical and biological properties of Ni-doped hydroxyapatite (HA) and Ni-doped HA mixed with graphene nanoplatelets (GNPs) were evaluated. Ni (3wt.% and 6wt.%)-doped HA was synthesized using a continuous precipitation method and calcined at 900°C for 1h. The GNP (0.5-2wt.%)-reinforced 6% Ni-doped HA (Ni6) composite was prepared using rotary ball milling for 15h. The sintering process was performed using hot isostatic pressing at processing conditions of 1150°C and 160MPa with a 1-h holding time. The results indicated that the phase compositions and structural features of the products were noticeably affected by the Ni and GNPs. The mechanical properties of Ni6 and 1.5Ni6 were increased by 55% and 75% in hardness, 59% and 163% in fracture toughness and 120% and 85% in elastic modulus compared with monolithic HA, respectively. The in-vitro biological behavior was investigated using h-FOB osteoblast cells in 1, 3 and 5days of culture. Based on the osteoblast results, the cytotoxicity of the products was indeed affected by the Ni doping. In addition, the effect of GNPs on the growth and proliferation of osteoblast cells was investigated in Ni6 composites containing different ratios of GNPs, where 1.5wt.% was the optimum value.
    Matched MeSH terms: Durapatite/pharmacology; Durapatite/chemistry
  3. Fulltext Partial purification of the molybdenum-reducing enzyme from Bacillus pumilus strain Lbna
    Abo-Shakeer, L.K.A., Yakasai, M.H., Rahman, M.F., Syed, M.A., Bakar, N.A., Othman, A.R.
    Bioremediation Science and Technology Research, 2016;4(1):14-17.
    MyJurnal
    Molybdenum is an emerging pollutant. Bioremediation of this heavy metal is possible by the
    mediation of Mo-reducing bacteria. These bacteria contain the Mo-reducing enzymes that can
    conver toxic soluble molybdenum into molybdenum blue; a less soluble and less toxic form of the
    metal. To date only the enzyme has been purified from only one bacterium. The aim of this study is
    to purify the Mo-reducing enzyme from a previously isolated Mo-reducing bacterium Bacillus
    pumilus strain Lbna using ammonium sulphate fractionation followed by ion exchange and then
    gel filtration. Two clear bands were obtained after the gel filtration step with molecular weights
    of 70 and 100 kDa. This indicates that further additional purification methods need to be used
    to get a purified fraction. Hence, additional steps of chromatography such as hydroxyapatite or
    chromatofocusing techniques can be applied in the future.
    Matched MeSH terms: Durapatite
  4. Comparison of Clinical Results and Pathological Examinations Between Locally Synthesized Bone-derived Hydroxyapatite and Medpor® Orbital Implants in Animal Models
    Roslinah M, Wan Hitam WH, Md Salleh MS, Abdul Hamid SS, Shatriah I
    Cureus, 2019 Jan 25;11(1):e3954.
    PMID: 30956907 DOI: 10.7759/cureus.3954
    We aimed to compare clinical and pathological reactions towards locally synthesized bovine bone derived from hydroxyapatite (bone docosahexaenoic acid (dHA)) and commercially available porous polyethylene (Medpor®, Porex Surgical Incorporation, Georgia, USA) orbital implants in animal models. An experimental study was performed on 14 New Zealand white rabbits. Group A (n=7) was implanted with bovine bone dHA and group B (n=7) was implanted with Medpor®. Clinical examinations were performed on Days 1, 7, 14, 28, and 42 post-implantation. The implanted eyes were enucleated on Day 42 and were sent for pathological evaluation. Serial clinical examinations included urine color and odor; feeding and physical activity demonstrated normal wellbeing in all the subjects. Localized minimal infection was observed in both groups during the first two weeks following implantation, and the subjects responded well to topical moxifloxacin. Both groups exhibited evidence of wound breakdown. No signs of implant migration or extrusion were observed in either group. The histopathological examination revealed no statistically significant difference in inflammatory cell reactions and fibrovascular tissue maturation between both types of implants. However, all (100%) of the bovine bone dHA implants displayed complete fibrovascular ingrowth compared to Medpor® implants (57.1%) at six weeks post-implantation (p=0.001). In conclusion, bovine bone dHA and Medpor® orbital implants were well-tolerated clinically and displayed similar inflammatory reactions and fibrovascular tissue maturation. Locally synthesized bovine bone dHA orbital implants displayed significantly greater complete fibrovascular ingrowth in comparison with Medpor® implants.
    Matched MeSH terms: Durapatite
  5. Thermomechanical investigations of PEKK-HAp-CS composites
    Singh R, Singh G, Singh J, Kumar R, Rahman MM, Ramakrishna S
    Proc Inst Mech Eng H, 2019 Nov;233(11):1196-1203.
    PMID: 31545132 DOI: 10.1177/0954411919877979
    In this experimental study, a composite of poly-ether-ketone-ketone by reinforcement of hydroxyapatite and chitosan has been prepared for possible applications as orthopaedic scaffolds. Initially, different weight percentages of hydroxyapatite and chitosan were reinforced in the poly-ether-ketone-ketone matrix and tested for melt flow index in order to check the flowability of different compositions/proportions. Suitable compositions revealed by the melt flow index test were then taken forward for the extrusion of filament required for fused deposition modelling. For thermomechanical investigations, Taguchi-based design of experiments has been used with input variables in the extrusion process as follows: temperature, load applied and different composition/proportions. The specimens in the form of feedstock filament produced by the extrusion process were made to undergo tensile testing. The specimens were also inspected by differential scanning calorimetry and photomicrographs. Finally, the specimen showing the best performance from the thermomechanical viewpoint has been selected to extrude the filament for the fused deposition modelling process.
    Matched MeSH terms: Durapatite
  6. Cellulose-hydroxyapatite carbon electrode composite for trace plumbum ions detection in aqueous and palm oil mill effluent: Interference, optimization and validation studies
    Ajab H, Ali Khan AA, Nazir MS, Yaqub A, Abdullah MA
    Environ Res, 2019 09;176:108563.
    PMID: 31280029 DOI: 10.1016/j.envres.2019.108563
    Environmental monitoring is important to determine the extent of eco-system pollution and degradation so that effective remedial strategies can be formulated. In this study, an environmentally friendly and cost-effective sensor made up of novel carbon electrode modified with cellulose and hydroxyapatite was developed for the detection of trace lead ions in aqueous system and palm oil mill effluent. Zinc, cadmium, and copper with lead were simultaneously detected using this method. The electrode exhibited high tolerance towards twelve common metal ions and three model surface active substances - sodium dodecyl sulfate, Triton X-100, and cetyltrimethylammonium bromide. Under optimum conditions, the sensor detected lead ions in palm oil mill effluent in the concentration range of 10-50 μg/L with 0.11 ± 0.37 μg/L limit of detection and 0.37 ± 0.37 μg/L limit of quantification. The validation using tap water, blood serum and palm oil mill effluent samples and compared with Atomic Absorption Spectroscopy, suggested excellent sensitivity of the sensor to detect lead ions in simple and complex matrices. The cellulose produced based on "green" techniques from agro-lignocellulosic wastes, in combination with hydroxyapatite, were proven effective as components in the carbon electrode composite. It has great potential in both clinical and environmental use.
    Matched MeSH terms: Durapatite
  7. Fulltext Antibacterial property of locally produced hydroxyapatite
    Tin-Oo, M.M., Gopalakrishnan, V., Samsuddin, A.R., Al Salihi, K.A., Shamsuria, O.
    Archives of Orofacial Sciences, 2007;2(1):41-44.
    MyJurnal
    Use of synthetic hydroxyapatite (HA) in biomedical applications is well warranted. It has shown to have an excellent biocompatibility in human tooth and bones. Additionally it has been documented to possess antibacterial potentials. The present study was conducted to assess the presence of any such potential in locally produced (HA) using Streptococcus mutans, a common pathogen in the oral cavity. The study was carried out using 50, 100, 150, 200, 300, 400 and 800 mg/ml concentration of HA. The antibacterial property of HA was assessed using Miles and Misra method. Our studies showed that bacterial growth inhibitions of S. mutans occurred from 50 mg/ml, and complete inhibition was perceived at concentrations at 200mg/ml of HA. The antibacterial property HA should be used to good advantage as a bioactive biomaterial in dental and maxillofacial applications.
    Matched MeSH terms: Durapatite
  8. Fulltext A review on hydroxyapatite-based scaffolds as a potential bone graft substitute for bone tissue engineering applications
    Krishnamurithy, G.
    JUMMEC, 2013;16(2):1-6.
    MyJurnal
    The biocompatibility and similarity of hydroxyapatite (HA) to the mineral composition of the bone has made HA a potential candidate in bone tissue engineering (BTE). Over the past few decades, its application as bone graft in combination with stem cells has gained much importance. The use of bone marrow-derived mesenchymal stromal cells (MSCs) will enhance the rate and quality of defect repair. However, application of hydroxyapatite as a material to develop a 3-dimension scaffold or carrier to support MSCs in vitro is still in its infant stage. This review will discuss the source, manufacturing methods and advantages of using HA scaffolds in bone tissue engineering applications.
    Matched MeSH terms: Durapatite
  9. Fulltext Comparison of Fusion Rate Between Autogenous Tricortical Iliac Crest Bone Graft and Hydroxyapatite Block Graft inAnterior Cervical Discectomy and Fusion Surgery
    Zulkefli, A., Jeyasilan, K., Zairul, A.K.B., Ramanathan, R.
    Malays Orthop J, 2009;3(2):36-39.
    MyJurnal
    Objective: To compare the fusion rate between autogenous tricortical iliac crest bone graft and hydroxyapatite block graft in anterior cervical discectomy and fusion (ACDF) surgery. Methodology: Retrospective review of cases that underwent ACDF surgery between 2005 and 2008. They were divided into two groups based on the graft material used. Assessment of fusion at 6 months post-surgery was carried out based on the static lateral cervical radiograph. Results: 32 cases were reviewed; 16 in each arm. There were 29 discectomies performed in the hydroxyapatite group as compared to 22 in the iliac crest group. 18 levels in the hydrxyapatite group showed radiological fusion while in the iliac crest group there were 21 levels fused. Seven patients had donor site pain. Conclusion: The fusion rate for autogenous tricortical iliac crest bone graft in anterior cervical discectomy and fusion surgery was 95%, a more superior fusion rate than that of hydroxyapatite block graft which was 62.1%.
    Matched MeSH terms: Durapatite
  10. Fulltext Spectroscopic studies of cow femurs and Porites species coral from Sabah
    Fadhlia Zafarina Zakaria, Fauziah Abdul Aziz, Thevarajah, Nahulan
    Journal of Nuclear and Related Technologies, 2007;2007(1):181-184.
    MyJurnal
    Some cortical bone specimens from the femurs of adult cows and sea coral of Porites species were studied by using Fourier Transform Infrared Spectroscopy, FTIR. Carbonate were shown to be present by indication of C-O stretch found between 1510-1410 cm -1 in both cortical bone and Porites. Based on the comparison of the relative intensity of CO3 2- bands with respect to the PO4 3- bands, peak intensity of Porites was found to be higher than peak intensity of cortical bone at carbonate band. This explains that Porites skeleton is made up of CaCO3 while bone consists of a mineral, hydroxyapatite Ca5(PO4)3OH with the present of carbonate ions, typically from 3 to 7 wt%.
    Matched MeSH terms: Durapatite
  11. In situ functionalizing calcium phosphate biomaterials with curcumin for the prevention of bacterial biofilm infections
    Lee WH, Rohanizadeh R, Loo CY
    Colloids Surf B Biointerfaces, 2021 Oct;206:111938.
    PMID: 34198233 DOI: 10.1016/j.colsurfb.2021.111938
    This study developed a novel bioactive bone substitute (hydroxyapatite, HA) with improved anti-biofilm activity by functionalizing with curcumin (anti-biofilm compound) which provide sufficient flux of curcumin concentration for 14 days. The released curcumin acts to inhibit biofilm formation and control the number of viable planktonic cells simultaneously. To prepare curcumin-functionalized HA, different concentrations of curcumin (up to 3% w/v) were added simultaneously during the precipitation process of HA. The highest loading (50 mg/g HA) of curcumin onto HA was achieved with 2% w/v of curcumin. Physicochemical characterizations of curcumin-functionalized HA composites revealed that curcumin was successfully incorporated onto HA. Curcumin was sustainably released over 14 days, while higher curcumin release was observed in acidic condition (pH 4.4) compared to physiological (pH 7.4). The cytotoxicity assays revealed that no significant difference on bone cells growth on curcumin-functionalized HA and non-functionalized HA. Curcumin-functionalized HA was effective to inhibit bacterial cell attachment and subsequent biofilm maturation stages. The anti-biofilm effect was stronger against Staphylococcus aureus compared to Pseudomonas aeruginosa. The curcumin-functionalized HA composite significantly delayed the maturation of S. aureus compared to non-functionalized HA in which microcolonies of cells only begin to appear at 96 h. Up to 3.0 log reduction in colony forming unit (CFU)/mL of planktonic cells was noted at 24 h of incubation for both microorganisms. Thus, in this study we have suggested that curcumin loaded HA could be an alternative antimicrobial agent to control the risk of infections in post-surgical implants.
    Matched MeSH terms: Durapatite
  12. Fulltext The State of Starch/Hydroxyapatite Composite Scaffold in Bone Tissue Engineering with Consideration for Dielectric Measurement as an Alternative Characterization Technique
    Mohd Roslan MR, Mohd Kamal NL, Abdul Khalid MF, Mohd Nasir NF, Cheng EM, Beh CY, et al.
    Materials (Basel), 2021 Apr 14;14(8).
    PMID: 33919814 DOI: 10.3390/ma14081960
    Hydroxyapatite (HA) has been widely used as a scaffold in tissue engineering. HA possesses high mechanical stress and exhibits particularly excellent biocompatibility owing to its similarity to natural bone. Nonetheless, this ceramic scaffold has limited applications due to its apparent brittleness. Therefore, this had presented some difficulties when shaping implants out of HA and for sustaining a high mechanical load. Fortunately, these drawbacks can be improved by combining HA with other biomaterials. Starch was heavily considered for biomedical device applications in favor of its low cost, wide availability, and biocompatibility properties that complement HA. This review provides an insight into starch/HA composites used in the fabrication of bone tissue scaffolds and numerous factors that influence the scaffold properties. Moreover, an alternative characterization of scaffolds via dielectric and free space measurement as a potential contactless and nondestructive measurement method is also highlighted.
    Matched MeSH terms: Durapatite
  13. Effect of exogenous nitric oxide on the proliferation of a human osteoblast (HOS) cell line induced by hydroxyapatite
    Sugiatno E, Samsudin AR, Sosroseno W
    J Appl Biomater Biomech, 2009 Jan-Apr;7(1):29-33.
    PMID: 20740436
    The aim of this study was to test the hypothesis that the proliferation of hydroxyapatite (HA)-induced human osteoblast cell line (HOS cells) may be up-regulated by exogenous nitric oxide (NO).
    Matched MeSH terms: Durapatite
  14. Different Intraorbital Implant Situations and Ocular Prosthetic Rehabilitation
    Aggarwal H, Kumar P, Eachempati P, Alvi HA
    J Prosthodont, 2016 Dec;25(8):687-693.
    PMID: 26447725 DOI: 10.1111/jopr.12369
    Enucleation is the removal of the entire globe of the eye and a portion of the optic nerve, while evisceration involves the removal of the contents of the globe leaving the sclera, extraocular muscles, and optic nerve. Following enucleation or evisceration, intraorbital implants are routinely placed to enhance the prosthetic outcome in addition to restoring the lost orbital volume. Current practice employs intraorbital implants made of nonporous silicone, hydroxyapatite, or porous polyethylene. Intraorbital implant selection and placement, being a highly demanding procedure in terms of knowledge, skill, and expertise, may be associated with a multiplicity of technical and surgical errors. Complications are usually minimal with these implants, but they do occur. The literature reveals many articles related to intraorbital implants, their benefits, and complications; however, the literature regarding the effect of various intraorbital implant situations on the subsequent prosthetic rehabilitation is markedly scarce. Moreover, the need for interdisciplinary surgical and prosthetic interventions required for successful rehabilitation in cases of compromised implant situations has been underemphasized. Hence, this review aimed to evaluate the effect of different intraorbital implant situations on ocular rehabilitation and the required interdisciplinary surgical and prosthetic treatment approach for rehabilitation of enucleated/eviscerated sockets with compromised implant situations, to provide a critical appraisal, and to present a simplified management strategy.
    Matched MeSH terms: Durapatite
  15. The synthesis, characterization and in vivo study of mineral substituted hydroxyapatite for prospective bone tissue rejuvenation applications
    Govindaraj D, Rajan M, Munusamy MA, Alarfaj AA, Sadasivuni KK, Kumar SS
    Nanomedicine, 2017 Nov;13(8):2661-2669.
    PMID: 28800874 DOI: 10.1016/j.nano.2017.07.017
    Minerals substituted apatite (M-HA) nanoparticles were prepared by the precipitation of minerals and phosphate reactants in choline chloride-Thiourea (ChCl-TU) deep eutectic solvent (DESs) as a facile and green way approach. After preparation of nanoparticles (F-M-HA (F=Fresh solvent)), the DESs was recovered productively and reprocess for the preparation of R-M-HA nanoparticles (R=Recycle solvent).The functional groups, phase, surface texture and the elemental composition of the M-HA nanoparticles were evaluated by advance characterization methods. The physicochemical results of the current work authoritative the successful uses of the novel (ChCl-TU) DESs as eco-friendly recuperate and give the medium for the preparation of M-HA nanoparticles. Moreover, the as-synthesized both M-HA nanoparticles exhibit excellent biocompatibility, consisting of cell co-cultivation and cell adhesion, in vivo according to surgical implantation of Wistar rats.
    Matched MeSH terms: Durapatite/therapeutic use*
  16. In vitro biocompatibility of hydroxyapatite-added GIC: An SEM study using human periodontal ligament fibroblasts
    Thomas B, Gupta K
    J Esthet Restor Dent, 2017 Nov 12;29(6):435-441.
    PMID: 28703476 DOI: 10.1111/jerd.12317
    OBJECTIVE: Nano-hydroxyapatite-added GIC has been developed to improve the physical properties of conventional GIC. However, biological response of periodontal cells to this potentially useful cervical restorative material has been unexplored. The aim of this study was to investigate the in vitro response of human periodontal ligament fibroblasts to hydroxyapatite-added GIC.

    MATERIALS AND METHODS: Three categories of materials, namely, test group 1 (cGIC or type IX GIC), test group 2 (HA-GIC or hydroxyapatite-added GIC), and positive control (glass cover slips) were incubated with human periodontal ligament fibroblasts. The samples were viewed under scanning electron microscope to study the morphological characteristics of fibroblasts. Additionally, elemental analysis was performed to differentiate between the two test groups based on surface chemical composition.

    RESULTS: Test group 1 (cGIC) exhibited cells with curled up morphology, indicative of poor attachment to the substrate. Test group 2 (Ha-GIC) exhibited cells with flattened morphology and numerous cellular extensions such as lamellipodia and blebs, indicative of good attachment to the substrate. The test group 2 (Ha-GIC) demonstrated higher surface elemental percentages of calcium and phosphorus.

    CONCLUSION: Within the limitations of this study, it may be concluded that hydroxyapatite-added GIC is more biocompatible than conventional GIC (type IX), probably attributed to high elemental percentages of calcium and phosphorus.

    CLINICAL SIGNIFICANCE: The search for an ideal cervical restorative dental material has been ever elusive. Hydroxyapatite-added GIC is a simple and economical dental material to fabricate from basic conventional GIC. The results from this study strengthen its candidature for cervical and root surface restorations which may later require soft tissue augmentation. The possibility of connective tissue adhesion to this material is an exciting prospect in the field of periorestorative dentistry.

    Matched MeSH terms: Durapatite/pharmacology*
  17. Synthesis and characterization of cellulose and hydroxyapatite-carbon electrode composite for trace plumbum ions detection and its validation in blood serum
    Ajab H, Dennis JO, Abdullah MA
    Int J Biol Macromol, 2018 Jul 01;113:376-385.
    PMID: 29486259 DOI: 10.1016/j.ijbiomac.2018.02.133
    A novel synthesis and characterization of cellulose, hydroxyapatite and chemically-modified carbon electrode (Cellulose-HAp-CME) composite was reported for the analysis of trace Pb(II) ions detection and its validation in blood serum. The Field Emission Scanning Electron Microscopy (FESEM) analyses showed that the composite retained the orderly porous structure but with scattered particle size agglomeration. The Fourier Transform Infrared Spectroscopy (FTIR) spectra suggested the presence of functional groups associated with the bending and stretching of carbon bonds and intermolecular H-bonding. X-ray Diffraction (XRD) analyses further elucidated that the crystallite size could have influenced the properties of the electrode. Based on Thermo-gravimetric Analysis (TGA/DTG), the composites showed thermal stability with more than 60% residual content at 700°C. The sensor was successfully developed for trace Pb(II) ions detection in complex medium such as blood serum, in the physiologically relevant range of 10-60ppb, with resulting Limit of Detection (LOD) of 0.11±0.36ppb and Limit of Quantification (LOQ) of 0.36±0.36ppb. The newly fabricated electrode could be advantageous as a sensing platform with favourable electrochemical characteristics for robust, in situ and rapid environmental and clinical analyses of heavy metal ions.
    Matched MeSH terms: Durapatite/chemistry*
  18. Immobilisation of hydroxyapatite-collagen on polydopamine grafted stainless steel 316L: Coating adhesion and in vitro cells evaluation
    Tapsir Z, Jamaludin FH, Pingguan-Murphy B, Saidin S
    J Biomater Appl, 2018 02;32(7):987-995.
    PMID: 29187035 DOI: 10.1177/0885328217744081
    The utilisation of hydroxyapatite and collagen as bioactive coating materials could enhance cells attachment, proliferation and osseointegration. However, most methods to form crystal hydroxyapatite coating do not allow the incorporation of polymer/organic compound due to production phase of high sintering temperature. In this study, a polydopamine film was used as an intermediate layer to immobilise hydroxyapatite-collagen without the introduction of high sintering temperature. The surface roughness, coating adhesion, bioactivity and osteoblast attachment on the hydroxyapatite-collagen coating were assessed as these properties remains unknown on the polydopamine grafted film. The coating was developed by grafting stainless steel 316L disks with a polydopamine film. Collagen type I fibres were then immobilised on the grafted film, followed by the biomineralisation of hydroxyapatite. The surface roughness and coating adhesion analyses were later performed by using AFM instrument. An Alamar Blue assay was used to determine the cytotoxicity of the coating, while an alkaline phosphatase activity test was conducted to evaluate the osteogenic differentiation of human fetal osteoblasts on the coating. Finally, the morphology of cells attachment on the coating was visualised under FESEM. The highest RMS roughness and coating adhesion were observed on the hydroxyapatite-collagen coating (hydroxyapatite-coll-dopa). The hydroxyapatite-coll-dopa coating was non-toxic to the osteoblast cells with greater cells proliferation, greater level of alkaline phosphate production and more cells attachment. These results indicate that the immobilisation of hydroxyapatite and collagen using an intermediate polydopamine is identical to enhance coating adhesion, osteoblast cells attachment, proliferation and differentiation, and thus could be implemented as a coating material on orthopaedic and dental implants.
    Matched MeSH terms: Durapatite/chemistry*
  19. Influence of citric acid on the physical and biomineralization ability of freeze/thaw poly(vinyl alcohol) hydrogel
    Wahid MNA, Abd Razak SI, Abdul Kadir MR, Hassan R, Nayan NHM, Mat Amin KA
    J Biomater Appl, 2018 07;33(1):94-102.
    PMID: 29716417 DOI: 10.1177/0885328218771195
    This work reports the modification of freeze/thaw poly(vinyl alcohol) hydrogel using citric acid as the bioactive molecule for hydroxyapatite formation in simulated body fluid. Inclusion of 1.3 mM citric acid into the poly(vinyl alcohol) hydrogel showed that the mechanical strength, crystalline phase, functional groups and swelling ability were still intact. Adding citric acid at higher concentrations (1.8 and 2.3 mM), however, resulted in physically poor hydrogels. Presence of 1.3 mM of citric acid showed the growth of porous hydroxyapatite crystals on the poly(vinyl alcohol) surface just after one day of immersion in simulated body fluid. Meanwhile, a fully covered apatite layer on the poly(vinyl alcohol) surface plus the evidence of apatite forming within the hydrogel were observed after soaking for seven days. Gel strength of the soaked poly(vinyl alcohol)/citric acid-1.3 mM hydrogel revealed that the load resistance was enhanced compared to that of the neat poly(vinyl alcohol) hydrogel. This facile method of inducing rapid growth of hydroxyapatite on the hydrogel surface as well as within the hydrogel network can be useful for guided bone regenerative materials.
    Matched MeSH terms: Durapatite/chemistry*
  20. Fulltext Effects of the Sintering Process on Nacre-Derived Hydroxyapatite Scaffolds for Bone Engineering
    Megat Abdul Wahab R, Abdullah N, Zainal Ariffin SH, Che Abdullah CA, Yazid F
    Molecules, 2020 Jul 08;25(14).
    PMID: 32650572 DOI: 10.3390/molecules25143129
    A hydroxyapatite scaffold is a suitable biomaterial for bone tissue engineering due to its chemical component which mimics native bone. Electronic states which present on the surface of hydroxyapatite have the potential to be used to promote the adsorption or transduction of biomolecules such as protein or DNA. This study aimed to compare the morphology and bioactivity of sinter and nonsinter marine-based hydroxyapatite scaffolds. Field emission scanning electron microscopy (FESEM) and micro-computed tomography (microCT) were used to characterize the morphology of both scaffolds. Scaffolds were co-cultured with 5 × 104/cm2 of MC3T3-E1 preosteoblast cells for 7, 14, and 21 days. FESEM was used to observe the cell morphology, and MTT and alkaline phosphatase (ALP) assays were conducted to determine the cell viability and differentiation capacity of cells on both scaffolds. Real-time polymerase chain reaction (rtPCR) was used to identify the expression of osteoblast markers. The sinter scaffold had a porous microstructure with the presence of interconnected pores as compared with the nonsinter scaffold. This sinter scaffold also significantly supported viability and differentiation of the MC3T3-E1 preosteoblast cells (p < 0.05). The marked expression of Col1α1 and osteocalcin (OCN) osteoblast markers were also observed after 14 days of incubation (p < 0.05). The sinter scaffold supported attachment, viability, and differentiation of preosteoblast cells. Hence, sinter hydroxyapatite scaffold from nacreous layer is a promising biomaterial for bone tissue engineering.
    Matched MeSH terms: Durapatite/chemistry*
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