Displaying publications 1 - 20 of 24 in total

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  1. Ramesh S, Tan CY, Aw KL, Yeo WH, Hamdi M, Sopyan I, et al.
    Med J Malaysia, 2008 Jul;63 Suppl A:89-90.
    PMID: 19024998
    The sintering behaviour of a commercial HA and synthesized HA was investigated over the temperature range of 700 degrees C to 1400 degrees C in terms of phase stability, bulk density, Young's modulus and Vickers hardness. In the present research, a wet chemical precipitation reaction was successfully employed to synthesize a submicron, highly crystalline, high purity and single phase stoichiometric HA powder that is highly sinteractive particularly at low temperature regimes below 1100 degrees C. It has been revealed that the sinterability of the synthesized HA was significantly greater than that of the commercial HA. The temperature for the onset of sintering and the temperature required to achieve densities above 98% of theoretical value were approximately 150 degrees C lower for the synthesized HA than the equivalent commercial HA. Nevertheless, decomposition of HA phase upon sintering was not observed in the present work for both powders.
    Matched MeSH terms: Biocompatible Materials/chemical synthesis
  2. Zarina O, Radzali O
    Med J Malaysia, 2004 May;59 Suppl B:160-1.
    PMID: 15468867
    Hydroxyapatite powder was mechanochemically synthesized from calcium pyrophosphate (Ca2P2O7) and calcium carbonate (CaCO3) using a solid-state reaction. The two powders were mixed in distilled water, milled for 8 hours, dried and calcined at 1100 degrees C for 1 hour. The phase(s) formed was analyzed by x-ray diffraction (XRD). It was found that hydroxyapatite was not the only one formed. This result will be used as the starting point to produce a single-phase hydroxyapatite in terms of excess hydroxyl group in a mechanochemical reaction.
    Matched MeSH terms: Biocompatible Materials/chemical synthesis*
  3. 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: Biocompatible Materials/chemical synthesis*
  4. Tan SA, Ahmad Fauzi MN, Luay BH, Radzali O
    Med J Malaysia, 2004 May;59 Suppl B:162-3.
    PMID: 15468868
    In this work, nanometer HA crystals have been synthesized via wet chemical precipitation and characterized. This research studies how key synthesis parameters affect the size and phase purity of the produced HA. Characterization work was carried out using X-ray powder diffraction method and scanning electron microscopy for phase identification and particle sizing, respectively.
    Matched MeSH terms: Biocompatible Materials/chemical synthesis*
  5. Idris B, Rusnah M, Reusmaazran YM, Rohaida CH
    Med J Malaysia, 2004 May;59 Suppl B:67-8.
    PMID: 15468822
    Matched MeSH terms: Biocompatible Materials/chemical synthesis*
  6. Lai KL, Roziyanna A, Ogunniyi DS, Zainal AM, Azlan AA
    Med J Malaysia, 2004 May;59 Suppl B:61-2.
    PMID: 15468819
    Various blend ratios of high-density polyethylene (HDPE) and ultra high molecular weight polyethylene (UHMWPE) were prepared with the objective of determining their suitability as biomaterials. In the unfilled state, a blend of 50/50 (HDPE/UHMWPE) ratio by weight was found to yield optimum properties in terms of processability and mechanical properties. Hydroxyapatite (HA) was compounded with the optimum blend ratio. The effects of HA loading, varied from 0 to 50wt% for both filled and unfilled blends were tested for mechanical properties. It was found that the inclusion of HA in the blend led to a remarkable improvement of mechanical properties compared to the unfilled blend. In order to improve the bonding between the polymer blend and the filler, the HA used was chemically treated with a coupling agent known as 3-(trimethoxysiyl) propyl methacrylate and the treated HA was mixed into the blend. The effect of mixing the blend with silane-treated HA also led to an overall improvement of mechanical properties.
    Matched MeSH terms: Biocompatible Materials/chemical synthesis*
  7. Hee SL, Nik Intan NI, Fazan F
    Med J Malaysia, 2004 May;59 Suppl B:77-8.
    PMID: 15468827
    There is a great demand of Hydroxyapatite (HA) material in Orthopaedics and Dental applications due to its similarity to human bone. However, the lack of availability and due to high import cost of this material in Malaysia, research in producing synthetic HA locally is therefore timely. The use of local resources as the raw materials for the production of HA is also desirable in reducing the overall cost of HA. In this study, two HA materials were synthesised from different starting precursors, i.e. commercial pure Ca(OH)2 (HAS) and Ca(OH)2 directly from a local natural limestone deposit (HAL). Whereas a commercially available HA "Captal 60" (HAC) was used as reference. The synthesised powders obtained were fired at 1000 degrees C and at 1250 degrees C. Characterisation evaluations on bulk properties were carried out using XRD, SEM-EDX, ICP and FTIR. The results indicate that both HAS and HAL are comparable to HAC even at 1000 degrees C. Thus, the local natural limestone can be used to form HA. However, the overall appearance of these materials are quite different (HAC - blue, HAS - greenish and HAL - light green). The reasons for this and the subsequent mechanical and bioactive effects of these materials are currently being investigated.
    Matched MeSH terms: Biocompatible Materials/chemical synthesis*
  8. Fazan F, Shahida KB
    Med J Malaysia, 2004 May;59 Suppl B:69-70.
    PMID: 15468823
    The paper presents a method of producing synthetic Hydroxyapatite (HA) Ca10(PO4)6(OH)2 and other apatites for biological use by solid-state reaction. The solid-state reaction involves mix-grinding dry powders of beta-tricalcium phosphate powder (TCP) and either calcium hydroxide (Ca(OH)2) or calcium carbonate (CaCO3) or combination thereof, from pure commercial chemicals or derived from natural limestone or from seashells, of total calcium/phosphorus molar ratio between 1.5 to 2.0, to particle size of less than 10 microns, and firing the resultant powder to temperature between 600 degrees C - 1250 degrees C in atmosphere or in controlled atmospheric condition. The resultant apatites formed were characterised using XRD, SEM-EDX and FTIR. The presented reaction process was found to be much simpler compared to conventional methods of producing synthetic apatites since it involves only dry mix-grinding of the reactants before firing at high temperatures based on the required levels of purity. It can also produce synthetic apatites with good reproducibility in a shorter time. Thus the presented method has a great industrial value.
    Matched MeSH terms: Biocompatible Materials/chemical synthesis*
  9. Shah RK, Fahmi MN, Mat AH, Zainal AA
    Med J Malaysia, 2004 May;59 Suppl B:75-6.
    PMID: 15468826
    Hydroxyapatite (HA) has been earmarked as suitable for implantation within the human of its chemical makeup to human bone. In this paper, HA powders were synthesized via the precipitation method where phosphoric acid (H3PO4) was titrated into calcium hydroxide solution [Ca(OH)2]. Two parameters such as temperature and stirring rate were identified as factors that influenced the amount and purity of HA powder. Phase identification of the synthesized powder was done using X-Ray Diffraction (XRD). The results show that HA phase can be synthesized from this titration process of Ca(OH)2 and H3PO4 with yield amount of HA powder around 45 - 61 grams but with less than hundred percent purity. In order to study the effect of heat treatment to HA crystals structure, HA powder was calcined at 850 degrees C for 2 hours. It's found that the degree of crystallinity increases after calcination because of lattice expansion when the materials were heated at higher temperature
    Matched MeSH terms: Biocompatible Materials/chemical synthesis*
  10. Doreya MI, Mona EW, Afaf ES, Hanan HB
    Med J Malaysia, 2004 May;59 Suppl B:21-2.
    PMID: 15468799
    The standard bioglass composition GS45 as well as with excess silica GS50 or with the addition of 5% titanium oxide GS45+Ti5, were prepared by the polymeric route. The different glass components were added to the formed polymer. Firing at 700 degrees C gave an amorphous product with microporous texture that readily crystallizes out at 900 degrees C. The prepared materials were highly porous with two modes of pore system micro-pores and macro-pores with a size ranging between 100 microm to 0.006 microm and a porosity reaching 73%. The measured bulk density was between 0.36 to 1.1g/cm3. The fired material preserved the former structure of the polymer precursor. Biocompatibility was verified in vitro and vivo. IR of the specimens previously immersed in SBF revealed the formation of apatite like layer. While the histology sections of implants in rate femurs showed new bone tissue or bone trabeculae after 21 days.
    Matched MeSH terms: Biocompatible Materials/chemical synthesis*
  11. Ngadiman NH, Mohd Yusof N, Idris A, Kurniawan D
    Proc Inst Mech Eng H, 2016 Aug;230(8):739-49.
    PMID: 27194535 DOI: 10.1177/0954411916649632
    Electrospinning is a simple and efficient process in producing nanofibers. To fabricate nanofibers made of a blend of two constituent materials, co-axial electrospinning method is an option. In this method, the constituent materials contained in separate barrels are simultaneously injected using two syringe nozzles arranged co-axially and the materials mix during the spraying process forming core and shell of the nanofibers. In this study, co-axial electrospinning method is used to fabricate nanofibers made of polyvinyl alcohol and maghemite (γ-Fe2O3). The concentration of polyvinyl alcohol and amount of maghemite nanoparticle loading were varied, at 5 and 10 w/v% and at 1-10 v/v%, respectively. The mechanical properties (strength and Young's modulus), porosity, and biocompatibility properties (contact angle and cell viability) of the electrospun mats were evaluated, with the same mats fabricated by regular single-nozzle electrospinning method as the control. The co-axial electrospinning method is able to fabricate the expected polyvinyl alcohol/maghemite nanofiber mats. It was noticed that the polyvinyl alcohol/maghemite electrospun mats have lower mechanical properties (i.e. strength and stiffness) and porosity, more hydrophilicity (i.e. lower contact angle), and similar cell viability compared to the mats fabricated by single-nozzle electrospinning method.
    Matched MeSH terms: Biocompatible Materials/chemical synthesis
  12. Amin Yavari S, Chai YC, Böttger AJ, Wauthle R, Schrooten J, Weinans H, et al.
    PMID: 25842117 DOI: 10.1016/j.msec.2015.02.050
    Anodizing could be used for bio-functionalization of the surfaces of titanium alloys. In this study, we use anodizing for creating nanotubes on the surface of porous titanium alloy bone substitutes manufactured using selective laser melting. Different sets of anodizing parameters (voltage: 10 or 20V anodizing time: 30min to 3h) are used for anodizing porous titanium structures that were later heat treated at 500°C. The nanotopographical features are examined using electron microscopy while the bioactivity of anodized surfaces is measured using immersion tests in the simulated body fluid (SBF). Moreover, the effects of anodizing and heat treatment on the performance of one representative anodized porous titanium structures are evaluated using in vitro cell culture assays using human periosteum-derived cells (hPDCs). It has been shown that while anodizing with different anodizing parameters results in very different nanotopographical features, i.e. nanotubes in the range of 20 to 55nm, anodized surfaces have limited apatite-forming ability regardless of the applied anodizing parameters. The results of in vitro cell culture show that both anodizing, and thus generation of regular nanotopographical feature, and heat treatment improve the cell culture response of porous titanium. In particular, cell proliferation measured using metabolic activity and DNA content was improved for anodized and heat treated as well as for anodized but not heat-treated specimens. Heat treatment additionally improved the cell attachment of porous titanium surfaces and upregulated expression of osteogenic markers. Anodized but not heat-treated specimens showed some limited signs of upregulated expression of osteogenic markers. In conclusion, while varying the anodizing parameters creates different nanotube structure, it does not improve apatite-forming ability of porous titanium. However, both anodizing and heat treatment at 500°C improve the cell culture response of porous titanium.
    Matched MeSH terms: Biocompatible Materials/chemical synthesis*
  13. Ngadiman NH, Yusof NM, Idris A, Misran E, Kurniawan D
    Mater Sci Eng C Mater Biol Appl, 2017 Jan 01;70(Pt 1):520-534.
    PMID: 27770924 DOI: 10.1016/j.msec.2016.09.002
    The use of electrospinning process in fabricating tissue engineering scaffolds has received great attention in recent years due to its simplicity. The nanofibers produced via electrospinning possessed morphological characteristics similar to extracellular matrix of most tissue components. Porosity plays a vital role in developing tissue engineering scaffolds because it influences the biocompatibility performance of the scaffolds. In this study, maghemite (γ-Fe2O3) was mixed with polyvinyl alcohol (PVA) and subsequently electrospun to produce nanofibers. Five factors; nanoparticles content, voltage, flow rate, spinning distance, and rotating speed were varied to produce the electrospun nanofibrous mats with high porosity value. Empirical model was developed using response surface methodology to analyze the effect of these factors to the porosity. The results revealed that the optimum porosity (90.85%) was obtained using 5% w/v nanoparticle content, 35kV of voltage, 1.1ml/h volume flow rate of solution, 8cm spinning distance and 2455rpm of rotating speed. The empirical model was verified successfully by performing confirmation experiments. The properties of optimum PVA/γ-Fe2O3 nanofiber mats such as fiber diameter, mechanical properties, and contact angle were investigated. In addition, cytocompatibility test, in vitro degradation rate, and MTT assay were also performed. Results revealed that high porosity biodegradable γ-Fe2O3/polyvinyl alcohol nanofiber mats have low mechanical properties but good degradation rates and cytocompatibility properties. Thus, they are suitable for low load bearing biomedical application or soft tissue engineering scaffold.
    Matched MeSH terms: Biocompatible Materials/chemical synthesis*
  14. Hild F, Nguyen NT, Deng E, Katrib J, Dimitrakis G, Lau PL, et al.
    Macromol Rapid Commun, 2016 Aug;37(15):1295-9.
    PMID: 27315130 DOI: 10.1002/marc.201600149
    The use of dielectric property measurements to define specific trends in the molecular structures of poly(caprolactone) containing star polymers and/or the interbatch repeatability of the synthetic procedures used to generate them is demonstrated. The magnitude of the dielectric property value is shown to accurately reflect: (a) the number of functional groups within a series of materials with similar molecular size when no additional intermolecular order is present in the medium, (b) the polymer molecular size for a series of materials containing a fixed core material and so functional group number, and/or (c) the batch to batch repeatability of the synthesis method. The dielectric measurements are validated by comparison to spectroscopic/chromatographic data.
    Matched MeSH terms: Biocompatible Materials/chemical synthesis*
  15. Ramesh S, Yaghoubi A, Lee KY, Chin KM, Purbolaksono J, Hamdi M, et al.
    J Mech Behav Biomed Mater, 2013 Sep;25:63-9.
    PMID: 23726923 DOI: 10.1016/j.jmbbm.2013.05.008
    Forsterite (Mg2SiO4) because of its exceptionally high fracture toughness which is close to that of cortical bones has been nominated as a possible successor to calcium phosphate bioceramics. Recent in vitro studies also suggest that forsterite possesses good bioactivity and promotes osteoblast proliferation as well as adhesion. However studies on preparation and sinterability of nanocrystalline forsterite remain scarce. In this work, we use a solid-state reaction with magnesium oxide (MgO) and talc (Mg3Si4(OH)2) as the starting precursors to synthesize forsterite. A systematic investigation was carried out to elucidate the effect of preparatory procedures including heat treatment, mixing methods and sintering temperature on development of microstructures as well as the mechanical properties of the sintered forsterite body.
    Matched MeSH terms: Biocompatible Materials/chemical synthesis*
  16. Mishra RK, Ramasamy K, Ahmad NA, Eshak Z, Majeed AB
    J Mater Sci Mater Med, 2014 Apr;25(4):999-1012.
    PMID: 24398912 DOI: 10.1007/s10856-013-5132-x
    Stimuli responsive hydrogels have shown enormous potential as a carrier for targeted drug delivery. In this study we have developed novel pH responsive hydrogels for the delivery of 5-fluorouracil (5-FU) in order to alleviate its antitumor activity while reducing its toxicity. We used 2-(methacryloyloxyethyl) trimetylammonium chloride a positively charged monomer and methacrylic acid for fabricating the pH responsive hydrogels. The released 5-FU from all except hydrogel (GEL-5) remained biologically active against human colon cancer cell lines [HT29 (IC50 = 110-190 μg ml(-1)) and HCT116 (IC50 = 210-390 μg ml(-1))] but not human skin fibroblast cells [BJ (CRL2522); IC50 ≥ 1000 μg ml(-1)]. This implies that the copolymer hydrogels (1-4) were able to release 5-FU effectively to colon cancer cells but not normal human skin fibroblast cells. This is probably due to the shorter doubling time that results in reduced pH in colon cancer cells when compared to fibroblast cells. These pH sensitive hydrogels showed well defined cell apoptosis in HCT116 cells through series of events such as chromatin condensation, membrane blebbing, and formation of apoptotic bodies. No cell killing was observed in the case of blank hydrogels. The results showed the potential of these stimuli responsive polymer hydrogels as a carrier for colon cancer delivery.
    Matched MeSH terms: Biocompatible Materials/chemical synthesis
  17. Lee SY, Wee AS, Lim CK, Abbas AA, Selvaratnam L, Merican AM, et al.
    J Mater Sci Mater Med, 2013 Jun;24(6):1561-70.
    PMID: 23512151 DOI: 10.1007/s10856-013-4907-4
    This study aims to pre-assess the in vitro and in vivo biocompatibility of poly(vinyl alcohol)-carboxylmethyl-chitosan-poly(ethylene glycol) (PCP) scaffold. PCP was lyophilised to create supermacroporous structures. 3-(4, 5-dimethyl-thiazol-2yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and immunohistochemistry (IHC) were used to evaluate the effectiveness of PCP scaffolds for chondrocytes attachment and proliferation. The ultrastructural was assessed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Extracellular matrix (ECM) formation was evaluated using collagen type-II staining, glycosaminoglycan (GAG) and collagen assays. Histological analysis was conducted on 3-week implanted Sprague-Dawley rats. The MTT, IHC, SEM and TEM analyses confirm that PCP scaffolds promoted cell attachment and proliferation in vitro. The chondrocyte-PCP constructs secreted GAG and collagen type-II, both increased significantly from day-14 to day-28 (P 
    Matched MeSH terms: Biocompatible Materials/chemical synthesis*
  18. Latfi ASA, Pramanik S, Poon CT, Gumel AM, Lai KW, Annuar MSM, et al.
    J Biomater Appl, 2019 01;33(6):854-865.
    PMID: 30458659 DOI: 10.1177/0885328218812490
    Natural biopolymers have many attractive medical applications; however, complications due to fibrosis caused a reduction in diffusion and dispersal of nutrients and waste products. Consequently, severe immunocompatibility problems and poor mechanical and degradation properties in synthetic polymers ensue. Hence, the present study investigates a novel hydrogel material synthesized from caprolactone, ethylene glycol, ethylenediamine, polyethylene glycol, ammonium persulfate, and tetramethylethylenediamine via chemo-enzymatic route. Spectroscopic analyses indicated the formation of polyurea and polyhydroxyurethane as the primary building block of the hydrogel starting material. Biocompatibility studies showed positive observation in biosafety test using direct contact cytotoxicity assay in addition to active cellular growth on the hydrogel scaffold based on fluorescence observation. The synthesized hydrogel also exhibited (self)fluorescence properties under specific wavelength excitation. Hence, synthesized hydrogel could be a potential candidate for medical imaging as well as tissue engineering applications as a tissue expander, coating material, biosensor, and drug delivery system.
    Matched MeSH terms: Biocompatible Materials/chemical synthesis
  19. Ujang Z, Abdul Rashid AH, Suboh SK, Halim AS, Lim CK
    J Appl Biomater Funct Mater, 2014 Dec 30;12(3):155-62.
    PMID: 24700269 DOI: 10.5301/jabfm.5000190
    BACKGROUND: The physical and biological characteristics of oligochitosan (O-C) film, including its barrier and mechanical properties, in vitro cytotoxicity and in vivo biocompatibility, were studied to assess its potential use as a wound dressing.

    METHODS: Membrane films were prepared from water-soluble O-C solution blended with various concentrations of glycerol to modify the physical properties of the films. In vitro and in vivo biocompatibility evaluations were performed using primary human skin fibroblast cultures and subcutaneous implantation in a rat model, respectively.

    RESULTS: Addition of glycerol significantly influenced the barrier and mechanical properties of the films. Water absorption capacity was in the range of 80%-160%, whereas water vapor transmission rate varied from 1,180 to 1,618 g/m2 per day. Both properties increased with increasing glycerol concentration. Tensile strength decreased while elongation at break increased with the addition of glycerol. O-C films were found to be noncytotoxic to human fibroblast cultures and histological examination proved that films are biocompatible.

    CONCLUSION: These results indicate that the membrane film from O-C has potential application as a wound-dressing material.

    Matched MeSH terms: Biocompatible Materials/chemical synthesis
  20. Ahmad MB, Gharayebi Y, Salit MS, Hussein MZ, Ebrahimiasl S, Dehzangi A
    Int J Mol Sci, 2012;13(4):4860-72.
    PMID: 22606014 DOI: 10.3390/ijms13044860
    Polyimide/SiO(2) composite films were prepared from tetraethoxysilane (TEOS) and poly(amic acid) (PAA) based on aromatic diamine (4-aminophenyl sulfone) (4-APS) and aromatic dianhydride (3,3,4,4-benzophenonetetracarboxylic dianhydride) (BTDA) via a sol-gel process in N-methyl-2-pyrrolidinone (NMP). The prepared polyimide/SiO(2) composite films were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and thermogravimetric analysis (TGA). The FTIR results confirmed the synthesis of polyimide (4-APS/BTDA) and the formation of SiO(2) particles in the polyimide matrix. Meanwhile, the SEM images showed that the SiO(2) particles were well dispersed in the polyimide matrix. Thermal stability and kinetic parameters of the degradation processes for the prepared polyimide/SiO(2) composite films were investigated using TGA in N(2) atmosphere. The activation energy of the solid-state process was calculated using Flynn-Wall-Ozawa's method without the knowledge of the reaction mechanism. The results indicated that thermal stability and the values of the calculated activation energies increased with the increase of the TEOS loading and the activation energy also varied with the percentage of weight loss for all compositions.
    Matched MeSH terms: Biocompatible Materials/chemical synthesis*
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