Displaying publications 301 - 311 of 311 in total

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  1. Incorporation of zinc oxide nanoparticles into chitosan-collagen 3D porous scaffolds: Effect on morphology, mechanical properties and cytocompatibility of 3D porous scaffolds
    Ullah S, Zainol I, Idrus RH
    Int J Biol Macromol, 2017 Nov;104(Pt A):1020-1029.
    PMID: 28668615 DOI: 10.1016/j.ijbiomac.2017.06.080
    The zinc oxide nanoparticles (particles size <50nm) incorporated into chitosan-collagen 3D porous scaffolds and investigated the effect of zinc oxide nanoparticles incorporation on microstructure, mechanical properties, biodegradation and cytocompatibility of 3D porous scaffolds. The 0.5%, 1.0%, 2.0% and 4.0% zinc oxide nanoparticles chitosan-collagen 3D porous scaffolds were fabricated via freeze-drying technique. The zinc oxide nanoparticles incorporation effects consisting in chitosan-collagen 3D porous scaffolds were investigated by mechanical and swelling tests, and effect on the morphology of scaffolds examined microscopically. The biodegradation and cytocompatibility tests were used to investigate the effects of zinc oxide nanoparticles incorporation on the ability of scaffolds to use for tissue engineering application. The mean pore size and swelling ratio of scaffolds were decreased upon incorporation of zinc oxide nanoparticles however, the porosity, tensile modulus and biodegradation rate were increased upon incorporation of zinc oxide nanoparticles. In vitro culture of human fibroblasts and keratinocytes showed that the zinc oxide nanoparticles facilitated cell adhesion, proliferation and infiltration of chitosan-collagen 3D porous scaffolds. It was found that the zinc oxide nanoparticles incorporation enhanced porosity, tensile modulus and cytocompatibility of chitosan-collagen 3D porous scaffolds.
    Matched MeSH terms: Tissue Engineering
  2. Fulltext The Role of Calcium in Wound Healing
    Subramaniam T, Fauzi MB, Lokanathan Y, Law JX
    Int J Mol Sci, 2021 Jun 17;22(12).
    PMID: 34204292 DOI: 10.3390/ijms22126486
    Skin injury is quite common, and the wound healing is a complex process involving many types of cells, the extracellular matrix, and soluble mediators. Cell differentiation, migration, and proliferation are essential in restoring the integrity of the injured tissue. Despite the advances in science and technology, we have yet to find the ideal dressing that can support the healing of cutaneous wounds effectively, particularly for difficult-to-heal chronic wounds such as diabetic foot ulcers, bed sores, and venous ulcers. Hence, there is a need to identify and incorporate new ideas and methods to design a more effective dressing that not only can expedite wound healing but also can reduce scarring. Calcium has been identified to influence the wound healing process. This review explores the functions and roles of calcium in skin regeneration and reconstruction during would healing. Furthermore, this review also investigates the possibility of incorporating calcium into scaffolds and examines how it modulates cutaneous wound healing. In summary, the preliminary findings are promising. However, some challenges remain to be addressed before calcium can be used for cutaneous wound healing in clinical settings.
    Matched MeSH terms: Tissue Engineering
  3. Synergistic effects of chitosan scaffold and TGFβ1 on the proliferation and osteogenic differentiation of dental pulp stem cells derived from human exfoliated deciduous teeth
    Farea M, Husein A, Halim AS, Abdullah NA, Mokhtar KI, Lim CK, et al.
    Arch Oral Biol, 2014 Dec;59(12):1400-11.
    PMID: 25222336 DOI: 10.1016/j.archoralbio.2014.08.015
    Multipotent stem cells derived from human exfoliated deciduous teeth (SHED) represent a promising cell source for tissue regeneration. In the present study we decided to test the inductive effect of chitosan and transforming growth factor-β1 (TGFβ1) as a scaffold/factor combination on SHED proliferation and osteogenic differentiation.
    Matched MeSH terms: Tissue Engineering
  4. Cytotoxic evaluation of biomechanically improved crosslinked ovine collagen on human dermal fibroblasts
    Awang MA, Firdaus MA, Busra MB, Chowdhury SR, Fadilah NR, Wan Hamirul WK, et al.
    Biomed Mater Eng, 2014;24(4):1715-24.
    PMID: 24948455 DOI: 10.3233/BME-140983
    Earlier studies in our laboratory demonstrated that collagen extracted from ovine tendon is biocompatible towards human dermal fibroblast. To be able to use this collagen as a scaffold in skin tissue engineering, a mechanically stronger scaffold is required that can withstand manipulation before transplantation. This study was conducted to improve the mechanical strength of this collagen sponge using chemical crosslinkers, and evaluate their effect on physical, chemical and biocompatible properties. Collagen sponge was crosslinked with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and glutaraldehyde (GA). Tensile test, FTIR study and mercury porosimetry were used to evaluate mechanical properties, chemical property and porosity, respectively. MTT assay was performed to evaluate the cytotoxic effect of crosslinked collagen sponge on human dermal fibroblasts. The FTIR study confirmed the successful crosslinking of collagen sponge. Crosslinking with EDC and GA significantly increased the mechanical strength of collagen sponge, with GA being more superior. Crosslinking of collagen sponge significantly reduced the porosity and the effect was predominant in GA-crosslinked collagen sponge. The GA-crosslinked collagen showed significantly lower, 60% cell viability towards human dermal fibroblasts compared to that of EDC-crosslinked collagen, 80% and non-crosslinked collagen, 100%. Although the mechanical strength was better when using GA but the more toxic effect on dermal fibroblast makes EDC a more suitable crosslinker for future skin tissue engineering.
    Matched MeSH terms: Tissue Engineering
  5. Biomimetic growth of bone-like apatite via simulated body fluid on hydroxyethyl cellulose/polyvinyl alcohol electrospun nanofibers
    Chahal S, Chalal S, Fathima SJ, Yusoff MB
    Biomed Mater Eng, 2014;24(1):799-806.
    PMID: 24211966 DOI: 10.3233/BME-130871
    In this study, randomly oriented hydroxyethyl cellulose/polyvinyl alcohol (HEC/PVA) nanofibers were fabricated by electrospinning. The blend solutions of HEC/PVA with different weight ratio of HEC to PVA were prepared using water as solvent to fabricate nanofibers. These nanofibrous scaffolds were coated with bone-like apatite by immersing into 10x simulated body fluid (SBF) for different time periods. The morphology and structure of the nanofibers were characterized by SEM, FTIR and DSC. FESEM-EDS and FTIR analysis were used to confirm the deposition of apatite on the surface of nanofibers. The results of this study suggest that this apatite coated nanofibrous scaffolds could be a suitable biomaterial for bone tissue engineering.
    Matched MeSH terms: Tissue Engineering
  6. Effect of growth differentiation factor 5 on the proliferation and tenogenic differentiation potential of human mesenchymal stem cells in vitro
    Tan SL, Ahmad RE, Ahmad TS, Merican AM, Abbas AA, Ng WM, et al.
    Cells Tissues Organs (Print), 2012;196(4):325-38.
    PMID: 22653337
    The use of growth differentiation factor 5 (GDF-5) in damaged tendons has been shown to improve tendon repair. It has been hypothesized that further improvements may be achieved when GDF-5 is used to promote cell proliferation and induce tenogenic differentiation in human bone marrow-derived mesenchymal stem cells (hMSCs). However, the optimal conditions required to produce these effects on hMSCs have not been demonstrated in previous studies. A study to determine cell proliferation and tenogenic differentiation in hMSCs exposed to different concentrations of GDF-5 (0, 5, 25, 50, 100 and 500 ng/ml) was thus conducted. No significant changes were observed in the cell proliferation rate in hMSCs treated at different concentrations of GDF-5. GDF-5 appeared to induce tenogenic differentiation at 100 ng/ml, as reflected by (1) a significant increase in total collagen expression, similar to that of the primary native human tenocyte culture; (2) a significant upregulation in candidate tenogenic marker gene expression, i.e. scleraxis, tenascin-C and type-I collagen; (3) the ratio of type-I collagen to type-III collagen expression was elevated to levels similar to that of human tenocyte cultures, and (4) a significant downregulation of the non-tenogenic marker genes runt-related transcription factor 2 and sex determining region Y (SRY)-box 9 at day 7 of GDF-5 induction, further excluding hMSC differentiation into other lineages. In conclusion, GDF-5 does not alter the proliferation rates of hMSCs, but, instead, induces an optimal tenogenic differentiation response at 100 ng/ml.
    Matched MeSH terms: Tissue Engineering
  7. Development of a novel model for the investigation of implant-soft tissue interface
    Chai WL, Moharamzadeh K, Brook IM, Emanuelsson L, Palmquist A, van Noort R
    J. Periodontol., 2010 Aug;81(8):1187-95.
    PMID: 20450401 DOI: 10.1902/jop.2010.090648
    In dental implant treatment, the long-term prognosis is dependent on the biologic seal formed by the soft tissue around the implant. The in vitro investigation of the implant-soft tissue interface is usually carried out using a monolayer cell-culture model that lacks a polarized-cell phenotype. This study developed a tissue-engineered three-dimensional oral mucosal model (3D OMM) to investigate the implant-soft tissue interface.
    Matched MeSH terms: Tissue Engineering
  8. In vitro generation of functional insulin-producing cells from lipoaspirated human adipose tissue-derived stem cells
    Mohamad Buang ML, Seng HK, Chung LH, Saim AB, Idrus RB
    Arch Med Res, 2012 Jan;43(1):83-8.
    PMID: 22374243 DOI: 10.1016/j.arcmed.2012.01.012
    BACKGROUND AND AIMS: Tissue engineering strategy has been considered as an alternative treatment for diabetes mellitus due to lack of permanent pharmaceutical treatment and islet donors for transplantation. Various cell lines have been used to generate functional insulin-producing cells (IPCs) including progenitor pancreatic cell lines, embryonic stem cells (ESCs), umbilical cord blood stem cells (UCB-SCs), adult bone marrow stem cells (BMSCs), and adipose tissue-derived stem cells (ADSCs).

    METHODS: Human ADSCs from lipoaspirated abdominal fat tissue was differentiated into IPCs following a two-step induction protocol based on a combination of alternating high and low glucose, nicotinamide, activin A and glucagon-like peptide 1 (GLP-1) for a duration of 3 weeks. During differentiation, histomorphological changes of the stem cells towards pancreatic β-islet characteristics were observed via light microscope and transmission electron microscope (TEM). Dithizone (DTZ) staining, which is selective towards IPCs, was used to stain the new islet-like cells. Production of insulin hormone by the cells was analyzed via enzyme-linked immunosorbent assay (ELISA), whereas its hormonal regulation was tested via a glucose challenge test.

    RESULTS: Histomorphological changes of the differentiated cells were noted to resemble pancreatic β-cells, whereas DTZ staining positively stained the cells. The differentiated cells significantly produced human insulin as compared to the undifferentiated ADSCs, and its production was increased with an increase of glucose concentration in the culture medium.

    CONCLUSIONS: These initial data indicate that human lipoaspirated ADSCs have the potential to differentiate into functional IPCs, and could be used as a therapy to treat diabetes mellitus in the future.

    Matched MeSH terms: Tissue Engineering
  9. Fulltext Fate of tenogenic differentiation potential of human bone marrow stromal cells by uniaxial stretching affected by stretch-activated calcium channel agonist gadolinium
    Nam HY, Balaji Raghavendran HR, Pingguan-Murphy B, Abbas AA, Merican AM, Kamarul T
    PLoS One, 2017;12(6):e0178117.
    PMID: 28654695 DOI: 10.1371/journal.pone.0178117
    The role for mechanical stimulation in the control of cell fate has been previously proposed, suggesting that there may be a role of mechanical conditioning in directing mesenchymal stromal cells (MSCs) towards specific lineage for tissue engineering applications. Although previous studies have reported that calcium signalling is involved in regulating many cellular processes in many cell types, its role in managing cellular responses to tensile loading (mechanotransduction) of MSCs has not been fully elucidated. In order to establish this, we disrupted calcium signalling by blocking stretch-activated calcium channel (SACC) in human MSCs (hMSCs) in vitro. Passaged-2 hMSCs were exposed to cyclic tensile loading (1 Hz + 8% for 6, 24, 48, and 72 hours) in the presence of the SACC blocker, gadolinium. Analyses include image observations of immunochemistry and immunofluorescence staining from extracellular matrix (ECM) production, and measuring related tenogenic and apoptosis gene marker expression. Uniaxial tensile loading increased the expression of tenogenic markers and ECM production. However, exposure to strain in the presence of 20 μM gadolinium reduced the induction of almost all tenogenic markers and ECM staining, suggesting that SACC acts as a mechanosensor in strain-induced hMSC tenogenic differentiation process. Although cell death was observed in prolonged stretching, it did not appear to be apoptosis mediated. In conclusion, the knowledge gained in this study by elucidating the role of calcium in MSC mechanotransduction processes, and that in prolonged stretching results in non-apoptosis mediated cell death may be potential useful for regenerative medicine applications.
    Matched MeSH terms: Tissue Engineering
  10. Platelet-rich concentrate in serum-free medium enhances cartilage-specific extracellular matrix synthesis and reduces chondrocyte hypertrophy of human mesenchymal stromal cells encapsulated in alginate
    Samuel S, Ahmad RE, Ramasamy TS, Karunanithi P, Naveen SV, Kamarul T
    Platelets, 2019;30(1):66-74.
    PMID: 29090639 DOI: 10.1080/09537104.2017.1371287
    Platelet-rich concentrate (PRC), used in conjunction with other chondroinductive growth factors, have been shown to induce chondrogenesis of human mesenchymal stromal cells (hMSC) in pellet culture. However, pellet culture systems promote cell hypertrophy and the presence of other chondroinductive growth factors in the culture media used in previous studies obscures accurate determination of the effect of platelet itself in inducing chondrogenic differentiation. Hence, this study aimed to investigate the effect of PRC alone in enhancing the chondrogenic differentiation potential of human mesenchymal stromal cells (hMSC) encapsulated in three-dimensional alginate constructs. Cells encapsulated in alginate were cultured in serum-free medium supplemented with only 15% PRC. Scanning electron microscopy was used to determine the cell morphology. Chondrogenic molecular signature of hMSCs was determined by quantitative real-time PCR and verified at protein levels via immunohistochemistry and enzyme-linked immunosorbent assay. Results showed that the cells cultured in the presence of PRC for 24 days maintained a chondrocytic phenotype and demonstrated minimal upregulation of cartilaginous extracellular matrix (ECM) marker genes (SOX9, TNC, COL2, ACAN, COMP) and reduced expression of chondrocyte hypertrophy genes (Col X, Runx2) compared to the standard chondrogenic medium (p 
    Matched MeSH terms: Tissue Engineering
  11. Synergistic interaction of platelet derived growth factor (PDGF) with the surface of PLLA/Col/HA and PLLA/HA scaffolds produces rapid osteogenic differentiation
    Raghavendran HR, Mohan S, Genasan K, Murali MR, Naveen SV, Talebian S, et al.
    Colloids Surf B Biointerfaces, 2016 Mar 1;139:68-78.
    PMID: 26700235 DOI: 10.1016/j.colsurfb.2015.11.053
    Scaffolds with structural features similar to the extracellular matrix stimulate rapid osteogenic differentiation in favorable microenvironment and with growth factor supplementation. In this study, the osteogenic potential of electrospun poly-l-lactide/hydroxyapatite/collagen (PLLA/Col/HA, PLLA/HA and PLLA/Col) scaffolds were tested in vitro with the supplementation of platelet derived growth factor-BB (PDGF-BB). Cell attachment and topography, mineralization, extracellular matrix protein localization, and gene expression of the human mesenchymal stromal cells were compared between the fibrous scaffolds PLLA/Col/HA, PLLA/Col, and PLLA/HA. The levels of osteocalcin, calcium, and mineralization were significantly greater in the PLLA/Col/HA and PLLA/HA compared with PLLA/Col. High expression of fibronectin, intracellular adhesion molecule, cadherin, and collagen 1 (Col1) suggests that PLLA/Col/HA and PLLA/HA scaffolds had superior osteoinductivity than PLLA/Col. Additionally, osteopontin, osteocalcin, osterix, Runt-related transcription factor 2 (Runx2), and bone morphogenic protein (BMP2) expression were higher in PLLA/Col/HA and PLLA/HA compared with PLLA/Col. In comparison with PLLA/Col, the PLLA/Col/HA and PLLA/HA scaffolds presented a significant upregulation of the genes Runx2, Col 1, Integrin, osteonectin (ON), bone gamma-carboxyglutamic acid-containing protein (BGALP), osteopontin (OPN), and BMP2. The upregulation of these genes was further increased with PDGF-BB supplementation. These results show that PDGF-BB acts synergistically with PLLA/Col/HA and PLLA/HA to enhance the osteogenic differentiation potential. Therefore, this combination can be used for the rapid expansion of bone marrow stromal cells into bone-forming cells for tissue engineering.
    Matched MeSH terms: Tissue Engineering
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