Displaying publications 61 - 80 of 983 in total

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  1. Cytotoxic evaluation of hydroxyapatite-filled and silica/hydroxyapatite-filled acrylate-based restorative composite resins: An in vitro study
    Chadda H, Naveen SV, Mohan S, Satapathy BK, Ray AR, Kamarul T
    J Prosthet Dent, 2016 Jul;116(1):129-35.
    PMID: 26873771 DOI: 10.1016/j.prosdent.2015.12.013
    STATEMENT OF PROBLEM: Although the physical and mechanical properties of hydroxyapatite-filled dental restorative composite resins have been examined, the biocompatibility of these materials has not been studied in detail.

    PURPOSE: The purpose of this in vitro study was to analyze the toxicity of acrylate-based restorative composite resins filled with hydroxyapatite and a silica/hydroxyapatite combination.

    MATERIAL AND METHODS: Five different restorative materials based on bisphenol A-glycidyl methacrylate (bis-GMA) and tri-ethylene glycol dimethacrylate (TEGDMA) were developed: unfilled (H0), hydroxyapatite-filled (H30, H50), and silica/hydroxyapatite-filled (SH30, SH50) composite resins. These were tested for in vitro cytotoxicity by using human bone marrow mesenchymal stromal cells. Surface morphology, elemental composition, and functional groups were determined by scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), and Fourier-transformed infrared spectroscopy (FTIR). The spectra normalization, baseline corrections, and peak integration were carried out by OPUS v4.0 software.

    RESULTS: Both in vitro cytotoxicity results and SEM analysis indicated that the composite resins developed were nontoxic and supported cell adherence. Elemental analysis with EDX revealed the presence of carbon, oxygen, calcium, silicon, and gold, while the presence of methacrylate, hydroxyl, and methylene functional groups was confirmed through FTIR analysis.

    CONCLUSIONS: The characterization and compatibility studies showed that these hydroxyapatite-filled and silica/hydroxyapatite-filled bis-GMA/TEGDMA-based restorative composite resins are nontoxic to human bone marrow mesenchymal stromal cells and show a favorable biologic response, making them potential biomaterials.

    Matched MeSH terms: Microscopy, Electron, Scanning
  2. Efficiency of barium removal from radioactive waste water using the combination of maghemite and titania nanoparticles in PVA and alginate beads
    Majidnia Z, Idris A, Majid M, Zin R, Ponraj M
    Appl Radiat Isot, 2015 Nov;105:105-113.
    PMID: 26275818 DOI: 10.1016/j.apradiso.2015.06.028
    In this paper, both maghemite (γ-Fe2O3) and titanium oxide (TiO2) nanoparticles were synthesized and mixed in various ratios and embedded in PVA and alginate beads. Batch sorption experiments were applied for removal of barium ions from aqueous solution under sunlight using the beads. The process has been investigated as a function of pH, contact time, temperature, initial barium ion concentration and TiO2:γ-Fe2O3 ratios (1:10, 1:60 and 1). The recycling attributes of these beads were also considered. Furthermore, the results revealed that 99% of the Ba(II) was eliminated in 150min at pH 8 under sunlight. Also, the maghemite and titania PVA-alginate beads can be readily isolated from the aqueous solution after the process and reused for at least 7 times without significant losses of their initial properties. The reduction of Ba(II) with maghemite and titania PVA-alginate beads fitted the pseudo first order and second order Langmuir-Hinshelwood (L-H) kinetic model.
    Matched MeSH terms: Microscopy, Electron, Scanning
  3. Antimicrobial activity of Cassia alata from Malaysia
    Ibrahim D, Osman H
    J Ethnopharmacol, 1995 Mar;45(3):151-6.
    PMID: 7623478
    Ethanolic extract of Cassia alata leaves was investigated for its antimicrobial activities on several microorganisms including bacteria, yeast, dermatophytic fungi and non-dermatophytic fungi. In vitro, the extract exhibited high activity against various species of dermatophytic fungi but low activity against non-dermatophytic fungi. However, bacterial and yeast species showed resistance against in vitro treatment with the extract. The minimum inhibitory concentration (MIC) values of the extract revealed that Trichophyton mentagorphytes var. interdigitale, Trichophyton mentagrophytes var. mentagorophytes, Trichophyton rubrum and Microsporum gypseum had the MIC of 125 mg/ml, whereas Microsporum canis had the MIC of 62.5 mg/ml. The inhibition can be observed on the macroconidia of Microsporum gypseum which resulted in structural degeneration beyond repair. The mechanism of inhibition can be related to the cell leakage as observed by irregular, wrinkle shape and loss in rigidity of the macroconidia.
    Matched MeSH terms: Microscopy, Electron, Scanning
  4. First Report of Lecanicephalidean Tapeworms (Eucestoda) from Freshwater, Including Description of Three New Species of Tetragonocephalum Shipley and Hornell, 1905
    Jensen K, Guyer R
    J Parasitol, 2021 01 01;107(1):1-15.
    PMID: 33429430 DOI: 10.1645/19-167
    The lecanicephalidean cestodes parasitizing the spiral intestine of the endangered giant freshwater whipray, Urogymnus polylepis (Bleeker), are investigated for the first time. Eight host specimens were collected between 2002 and 2008 at 2 collecting sites off the eastern coast of Borneo: 6 from the Kinabatangan River (Malaysia) and 2 from a fish market in Tarakan (Indonesia). Two of these individuals were found to be infected with a total of 3 new species of TetragonocephalumShipley and Hornell, 1905. Tetragonocephalum georgei n. sp. and Tetragonocephalum opimum n. sp. were recovered from a host specimen from the Kinabatangan River, and Tetragonocephalum levicorpum n. sp. was found parasitizing a host specimen purchased at a fish market in Tarakan. Specimens of each of the new species were prepared for light microscopy; specimens of 2 of the new species were prepared for scanning electron microscopy, and histological sections were prepared for 1 of the new species. The 3 new species are distinct from the 9 valid species of Tetragonocephalum and the 1 species inquirendum based on, for example, total length, number of proglottids and testes, and size of the scolex and acetabula. Tetragonocephalum georgei n. sp. and T. levicorpum n. sp. are unusual among their congeners in that they are euapolytic (i.e., gravid proglottids were not observed) rather than apolytic. They differ from one another in scolex and acetabula size. Tetragonocephalum opimum n. sp. is unusual among its congeners in its possession of vitelline follicles arranged in 2, rather than 3, regions in the proglottid. These new species increase the total number of valid species of Tetragonocephalum to 12 and the total number of known cestodes from U. polylepis to 13 species across 6 genera in 4 orders. This is the first account of lecanicephalideans reported from freshwater. The taxonomic status of each of the 32 nominal taxa historically associated with Tetragonocephalum is re-assessed. Type host identities of all valid species are revised and discussed in light of recent taxonomic efforts in the Dasyatidae Jordan and Gilbert.
    Matched MeSH terms: Microscopy, Electron, Scanning
  5. Inflammation targeted chitosan-based hydrogel for controlled release of diclofenac sodium
    Gull N, Khan SM, Butt OM, Islam A, Shah A, Jabeen S, et al.
    Int J Biol Macromol, 2020 Nov 01;162:175-187.
    PMID: 32562726 DOI: 10.1016/j.ijbiomac.2020.06.133
    Inflammation is a key challenge in the treatment of chronic diseases. Spurred by topical advancement in polymer chemistry and drug delivery, hydrogels that release a drug in temporal, spatial and dosage controlled fashion have been trendy. This research focused on the fabrication of hydrogels with controlled drug release properties to control inflammation. Chitosan and polyvinyl pyrrolidone were used as base polymers and crosslinked with epichlorohydrin to form hydrogel films by solution casting technique. Prepared hydrogels were analyzed by swelling analysis in deionized water, buffer and electrolyte solutions and gel fraction. Functional groups confirmation and development of new covalent and hydrogen bonds, thermal stability (28.49%) and crystallinity were evaluated by FTIR, TGA and WAXRD, respectively. Rheological properties including gel strength and yield stress, elasticity (2309 MPa), porosity (75%) and hydrophilicity (73°) of prepared hydrogels were also evaluated. In vitro studies confirmed that prepared hydrogels have good biodegradability, excellent antimicrobial property and admirable cytotoxicity. Drug release profile (87.56% in 130 min) along with the drug encapsulation efficiency (84%) of prepared hydrogels was also studied. These results paved the path towards the development of hydrogels that can release the drugs with desired temporal patterns.
    Matched MeSH terms: Microscopy, Electron, Scanning
  6. Involvement of metabolites in early defense mechanism of oil palm (Elaeis guineensis Jacq.) against Ganoderma disease
    Nusaibah SA, Siti Nor Akmar A, Idris AS, Sariah M, Mohamad Pauzi Z
    Plant Physiol Biochem, 2016 Dec;109:156-165.
    PMID: 27694009 DOI: 10.1016/j.plaphy.2016.09.014
    Understanding the mechanism of interaction between the oil palm and its key pathogen, Ganoderma spp. is crucial as the disease caused by this fungal pathogen leads to a major loss of revenue in leading palm oil producing countries in Southeast Asia. Here in this study, we assess the morphological and biochemical changes in Ganoderma disease infected oil palm seedling roots in both resistant and susceptible progenies. Rubber woodblocks fully colonized by G. boninense were applied as a source of inoculum to artificially infect the roots of resistant and susceptible oil palm progenies. Gas chromatography-mass spectrometry was used to measure an array of plant metabolites in 100 resistant and susceptible oil palm seedling roots treated with pathogenic Ganoderma boninense fungus. Statistical effects, univariate and multivariate analyses were used to identify key-Ganoderma disease associated metabolic agitations in both resistant and susceptible oil palm root tissues. Ganoderma disease related defense shifts were characterized based on (i) increased antifungal activity in crude extracts, (ii) increased lipid levels, beta- and gamma-sitosterol particularly in the resistant progeny, (iii) detection of heterocyclic aromatic organic compounds, benzo [h] quinoline, pyridine, pyrimidine (iv) elevation in antioxidants, alpha- and beta-tocopherol (iv) degraded cortical cell wall layers, possibly resulting from fungal hydrolytic enzyme activity needed for initial penetration. The present study suggested that plant metabolites mainly lipids and heterocyclic aromatic organic metabolites could be potentially involved in early oil palm defense mechanism against G. boninense infection, which may also highlight biomarkers for disease detection, treatment, development of resistant variety and monitoring.
    Matched MeSH terms: Microscopy, Electron, Scanning
  7. Fulltext dsRNA silencing of an R2R3-MYB transcription factor affects flower cell shape in a Dendrobium hybrid
    Lau SE, Schwarzacher T, Othman RY, Harikrishna JA
    BMC Plant Biol, 2015;15:194.
    PMID: 26260631 DOI: 10.1186/s12870-015-0577-3
    The R2R3-MYB genes regulate pigmentation and morphogenesis of flowers, including flower and cell shape, and therefore have importance in the development of new varieties of orchids. However, new variety development is limited by the long breeding time required in orchids. In this study, we identified a cDNA, DhMYB1, that is expressed during flower development in a hybrid orchid, Dendrobium hybrida (Dendrobium bobby messina X Dendrobium chao phraya) then used the direct application of dsRNA to observe the effect of gene silencing on flower phenotype and floral epidermal cell shape.
    Matched MeSH terms: Microscopy, Electron, Scanning
  8. Fulltext Attachment of Salmonella strains to a plant cell wall model is modulated by surface characteristics and not by specific carbohydrate interactions
    Tan MS, Moore SC, Tabor RF, Fegan N, Rahman S, Dykes GA
    BMC Microbiol, 2016 09 15;16:212.
    PMID: 27629769 DOI: 10.1186/s12866-016-0832-2
    BACKGROUND: Processing of fresh produce exposes cut surfaces of plant cell walls that then become vulnerable to human foodborne pathogen attachment and contamination, particularly by Salmonella enterica. Plant cell walls are mainly composed of the polysaccharides cellulose, pectin and hemicelluloses (predominantly xyloglucan). Our previous work used bacterial cellulose-based plant cell wall models to study the interaction between Salmonella and the various plant cell wall components. We demonstrated that Salmonella attachment was favoured in the presence of pectin while xyloglucan had no effect on its attachment. Xyloglucan significantly increased the attachment of Salmonella cells to the plant cell wall model only when it was in association with pectin. In this study, we investigate whether the plant cell wall polysaccharides mediate Salmonella attachment to the bacterial cellulose-based plant cell wall models through specific carbohydrate interactions or through the effects of carbohydrates on the physical characteristics of the attachment surface.

    RESULTS: We found that none of the monosaccharides that make up the plant cell wall polysaccharides specifically inhibit Salmonella attachment to the bacterial cellulose-based plant cell wall models. Confocal laser scanning microscopy showed that Salmonella cells can penetrate and attach within the tightly arranged bacterial cellulose network. Analysis of images obtained from atomic force microscopy revealed that the bacterial cellulose-pectin-xyloglucan composite with 0.3 % (w/v) xyloglucan, previously shown to have the highest number of Salmonella cells attached to it, had significantly thicker cellulose fibrils compared to other composites. Scanning electron microscopy images also showed that the bacterial cellulose and bacterial cellulose-xyloglucan composites were more porous when compared to the other composites containing pectin.

    CONCLUSIONS: Our study found that the attachment of Salmonella cells to cut plant cell walls was not mediated by specific carbohydrate interactions. This suggests that the attachment of Salmonella strains to the plant cell wall models were more dependent on the structural characteristics of the attachment surface. Pectin reduces the porosity and space between cellulose fibrils, which then forms a matrix that is able to retain Salmonella cells within the bacterial cellulose network. When present with pectin, xyloglucan provides a greater surface for Salmonella cells to attach through the thickening of cellulose fibrils.

    Matched MeSH terms: Microscopy, Electron, Scanning
  9. Morphological changes of post-isolation of caprine pancreatic islet
    Hani H, Allaudin ZN, Tengku Ibrahim TA, Mohd-Lila MA, Sarsaifi K, Camalxaman SN, et al.
    In Vitro Cell Dev Biol Anim, 2015 Feb;51(2):113-20.
    PMID: 25303943 DOI: 10.1007/s11626-014-9821-7
    Pancreatic islet transplantation is commonly used to treat diabetes. Cell isolation and purification methods can affect the structure and function of the isolated islet cells. Thus, the development of cell isolation techniques that preserve the structure and function of pancreatic islet cells is essential for enabling successful transplantation procedures. The impact of purification procedures on cell function can be assessed by performing ultrastructure and in vivo studies. Thus, the aim of this study was to evaluate the effect of caprine islets purification procedure on islet cell ultrastructure and functional integrity prior to and post-isolation/purification. The islets were isolated from caprine pancreas by using an optimized collagenase XI-S concentration, and the cells were subsequently purified using Euro-Ficoll density gradient. In vitro viability of islets was determined by fluorescein diacetate and propidium iodide staining. Static incubation was used to assess functionality and insulin production by islet cells in culture media when exposed to various levels of glucose. Pancreatic tissues were examined by using light microscopy, fluorescence microscopy, scanning, and transmission electron microscopy. In vivo viability and functionality of caprine islets were assessed by evaluating the transplanted islets in diabetic mice. Insulin assay of glucose-stimulated insulin secretion test showed that the insulin levels increased with increasing concentration of glucose. Thus, purified islets stimulated with high glucose concentration (25 mM) secreted higher levels of insulin (0.542 ± 0.346 μg/L) than the insulin levels (0.361 ± 0.219, 0.303 ± 0.234 μg/L) secreted by exposure to low glucose concentrations (1.67 mM). Furthermore, insulin levels of recipient mice were significantly higher (p 
    Matched MeSH terms: Microscopy, Electron, Scanning
  10. Evaluation of in vitro efficacy of docetaxel-loaded calcium carbonate aragonite nanoparticles (DTX-CaCO3NP) on 4T1 mouse breast cancer cell line
    Hammadi NI, Abba Y, Hezmee MNM, Razak ISA, Kura AU, Zakaria ZAB
    In Vitro Cell Dev Biol Anim, 2017 Dec;53(10):896-907.
    PMID: 28916966 DOI: 10.1007/s11626-017-0197-3
    Cockle shell-derived calcium carbonate nanoparticles have shown promising potentials as slow drug-releasing compounds in cancer chemotherapy. In this study, we evaluated the in vitro efficacy of docetaxel (DTX)-loaded CaCO3NP on 4T1 cell line. This was achieved by evaluating the following: cytotoxicity using MTT assay, fluorescence imaging, apoptosis with Annexin V assay, cell cycle analysis, scanning (SEM) and transmission electron microscopy (TEM), and scratch assay. Based on the results, DTX-CaCO3NP with a DTX concentration of 0.5 μg/mL and above had comparable cytotoxic effects with free DTX at 24 h, while all concentrations had similar cytotoxic effect on 4T1 cells at 48 and 72 h. Fluorescence and apoptosis assay showed a higher (p 
    Matched MeSH terms: Microscopy, Electron, Scanning
  11. Self-assembled nanocomposite of organic-inorganic hybrid: 2,4-dichlorophenoxyacetate in Zn-Al hydrotalcite-like layers
    Hussein MZ, Mohd Amin JB, Zainal Z, Yahaya AH
    J Nanosci Nanotechnol, 2002 Apr;2(2):143-6.
    PMID: 12908300
    Hydrotalcite-like inorganic layers of Zn-Al, a host containing an organic moiety, 2,4-dichlorophenoxy-acetate, as a guest, was prepared by the spontaneous self-assembly method from an aqueous solution for the formation of a new layered organic-inorganic hybrid nanocomposite material. In this synthesis, the host- and guest-forming species were simultaneously included in the mother liquor, aged, and separated. Various Zn/Al ratios (R = 2, 3, and 4), concentrations of 2,4-dichlorophenoxyacetic acid (0.03-0.1 M), and pH (7 and 10) were studied to optimize the formation of the layered nancomposite. It was found that the optimum conditions for the formation of the nanocomposite were R = 4, pH 7, and concentration of 2,4-dichlorophenoxyacetic acid = 0.08 M. X-ray diffraction shows that this sample affords a nanolayered structure with a basal spacing of 24.6 A.
    Matched MeSH terms: Microscopy, Electron, Scanning
  12. Fulltext Growth profile and SEM analyses of Candida albicans and Escherichia coli with Hymenocallis littoralis (Jacq.) Salisb leaf extract
    Rosli N, Sumathy V, Vikneswaran M, Sreeramanan S
    Trop Biomed, 2014 Dec;31(4):871-9.
    PMID: 25776614 MyJurnal
    Hymenocallis littoralis (Jacq.) Salisb (Melong kecil) commonly known as 'Spider Lily' is an herbaceous plant from the family Amaryllidaceae. Study was carried out to determine the effect of H. littoralis leaf extract on the growth and morphogenesis of two pathogenic microbes, Candida albicans and Escherichia coli. The leaf extract displayed favourable anticandidal and antibacterial activity with a minimum inhibition concentration (MIC) of 6.25 mg/mL. Time kill study showed both microbes were completely killed after treated with leaf extract at 20 h. Both microbes' cell walls were heavily ruptured based on scanning electron microscopy (SEM) analysis. The significant anticandidal and antibacterial activities showed by H. littoralis leaf extract suggested the potential antimicrobial agent against C. albicans and E. coli.
    Matched MeSH terms: Microscopy, Electron, Scanning
  13. Fulltext In vitro and in vivo anticandidal activity of Swietenia mahogani methanolic seed extract
    Sahgal G, Ramanathan S, Sasidharan S, Mordi MN, Ismail S, Mansor SM
    Trop Biomed, 2011 Apr;28(1):132-7.
    PMID: 21602779 MyJurnal
    Swietenia mahogani crude methanolic (SMCM) seed extract was investigated for the antifungal activity against Candida albicans which has not been evaluated previously. The antifungal activity was evaluated against C. albicans via disk diffusion, minimum inhibition concentration (MIC), scanning electron microscope (SEM), transmission electron microscope (TEM) and time killing profile. The MIC value of SMCM seed extract is 12.5 mg/ml. The SEM and TEM findings showed there is morphological changes and cytological destruction of C. albicans at the MIC value. Animal model was used to evaluate the in vivo antifungal activity of SMCM seed extract. The colony forming unit (CFU) were calculated per gram of kidney sample and per ml of blood sample respectively for control, curative and ketaconazole treated groups. There was significant reduction for the CFU/ml of blood and CFU/g of kidney. This indicated that the extract was observed to be effective against C. albicans in vitro and in vivo conditions.
    Matched MeSH terms: Microscopy, Electron, Scanning
  14. Polyvinylpyrrolidone oral films of enrofloxacin: film characterization and drug release
    Kumar GP, Phani AR, Prasad RG, Sanganal JS, Manali N, Gupta R, et al.
    Int J Pharm, 2014 Aug 25;471(1-2):146-52.
    PMID: 24858388 DOI: 10.1016/j.ijpharm.2014.05.033
    Enrofloxacin is a fluoroquinolone derivative used for treating urinary tract, respiratory and skin infections in animals. However, low solubility and low bioavailability prevented it from using on humans. Polyvinylpyrrolidone (PVP) is an inert, non toxic polymer with excellent hydrophilic properties, besides it can enhance bioavailability by forming drug polymer conjugates. With the aim of increasing solubility and bioavailability, enrofloxacin thin films were prepared using PVP as a polymer matrix. The obtained oral thin films exhibited excellent uniformity and mechanical properties. Swelling properties of the oral thin films revealed that the water uptake was enhanced by 21%. The surface pH has been found to be 6.8±0.1 indicating that these films will not cause any irritation to oral mucosa. FTIR data of the oral thin films indicated physical interaction between drug and polymer. SEM analysis revealed uniform distribution of drug in polymer matrix. In vitro drug release profiles showed enhanced release profiles (which are also pH dependant) for thin films compared to pure drug. Antibacterial activity was found to be dose dependent and maximum susceptibility was found on Klebsiella pneumonia making this preparation more suitable for respiratory infections.
    Matched MeSH terms: Microscopy, Electron, Scanning
  15. A novel study based on adaptive metal tolerance behavior in fungi and SEM-EDX analysis
    Chen SH, Ng SL, Cheow YL, Ting ASY
    J Hazard Mater, 2017 Jul 15;334:132-141.
    PMID: 28407540 DOI: 10.1016/j.jhazmat.2017.04.004
    Four fungal isolates: Simplicillium chinense (iso 9, accession no. KX425621), Penicillium simplicissimum (iso 10, KP713758), Trichoderma asperellum (iso 11, KP792512), and Coriolopsis sp. (1c3, KM403574) were subjected to a series of induced-tolerance training under high metal concentrations to determine if greater tolerance could be achieved from constant exposure to such conditions. Adaptive tolerance assay (Tolerance Index, TI) and Field-Emission Scanning Electron Microscopy with Energy Dispersive X-ray (SEM-EDX) characterized their metal tolerance. "Untrained" S. chinense, P. simplicissimum and T. asperellum showed tolerance towards 4000-4500ppm Al(III) (TI: 0.64-0.71), 1000ppm Cr(III) (0.52-0.83) and Pb(II) (0.32-0.88). With tolerance training, tolerance towards 2000-6000ppm Al(III), 500-3000ppm Pb(II) and 2000-3000ppm Cr(III) were achieved (TI: 0.01-0.82) compared to untrained cultures (0.00-0.59). In contrast, tolerance training for Coriolopsis sp. and P. simplicissimum was less successful, with TI values similar or lower than untrained cultures. SEM-EDX analysis proposed biosorption and bioaccumulation as mechanisms for metal removal. The latter was demonstrated with the removal of Cr(III) and Pb(II) by S. chinense (12.37 and 11.52mgg-1, respectively) and T. asperellum (10.44 and 7.50mgg-1). Induced-tolerance training may render benefit in the long run, but this delicate approach is suggestively species and metal dependent.
    Matched MeSH terms: Microscopy, Electron, Scanning
  16. Carbon nanotube-based aptasensor for sensitive electrochemical detection of whole-cell Salmonella
    Hasan MR, Pulingam T, Appaturi JN, Zifruddin AN, Teh SJ, Lim TW, et al.
    Anal Biochem, 2018 08 01;554:34-43.
    PMID: 29870692 DOI: 10.1016/j.ab.2018.06.001
    In this study, an amino-modified aptasensor using multi-walled carbon nanotubes (MWCNTs)-deposited ITO electrode was prepared and evaluated for the detection of pathogenic Salmonella bacteria. An amino-modified aptamer (ssDNA) which binds selectively to whole-cell Salmonella was immobilised on the COOH-rich MWCNTs to produce the ssDNA/MWCNT/ITO electrode. The morphology of the MWCNT before and after interaction with the aptamers were observed using scanning electron microscopy (SEM). Cyclic voltammetry and electrochemical impedance spectroscopy techniques were used to investigate the electrochemical properties and conductivity of the aptasensor. The results showed that the impedance measured at the ssDNA/MWCNT/ITO electrode surface increased after exposure to Salmonella cells, which indicated successful binding of Salmonella on the aptamer-functionalised surface. The developed ssDNA/MWCNT/ITO aptasensor was stable and maintained linearity when the scan rate was increased from 10 mV s-1 to 90 mV s-1. The detection limit of the ssDNA/MWCNT/ITO aptasensor, determined from the sensitivity analysis, was found to be 5.5 × 101 cfu mL-1 and 6.7 × 101 cfu mL-1 for S. Enteritidis and S. Typhimurium, respectively. The specificity test demonstrated that Salmonella bound specifically to the ssDNA/MWCNT/ITO aptasensor surface, when compared with non-Salmonella spp. The prepared aptasensor was successfully applied for the detection of Salmonella in food samples.
    Matched MeSH terms: Microscopy, Electron, Scanning
  17. Enhanced amperometric detection of paracetamol by immobilized cobalt ion on functionalized MWCNTs - Chitosan thin film
    Akhter S, Basirun WJ, Alias Y, Johan MR, Bagheri S, Shalauddin M, et al.
    Anal Biochem, 2018 06 15;551:29-36.
    PMID: 29753720 DOI: 10.1016/j.ab.2018.05.004
    In the present study, a nanocomposite of f-MWCNTs-chitosan-Co was prepared by the immobilization of Co(II) on f-MWCNTs-chitosan by a self-assembly method and used for the quantitative determination of paracetamol (PR). The composite was characterized by field emission scanning electron microscopy (FESEM) and energy dispersive x-ray analysis (EDX). The electroactivity of cobalt immobilized on f-MWCNTs-chitosan was assessed during the electro-oxidation of paracetamol. The prepared GCE modified f-MWCNTs/CTS-Co showed strong electrocatalytic activity towards the oxidation of PR. The electrochemical performances were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). Under favorable experimental conditions, differential pulse voltammetry showed a linear dynamic range between 0.1 and 400 μmol L-1 with a detection limit of 0.01 μmol L-1 for the PR solution. The fabricated sensor exhibited significant selectivity towards PR detection. The fabricated sensor was successfully applied for the determination of PR in commercial tablets and human serum sample.
    Matched MeSH terms: Microscopy, Electron, Scanning
  18. Fulltext Molecular study of wound healing after using biosynthesized BNC/Fe3O4 nanocomposites assisted with a bioinformatics approach
    Moniri M, Boroumand Moghaddam A, Azizi S, Abdul Rahim R, Zuhainis Saad W, Navaderi M, et al.
    Int J Nanomedicine, 2018;13:2955-2971.
    PMID: 29861630 DOI: 10.2147/IJN.S159637
    Background: Molecular investigation of wound healing has allowed better understanding about interaction of genes and pathways involved in healing progression.

    Objectives: The aim of this study was to prepare magnetic/bacterial nanocellulose (Fe3O4/BNC) nanocomposite films as ecofriendly wound dressing in order to evaluate their physical, cytotoxicity and antimicrobial properties. The molecular study was carried out to evaluate expression of genes involved in healing of wounds after treatment with BNC/Fe3O4 films.

    Study design materials and methods: Magnetic nanoparticles were biosynthesized by using Aloe vera extract in new isolated bacterial nanocellulose (BNC) RM1. The nanocomposites were characterized using X-ray diffraction, Fourier transform infrared, and field emission scanning electron microscopy. Moreover, swelling property and metal ions release profile of the nanocomposites were investigated. The ability of nanocomposites to promote wound healing of human dermal fibroblast cells in vitro was examined. Bioinformatics databases were used to identify genes with important healing effect. Key genes which interfered with healing were studied by quantitative real time PCR.

    Results: Spherical magnetic nanoparticles (15-30 nm) were formed and immobilized within the structure of BNC. The BNC/Fe3O4 was nontoxic (IC50>500 μg/mL) with excellent wound healing efficiency after 48 hours. The nanocomposites showed good antibacterial activity ranging from 6±0.2 to 13.40±0.10 mm against Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa. The effective genes for the wound healing process were TGF-B1, MMP2, MMP9, Wnt4, CTNNB1, hsa-miR-29b, and hsa-miR-29c with time dependent manner. BNC/Fe3O4 has an effect on microRNA by reducing its expression and therefore causing an increase in the gene expression of other genes, which consequently resulted in wound healing.

    Conclusion: This eco-friendly nanocomposite with excellent healing properties can be used as an effective wound dressing for treatment of cutaneous wounds.

    Matched MeSH terms: Microscopy, Electron, Scanning
  19. Green synthesis of graphene-silver nanocomposites and its application as a potent marine antifouling agent
    Yee MS, Khiew PS, Chiu WS, Tan YF, Kok YY, Leong CO
    Colloids Surf B Biointerfaces, 2016 Dec 01;148:392-401.
    PMID: 27639489 DOI: 10.1016/j.colsurfb.2016.09.011
    Fouling of marine surfaces has been a perpetual problem ever since the days of the early sailors. The tenacious attachment of seaweed and invertebrates to man-made surfaces, notably on ship hulls, has incurred undesirable economic losses. Graphene receives great attention in the materials world for its unique combination of physical and chemical properties. Herein, we present a novel 2-step synthesis method of graphene-silver nanocomposites which bypasses the formation of graphene oxide (GO), and produces silver nanoparticles supported on graphene sheets through a mild hydrothermal reduction process. The graphene-Ag (GAg) nanocomposite combines the antimicrobial property of silver nanoparticles and the unique structure of graphene as a support material, with potent marine antifouling properties. The GAg nanocomposite was composed of micron-scaled graphene flakes with clusters of silver nanoparticles. The silver nanoparticles were estimated to be between 72 and 86nm (SEM observations) while the crystallite size of the silver nanoparticles (AgNPs) was estimated between 1 and 5nm. The nanocomposite also exhibited the SERS effect. GAg was able to inhibit Halomonas pacifica, a model biofilm-causing microbe, from forming biofilms with as little as 1.3wt.% loading of Ag. All GAg samples displayed significant biofilm inhibition property, with the sample recording the highest Ag loading (4.9wt.% Ag) associated with a biofilm inhibition of 99.6%. Moreover, GAg displayed antiproliferative effects on marine microalgae, Dunaliella tertiolecta and Isochrysis sp. and inhibited the growth of the organisms by more than 80% after 96h. The marine antifouling properties of GAg were a synergy of the biocidal AgNPs anchored on the stable yet flexible graphene sheets, providing maximum active contact surface areas to the target organisms.
    Matched MeSH terms: Microscopy, Electron, Scanning
  20. Chondrocyte-alginate constructs with or without TGF-β1 produces superior extracellular matrix expression than monolayer cultures
    Ab-Rahim S, Selvaratnam L, Raghavendran HR, Kamarul T
    Mol Cell Biochem, 2013 Apr;376(1-2):11-20.
    PMID: 23238871 DOI: 10.1007/s11010-012-1543-0
    Tissue engineering approaches often require expansion of cell numbers in vitro to accelerate tissue regenerative processes. Although several studies have used this technique for therapeutic purposes, a major concern involving the use of isolated chondrocyte culture is the reduction of extracellular matrix (ECM) protein expressed due to the transfer of cells from the normal physiological milieu to the artificial 2D environment provided by the cell culture flasks. To overcome this issue, the use of alginate hydrogel beads as a substrate in chondrocyte cultures has been suggested. However, the resultant characteristics of cells embedded in this bead is elusive. To elucidate this, a study using chondrocytes isolated from rabbit knee articular cartilage expanded in vitro as monolayer and chondrocyte-alginate constructs was conducted. Immunohistochemical evaluation and ECM distribution was examined with or without transforming growth factor (TGF-β1) supplement to determine the ability of cells to express major chondrogenic proteins in these environments. Histological examination followed by transmission electron microscopy and scanning electron microscopy was performed to determine the morphology and the ultrastructural characteristics of these cells. Results demonstrated a significant increase in glycosaminoglycan/mg protein levels in chondrocyte cultures grown in alginate construct than in monolayer cultures. In addition, an abundance of ECM protein distribution surrounding chondrocytes cultured in alginate hydrogel was observed. In conclusion, the current study demonstrates that the use of alginate hydrogel beads in chondrocyte cultures with or without TGF-β1 supplement provided superior ECM expression than monolayer cultures.
    Matched MeSH terms: Microscopy, Electron, Scanning
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