Displaying publications 1 - 20 of 378 in total

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  1. Fulltext Surface Dissolution UV Imaging for Investigation of Dissolution of Poorly Soluble Drugs and Their Amorphous Formulation
    Long CM, Tang K, Chokshi H, Fotaki N
    AAPS PharmSciTech, 2019 Feb 13;20(3):113.
    PMID: 30761437 DOI: 10.1208/s12249-019-1317-z
    The aim of this study is to investigate the dissolution properties of poorly soluble drugs from their pure form and their amorphous formulation under physiological relevant conditions for oral administration based on surface dissolution ultraviolet (UV) imaging. Dissolution of two poorly soluble drugs (cefuroxime axetil and itraconazole) and their amorphous formulations (Zinnat® and Sporanox®) was studied with the Sirius Surface Dissolution Imager (SDI). Media simulating the fasted state conditions (compendial and biorelevant) with sequential media/flow rate change were used. The dissolution mechanism of cefuroxime axetil in simulated gastric fluid (SGF), fasted state simulated gastric fluid (FaSSGF) and simulated intestinal fluid (SIF) is predominantly swelling as opposed to the convective flow in fasted state simulated intestinal fluid (FaSSIF-V1), attributed to the effect of mixed micelles. For the itraconazole compact in biorelevant media, a clear upward diffusion of the dissolved itraconazole into the bulk buffer solution is observed. Dissolution of itraconazole from the Sporanox® compact is affected by the polyethylene glycol (PEG) gelling layer and hydroxypropyl methylcellulose (HPMC) matrix, and a steady diffusional dissolution pattern is revealed. A visual representation and a quantitative assessment of dissolution properties of poorly soluble compounds and their amorphous formulation can be obtained with the use of surface dissolution imaging under in vivo relevant conditions.
    Matched MeSH terms: Surface Properties
  2. Co-Adsorptive Removal of Creatinine and Urea by a Three-Component Dual-Layer Hollow Fiber Membrane
    Zainol Abidin MN, Goh PS, Said N, Ismail AF, Othman MHD, Hasbullah H, et al.
    ACS Appl Mater Interfaces, 2020 Jul 22;12(29):33276-33287.
    PMID: 32589391 DOI: 10.1021/acsami.0c08947
    The development of wearable artificial kidney demands an efficient dialysate recovery, which relies upon the adsorption process. This study proposes a solution to solve the problem of competitive adsorption between the uremic toxins by employing two adsorptive components in a membrane separation process. Dual-layer hollow fiber (DLHF) membranes, which are composed of a polysulfone (PSf)/activated carbon (AC) inner layer and a PSf/poly(methyl methacrylate) (PMMA) outer layer, were prepared for co-adsorptive removal of creatinine and urea from aqueous solution. The DLHF membranes were characterized in terms of morphological, physicochemical, water transport, and creatinine adsorption properties. The membrane was then subjected to an ultrafiltration adsorption study for performance evaluation. The incorporation of AC in membrane, as confirmed by microscopic and surface analyses, has improved the pure water flux up to 25.2 L/(m2 h). A membrane with optimum AC loading (9 wt %) demonstrated the highest maximum creatinine adsorption capacity (86.2 mg/g) based on the Langmuir adsorption isotherm model. In the ultrafiltration adsorption experiment, the membrane removed creatinine and urea with a combined average percent removal of 29.3%. Moreover, the membrane exhibited creatinine and urea uptake recoveries of 98.8 and 81.2%, respectively. The combined action of PMMA and AC in the PSf DLHF membrane has made the adsorption of multiple uremic toxins possible during dialysate recovery.
    Matched MeSH terms: Surface Properties
  3. Ag-ZnO nanoreactor grown on FTO substrate exhibiting high heterogeneous photocatalytic efficiency
    Tan ST, Ali Umar A, Balouch A, Nafisah S, Yahaya M, Yap CC, et al.
    ACS Comb Sci, 2014 Jul 14;16(7):314-20.
    PMID: 24919039 DOI: 10.1021/co400157m
    This Research Article reports an unusually high efficiency heterogeneous photodegradation of methyl orange (MO) in the presence of Ag nanoparticle-loaded ZnO quasi-nanotube or nanoreactor (A-ZNRs) nanocatalyst grown on FTO substrate. In typical process, photodegradation efficiency of as high as 21.6% per μg per Watts of used catalyst and UV power can be normally obtained within only a 60-min reaction time from this system, which is 10(3) order higher than the reported results. This is equivalent to the turnover frequency of 360 mol mol(-1) h(-1). High-density hexagonal A-ZNRs catalysts were grown directly on FTO substrate via a seed-mediated microwave-assisted hydrolysis growth process utilizing Ag nanoparticle of approximately 3 nm in size as nanoseed and mixture aqueous solution of Zn(NO3)·6H2O, hexamethylenetetramine (HMT), and AgNO3 as the growth solution. A-ZNRs adopts hexagonal cross-section morphology with the inner surface of the reactor characterized by a rough and rugged structure. Transmission electron microscopy imaging shows the Ag nanoparticle grows interstitially in the ZnO nanoreactor structure. The high photocatalytic property of the A-ZNRs is associated with the highly active of inner side's surface of A-ZNRs and the oxidizing effect of Ag nanoparticle. The growth mechanism as well as the mechanism of the enhanced-photocatalytic performance of the A-ZNRs will be discussed.
    Matched MeSH terms: Surface Properties
  4. Unconfined compression properties of a porous poly(vinyl alcohol)-chitosan-based hydrogel after hydration
    Lee SY, Pereira BP, Yusof N, Selvaratnam L, Yu Z, Abbas AA, et al.
    Acta Biomater, 2009 Jul;5(6):1919-25.
    PMID: 19289306 DOI: 10.1016/j.actbio.2009.02.014
    A poly(vinyl alcohol) (PVA) hydrogel composite scaffold containing N,O-carboxymethylated chitosan (NOCC) was tested to assess its potential as a scaffold for cartilage tissue engineering in a weight-bearing environment. The mechanical properties under unconfined compression for different hydration periods were investigated. The effect of supplementing PVA with NOCC (20wt.% PVA:5vol.% NOCC) produced a porosity of 43.3% and this was compared against a non-porous PVA hydrogel (20g PVA: 100ml of water, control). Under non-hydrated conditions, the porous PVA-NOCC hydrogel behaved in a similar way to the control non-porous PVA hydrogel, with similar non-linear stress-strain response under unconfined compression (0-30% strain). After 7days' hydration, the porous hydrogel demonstrated a reduced stiffness (0.002kPa, at 25% strain), resulting in a more linear stiffness relationship over a range of 0-30% strain. Poisson's ratio for the hydrated non-porous and porous hydrogels ranged between 0.73 and 1.18, and 0.76 and 1.33, respectively, suggesting a greater fluid flow when loaded. The stress relaxation function for the porous hydrogel was affected by the hydration period (from 0 to 600s); however the percentage stress relaxation regained by about 95%, after 1200s for all hydration periods assessed. No significant differences were found between the different hydration periods between the porous hydrogels and control. The calculated aggregate modulus, H(A), for the porous hydrogel reduced drastically from 10.99kPa in its non-hydrated state to about 0.001kPa after 7days' hydration, with the calculated shear modulus reducing from 30.92 to 0.14kPa, respectively. The porous PVA-NOCC hydrogel conformed to a biphasic, viscoelastic model, which has the desired properties required for any scaffold in cartilage tissue engineering.
    Matched MeSH terms: Surface Properties
  5. Surface characterization analysis of failed dental implants using scanning electron microscopy
    Daood U, Bandey N, Qasim SB, Omar H, Khan SA
    Acta Odontol Scand, 2011 Nov;69(6):367-73.
    PMID: 21449690 DOI: 10.3109/00016357.2011.569507
    To investigate the failure of 15 dental implants (Paragon/Zimmer) in relation to their surface quality.
    Matched MeSH terms: Surface Properties
  6. Decontamination of textile wastewater via TiO2/activated carbon composite materials
    Foo KY, Hameed BH
    Adv Colloid Interface Sci, 2010 Sep 15;159(2):130-43.
    PMID: 20673570 DOI: 10.1016/j.cis.2010.06.002
    Water scarcity and pollution rank equal to climate change as the most urgent environmental turmoil for the 21st century. To date, the percolation of textile effluents into the waterways and aquifer systems, remain an intricate conundrum abroad the nations. With the renaissance of activated carbon, there has been a steadily growing interest in the research field. Recently, the adoption of titanium dioxide, a prestigious advanced photo-catalyst which formulates the new growing branch of activated carbon composites for enhancement of adsorption rate and discoloration capacity, has attracted stern consideration and supports worldwide. Confirming the assertion, this paper presents a state of art review of titanium dioxide/activated carbon composites technology, its fundamental background studies, and environmental implications. Moreover, its major challenges together with the future expectation are summarized and discussed. Conclusively, the expanding of activated carbons composites material represents a potentially viable and powerful tool, leading to the plausible improvement of environmental conservation.
    Matched MeSH terms: Surface Properties
  7. Ordered mesoporous silica (OMS) as an adsorbent and membrane for separation of carbon dioxide (CO2)
    Chew TL, Ahmad AL, Bhatia S
    Adv Colloid Interface Sci, 2010 Jan 15;153(1-2):43-57.
    PMID: 20060956 DOI: 10.1016/j.cis.2009.12.001
    Separation of carbon dioxide (CO(2)) from gaseous mixture is an important issue for the removal of CO(2) in natural gas processing and power plants. The ordered mesoporous silicas (OMS) with uniform pore structure and high density of silanol groups, have attracted the interest of researchers for separation of carbon dioxide (CO(2)) using adsorption process. These mesoporous silicas after functionalization with amino groups have been studied for the removal of CO(2). The potential of functionalized ordered mesoporous silica membrane for separation of CO(2) is also recognized. The present paper reviews the synthesis of mesoporous silicas and important issues related to the development of mesoporous silicas. Recent studies on the CO(2) separation using ordered mesoporous silicas (OMS) as adsorbent and membrane are highlighted. The future prospectives of mesoporous silica membrane for CO(2) adsorption and separation are also presented and discussed.
    Matched MeSH terms: Surface Properties
  8. Fulltext Surface, thermal and hemocompatible properties of novel single stage electrospun nanocomposites comprising polyurethane blended with bio oilTM
    Ayyar M, Mani MP, Jaganathan SK, Rathinasamy R, Khudzari AZ, Krishnasamy NP
    An Acad Bras Cienc, 2017;89(3 Suppl):2411-2422.
    PMID: 29091109 DOI: 10.1590/0001-3765201720170230
    In this work, the physicochemical and blood compatibility properties of prepared PU/Bio oil nanocomposites were investigated. Scanning electron microscope (SEM) studies revealed the reduction of mean fiber diameter (709 ± 211 nm) compared to the pristine PU (969 nm ± 217 nm). Fourier transform infrared spectroscopy (FTIR) analysis exposed the characteristic peaks of pristine PU. Composite peak intensities were decreased insinuating the interaction of the bio oilTM with the PU. Contact angle analysis portrayed the hydrophobic nature of the fabricated patch compared to pristine PU. Thermal gravimetric analysis (TGA) depicted the better thermal stability of the novel nanocomposite patch and its different thermal behavior in contrast with the pristine PU. Atomic force microscopy (AFM) analysis revealed the increase in the surface roughness of the composite patch. Activated partial thromboplastin time (APTT) and prothrombin time (PT) signified the novel nanocomposite patch ability in reducing the thrombogenicity and promoting the anticoagulant nature. Finally the hemolytic percentage of the fabricated composite was in the acceptable range revealing its safety and compatibility with the red blood cells. To reinstate, the fabricated patch renders promising physicochemical and blood compatible nature making it a new putative candidate for wound healing application.
    Matched MeSH terms: Surface Properties
  9. Fulltext UV induced surface modification on improving the cytocompatibility of metallocene polyethylene
    Jaganathan SK, Prasath MM
    An Acad Bras Cienc, 2018 4 12;90(1):195-204.
    PMID: 29641759 DOI: 10.1590/0001-3765201820170736
    Demand for medical implants is rising day by day as the world becomes the place for more diseased and older people. Accordingly, in this research, metallocene polyethylene (mPE), a commonly used polymer was treated with UV rays for improving its biocompatibility. Scanning electron microscopy (SEM) images confirmed the formation of crests and troughs, which depicts the improvement of surface roughness of mPE substrates caused by UV etching. Accordingly, the contact angle measurements revealed that the wettability of mPE-2.5 J/cm2 (68.09º) and mPE-5 J/cm2 (57.93º) samples were found to be increased compared to untreated mPE (86.84º) indicating better hydrophilicity. Further, the UV treated surface exhibited enhanced blood compatibility as determined in APTT (untreated mPE- 55.3 ± 2.5 s, mPE-2.5 J/cm2 - 76.7 ± 4.1 s and mPE-5 J/cm2 - 112.3 ± 2 s) and PT (untreated mPE - 24.7 ± 1.5 s, mPE- 2.5 J/cm2 - 34.3 ± 1.1 s and mPE-5 J/cm2 - 43 ± 2 s) assay. Moreover, the treated mPE-2.5 J/cm2 (4.88%) and mPE-5 J/cm2 (1.79%) showed decreased hemolytic percentage compared to untreated mPE (15.40%) indicating better safety to red blood cells. Interestingly, the changes in physicochemical properties of mPE are directly proportional to the dosage of the UV rays. UV modified mPE surfaces were found to be more compatible as identified through MTT assay, photomicrograph and SEM images of the seeded 3T3 cell population. Hence UV-modified surface of mPE may be successfully exploited for medical implants.
    Matched MeSH terms: Surface Properties/radiation effects
  10. Electrospin-coating of nitrocellulose membrane enhances sensitivity in nucleic acid-based lateral flow assay
    Yew CT, Azari P, Choi JR, Li F, Pingguan-Murphy B
    Anal Chim Acta, 2018 Jun 07;1009:81-88.
    PMID: 29422135 DOI: 10.1016/j.aca.2018.01.016
    Point-of-care biosensors are important tools developed to aid medical diagnosis and testing, food safety and environmental monitoring. Paper-based biosensors, especially nucleic acid-based lateral flow assays (LFA), are affordable, simple to produce and easy to use in remote settings. However, the sensitivity of such assays to infectious diseases has always been a restrictive challenge. Here, we have successfully electrospun polycaprolactone (PCL) on nitrocellulose (NC) membrane to form a hydrophobic coating to reduce the flow rate and increase the interaction rate between the targets and gold nanoparticles-detecting probes conjugates, resulting in the binding of more complexes to the capture probes. With this approach, the sensitivity of the PCL electrospin-coated test strip has been increased by approximately ten-fold as compared to the unmodified test strip. As a proof of concept, this approach holds great potential for sensitive detection of targets at point-of-care testing.
    Matched MeSH terms: Surface Properties
  11. Morphology and kinetic modeling of molecularly imprinted organosilanol polymer matrix for specific uptake of creatinine
    Ang QY, Low SC
    Anal Bioanal Chem, 2015 Sep;407(22):6747-58.
    PMID: 26163132 DOI: 10.1007/s00216-015-8841-9
    Molecular imprinting is an emerging technique to create imprinted polymers that can be applied in affinity-based separation, in particular, biomimetic sensors. In this study, the matrix of siloxane bonds prepared from the polycondensation of hydrolyzed tetraethoxysilane (TEOS) was employed as the inorganic monomer for the formation of a creatinine (Cre)-based molecularly imprinted polymer (MIP). Doped aluminium ion (Al(3+)) was used as the functional cross-linker that generated Lewis acid sites in the confined silica matrix to interact with Cre via sharing of lone pair electrons. Surface morphologies and pore characteristics of the synthesized MIP were determined by field emission scanning electron microscopy (FESEM) and Brunauer-Emmet-Teller (BET) analyses, respectively. The imprinting efficiency of MIPs was then evaluated through the adsorption of Cre with regard to molar ratios of Al(3+). A Cre adsorption capacity of up to 17.40 mg Cre g(-1) MIP was obtained and adsorption selectivity of Cre to its analogues creatine (Cr) and N-hydroxysuccinimide (N-hyd) were found to be 3.90 ± 0.61 and 4.17 ± 3.09, respectively. Of all the studied MIP systems, chemisorption was predicted as the rate-limiting step in the binding of Cre. The pseudo-second-order chemical reaction kinetic provides the best correlation of the experimental data. Furthermore, the equilibrium adsorption capacity of MIP fit well with a Freundlich isotherm (R (2) = 0.98) in which the heterogeneous surface was defined.
    Matched MeSH terms: Surface Properties
  12. Serological diagnosis of dengue infection in blood plasma using long-range surface plasmon waveguides
    Wong WR, Krupin O, Sekaran SD, Mahamd Adikan FR, Berini P
    Anal Chem, 2014 Feb 4;86(3):1735-43.
    PMID: 24410440 DOI: 10.1021/ac403539k
    We present a compact, cost-effective, label-free, real-time biosensor based on long-range surface plasmon polariton (LRSPP) gold (Au) waveguides for the detection of dengue-specific immunoglobulin M (IgM) antibody, and we demonstrate detection in actual patient blood plasma samples. Two surface functionalization approaches are proposed and demonstrated: a dengue virus serotype 2 (DENV-2) functionalized surface to capture dengue-specific IgM antibody in blood plasma and the reverse, a blood plasma functionalized surface to capture DENV-2. The results obtained via these two surface functionalization approaches are comparable to, or of greater quality, than those collected by conventional IgM antibody capture enzyme linked immunosorbent assay (MAC-ELISA). Our second functionalization approach was found to minimize nonspecific binding, thus improving the sensitivity and accuracy of the test. We also demonstrate reuse of the biosensors by regenerating the sensing surface down to the virus (or antibody) level or down to the bare Au.
    Matched MeSH terms: Surface Properties
  13. Targeted polymeric nanoparticle for anthracycline delivery in hypoxia-induced drug resistance in metastatic breast cancer cells
    Almoustafa HA, Alshawsh MA, Chik Z
    Anticancer Drugs, 2021 Aug 01;32(7):745-754.
    PMID: 33675612 DOI: 10.1097/CAD.0000000000001065
    Poly lactic-co-glycolic acid (PLGA) nanoparticles are intensively studied nanocarriers in drug delivery because of their biodegradability and biochemical characteristics. Polyethylene glycol (PEG) coating for nanocarriers gives them long circulation time in blood and makes them invisible to the reticuloendothelial system. Breast cancer cells have greater uptake of hyaluronic acid compared to normal cells as it binds to their overexpressed CD44 receptors. Since hypoxia plays an important role in cancer metastasis; we formulated PEG-PLGA nanoparticles coated with hyaluronic acid as targeted delivery system for doxorubicin (DOX) using nanoprecipitation method, and characterized them for chemical composition, size, surface charge, shape, and encapsulation efficiency. Then we tested them in vitro on hypoxia-optimized metastatic breast cancer cells. The nanoparticles were spherical with an average size of about 106 ± 53 nm, a negative surface charge (-15 ± 3 mV), and high encapsulation efficiency (73.3 ± 4.1%). In vitro investigation with hypoxia-elevated CD44 MDA-MB-231 cells showed that hyaluronic acid-targeted nanoparticles maintained their efficacy despite hypoxia-induced drug resistance unlike free DOX and nontargeted nanoparticles. In conclusion, this study revealed a simple third generation nanoparticle formulation for targeted treatment of hypoxia-induced drug resistance in breast cancer metastatic cells. Further, optimization is needed including In vivo efficacy and nanoparticle-specific pharmacokinetic studies.
    Matched MeSH terms: Surface Properties
  14. A review: potential usage of cellulose nanofibers (CNF) for enzyme immobilization via covalent interactions
    Sulaiman S, Mokhtar MN, Naim MN, Baharuddin AS, Sulaiman A
    Appl Biochem Biotechnol, 2015 Feb;175(4):1817-42.
    PMID: 25427594 DOI: 10.1007/s12010-014-1417-x
    Nanobiocatalysis is a new frontier of emerging nanosized material support in enzyme immobilization application. This paper is about a comprehensive review on cellulose nanofibers (CNF), including their structure, surface modification, chemical coupling for enzyme immobilization, and potential applications. The CNF surface consists of mainly -OH functional group that can be directly interacted weakly with enzyme, and its binding can be improved by surface modification and interaction of chemical coupling that forms a strong and stable covalent immobilization of enzyme. The knowledge of covalent interaction for enzyme immobilization is important to provide more efficient interaction between CNF support and enzyme molecule. Enzyme immobilization onto CNF is having potential for improving enzymatic performance and production yield, as well as contributing toward green technology and sustainable sources.
    Matched MeSH terms: Surface Properties
  15. Mode-locked thulium-bismuth codoped fiber laser using graphene saturable absorber in ring cavity
    Zen DI, Saidin N, Damanhuri SS, Harun SW, Ahmad H, Ismail MA, et al.
    Appl Opt, 2013 Feb 20;52(6):1226-9.
    PMID: 23434993 DOI: 10.1364/AO.52.001226
    We demonstrate mode locking of a thulium-bismuth codoped fiber laser (TBFL) operating at 1901.6 nm, using a graphene-based saturable absorber (SA). In this work, a single layer graphene is mechanically exfoliated using the scotch tape method and directly transferred onto the surface of a fiber pigtail to fabricate the SA. The obtained Raman spectrum characteristic indicates that the graphene on the core surface has a single layer. At 1552 nm pump power of 869 mW, the mode-locked TBFL self starts to generate an optical pulse train with a repetition rate of 16.7 MHz and pulse width of 0.37 ps. This is a simple, low-cost, stable, and convenient laser oscillator for applications where eye-safe and low-photon-energy light sources are required, such as sensing and biomedical diagnostics.
    Matched MeSH terms: Surface Properties
  16. Macrophage response and surface analysis of dental cementum after treatment with high intensity focused ultrasound
    Daood U, Fawzy AS
    Arch Oral Biol, 2019 Feb;98:195-203.
    PMID: 30502562 DOI: 10.1016/j.archoralbio.2018.10.019
    OBJECTIVE: To investigate effects of HIFU on macrophage phenotype, surface micro-topography and nano-scale surface mechanical properties of dental cementum.

    MATERIALS AND METHODS: Root discs (2 mm thickness) were cut apical to CEJ and sectioned into quadrants. HIFU setup with bowl-shaped piezo ceramic transducer submerged in a water tank was used for exposure on each specimen for 15 s, 30 s or 60 s. The specimens of the control group were left without any HIFU exposure. HIFU was generated with a continuous sinusoidal wave of 120Vpp amplitude, 250 KHZ resonance-frequency and highest ultrasonic pressure of ∼10 bar at the focus. Specimens for SEM were viewed, and micro-topography characterization performed, using AFM and Ra parameter and surface area (SA) calculated by specialized SPM surface analysis software. For nano-indentation testing, experiments were carried out using AFM. Macrophage cell isolation and culturing was performed on cementum to receive the HIFU treatment at different time periods. Raman spectroscopy were scanned to create spectra perpendicular to the cementum substrate to analyze generation of standard spectra for Raman intensity ratio of hydroxyapatite normalized to the peaks ν1 960 cm-1. Data was expressed as means ± standard deviations and analyzed by one-way ANOVA in term of Ra, SA, H and Er. Different points for fluorescence intensity ratio were analyzed by Raman using Wilcoxon rank sum test.

    RESULTS: HIFU exposure at 60 s removed the smear layer and most of cementum appeared smoothened. AFM characterisation, showed a slight decrease in the irregularity of the surface as exposure time increased. Intact macrophages can be identified in control and all experimental HIFU groups. The level of fluorescence for the control and HIFU 15 and 30 s were low as compared to HIFU 60 s.

    CONCLUSION: If HIFU can be successfully implemented, it may be a possible alternative to current methods used in periodontal therapy to achieve smooth root surfaces.

    Matched MeSH terms: Surface Properties/radiation effects
  17. Differential genotoxicity mechanisms of silver nanoparticles and silver ions
    Li Y, Qin T, Ingle T, Yan J, He W, Yin JJ, et al.
    Arch Toxicol, 2017 Jan;91(1):509-519.
    PMID: 27180073 DOI: 10.1007/s00204-016-1730-y
    In spite of many reports on the toxicity of silver nanoparticles (AgNPs), the mechanisms underlying the toxicity are far from clear. A key question is whether the observed toxicity comes from the silver ions (Ag(+)) released from the AgNPs or from the nanoparticles themselves. In this study, we explored the genotoxicity and the genotoxicity mechanisms of Ag(+) and AgNPs. Human TK6 cells were treated with 5 nM AgNPs or silver nitrate (AgNO3) to evaluate their genotoxicity and induction of oxidative stress. AgNPs and AgNO3 induced cytotoxicity and genotoxicity in a similar range of concentrations (1.00-1.75 µg/ml) when evaluated using the micronucleus assay, and both induced oxidative stress by measuring the gene expression and reactive oxygen species in the treated cells. Addition of N-acetylcysteine (NAC, an Ag(+) chelator) to the treatments significantly decreased genotoxicity of Ag(+), but not AgNPs, while addition of Trolox (a free radical scavenger) to the treatment efficiently decreased the genotoxicity of both agents. In addition, the Ag(+) released from the highest concentration of AgNPs used for the treatment was measured. Only 0.5 % of the AgNPs were ionized in the culture medium and the released silver ions were neither cytotoxic nor genotoxic at this concentration. Further analysis using electron spin resonance demonstrated that AgNPs produced hydroxyl radicals directly, while AgNO3 did not. These results indicated that although both AgNPs and Ag(+) can cause genotoxicity via oxidative stress, the mechanisms are different, and the nanoparticles, but not the released ions, mainly contribute to the genotoxicity of AgNPs.
    Matched MeSH terms: Surface Properties
  18. Biocompatible disulphide cross-linked sodium alginate derivative nanoparticles for oral colon-targeted drug delivery
    Ayub AD, Chiu HI, Mat Yusuf SNA, Abd Kadir E, Ngalim SH, Lim V
    Artif Cells Nanomed Biotechnol, 2019 Dec;47(1):353-369.
    PMID: 30691309 DOI: 10.1080/21691401.2018.1557672
    The application of layer-by-layer (LbL) approach on nanoparticle surface coating improves the colon-specific drug delivery of insoluble drugs. Here, we aimed to formulate a self-assembled cysteamine-based disulphide cross-linked sodium alginate with LbL self-assembly to improve the delivery of paclitaxel (PCX) to colonic cancer cells. Cysteamine was conjugated to the backbone of oxidized SA to form a core of self-assembled disulphide cross-linked nanospheres. P3DL was selected for PCX loading and fabricated LbL with poly(allylamine hydrochloride) (PAH) and poly(4-styrenesulfonic acid-co-maleic acid) sodium salt (PSSCMA) resulting from characterization and drug release studies. P3DL-fabricated PCX-loaded nanospheres (P3DL/PAH/PSSCMA) exhibited an encapsulation efficiency of 77.1% with cumulative drug release of 45.1%. Dynamic light scattering analysis was reported at 173.6 ± 2.5 nm with polydispersity index of 0.394 ± 0.105 (zeta potential= -58.5 mV). P3DL/PAH/PSSCMA demonstrated a pH-dependent swelling transition; from pH 1 to 7 (102.2% increase). The size increased by 33.0% in reduction response study after incubating with 10 mM glutathione (day 7). HT-29 cells showed high viabilities (86.7%) after treatment with the fabricated nanospheres at 0.8 µg/mL. Cellular internalization was successful with more than 70.0% nanospheres detected in HT-29 cells. Therefore, this fabricated nanospheres may be considered as potential nanocarriers for colon cancer-targeted chemotherapeutic drug delivery.
    Matched MeSH terms: Surface Properties
  19. Cleansing and surface modifying agents on implants: fixation and related aspects of aesthetics
    Ling BC, Gillings BR
    Asian J Aesthet Dent, 1995;3:17-21.
    PMID: 9063105
    With the prognosis of dental implant replacement of missing teeth becoming better each year, practitioners are focusing their attention on the aesthetic aspects of implantology. However, improvement in aesthetics is only possible with the improvement in implant technology, surgical techniques and prosthodontic procedures. This study aimed at evaluating the effects of various physical and chemical agents on the implant surface; with the view of obtaining increased surface area and biocompatibility. The study found that the treatment of air-aluminum oxide blasted implants using a mixture of 30% HNO3-5% HF acids produced a surface which meets the consideration of aesthetics for implants placed in the anterior maxillary region.
    Matched MeSH terms: Surface Properties
  20. SEM analyses of repaired glass-ionomer cements
    Jamaluddin A, Pearson GJ
    Asian J Aesthet Dent, 1993 Jan;1(1):19-23.
    PMID: 8149147
    This study assessed the nature of the adhesion in repaired glass-ionomer restorative materials. Two chemically different glass-ionomer cements, Ketac Fil and Chemfil II Cap, and three different methods of conditioning the surface for repair were employed. Specimens of each material were prepared and the cut surfaces were then treated with either 35% phosphoric acid, 35% polyacrylic acid or a combination of phosphoric acid followed by polyacrylic acid. Freshly mixed material was injected against these treated surfaces and allowed to set under simulated intraoral conditions. The specimens were tested to failure in flexion after seven days storage. Assessment of the fractured surfaces was then carried out using the scanning electron microscope. The results showed the occurrence of both adhesive and cohesive failure.
    Matched MeSH terms: Surface Properties
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