Displaying publications 1 - 20 of 311 in total

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  1. Fulltext Enhancement of Viscoelastic and Electrical Properties of Magnetorheological Elastomers with Nanosized Ni-Mg Cobalt-Ferrites as Fillers
    Abdul Aziz SA, Mazlan SA, Ubaidillah U, Shabdin MK, Yunus NA, Nordin NA, et al.
    Materials (Basel), 2019 Oct 28;12(21).
    PMID: 31661837 DOI: 10.3390/ma12213531
    Carbon-based particles, such as graphite and graphene, have been widely used as a filler in magnetorheological elastomer (MRE) fabrication in order to obtain electrical properties of the material. However, these kinds of fillers normally require a very high concentration of particles to enhance the conductivity property. Therefore, in this study, the nanosized Ni-Mg cobalt ferrite is introduced as a filler to soften MRE and, at the same time, improve magnetic, rheological, and conductivity properties. Three types of MRE samples without and with different compositions of Mg, namely Co0.5Ni0.2Mg0.3Fe2O4 (A1) and Co0.5Ni0.1Mg0.4Fe2O4 (A2), are fabricated. The characterization related to the micrograph, magnetic, and rheological properties of the MRE samples are analyzed using scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and the rheometer. Meanwhile, the effect of the nanosized Ni-Mg cobalt ferrites on the electrical resistance property is investigated and compared with the different Mg compositions. It is shown that the storage modulus of the MRE sample with the nanosized Ni-Mg cobalt ferrites is 43% higher than that of the MRE sample without the nanomaterials. In addition, it is demonstrated that MREs with the nanosized Ni-Mg cobalt ferrites exhibit relatively low electrical resistance at the on-state as compared to the off-state condition, because MRE with a higher Mg composition shows lower electrical resistance when higher current flow occurs through the materials. This salient property of the proposed MRE can be effectively and potentially used as an actuator to control the viscoelastic property of the magnetic field or sensors to measure the strain of the flexible structures by the electrical resistance signal.
    Matched MeSH terms: Nanostructures
  2. Enhancing the efficiency of polymerase chain reaction using graphene nanoflakes
    Abdul Khaliq R, Kafafy R, Salleh HM, Faris WF
    Nanotechnology, 2012 Nov 16;23(45):455106.
    PMID: 23085573 DOI: 10.1088/0957-4484/23/45/455106
    The effect of the recently developed graphene nanoflakes (GNFs) on the polymerase chain reaction (PCR) has been investigated in this paper. The rationale behind the use of GNFs is their unique physical and thermal properties. Experiments show that GNFs can enhance the thermal conductivity of base fluids and results also revealed that GNFs are a potential enhancer of PCR efficiency; moreover, the PCR enhancements are strongly dependent on GNF concentration. It was found that GNFs yield DNA product equivalent to positive control with up to 65% reduction in the PCR cycles. It was also observed that the PCR yield is dependent on the GNF size, wherein the surface area increases and augments thermal conductivity. Computational fluid dynamics (CFD) simulations were performed to analyze the heat transfer through the PCR tube model in the presence and absence of GNFs. The results suggest that the superior thermal conductivity effect of GNFs may be the main cause of the PCR enhancement.
    Matched MeSH terms: Nanostructures/ultrastructure; Nanostructures/chemistry*
  3. Carbon nanomaterial properties help to enhance xylanase production from recombinant Kluyveromyces lactis through a cell immobilization method
    Abdul Manaf SA, Mohamad Fuzi SFZ, Low KO, Hegde G, Abdul Manas NH, Md Illias R, et al.
    Appl Microbiol Biotechnol, 2021 Nov;105(21-22):8531-8544.
    PMID: 34611725 DOI: 10.1007/s00253-021-11616-0
    Carbon nanomaterials, due to their catalytic activity and high surface area, have potential as cell immobilization supports to increase the production of xylanase. Recombinant Kluyveromyces lactis used for xylanase production was integrated into a polymeric gel network with carbon nanomaterials. Carbon nanomaterials were pretreated before cell immobilization with hydrochloric acid (HCl) treatment and glutaraldehyde (GA) crosslinking, which contributes to cell immobilization performance. Carbon nanotubes (CNTs) and graphene oxide (GO) were further screened using a Plackett-Burman experimental design. Cell loading and agar concentration were the most important factors in xylanase production with low cell leakage. Under optimized conditions, xylanase production was increased by more than 400% compared to free cells. Immobilized cell material containing such high cell densities may exhibit new and unexplored beneficial properties because the cells comprise a large fraction of the component. The use of carbon nanomaterials as a cell immobilization support along with the entrapment method successfully enhances the production of xylanase, providing a new route to improved bioprocessing, particularly for the production of enzymes. KEY POINTS: • Carbon nanomaterials (CNTs, GO) have potential as cell immobilization supports. • Entrapment in a polymeric gel network provides space for xylanase production. • Plackett-Burman design screen for the most important factor for cell immobilization.
    Matched MeSH terms: Nanostructures*
  4. Rhizomucor miehei lipase immobilized on reinforced chitosan-chitin nanowhiskers support for synthesis of eugenyl benzoate
    Abdul Manan FM, Attan N, Widodo N, Aboul-Enein HY, Wahab RA
    Prep Biochem Biotechnol, 2018 Jan 02;48(1):92-102.
    PMID: 29194017 DOI: 10.1080/10826068.2017.1405021
    An alternative environmentally benign support was prepared from chitosan-chitin nanowhiskers (CS/CNWs) for covalent immobilization of Rhizomucor miehei lipase (RML) to increase the operational stability and recyclability of RML in synthesizing eugenyl benzoate. The CS/CNWs support and RML-CS/CNWs were characterized using X-ray diffraction, fluorescent microscopy, and Fourier transform infrared spectroscopy. Efficiency of the RML-CS/CNWs was compared to the free RML to synthesize eugenyl benzoate for parameters: reaction temperature, stirring rate, reusability, and thermal stability. Under optimal experimental conditions (50°C, 250 rpm, catalyst loading 3 mg/mL), a twofold increase in yield of eugenyl benzoate was observed for RML-CS/CNWs as compared to free RML, with the former achieving maximum yield of the ester at 62.1% after 5 hr. Results demonstrated that the strategy adopted to prepare RML-CS/CNWs was useful, producing an improved and prospectively greener biocatalyst that supported a sustainable process to prepare eugenyl benzoate. Moreover, RML-CS/CNWs are biodegradable and perform esterification reactions under ambient conditions as compared to the less eco-friendly conventional acid catalyst. This research provides a facile and promising approach for improving activity of RML in which the resultant RML-CS/CNWs demonstrated good operational stability for up to eight successive esterification cycles to synthesize eugenyl benzoate.
    Matched MeSH terms: Nanostructures/chemistry
  5. Fulltext Molecular Dynamics Study of Poly(dimethylsiloxane) Nanostructure Distortion in a Soft Lithography Demolding Process
    Abdul Manap AH, Md Izah SS, Mohamed K
    ACS Omega, 2019 Dec 03;4(23):20257-20264.
    PMID: 31815228 DOI: 10.1021/acsomega.9b02547
    This study aims at investigating the distortion of poly(dimethylsiloxane) (PDMS) nanostructures in a soft lithography demolding process using molecular dynamics simulation. Experimental results show that after peeling, PDMS nanopillars became 10-60% longer in height than the mold size. Molecular dynamics simulations have been employed to plot the stress-strain curve of the nanopillars when subjected to uniaxial stress. Three force fields (COMPASS, CVFF, and PCFF) were used for modeling. The demolding process in soft lithography and nanoimprint lithography causes significant deformation in replication. The experimental results show clear signs of elongation after demolding. Molecular dynamics simulations are employed to study the stress-strain relationship of the PDMS nanopillars. The results from the simulation show that a PDMS nanopillar at temperature T = 300 K under tensile stress shows characteristics of flexible plastic under tensile stress and has a lower Young's modulus, ultimate tensile stress, and Poisson's ratio.
    Matched MeSH terms: Nanostructures
  6. Fulltext Topical piroxicam in vitro release and in vivo anti-inflammatory and analgesic effects from palm oil esters-based nanocream
    Abdulkarim MF, Abdullah GZ, Chitneni M, Salman IM, Ameer OZ, Yam MF, et al.
    Int J Nanomedicine, 2010 Nov 04;5:915-24.
    PMID: 21116332 DOI: 10.2147/IJN.S13305
    INTRODUCTION: During recent years, there has been growing interest in use of topical vehicle systems to assist in drug permeation through the skin. Drugs of interest are usually those that are problematic when given orally, such as piroxicam, a highly effective anti-inflammatory, anti-pyretic, and analgesic, but with the adverse effect of causing gastrointestinal ulcers. The present study investigated the in vitro and in vivo pharmacodynamic activity of a newly synthesized palm oil esters (POEs)-based nanocream containing piroxicam for topical delivery.

    METHODS: A ratio of 25:37:38 of POEs: external phase: surfactants (Tween 80:Span 20, in a ratio 80:20), respectively was selected as the basic composition for the production of a nanocream with ideal properties. Various nanocreams were prepared using phosphate-buffered saline as the external phase at three different pH values. The abilities of these formulae to deliver piroxicam were assessed in vitro using a Franz diffusion cell fitted with a cellulose acetate membrane and full thickness rat skin. These formulae were also evaluated in vivo by comparing their anti-inflammatory and analgesic activities with those of the currently marketed gel.

    RESULTS: After eight hours, nearly 100% of drug was transferred through the artificial membrane from the prepared formula F3 (phosphate-buffered saline at pH 7.4 as the external phase) and the marketed gel. The steady-state flux through rat skin of all formulae tested was higher than that of the marketed gel. Pharmacodynamically, nanocream formula F3 exhibited the highest anti- inflammatory and analgesic effects as compared with the other formulae.

    CONCLUSION: The nanocream containing the newly synthesized POEs was successful for trans-dermal delivery of piroxicam.

    Matched MeSH terms: Nanostructures/administration & dosage*; Nanostructures/chemistry*
  7. Fulltext In vitro permeation and in vivo anti-inflammatory and analgesic properties of nanoscaled emulsions containing ibuprofen for topical delivery
    Abdullah GZ, Abdulkarim MF, Salman IM, Ameer OZ, Yam MF, Mutee AF, et al.
    Int J Nanomedicine, 2011;6:387-96.
    PMID: 21499428 DOI: 10.2147/IJN.S14667
    As a topical delivery system, a nanoscaled emulsion is considered a good carrier of several active ingredients that convey several side effects upon oral administration, such as nonsteroidal anti-inflammatory drugs (NSAIDs).
    Matched MeSH terms: Nanostructures/administration & dosage*; Nanostructures/chemistry
  8. Fulltext Recent Advances in Shape-Controlled Synthesis of Noble Metal Nanoparticles by Radiolysis Route
    Abedini A, Bakar AA, Larki F, Menon PS, Islam MS, Shaari S
    Nanoscale Res Lett, 2016 Dec;11(1):287.
    PMID: 27283051 DOI: 10.1186/s11671-016-1500-z
    This paper focuses on the recent advances on radiolysis-assisted shape-controlled synthesis of noble metal nanostructures. The techniques and protocols for producing desirable shapes of noble metal nanoparticles are discussed through introducing the critical parameters which can influence the nucleation and growth mechanisms. Nucleation rate plays a vital role on the crystallinity of seeds while growth rate of different seeds' facets determines the final shape of resultant nanoparticles. Nucleation and growth rate both can be altered with factors such as absorbed dose, capping agents, and experimental environment condition to control the final shape. Remarkable physical and chemical properties of synthesized noble metal nanoparticles by controlled morphology have been systematically evaluated to fully explore their applications.
    Matched MeSH terms: Nanostructures
  9. Fulltext Sesame Oil-Based Nanostructured Lipid Carriers of Nicergoline, Intranasal Delivery System for Brain Targeting of Synergistic Cerebrovascular Protection
    Abourehab MAS, Khames A, Genedy S, Mostafa S, Khaleel MA, Omar MM, et al.
    Pharmaceutics, 2021 Apr 19;13(4).
    PMID: 33921796 DOI: 10.3390/pharmaceutics13040581
    Nicergoline (NIC) is a semisynthetic ergot alkaloid derivative applied for treatment of dementia and other cerebrovascular disorders. The efficacy of sesame oil to slow and reverse the symptoms of neurodegenerative cognitive disorders has been proven. This work aimed to formulate and optimize sesame oil-based NIC-nanostructured lipid carriers (NIC-NLCs) for intranasal (IN) delivery with expected synergistic and augmented neuroprotective properties. The NIC-NLC were prepared using sesame oil as a liquid lipid. A three-level, three-factor Box-Behnken design was applied to statistically optimize the effect of sesame oil (%) of the total lipid, surfactant concentration, and sonication time on particle size, zeta potential, and entrapment efficacy as responses. Solid-state characterization, release profile, and ex vivo nasal permeation in comparison to NIC solution (NIC-SOL) was studied. In vivo bioavailability from optimized NIC-NLC and NIC-SOL following IN and IV administration was evaluated and compared. The optimized NIC-NLC formula showed an average particle size of 111.18 nm, zeta potential of -15.4 mV, 95.11% entrapment efficacy (%), and 4.6% loading capacity. The NIC-NLC formula showed a biphasic, extended-release profile (72% after 48 h). Permeation of the NIC-NLC formula showed a 2.3 enhancement ratio. Bioavailability studies showed a 1.67 and 4.57 fold increase in plasma and brain following IN administration. The results also indicated efficient direct nose-to-brain targeting properties with the brain-targeting efficiency (BTE%) and direct transport percentage (DTP%) of 187.3% and 56.6%, respectively, after IN administration. Thus, sesame oil-based NIC-NLC can be considered as a promising IN delivery system for direct and efficient brain targeting with improved bioavailability and expected augmented neuroprotective action for the treatment of dementia.
    Matched MeSH terms: Nanostructures
  10. Optimization of fluorescent silicon nanomaterial production using peroxide/acid/salt technique
    Abu Hassan LH
    Sains Malaysiana, 2009;38.
    Silicon nanomaterial was prepared using the peroxide/acid/salt technique in which an aqueous silicon-based salt solution was added to H2O2/HF etchants. In order to optimize the experimental conditions for silicon nanomaterial production, the amount of nanomaterial produced was studied as a function of the volume of the silicon salt solution used in the synthesis. A set of samples was prepared using: 0, 5, 10, 15, and 20 mL of an aqueous 1 mg/L metasilicate solution. The area under the corresponding peaks in the infrared (ir) absorption spectra was used as a qualitative indicator to the amount of the nanomaterial present. The results indicated that using 10 mL of the metasilicate solution produced the highest amount of nanomaterial. Furthermore, the results demonstrated that the peroxide/acid/salt technique results in the enhancement of the production yield of silicon nanomaterial at a reduced power demand and with a higher material to void ratio. A model in which the silicon salt forms a secondary source of silicon nanomaterial is proposed. The auxiliary nanomaterial is deposited into the porous network causing an increase in the amount of nanomaterial produced and a reduction in the voids present. Thus a reduction in the resistance of the porous layer, and consequently reduction in the power required, are expected.
    Matched MeSH terms: Nanostructures
  11. Sono-nano chemistry: A new era of synthesising polyhydroxylated carbon nanomaterials with hydroxyl groups and their industrial aspects
    Afreen S, Muthoosamy K, Manickam S
    Ultrason Sonochem, 2019 Mar;51:451-461.
    PMID: 30224290 DOI: 10.1016/j.ultsonch.2018.07.015
    The main objective of this review is to derive the salient features of previously developed ultrasound-assisted methods for hydroxylating graphene and Buckminsterfullerene (C60). The pros and cons associated to ultrasound-assisted synthesis of hydroxy-carbon nanomaterials in designing the strategical methods for the industrial bulk production are also discussed. A guideline on the statistical methods has also been considered to further provide the scopes towards the application of the previously reported methods. Irrespective of many useful methods that have been developed in order to functionalize C60 and graphene by diverse oxygenated functional groups e.g. epoxide, hydroxyl, carboxyl as well as metal/metal oxide via a combination of organic chemistry and sonochemistry, there is no report dealing exclusively on the application of ultrasonic cavitation particularly to synthesising polyhydroxylated carbon nanomaterials. On this context, this review emphasizes in investigating the critical aspects of sono-nanochemistry and the statistical approaches to optimize the variables in the sonochemical process towards a large-scale synthesis of polyhydroxylated graphene and C60.
    Matched MeSH terms: Nanostructures
  12. Synthesis and characterization of polymeric V2O5/AlO(OH) with nanopores on alumina support
    Ahmad AL, Abd Shukor SR, Leo CP
    J Nanosci Nanotechnol, 2006 Dec;6(12):3910-4.
    PMID: 17256351
    Polymeric vanadium pentoxide gel was formed via the reaction of V2O5 powder with hydrogen peroxide. The polymeric vanadium pentoxide gel was then dispersed in alumina gel. Different vanadium loading composites were coated on alumina support and calcined at 500 degrees C for 1 hr. These composite layers were characterized using TGA, FT-IR, XRD, SEM, and Autosorb. It was found that the lamellar structure of polymerized vanadium pentoxide was retained in the inorganic matrix. Crystalline alumina in gamma phase was formed after calcinations. However, the vanadium-alumina mixed oxides are lack of the well defined PXRD peaks for polycrystalline V2O5. This is possibly because the vanadia species are highly dispersed in the alumina matrix or the vanadia species are dispersed as crystalline which is smaller than 4 nm. In addition, the imbedded polymeric vanadium oxide improved the specific area and average pore diameter of the composite layer.
    Matched MeSH terms: Nanostructures/ultrastructure*; Nanostructures/chemistry*
  13. Nanofork for single cells adhesion measurement via ESEM-nanomanipulator system
    Ahmad MR, Nakajima M, Kojima M, Kojima S, Homma M, Fukuda T
    IEEE Trans Nanobioscience, 2012 Mar;11(1):70-8.
    PMID: 22275723 DOI: 10.1109/TNB.2011.2179809
    In this paper, single cells adhesion force was measured using a nanofork. The nanofork was used to pick up a single cell on a line array substrate inside an environmental scanning electron microscope (ESEM). The line array substrate was used to provide small gaps between the single cells and the substrate. Therefore, the nanofork could be inserted through these gaps in order to successfully pick up a single cell. Adhesion force was measured during the cell pick-up process from the deflection of the cantilever beam. The nanofork was fabricated using focused ion beam (FIB) etching process while the line array substrate was fabricated using nanoimprinting technology. As to investigate the effect of contact area on the strength of the adhesion force, two sizes of gap distance of line array substrate were used, i.e., 1 μm and 2 μm. Results showed that cells attached on the 1 μm gap line array substrate required more force to be released as compared to the cells attached on the 1 μm gap line array substrate.
    Matched MeSH terms: Nanostructures/ultrastructure*
  14. Toxicity assessment of reduced graphene oxide and titanium dioxide nanomaterials on gram-positive and gram-negative bacteria under normal laboratory lighting condition
    Ahmad NS, Abdullah N, Yasin FM
    Toxicol Rep, 2020;7:693-699.
    PMID: 32528857 DOI: 10.1016/j.toxrep.2020.04.015
    Toxicity effect of reduced graphene oxide (rGO) and titanium dioxide (TiO2) nanomaterials (NMs) on Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) bacteria was assessed. For both strains, study demonstrated that the toxicity was time and concentration dependent which led to reduction in growth rate and cell death. Upon NMs exposure, an instantaneous cell death in E. coli culture was observed. This is in contrast with B. subtilis, in which the culture growth remained in the log phase; however their growth rate constant,

    μ
    g

    was reduced by ∼70%. The discrepancy between E. coli and B. subtilis was due to strain-specific response upon contact with NMs. TEM, SEM and EDX analysis revealed direct physical surface-surface interaction, as evidence from the adherence of NMs on the cell surface.
    Matched MeSH terms: Nanostructures
  15. Size selectivity in antibiofilm activity of 3-(diphenylphosphino)propanoic acid coated gold nanomaterials against Gram-positive Staphylococcus aureus and Streptococcus mutans
    Ahmed D, Anwar A, Khan AK, Ahmed A, Shah MR, Khan NA
    AMB Express, 2017 Nov 21;7(1):210.
    PMID: 29164404 DOI: 10.1186/s13568-017-0515-x
    Biofilm formation by pathogenic bacteria is one of the major threats in hospital related infections, hence inhibiting and eradicating biofilms has become a primary target for developing new anti-infection approaches. The present study was aimed to develop novel antibiofilm agents against two Gram-positive bacteria; Staphylococcus aureus (ATCC 43300) and Streptococcus mutans (ATCC 25175) using gold nanomaterials conjugated with 3-(diphenylphosphino)propionic acid (Au-LPa). Gold nanomaterials with different sizes as 2-3 nm small and 9-90 nm (50 nm average size) large were stabilized by LPa via different chemical synthetic strategies. The nanomaterials were fully characterized using atomic force microscope (AFM), transmission electron microscope, ultraviolet-visible absorption spectroscopy, and Fourier transformation infrared spectroscopy. Antibiofilm activity of Au-LPa nanomaterials was tested using LPa alone, Au-LPa and unprotected gold nanomaterials against the both biofilm-producing bacteria. The results showed that LPa alone did not inhibit biofilm formation to a significant extent below 0.025 mM, while conjugation with gold nanomaterials displayed manifold enhanced antibiofilm potential against both strains. Moreover, it was also observed that the antibiofilm potency of the Au-LPa nanomaterials varies with size variations of nanomaterials. AFM analysis of biofilms further complemented the assay results and provided morphological aspects of the antibiofilm action of Au-LPa nanomaterials.
    Matched MeSH terms: Nanostructures
  16. Nanostructured lipid carrier to overcome stratum corneum barrier for the delivery of agomelatine in rat brain; formula optimization, characterization and brain distribution study
    Ahmed S, Mahmood S, Danish Ansari M, Gull A, Sharma N, Sultana Y
    Int J Pharm, 2021 Sep 25;607:121006.
    PMID: 34391848 DOI: 10.1016/j.ijpharm.2021.121006
    The current work attempted to achieve bypassed hepatic metabolism, controlled release, and boosted brain distribution of agomelatine by loading in NLC and administering via transdermal route. Agomelatine-loaded NLC (AG-NLC) was fabricated employing melt-emulsification technique and optimized using central composite design. The optimized AG-NLC had 183.16 ± 6.82 nm particle size, 0.241 ± 0.0236 polydispersity index, and 83.29 ± 2.76% entrapment efficiency. TEM and FESEM visually confirmed the size and surface morphology of AG-NLC, respectively. DSC thermogram confirmed the conversion of AG from crystalline to amorphous form, which indicates improved solubility of AG when loaded in NLC. For further stability and improved applicability, AG-NLC was converted into a hydrogel. The texture analysis of AG-NLC-Gel showed appropriate gelling property in terms of hardness (142.292 g), cohesiveness (0.955), and adhesiveness (216.55 g.sec). In comparison to AG-suspension-Gel (38.036 ± 6.058%), AG-NLC-Gel (89.440 ± 2.586%) exhibited significantly higher (P 
    Matched MeSH terms: Nanostructures*
  17. Solid dispersions of α-mangostin improve its aqueous solubility through self-assembly of nanomicelles
    Aisha AF, Ismail Z, Abu-Salah KM, Majid AM
    J Pharm Sci, 2012 Feb;101(2):815-25.
    PMID: 22081501 DOI: 10.1002/jps.22806
    α-Mangostin is an oxygenated heterocyclic xanthone with remarkable pharmacological properties, but poor aqueous solubility and low oral bioavailability hinder its therapeutic application. This study sought to improve the compound's solubility and study the mechanism underlying solubility enhancement. Solid dispersions of α-mangostin were prepared in polyvinylpyrrolidone (PVP) by solvent evaporation method and showed substantial enhancement of α-mangostin's solubility from 0.2 ± 0.2 μg/mL to 2743 ± 11 μg/mL. Fourier transform infrared spectroscopy and differential scanning calorimetry indicated interaction between α-mangostin and PVP. Transmission electron microscopy and dynamic light scattering showed self-assembly of round anionic nanomicelles with particle size in the range 99-127 nm. Powder X-ray diffraction indicated conversion of α-mangostin from crystalline into amorphous state, and scanning electron microscopy showed the presence of highly porous powder. Studies using the fluorescent probe pyrene showed that the critical micellar concentration is about 77.4 ± 4 μg/mL. Cellular uptake of nanomicelles was found to be mediated via endocytosis and indicated intracellular delivery of α-mangostin associated with potent cytotoxicity (median inhibitory concentration of 8.9 ± 0.2 μg/mL). Improved solubility, self-assembly of nanomicelles, and intracellular delivery through endocytosis may enhance the pharmacological properties of α-mangostin, particularly antitumor efficacy.
    Matched MeSH terms: Nanostructures*
  18. Comparison between Nucleate Pool Boiling Heat Transfer of Graphene Nanoplatelet- and Carbon Nanotube- Based Aqueous Nanofluids
    Akbari A, Mohammadian E, Alavi Fazel SA, Shanbedi M, Bahreini M, Heidari M, et al.
    ACS Omega, 2019 Nov 19;4(21):19183-19192.
    PMID: 31763542 DOI: 10.1021/acsomega.9b02474
    An increase of nucleate pool boiling with the use of different fluid properties has received much attention. In particular, the presence of nanostructures in fluids to enhance boiling was given special consideration. This study compares the effects of graphene nanoplatelet (GNP), functionalized GNP with polyethylene glycol (PEG), and multiwalled carbon nanotube (CNT) nanofluids on the pool boiling heat transfer coefficient and the critical heat flux (CHF). Our findings showed that at the same concentration, CHF for functionalized GNP with PEG (GNP-PEG)/deionized water (DW) nanofluids was higher in comparison with GNP- and CNT-based nanofluids. The CHF of the GNP/DW nanofluids was also higher than that of CNT/DW nanofluids. The CHF of GNP-PEG was 72% greater than that of DW at the concentration of 0.1 wt %. There is good agreement between measured critical heat fluxes and the Kandlikar correlation. In addition, the current results proved that the GNP-PEG/DW nanofluids are highly stable over 3 months at a concentration of 0.1 wt %.
    Matched MeSH terms: Nanostructures
  19. Self-assembled potential bio nanocarriers for drug delivery
    Akter N, Radiman S, Mohamed F, Reza MI
    Mini Rev Med Chem, 2013 Jul;13(9):1327-39.
    PMID: 23544469
    Self-assembled nanocarriers attract increasing attention due to their wide application in various practical fields; among them, one of the most focused fields is drug delivery. Appropriate selection of surfactant is the basis for preparing a successful nanocarrier. Until now, from phospholipid to synthetic surfactants, many surfactants have been used to explore a suitable drug delivery vehicle for the complex in-vivo environment. Among all, bio surfactants are found to be more suitable due to their bio-origin, less-toxicity, biodegradability, cheaper rate and above all, their versatile molecular structures. This molecular property enables them to self assemble into fascinating structures. Moreover, binding DNA, enhancing pH sensitivity and stability allows novelty over their synthetic counterparts and phospholipid. This review paper focuses on the properties and applications of bio-nano-carriers for drug delivery. Micelle, microemulsion, and vesicle are the three nanocarriers which are discussed herein.
    Matched MeSH terms: Nanostructures*
  20. Formulation and stability of whitening VCO-in-water nano-cream
    Al-Edresi S, Baie S
    Int J Pharm, 2009 May 21;373(1-2):174-8.
    PMID: 19429303 DOI: 10.1016/j.ijpharm.2009.02.011
    Virgin coconut oil (VCO)-in-water, nano-emulsion in the form of cream stabilized by Emulium Kappa as an emulsifier, was prepared by using the Emulsion Inversion Point method. A nano-emulsion with droplet size <300 nm was then obtained. VCO has recently become a more popular new material in the cosmetic industries. Emulium Kappa is an ionic emulsifier that contains sodium stearoyl lactylate, the active whitening ingredient was Kojic Dipalmitate. Ostwald ripening is the main destabilizing factor for the nano-emulsion. This decline can be reduced by adding non-soluble oil, namely squalene, to the virgin coconut oil. We tested VCO:squalene in the ratios of 10:0, 9.8:0.2, 9.6:0.4, 9.4:0.6, 9.2:0.8, 9:1 and 8:2 and discovered that squalene's higher molecular weight (above critical molecular weight) resulted in low polarity and insolubility in the continuous phase. The continuous partitioning between the droplets results in the decline of Ostwald ripening. Furthermore, flocculation may occur due to the instability of nano-emulsion, especially for the preparations with little or no squalene at all. The stability of the nano-emulsion was evaluated by the electrophoretic properties of the emulsion droplets. The zeta potential values for the emulsion increased as the percentage of squalene oil increased.
    Matched MeSH terms: Nanostructures/chemistry*
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