Displaying publications 81 - 100 of 437 in total

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  1. Fulltext Low-dose AgNPs reduce lung mechanical function and innate immune defense in the absence of cellular toxicity
    Botelho DJ, Leo BF, Massa CB, Sarkar S, Tetley TD, Chung KF, et al.
    Nanotoxicology, 2016;10(1):118-27.
    PMID: 26152688 DOI: 10.3109/17435390.2015.1038330
    Multiple studies have examined the direct cellular toxicity of silver nanoparticles (AgNPs). However, the lung is a complex biological system with multiple cell types and a lipid-rich surface fluid; therefore, organ level responses may not depend on direct cellular toxicity. We hypothesized that interaction with the lung lining is a critical determinant of organ level responses. Here, we have examined the effects of low dose intratracheal instillation of AgNPs (0.05 μg/g body weight) 20 and 110 nm diameter in size, and functionalized with citrate or polyvinylpyrrolidone. Both size and functionalization were significant factors in particle aggregation and lipid interaction in vitro. One day post-intratracheal instillation lung function was assessed, and bronchoalveolar lavage (BAL) and lung tissue collected. There were no signs of overt inflammation. There was no change in surfactant protein-B content in the BAL but there was loss of surfactant protein-D with polyvinylpyrrolidone (PVP)-stabilized particles. Mechanical impedance data demonstrated a significant increase in pulmonary elastance as compared to control, greatest with 110 nm PVP-stabilized particles. Seven days post-instillation of PVP-stabilized particles increased BAL cell counts, and reduced lung function was observed. These changes resolved by 21 days. Hence, AgNP-mediated alterations in the lung lining and mechanical function resolve by 21 days. Larger particles and PVP stabilization produce the largest disruptions. These studies demonstrate that low dose AgNPs elicit deficits in both mechanical and innate immune defense function, suggesting that organ level toxicity should be considered.
    Matched MeSH terms: Metal Nanoparticles/toxicity*
  2. Predicting the fluorescent enhancement rate by gold and silver nanospheres using finite-difference time-domain analysis
    Centeno A, Xie F, Alford N
    IET Nanobiotechnol, 2013 Jun;7(2):50-8.
    PMID: 24046905
    Metal-induced fluorescence enhancement (MIFE) is a promising strategy for increasing the sensitivity of fluorophores used in biological sensors. This study uses the finite-difference time-domain technique to predict the fluorescent enhancement rate of a fluorophore molecule in close proximity to a gold or silver spherical nanoparticle. By considering commercially available fluorescent dyes the computed results are compared with the published experimental data. The results show that MIFE is a complex coupling process between the fluorophore molecule and the metal nanoparticle. Nevertheless using computational electromagnetic techniques to perform calculations it is possible to calculate, with reasonable accuracy, the fluorescent enhancement. Using this methodology it will be possible to consider different shaped metal nanoparticles and any supporting substrate material in the future, an important step in building reliable biosensors capable of detecting low levels of proteins tagged with fluorescence molecules.
    Matched MeSH terms: Metal Nanoparticles/chemistry
  3. DNA Switch: Toehold-Mediated DNA Isothermal Amplification for Dengue Serotyping
    Chan SK, Kuzuya A, Choong YS, Lim TS
    SLAS Discov, 2019 01;24(1):68-76.
    PMID: 30063871 DOI: 10.1177/2472555218791743
    The inherent ability of nucleic acids to recognize a complementary pair has gained wide popularity in DNA sensor applications. DNA molecules can be produced in bulk and easily incorporated with various nanomaterials for sensing applications. More complex designs and sophisticated DNA sensors have been reported over the years to allow DNA detection in a faster, cheaper, and more convenient manner. Here, we report a DNA sensor designed to function like a switch to turn "on" silver nanocluster (AgNC) generation in the presence of a specific DNA target. By defining the probe region sequence, we are able to tune the color of the AgNC generated in direct relation to the different targets. As a proof of concept, we used dengue RNA-dependent RNA polymerase conserved sequences from all four serotypes as targets. This method was able to distinguish each dengue serotype by generating the serotype-respective AgNCs. The DNA switch was also able to identify and amplify the correct target in a mixture of targets with good specificity. This strategy has a detection limit of between 1.5 and 2.0 µM depending on the sequence of AgNC. The DNA switch approach provides an attractive alternative for single-target or multiplex DNA detection.
    Matched MeSH terms: Metal Nanoparticles/chemistry
  4. Biosynthesis and structural characterization of Ag nanoparticles from white rot fungi
    Chan YS, Mat Don M
    Mater Sci Eng C Mater Biol Appl, 2013 Jan 1;33(1):282-8.
    PMID: 25428073 DOI: 10.1016/j.msec.2012.08.041
    Five species of white rot fungi were screened for their capability to synthesize Ag nanoparticles (AgNPs). Three modes of AgNP bioreduction were developed. Pycnoporus sanguineus is found as a potential candidate for the synthesis of AgNPs with a yield at 98.9%. The synthesized AgNPs were characterized using UV-vis spectroscopy, DLS, FTIR, TEM, and SEM. Results showed that AgNP absorption band was located at a peak of 420 nm. Both the SEM and TEM confirmed that the formation of AgNPs were mainly spherical with average diameters of 52.8-103.3 nm. The signals of silver atoms' presence in the mycelium were observed by SEM-EDS spectrum.
    Matched MeSH terms: Metal Nanoparticles/toxicity; Metal Nanoparticles/ultrastructure; Metal Nanoparticles/chemistry*
  5. A review on colorimetric methods for determination of organophosphate pesticides using gold and silver nanoparticles
    Che Sulaiman IS, Chieng BW, Osman MJ, Ong KK, Rashid JIA, Wan Yunus WMZ, et al.
    Mikrochim Acta, 2020 01 15;187(2):131.
    PMID: 31940088 DOI: 10.1007/s00604-019-3893-8
    This review (with 99 refs.) summarizes the progress that has been made in colorimetric (i.e. spectrophotometric) determination of organophosphate pesticides (OPPs) using gold and silver nanoparticles (NPs). Following an introduction into the field, a first large section covers the types and functions of organophosphate pesticides. Methods for colorimetric (spectrophotometric) measurements including RGB techniques are discussed next. A further section covers the characteristic features of gold and silver-based NPs. Syntheses and modifications of metal NPs are covered in section 5. This is followed by overviews on enzyme inhibition-based assays, aptamer-based assays and chemical (non-enzymatic) assays, and a discussion of specific features of colorimetric assays. Several Tables are presented that give an overview on the wealth of methods and materials. A concluding section addresses current challenges and discusses potential future trends and opportunities. Graphical abstractSchematic representation of organophosphate pesticide determinations based on aggregation of nanoparticles (particular silver or gold nanoparticles). This leads to a color change which can be determined visually and monitored by a red shift in the absorption spectrum.
    Matched MeSH terms: Metal Nanoparticles/chemistry*
  6. Biogenic Synthesis, Characterization and Evaluation of Silver Nanoparticles from Aspergillus niger JX556221 Against Human Colon Cancer Cell Line HT-29
    Chengzheng W, Jiazhi W, Shuangjiang C, Swamy MK, Sinniah UR, Akhtar MS, et al.
    J Nanosci Nanotechnol, 2018 May 01;18(5):3673-3681.
    PMID: 29442882 DOI: 10.1166/jnn.2018.15364
    Nanobiotechnology has emerged as a promising technology to develop new therapeutically active nanomaterials. The present study was aimed to biosynthesize AgNPs extracellularly using Aspergillus niger JX556221 fungal extract and to evaluate their anticancer potential against colon cancer cell line, HT-29. UV-visible spectral characterization of the synthesized AgNPs showed higher absorption peak at 440 nm wavelength. Transmission Electron Microscopy (TEM) analysis revealed the monodispersed nature of synthesized AgNPs occurring in spherical shape with a size in the range of 20-25 nm. Further, characterization using Energy Dispersive Spectroscopy (EDX) confirmed the face-centred cubic crystalline structure of metallic AgNPs. FTIR data revealed the occurrence of various phytochemicals in the cell free fungal extract which substantiated the fungal extract mediated AgNPs synthesis. The cytotoxic effect of AgNPs was studied by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The results evidenced the cytotoxic effect of AgNPs on HT-29 cell lines in a dose dependent manner. The highest activity was found at 100 μg/ml concentration after 24 h of incubation. Use of propidium iodide staining examination method confirmed the cytotoxic effect of AgNPs through inducing cell apoptosis. AgNPs cytotoxicity was found to be through elevating reactive oxygen species (ROS), and caspase-3 activation resulting in induced apoptosis. Therefore, this research finding provides an insight towards the development of novel anticancer agents using biological sources.
    Matched MeSH terms: Metal Nanoparticles/therapeutic use*
  7. Fulltext The Potential of Roselle (Hibiscus sabdariffa) Plant in Industrial Applications: A Promising Source of Functional Compounds
    Chew LY, Teng SK, Neo YP, Sim YY, Chew SC
    J Oleo Sci, 2024;73(3):275-292.
    PMID: 38432993 DOI: 10.5650/jos.ess23111
    Roselle is an annual botanical plant that widely planted in different countries worldwide. Its different parts, including seeds, leaves, and calyces, can offer multi-purpose applications with economic importance. The present review discusses the detailed profile of bioactive compounds present in roselle seeds, leaves, and calyces, as well as their extraction and processing, to explore their potential application in pharmaceutical, cosmetic, nutraceutical, food and other industries. Roselle seeds with high phenolics, fiber, and protein contents, which are suitable to use in functional food product development. Besides, roselle seeds can yield 17-20% of roselle seed oil with high content of linoleic acid (35.0-45.3%) and oleic acid (27.1- 36.9%). This unique fatty acid composition of roselle seed oil makes it suitable to use as edible oil to offer the health benefits of essential fatty acid. Moreover, high contents of tocopherols, phenolics, and phytosterols were detected in roselle seed oil to provide nutritional, pharmaceutical, and therapeutic properties. On the other hand, roselle leaves with valuable contents of phenols, flavonoids, organic acid, and tocopherols can be applied in silver nanoparticles, food product development, and the pharmaceutical industry. Roselle calyces with high content of anthocyanins, protocatechuic acids, and organic acids are widely applied in food and colorant industries.
    Matched MeSH terms: Metal Nanoparticles*
  8. Fulltext Targeting Gut Microbial Biofilms-A Key to Hinder Colon Carcinogenesis?
    Chew SS, Tan LT, Law JW, Pusparajah P, Goh BH, Ab Mutalib NS, et al.
    Cancers (Basel), 2020 Aug 13;12(8).
    PMID: 32823729 DOI: 10.3390/cancers12082272
    Colorectal cancer (CRC) is a global public health issue which poses a substantial humanistic and economic burden on patients, healthcare systems and society. In recent years, intestinal dysbiosis has been suggested to be involved in the pathogenesis of CRC, with specific pathogens exhibiting oncogenic potentials such as Fusobacterium nucleatum, Escherichia coli and enterotoxigenic Bacteroides fragilis having been found to contribute to CRC development. More recently, it has been shown that initiation of CRC development by these microorganisms requires the formation of biofilms. Gut microbial biofilm forms in the inner colonic mucus layer and is composed of polymicrobial communities. Biofilm results in the redistribution of colonic epithelial cell E-cadherin, increases permeability of the gut and causes a loss of function of the intestinal barrier, all of which enhance intestinal dysbiosis. This literature review aims to compile the various strategies that target these pathogenic biofilms and could potentially play a role in the prevention of CRC. We explore the potential use of natural products, silver nanoparticles, upconverting nanoparticles, thiosalicylate complexes, anti-rheumatic agent (Auranofin), probiotics and quorum-sensing inhibitors as strategies to hinder colon carcinogenesis via targeting colon-associated biofilms.
    Matched MeSH terms: Metal Nanoparticles
  9. Polydimethylsiloxane-Paper Hybrid Lateral Flow Assay for Highly Sensitive Point-of-Care Nucleic Acid Testing
    Choi JR, Liu Z, Hu J, Tang R, Gong Y, Feng S, et al.
    Anal Chem, 2016 06 21;88(12):6254-64.
    PMID: 27012657 DOI: 10.1021/acs.analchem.6b00195
    In nucleic acid testing (NAT), gold nanoparticle (AuNP)-based lateral flow assays (LFAs) have received significant attention due to their cost-effectiveness, rapidity, and the ability to produce a simple colorimetric readout. However, the poor sensitivity of AuNP-based LFAs limits its widespread applications. Even though various efforts have been made to improve the assay sensitivity, most methods are inappropriate for integration into LFA for sample-to-answer NAT at the point-of-care (POC), usually due to the complicated fabrication processes or incompatible chemicals used. To address this, we propose a novel strategy of integrating a simple fluidic control strategy into LFA. The strategy involves incorporating a piece of paper-based shunt and a polydimethylsiloxane (PDMS) barrier to the strip to achieve optimum fluidic delays for LFA signal enhancement, resulting in 10-fold signal enhancement over unmodified LFA. The phenomena of fluidic delay were also evaluated by mathematical simulation, through which we found the movement of fluid throughout the shunt and the tortuosity effects in the presence of PDMS barrier, which significantly affect the detection sensitivity. To demonstrate the potential of integrating this strategy into a LFA with sample-in-answer-out capability, we further applied this strategy into our prototype sample-to-answer LFA to sensitively detect the Hepatitis B virus (HBV) in clinical blood samples. The proposed strategy offers great potential for highly sensitive detection of various targets for wide application in the near future.
    Matched MeSH terms: Metal Nanoparticles/chemistry
  10. An integrated paper-based sample-to-answer biosensor for nucleic acid testing at the point of care
    Choi JR, Hu J, Tang R, Gong Y, Feng S, Ren H, et al.
    Lab Chip, 2016 Feb 7;16(3):611-21.
    PMID: 26759062 DOI: 10.1039/c5lc01388g
    With advances in point-of-care testing (POCT), lateral flow assays (LFAs) have been explored for nucleic acid detection. However, biological samples generally contain complex compositions and low amounts of target nucleic acids, and currently require laborious off-chip nucleic acid extraction and amplification processes (e.g., tube-based extraction and polymerase chain reaction (PCR)) prior to detection. To the best of our knowledge, even though the integration of DNA extraction and amplification into a paper-based biosensor has been reported, a combination of LFA with the aforementioned steps for simple colorimetric readout has not yet been demonstrated. Here, we demonstrate for the first time an integrated paper-based biosensor incorporating nucleic acid extraction, amplification and visual detection or quantification using a smartphone. A handheld battery-powered heating device was specially developed for nucleic acid amplification in POC settings, which is coupled with this simple assay for rapid target detection. The biosensor can successfully detect Escherichia coli (as a model analyte) in spiked drinking water, milk, blood, and spinach with a detection limit of as low as 10-1000 CFU mL(-1), and Streptococcus pneumonia in clinical blood samples, highlighting its potential use in medical diagnostics, food safety analysis and environmental monitoring. As compared to the lengthy conventional assay, which requires more than 5 hours for the entire sample-to-answer process, it takes about 1 hour for our integrated biosensor. The integrated biosensor holds great potential for detection of various target analytes for wide applications in the near future.
    Matched MeSH terms: Metal Nanoparticles/chemistry
  11. Lateral Flow Assay Based on Paper-Hydrogel Hybrid Material for Sensitive Point-of-Care Detection of Dengue Virus
    Choi JR, Yong KW, Tang R, Gong Y, Wen T, Yang H, et al.
    Adv Healthc Mater, 2017 Jan;6(1).
    PMID: 27860384 DOI: 10.1002/adhm.201600920
    Paper-based devices have been broadly used for the point-of-care detection of dengue viral nucleic acids due to their simplicity, cost-effectiveness, and readily observable colorimetric readout. However, their moderate sensitivity and functionality have limited their applications. Despite the above-mentioned advantages, paper substrates are lacking in their ability to control fluid flow, in contrast to the flow control enabled by polymer substrates (e.g., agarose) with readily tunable pore size and porosity. Herein, taking the benefits from both materials, the authors propose a strategy to create a hybrid substrate by incorporating agarose into the test strip to achieve flow control for optimal biomolecule interactions. As compared to the unmodified test strip, this strategy allows sensitive detection of targets with an approximately tenfold signal improvement. Additionally, the authors showcase the potential of functionality improvement by creating multiple test zones for semi-quantification of targets, suggesting that the number of visible test zones is directly proportional to the target concentration. The authors further demonstrate the potential of their proposed strategy for clinical assessment by applying it to their prototype sample-to-result test strip to sensitively and semi-quantitatively detect dengue viral RNA from the clinical blood samples. This proposed strategy holds significant promise for detecting various targets for diverse future applications.
    Matched MeSH terms: Metal Nanoparticles/chemistry*
  12. Fulltext Protein-Protein Interactions: Insight from Molecular Dynamics Simulations and Nanoparticle Tracking Analysis
    Chong WL, Chupradit K, Chin SP, Khoo MM, Khor SM, Tayapiwatana C, et al.
    Molecules, 2021 Sep 20;26(18).
    PMID: 34577167 DOI: 10.3390/molecules26185696
    Protein-protein interaction plays an essential role in almost all cellular processes and biological functions. Coupling molecular dynamics (MD) simulations and nanoparticle tracking analysis (NTA) assay offered a simple, rapid, and direct approach in monitoring the protein-protein binding process and predicting the binding affinity. Our case study of designed ankyrin repeats proteins (DARPins)-AnkGAG1D4 and the single point mutated AnkGAG1D4-Y56A for HIV-1 capsid protein (CA) were investigated. As reported, AnkGAG1D4 bound with CA for inhibitory activity; however, it lost its inhibitory strength when tyrosine at residue 56 AnkGAG1D4, the most key residue was replaced by alanine (AnkGAG1D4-Y56A). Through NTA, the binding of DARPins and CA was measured by monitoring the increment of the hydrodynamic radius of the AnkGAG1D4-gold conjugated nanoparticles (AnkGAG1D4-GNP) and AnkGAG1D4-Y56A-GNP upon interaction with CA in buffer solution. The size of the AnkGAG1D4-GNP increased when it interacted with CA but not AnkGAG1D4-Y56A-GNP. In addition, a much higher binding free energy (∆GB) of AnkGAG1D4-Y56A (-31 kcal/mol) obtained from MD further suggested affinity for CA completely reduced compared to AnkGAG1D4 (-60 kcal/mol). The possible mechanism of the protein-protein binding was explored in detail by decomposing the binding free energy for crucial residues identification and hydrogen bond analysis.
    Matched MeSH terms: Metal Nanoparticles/analysis; Metal Nanoparticles/chemistry*
  13. Fulltext Antibacterial performance of Ag nanoparticles and AgGO nanocomposites prepared via rapid microwave-assisted synthesis method
    Chook SW, Chia CH, Zakaria S, Ayob MK, Chee KL, Huang NM, et al.
    Nanoscale Res Lett, 2012;7(1):541.
    PMID: 23020815 DOI: 10.1186/1556-276X-7-541
    Silver nanoparticles and silver-graphene oxide nanocomposites were fabricated using a rapid and green microwave irradiation synthesis method. Silver nanoparticles with narrow size distribution were formed under microwave irradiation for both samples. The silver nanoparticles were distributed randomly on the surface of graphene oxide. The Fourier transform infrared and thermogravimetry analysis results showed that the graphene oxide for the AgNP-graphene oxide (AgGO) sample was partially reduced during the in situ synthesis of silver nanoparticles. Both silver nanoparticles and AgGO nanocomposites exhibited stronger antibacterial properties against Gram-negative bacteria (Salmonella typhi and Escherichia coli) than against Gram-positive bacteria (Staphyloccocus aureus and Staphyloccocus epidermidis). The AgGO nanocomposites consisting of approximately 40 wt.% silver can achieve antibacterial performance comparable to that of neat silver nanoparticles.
    Matched MeSH terms: Metal Nanoparticles
  14. Highly porous chitosan beads embedded with silver-graphene oxide nanocomposites for antibacterial application
    Chook SW, Chia CH, Hatika Kaco, Sarani Zakaria, Huang NM, Neoh HM
    Sains Malaysiana, 2016;45:1663-1667.
    Incorporation of silver nanomaterial into polymer matrix can further accomplished their potential usage in real life
    applications. In our previous study, silver nanoparticles (AgNPs) and silver-graphene oxide nanocomposites (AgGO)
    were prepared via a rapid microwave-assisted method. Hereby, the as-synthesized AgNPs or AgGO was dispersed in a
    chitosan solution. Subsequently, the resultant mixture solution was further coagulated in a coagulation bath containing
    sodium hydroxide via a neutralization process. This resulted in the formation of spherical-shaped chitosan beads.
    The structure of the beads showed that the chitosan beads embedded with AgGO exhibited a more porous structure as
    compared to the plain chitosan beads. Furthermore, the chitosan beads containing AgNPs or AgGO were tested for
    their antibacterial activity against Escherichia coli and Staphylococcus aureus. The antibacterial results indicated that
    the silver nanomaterial contained chitosan beads could effectively inhibit the growth of both E. coli and S. aureus as
    compared to the bare chitosan beads. The produced chitosan nanocomposite envisioned that can be potentially employed
    for water disinfection purpose.
    Matched MeSH terms: Metal Nanoparticles
  15. Silver nanoparticles: Advanced and promising technology in diabetic wound therapy
    Choudhury H, Pandey M, Lim YQ, Low CY, Lee CT, Marilyn TCL, et al.
    Mater Sci Eng C Mater Biol Appl, 2020 Jul;112:110925.
    PMID: 32409075 DOI: 10.1016/j.msec.2020.110925
    Wounds associated with diabetes mellitus are the most severe co-morbidities, which could be progressed to cause cell necrosis leading to amputation. Statistics on the recent status of the diabetic wounds revealed that the disease affects 15% of diabetic patients, where 20% of them undergo amputation of their limb. Conventional therapies are found to be ineffective due to changes in the molecular architecture of the injured area, urging novel deliveries for effective treatment. Therefore, recent researches are on the development of new and effective wound care materials. Literature is evident in providing potential tools in topical drug delivery for wound healing under the umbrella of nanotechnology, where nano-scaffolds and nanofibers have shown promising results. The nano-sized particles are also known to promote healing of wounds by facilitating proper movement through the healing phases. To date, focuses have been made on the efficacy of silver nanoparticles (AgNPs) in treating the diabetic wound, where these nanoparticles are known to exploit potential biological properties in producing anti-inflammatory and antibacterial activities. AgNPs are also known to activate cellular mechanisms towards the healing of chronic wounds; however, associated toxicities of AgNPs are of great concern. This review is an attempt to illustrate the use of AgNPs in wound healing to facilitate this delivery system in bringing into clinical applications for a superior dressing and treatment over wounds and ulcers in diabetes patients.
    Matched MeSH terms: Metal Nanoparticles/therapeutic use*; Metal Nanoparticles/chemistry
  16. Use of UV-vis-NIR spectroscopy to monitor label-free interaction between molecular recognition elements and erythropoietin on a gold-coated polycarbonate platform
    Citartan M, Gopinath SC, Tominaga J, Chen Y, Tang TH
    Talanta, 2014 Aug;126:103-9.
    PMID: 24881539 DOI: 10.1016/j.talanta.2014.03.043
    Label-free-based detection is pivotal for real-time monitoring of biomolecular interactions and to eliminate the need for labeling with tags that can occupy important binding sites of biomolecules. One simplest form of label-free-based detection is ultraviolet-visible-near-infrared (UV-vis-NIR) spectroscopy, which measure changes in reflectivity as a means to monitor immobilization and interaction of biomolecules with their corresponding partners. In biosensor development, the platform used for the biomolecular interaction should be suitable for different molecular recognition elements. In this study, gold (Au)-coated polycarbonate was used as a platform and as a proof-of-concept, erythropoietin (EPO), a doping substance widely abused by the athletes was used as the target. The interaction of EPO with its corresponding molecular recognition elements (anti-EPO monoclonal antibody and anti-EPO DNA aptamer) is monitored by UV-vis-NIR spectroscopy. Prior to this, to show that UV-vis-NIR spectroscopy is a suitable method for measuring biomolecular interaction, the interaction between biotin and streptavidin was demonstrated via this strategy and reflectivity of this interaction decreased by 25%. Subsequent to this, interaction of the EPO with anti-EPO monoclonal antibody and anti-EPO DNA aptamer resulted in the decrease of reflectivity by 5% and 10%, respectively. The results indicated that Au-coated polycarbonate could be an ideal biosensor platform for monitoring biomolecular interactions using UV-vis-NIR spectroscopy. A smaller version of the Au-coated polycarbonate substrates can be derived from the recent set-up, to be applied towards detecting EPO abuse among atheletes.
    Matched MeSH terms: Metal Nanoparticles/ultrastructure; Metal Nanoparticles/chemistry
  17. Triggering Mechanisms of Thermosensitive Nanoparticles Under Hyperthermia Condition
    Dabbagh A, Abdullah BJ, Abdullah H, Hamdi M, Kasim NH
    J Pharm Sci, 2015 Aug;104(8):2414-28.
    PMID: 26073304 DOI: 10.1002/jps.24536
    Nanoparticle-based hyperthermia is an effective therapeutic approach that allows time- and site-specific treatment with minimized off-site effects. The recent advances in materials science have led to design a diversity of thermosensitive nanostructures that exhibit different mechanisms of thermal response to the external stimuli. This article aims to provide an extensive review of the various triggering mechanisms in the nanostructures used as adjuvants to hyperthermia modalities. Understanding the differences between various mechanisms of thermal response in these nanostructures could help researchers in the selection of appropriate materials for each experimental and clinical condition as well as to address the current shortcomings of these mechanisms with improved material design.
    Matched MeSH terms: Metal Nanoparticles/chemistry
  18. Molybdenum disulfide-gold nanoparticle nanocomposite in field-effect transistor back-gate for enhanced C-reactive protein detection
    Dalila NR, Arshad MKM, Gopinath SCB, Nuzaihan MNM, Fathil MFM
    Mikrochim Acta, 2020 10 05;187(11):588.
    PMID: 33015730 DOI: 10.1007/s00604-020-04562-7
    Nanofabricated gold nanoparticles (Au-NPs) on MoS2 nanosheets (Au-NPs/MoS2) in back-gated field-effect transistor (BG-FET) are presented, which acts as an efficient semiconductor device for detecting a low concentration of C-reactive protein (C-RP). The decorated nanomaterials lead to an enhanced electron conduction layer on a 100-μm-sized transducing channel. The sensing surface was characterized by Raman spectroscopy, ultraviolet-visible spectroscopy (UV-Vis), atomic force microscopy (AFM), scanning electron microscopy (SEM), and high-power microscopy (HPM). The BG-FET device exhibits an excellent limit of detection of 8.38 fg/mL and a sensitivity of 176 nA/g·mL-1. The current study with Au-NPs/MoS2 BG-FET displays a new potential biosensing technology; especially for integration into complementary metal oxide (CMOS) technology for hand-held future device application.
    Matched MeSH terms: Metal Nanoparticles/chemistry*
  19. Dentine collagen cross-linking using tiopronin-protected Au/EDC nanoparticles formulations
    Daood U, Akram Z, Matinlinna JP, Fawzy AS
    Dent Mater, 2019 07;35(7):1017-1030.
    PMID: 31064669 DOI: 10.1016/j.dental.2019.04.005
    OBJECTIVE: The aim of this study was to investigate EDC-assisted collagen crosslinking effect with different concentrations of tiopronin-protected gold (TPAu) nanoparticles on demineralized dentine.

    METHODS: TPAu nanoparticles were fabricated from 0.31-g tetrachloroauric acid and 0.38-g of N-(2-mercaptopropionyl) glycine (2.4-mmol). Then co-dissolved using 35-mL of 6:1 methanol/acetic acid and mixed using NaBH4. EDC (0.3-M) was conjugated to TPAu nanoparticles at TPAU/EDC-0.25:1, and TPAU/EDC-0.5:1 treatment formulations ratios. Dentin specimens treated with 0.3-M EDC solution alone or left untreated were used as control. Nanoparticles formulations were characterized in term of particles morphology and size, Zeta potential, thermogravimetric analysis and small-angle X-ray scattering. Dentin substrates were characterized in term of TEM investigation, dentin proteases characterization, hydroxyproline liberation, elastic modulus measurement, Raman analysis and confocal microscopy viewing.

    RESULTS: TEM evaluation of tiopronin protected gold nanoparticles dispersion revealed nano-clusters formations in both groups. However, based on our TEM measurements, the particle-size was ranging from ˜20 to 50 nm with spherical core-shape which were almost similar for both TPAu/EDC ratios (0.5:1 and 0.25:1). Zeta potential measurements indicate negative nanoparticles surface charge. SAXS profiles for both formulations, suggest a typical profile for uni-lamellar nanoparticles. Superior dentin collagen cross-linking effect was found with the TPAu/EDC nanoparticles formulations compared to the control and EDC treated groups.

    SIGNIFICANCE: Cross-linking of dentin collagen using TPAu coupled with EDC through TPAu/EDC nanoparticles formulations is of potential significance in improving the biodegradation resistance, proteases inhibition, mechanical and structural stability of demineralized dentin substrates. In addition, the cross-linking effect is dependent on TPAu/EDC ratio, whereas higher cross-linking effect was found at TPAu/EDC ratio of 0.5:1.

    Matched MeSH terms: Metal Nanoparticles*
  20. Fulltext Fabrication and characterization of gelatin stabilized silver nanoparticles under UV-light
    Darroudi M, Ahmad MB, Zak AK, Zamiri R, Hakimi M
    Int J Mol Sci, 2011;12(9):6346-56.
    PMID: 22016663 DOI: 10.3390/ijms12096346
    Silver nanoparticles (Ag-NPs) were successfully synthesized using the UV irradiation of aqueous solutions containing AgNO(3) and gelatin as a silver source and stabilizer, respectively. The UV irradiation times influence the particles' diameter of the Ag-NPs, as evidenced from surface plasmon resonance (SPR) bands and transmission electron microscopy (TEM) images. When the UV irradiation time was increased, the mean size of particles continuously decreased as a result of photoinduced Ag-NPs fragmentation. Based on X-ray diffraction (XRD), the UV-irradiated Ag-NPs were a face-centered cubic (fcc) single crystal without any impurity. This study reveals that the UV irradiation-mediated method is a green chemistry and promising route for the synthesis of stable Ag-NPs for several applications (e.g., medical and surgical devices). The important advantages of this method are that it is cheap, easy, and free of toxic materials.
    Matched MeSH terms: Metal Nanoparticles/ultrastructure; Metal Nanoparticles/chemistry*
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