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Influence of Phase Structure of TiO2 Nanoparticles on Resistive Switching Devices
(2024-01-03)
Tunhoo, Benchapol
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Chantarawong, Direklit
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Thiwawong, Thutiyaporn
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Onlaor, Korakot
In this work, the electrical memory properties of a bi-stable device based on the structure of aluminum/poly (9-vinyl carbazole) (PVK): TiO<inf>2</inf> NPs/indium-tin-oxide (ITO) were reported. The effects of the modified phase structural of titanium dioxide nanoparticles (TiO<inf>2</inf> NPs) on the electrical memory characteristics were determined. The TiO<inf>2</inf> NPs were annealed at different annealing temperatures. The physical properties of the annealed TiO<inf>2</inf> NPs were characterized by transmission electron microscope and X-ray diffraction, which revealed the composition and structure of the anatase and rutile phases. Current-voltage measurements showed that the bi-stable characteristics were affected by the phase structure of the TiO<inf>2</inf> NPs. The ON/OFF current ratio of the fabricated device was noted to be approximately 2.06×10<sup>5</sup> in the case of TiO<inf>2</inf> NPs annealed at 500°C. A theoretical model was used to explain the charge injection mechanisms of the device. Moreover, the temperature dependence and retention-time measurements of the device were demonstrated.
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Use of Ag-Au-ICG to increase fluorescence image of human hepatocellular carcinoma cell lines
(2023-01-01)
Sittisart, Pattarapol
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Locharoenrat, Kitsakorn
Indocyanine green (ICG) is effective for a variety of applications including liver tumour imaging and operates in the near-infrared window. Agents for near-infrared imaging are, however, still in clinical development. The present study aimed to prepare and investigate fluorescence emission properties of ICG in combination with Ag-Au in order to enhance their specific interactions with human hepatocellular carcinoma cell lines (HepG-2). The Ag-Au-ICG complex was prepared via physical adsorption, and hence evaluated for fluorescence spectra using a spectrophotometer. Ag-Au-ICG at an optimised dosage (Ag-Au:ICG = 0.0147:1 molar ratio) in Intralipid medium was added to HepG-2 to observe the maximum fluorescence signal intensity, which further enhanced HepG-2 contrast fluorescence. Ag-Au-ICG served as a fluorescence enhancer bound onto the liposome membrane, whilst free Ag, Au, and pure ICG induced low levels of cytotoxicity in HepG-2 and a normal human cell line. Thus, our findings provided new insights for the liver cancer imaging.Highlights Concentration-dependent fluorescence peaking in the near-infrared window revealed ICG aggregation in Ag-Au molecules. Ag-Au-ICG fluorescence intensity depended strongly on the environmental media. Human hepatocellular carcinoma cell lines treated with Ag-Au-ICG in Intralipid enhanced the contrast of fluorescence microscopy images by decreasing the level of scattering in the cell lines with the contrast values being approximately five times those observed in pure ICG in Intralipid.
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Fabrication of Water-insoluble Polyethylene Oxide and Sodium Alginate using Electrostatic Repulsive Forces: A Preliminary Study
(2023-01-01)
Niyomchon, Phuphinee
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Srirussamee, Kasama
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Treebupachatsakul, Treesukon
Polyethylene oxide (PEO) and sodium alginate (NaAlg) are widely used in biomedical applications due to their biocompatibility. The use of electrostatic repulsive forces could be employed to fabricate these polymers into various shapes, including fibers and particles. However, in some cases, their solubility in water could be a drawback. Therefore, this study aims to fabricate samples from PEO-NaAlg blends using electrostatic repulsive forces and stabilize their structure in water using calcium chloride (CaCl<inf>2</inf>) crosslinking method. The preliminary results have shown that the water solubility of the fabricated samples in this study was reduced by crosslinking, as analyzed by Fourier-transform spectroscopy (FTIR). Moreover, the images from scanning electron microscope (SEM) reveal that the fabricated samples were particle-like, and the increased NaAlg content could increase fiber density before crosslinking and particle aggregate formation after crosslinking. However, further studies are still required to optimize the parameters for fiber fabrication and also for future incorporation of bioactive molecules.
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Effects of Nanocrystal Cellulose from Bamboo on the Flexural Strength of Acrylic Resin: In Vitro
(2022-07-01)
Aupaphong, Visakha
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Kraiwattanawong, Kriangsak
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Thanathornwong, Bhornsawan
The purpose of this study is to evaluate the effects of nanocrystal cellulose (NCC) from bamboo on the flexural strength of heat-cured acrylic resin. A total of 35 specimens (3.3 mm × 10 mm × 64 mm) were prepared and the specimens were divided into five groups of seven specimens each. Group 1 used conventional acrylic resin that was prepared based on the instructions of the manufacturer (0%). The filled NCC from bamboo fiber in four concentrations (0.25, 0.5, 1, and 2% w/w) was used in the four-reinforcing resin workpiece groups. The specimens were loaded until failure occurred on a three-point bending test machine. One-way analysis of variance and Dunnett’s multiple comparison test at a 95% confidence level were used to determine the statistical differences in the flexural strength among the five groups. The results found that the average flexural strength of five specimen groups (0, 0.25, 0.5, 1, and 2% w/w) were 60.11 ± 2.4, 60.75 ± 2.18, 66.50 ± 5.08, 56.04 ± 0.31, and 48.05 ± 2.61 MPa, respectively. The flexural strength of 0.5 mg% w/w NCC-reinforced acrylic resin was significantly higher than the control group (p < 0.01). The reinforced NCC from bamboo fiber to acrylic resin improved the flexural strength properties.
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Effective detection of ZnO in nicotine using butterfly wing scales
(2022-01-01)
Changcharoen, Thanachai
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Apiphatnaphakul, Thidsanu
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Watjanavarreerat, Wasupon
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Locharoenrat, Kitsakorn
This study aimed to elucidate the optical functions of naturally butterfly wing scales via precise control of morphology as an effective photonic sensor and confirm the content of metal oxide nanoparticles in surrounding nicotine. Metal oxide nanoparticles mixed with nicotine were deposited on the wing scales through the spin-coating method and hence investigated using optical microscopy and spectroscopy. Experimental results demonstrated that absorption intensities of ZnO and TiO<inf>2</inf> mixed with nicotine on Danaus genutia were remarkably enhanced. Due to the relatively high concentration of zinc found in e-cigarette aerosol, the intensity of ZnO/nicotine modelled as aerosol adsorption on Danaus genutia, further held a certain linear relationship with the concentration of ZnO. The limit of detection of ZnO was as low as 1 nM. The working mechanism of our sensor was explained through the molecular adsorption after H-bond formation of ZnO/nicotine molecules as high-index materials on the wing scales of Danaus genutia without aggregation. This photonic sensor is an alternative to the present-day methods for the rapid test of ZnO content, which is very simple without complicated instrumentation. Furthermore, our method might become a starting point for the advancement of portable instruments for onsite ZnO detection.
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Use of zinc oxide nanoparticles for detection of fluoride in toothpaste gel
(2022-01-01)
Watjanavarreerat, Wasupon
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Steier, Liviu
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Locharoenrat, Kitsakorn
This study aimed to investigate the metal-binding effect of fluoride, contained in different commercial toothpaste gels; the study aimed to determine if the toothpastes contained excessive concentrations of fluoride, which result in white spot lesions. A spectrophotometric method that used spectrophotometric reagents, including zinc oxide nanoparticles and iron chloride, was used to determine fluoride distribution; the analysis was based on the selective attack of fluoride ions on metals. Fluoride concentrations between 0 and 1450 ppm were analyzed. Although the iron–fluoride complex was a more sensitive reagent, the zinc–fluoride complex could serve as a suitable alternative to it for fluoride analysis, partly because the method was less time consuming and more stable. The detection and quantification limits obtained from the linear calibration curves of the zinc–fluoride complexes, in deionized water, were 0.191:1 and 0.579:1 w/w ZnO, respectively. A model calibration curve was suggested to detect the unknown products of fluoride degradation. Dentists could use a fluoride treatment similar to the protocol used in this study, to prevent potential enamel demineralization, and exclude physical cavity preparation and restoration.
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Antitumor activities of carboplatin–doxorubicin–ZnO complexes in different human cancer cell lines (breast, cervix uteri, colon, liver and oral) under UV exposition
(2021-01-01)
Pairoj, Suttirak
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Damrongsak, Pattareeya
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Damrongsak, Badin
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Jinawath, Natini
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Kaewkhaw, Rossukon
This study aimed to examine the pharmacological profiles of multiple chemo drug candidates in systematic circulation to enhance their specific interactions with five human cancer cell lines. ZnO nanoparticles were successfully bound with chemo drugs via physical adsorption. The drug loading capacity was confirmed by FTIR, whereas the loading efficiency was determined via UV–vis spectrometry. The mean hydrodynamic size increased to 69–82 nm after chemo-drug immobilization via non-covalent interaction with ZnO. Among the nine formulated chemo drugs, the carboplatin (CP)–doxorubicin (DOX)–ZnO complex under UV light irradiation exhibited high sensitivity towards human breast adenocarcinoma cells without affecting human keratinocyte immortal cells with an IC<inf>50</inf> of 0.137 µg/mL, whereas the loading capacity and efficiency of CP–DOX–ZnO were 77.81% and 99.05%, respectively. Fluorescence images confirmed that CP–DOX–ZnO using DOX served as a fluorescence enhancer specifically bound onto the cell membranes, which became almost saturated after 24 h incubation. Carboplatin–DOX–ZnO was possibly endocytosed by cancer cells and was selectively internalized into the target cells; thus, free chemo drug was released in the cytoplasm, which induced acute apoptosis. This resulted in complete inhabitation of growth signal of target cancer cells.
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Dielectric Properties of Natural Ester Mixed with Nanoparticles under Thermal Stress
(2020-10-25)
Kittikhuntharadol, Yannaphol
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Vittayakorn, Wanwilai
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Pattanadech, Norasage
This paper aim to study of the dielectric properties of thermal stressed natural ester mixed with TiO2, and ZnO. Polarization and depolarization current (PDC) along with dielectric loss factor (tanδ) of the test specimens were investigated. The test specimens comprised of unmodified natural ester and natural ester mixed with different volume concentration, i.e., 0.01%, and 0.03% of TiO2, and ZnO. After preparing the natural ester and the natural ester nanofluid specimen, such specimens were undergone with thermal stress at 110 degree Celsius for 72 hours in vacuum oven. Then, a PDC-Analyser-1MOD was utilized for PDC measurement of the test samples. For tanδ measurement, test circuit was set-up according to IEC 60247 and the C and tanδ meter with the liquid electrode were used. From the test result, thermal stress strongly affects the PDC and tanδ characteristics of the liquid samples. Besides, natural ester mixed with 0.01% of TiO2 concentration shows the high potential dielectric liquids compared with other specimens.
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AC Breakdown and Resistivity of Natural Ester Based Nanofluids
(2020-10-25)
Maneerat, Noppadol
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Makmork, Kawee
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Kittikhuntharadol, Yannaphol
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Suksai, Nattapat
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Chusang, Thanapat
In this paper, AC breakdown including resistivity of natural ester and natural ester mixed with nanoparticles were studied. Two types of nanoparticles i.e. Barium titanate (BaTiO3) and Titanium dioxide (TiO2) which have their diameter less than 100 nm were used in experiment. For the nanofluid samples, three concentration of nanoparticles including 0.01%, 0.03% and 0.05% were prepared in five processes. Firstly, the natural ester mixed was with 0.01%, 0.03% and 0.05% of volume fraction of nanoparticles. Second, a magnetic stirrer was used to diffuse them evenly over the liquid later, ultrasonic dispersion was also used to ensure that the prepared nanofluids were homogeneous. Then, the nanofluid liquid was heated at 80 degree Celsius in vacuum oven for 15 hours. Finally, this liquid was dispersed by using magnetic stirrer again. Besides, the mixed liquid sample was heated at 110, and 130 degree Celsius for 72 hours to simulated thermal stress. To measure the AC breakdown voltage, a dielectric breakdown testing device was used. The test circuit was set up according to ASTM D1816. The gap distance between electrode was set at 2.0 mm. Furthermore, the test cell for liquid insulation testing (Model DAC-OBE-2: SOKEN) was used for polarization and depolarization current (PDC) experiment. The PDC test result was then used to calculated the resistivity of the liquid samples. The test results show that the AC breakdown voltages of the natural ester mixed with nanoparticles is higher than unmodified natural ester. Additionally, Barium titanate nanoparticles and Titanium dioxide nanoparticles enhance the breakdown strength and the resistivity of the ester nanofluid tested. According to the results, it concluded that nanoparticles were an good alternative to enhance the dielectric properties of natural ester for dielectric application.
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Efficacy of nanodiamond–doxorubicin complexes on human breast adenocarcinoma cell lines
(2019-12-04)
Locharoenrat, Kitsakorn
This paper aims to demonstrate the efficacy of the immobilisation of the chemotherapy drug doxorubicin on nanodiamond platforms as a potential cancer therapy. This effective drug is experimentally fed into a human breast adenocarcinoma cell lines. Drug loading activity and cell viability are detected by spectrometer, microscopy, and MTT assay in this study at Biomedical Physics Research Unit, Department of Physics, Faculty of Science, King Mongkut’s Institute of Technology Ladkrabang, Bangkok 10520, Thailand between 1 Oct 2018 and 10 Jun 2019. Experimental results show that in the basic environment (pH = 8.0), the nanodiamond carboxylic group cooperated with the doxorubicin amino group to form a stable and non-covalent bond on nanodiamond surfaces served as a simple physical adsorption. In an acidic environment suitable to targeting the cancer cells, the nanodiamond carboxylic group ionised so that doxorubicin is effectively released. Doxorubicin therefore affirmatively absorbed into the cytoplasm and later into the nucleus. The significant finding of the study is that IC-50 equivalent to 0.40 mg/mL and viable nanodiamond–doxorubicin is a good candidate material for drug delivery.

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