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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
;
Damrongsak, Badin
;
Jinawath, Natini
;
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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Antiradical properties of chemo drug, carboplatin, in cooperation with ZnO nanoparticles under UV irradiation in putative model of cancer cells
(2019-07-01)
Pairoj, Suttirak
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Damrongsak, Pattareeya
;
Damrongsak, Badin
;
Jinawath, Natini
;
Kaewkhaw, Rossukon
The main objective of this study was to assess the antiradical properties of zinc oxide (ZnO) nanoparticles upon exposure to ultraviolet radiation with carboplatin, an anti-proliferative drug used in the treatment of retinoblastoma. For the purpose of this study, the decomposition of 2,2(diphenyl-1-picryhydrazyl) radical (DPPH*) was used to assess the free radical capacity of antioxidants and was followed by MTT measurements. To test the antiradical capacity, the effective concentration, antiradical power, stoichiometry, and number of reduced DPPH* were investigated. DPPH* has a peak absorbance at a wavelength of 515 nm, which disappears upon the introduction of the antiradical agents. Four agents were reacted with DPPH* and represented the possible reaction kinetic categories. ZnO nanoparticles and carboplatin-loaded ZnO nanoparticles reacted more strongly with DPPH* and approached a saturation state at 420 min. The remaining two antiradical agents, ZnO nanoparticles under UV radiation and carboplatin-loaded ZnO nanoparticles under UV radiation, reacted a bit slower with DPPH* and approached a steady state at 1440 min. Among the different four antiradical agents, carboplatin-loaded ZnO nanoparticles under UV light had the highest antiradical response with the lowest effective concentration value to the reduced DPPH* molecules. ZnO nanoparticles alone were found to be poor antiradical agent. Possible mechanisms were attributed to the number of hydroxyl groups available to decrease the number of DPPH*.
2
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Apparatus for inspection of low-coercivity magnetic force microscopy tips
(2018-08-13)
Damrongsak, Badin
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Photaram, Worachote
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Saengkaew, Karnt
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Cheowanish, Ittipon
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Damrongsak, Pattareeya
In hard disk drive manufacturing, magnetic force microscopy (MFM) is employed to provide feedback for process control. This requires accurate and precise measurement of the intensity and the width of the write field generated from fabricated recording heads. Thus, the response of MFM tips when exposed to the write field must be consistency, run to run and machine to machine; however, no specific tool that can inspect and separate out-of-spec or defective MFM tips is available so far. In this present work, we designed and developed a new apparatus that is suitable to quantitatively evaluate the performance of low-coercivity MFM tips. The detailed discussion of the design of the proposed system is given as well as the inspection algorithm. Basically, a solenoid coil is used as a magnetic field generator which can generate the field strength up to 500 Oe, enough to saturate the tip magnetization. When the tip was exposed, a phase difference of the oscillating MFM tip, which is directly proportional to the field intensity, is employed as a measure of the tip response. In addition, the capability of the implemented apparatus to inspect low-coercivity MFM tips was demonstrated. Results were then compared with those obtained from a conventional MFM machine with the reference magnetic write head as a test sample. Several tests with different sets of low-coercivity MFM tips were carried out to evaluate the implemented system. Results showed that it can distinguish the response of different MFM tips; however, as the results were not too different, only three samples were selected to present here, including the tips with typical magnetic response, low response and out-of-spec response. The measured phase shifts of those samples were 54.5 ± 0.3, 36.3 ± 0.3 and 15.4 ± 0.2 degrees, respectively.
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Improved light harvesting in N719 sensitized nanocrystalline Tio2 solar cells with coumarin 6 dye
(2014-01-01)
Kittidachachan, Pattareeya
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Soonpanich, Wichayapom
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Damrongsak, Badin
Dye-sensitized solar cells (DSSCs) are a promising alternative to conventional semiconductor solar cells due to their ease of fabrication and low manufacturing cost. Ru-based dyes, particularly N719, are the typical dye for DSSC applications. However, N719-based DSSCs have weak absorbance at a wavelength around 440 nm. In this work, we aimed to improve light absorption of the N719-based DSSCs by adding a luminescent dye, Coumarin 6(C6), into an electrolyte. C6 dye were chosen as it has an absoption and luminescence spectrum complementary to that of N719. The absorption and luminescence spectra of the C6 solution with different dye concentrations, ranging from 1-25 uM, were investigated in order to find the optimum concentration that is suitbale for the DSSC applications. Moreover, N719 based DSSCs with and without C6 added were fabricated and experimental compared. The measurement results show that the N719-based DSSC with C6 dye has the improvement in both short circuit current and device efficiency.
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Prototype microfluidic system for fluorescence-based chemical sensing
(2014-01-01)
Kittidachachan, Pattareeya
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Rujihan, Suparat
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Damrongsak, Badin
A prototype microfluidic system for fluorescence detection is presented in this paper. The system consists of an excitation light source, a polymer-based microfluidic channel and an optical detector. Experiments are conducted to demonstrate use of the developed system for fluorescence detection in chemical applications. Three fluorescent dyes - Rhodamine 6G, Coumarin 153 and DCM - with different concentrations ranging from 100 nM to 5 mM are used as the analyte in the experiments. Relationship between the photo-response of the microfluidic system and concentration of fluorescent dyes is investigated. The results are compared to that obtained from a bulk system where the analyte under test is dispensed into a standard-size cuvette. In the bulk system, we found a decrease in the fluorescence signal when dye concentration is higher than 10-5 M for Rhodamine 6G and 10-4 M for Coumarin 153 and DCM. This is probably due to the re-absorption and self-quenching phenomena, which result in low quantum yield of fluorescent dyes at high concentration. However, this problem is not found in microfluidic systems with a low detection volume. In addition, the relationship between the photo-response of the system corresponding to different dye concentrations was modeled based on Beer Lambert's law. The measured results agreed will with the theoretical model.
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Poly(dimethylsiloxane) microlens array integrated with microfluidic channel for fluorescence spectroscopy detection
(2013-09-18)
Rujihan, Suparat
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Damrongsak, Badin
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Kittidachachan, Pattareeya
Fluorescence spectroscopy detection has been commonly used in chemical and biochemical applications as it provides a good reliability and high sensitivity. Commercially available fluorescence spectroscopy system is typically bulky and expensive, hence making it inconvenience for on-site measurement which requires portable systems. However, the drawback of small devices is that it has a low detection volume, resulting in low fluorescence signal. In this paper, we report a microfluidic channel implemented with a microlens array for enhancing the performance of fluorescence spectroscopy detection. The microlens array was used to focus an excitation light onto the microchannel, thus expecting the increase in fluorescence detection signal. Both microchannels and microlens arrays were individually fabricated from poly-dimethylsiloxane (PDMS) using low-cost printed-circuit-board master molds. The fabrication and characterization of PDMS-based microlens arrays are discussed. In short, the microlens in plano-convex shape was designed with diameters of 700, 800 and 900 microns. The fabricated microlens arrays were characterized for radius of curvatures, SAGs and focal lengths. The plano-convex microlens array was then integrated into a microfluidic system in order to investigate the overall performance of fluorescence spectroscopy detection. Experiments were conducted with two fluorescence dyes, i.e. Rhodamine 6G and Coumarin 153. The preliminary results revealed that the PDMS microlens array implemented on the designed system shows potential for improving excitation and emission light intensity and, as a consequence, signal to background ratio of the fluorescence spectroscopy detection. © 2013 SPIE.

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