Rahong, Sakon
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Preferred name
Rahong, Sakon
Alternative Name
Rahong, S.
Main Affiliation
Email
sakon.ra@kmitl.ac.th
26 results
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Item type:Publication, ZnO Nanorods Grown on Heterogenous Ag Seed Layers for Single-Cell Fluorescence Bioassays(2021-07-23) ;Muensri, Phitchaya ;Treetong, Alongkot ;Namdee, Katawut ;Kasamechonchung, PanitaWutikhun, TuksadonHere we demonstrate the controllability of the morphology of hydrothermal ZnO nanorods (ZnO-NRs) grown on heterogenous Ag seed layers. By varying the crystal orientation of silver thin films (Ag), a high density of ZnO-NRs could be obtained. We find that the density of ZnO-NRs strongly relates to the peak intensity ratio between (111) and (200) planes of Ag thin films due to a heteroepitaxy between (0002) ZnO and (111) Ag rather than that of grain boundary nucleation and/or surface nucleation. In addition, the optimized heterostructure of ZnO nanorod/Ag arrays is investigated via a critical concentration for nucleation and used as a fluorescence enhancement substrate (FES). The experimental results have shown that the FES presents an ability to detect a biological sample (PC-3 cell) with a high sensitivity and low detection limit of 1 cell/μL. Our results highlight that understanding an important key to control and design the morphology of heterogeneous hydrothermal ZnO-NR growth is essential to open up the opportunities for fundamental studies and applications in high-performance integrated nanodevices. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Metal Oxide Nanostructures Enhanced Microfluidic Platform for Efficient and Sensitive Immunofluorescence Detection of Dengue Virus(2023-11-01) ;Pormrungruang, Pareesa ;Phanthanawiboon, Supranee ;Jessadaluk, Sukittaya ;Larpthavee, PreedaThaosing, JiraphonRapid and sensitive detection of Dengue virus remains a critical challenge in global public health. This study presents the development and evaluation of a Zinc Oxide nanorod (ZnO NR)-surface-integrated microfluidic platform for the early detection of Dengue virus. Utilizing a seed-assisted hydrothermal synthesis method, high-purity ZnO NRs were synthesized, characterized by their hexagonal wurtzite structure and a high surface-to-volume ratio, offering abundant binding sites for bioconjugation. Further, a comparative analysis demonstrated that the ZnO NR substrate outperformed traditional bare glass substrates in functionalization efficiency with 4G2 monoclonal antibody (mAb). Subsequent optimization of the functionalization process identified 4% (3-Glycidyloxypropyl)trimethoxysilane (GPTMS) as the most effective surface modifier. The integration of this substrate within a herringbone-structured microfluidic platform resulted in a robust device for immunofluorescence detection of DENV-3. The limit of detection (LOD) for DENV-3 was observed to be as low as 3.1 × 10<sup>−4</sup> ng/mL, highlighting the remarkable sensitivity of the ZnO NR-integrated microfluidic device. This study emphasizes the potential of ZnO NRs and the developed microfluidic platform for the early detection of DENV-3, with possible expansion to other biological targets, hence paving the way for enhanced public health responses and improved disease management strategies. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, The enhancement of sensitivity and response times of PDMS-based capacitive force sensor by means of active layer modification(2021-06-01) ;Siangkhio, Yasumin; ; ; Jessadaluk, SukittiyaIn this work, sensitivity and response times of PDMS-based capacitive force sensors are enhanced via the modifications of the PDMS layer. Two modifying approaches are proposed; (i) change PDMS's (elastomer:curing agent) ratio and (ii) adding conductive polymer PEDOT:PSS into the PDMS layer. The change of PDMS (elastomer:curing agent) ratio from (10:1) to (30:1) increases the sensitivity from 0.4 0.08 to 0.72 0.23 kPa-1 (+80%) but it does not significantly affect the response/recovery times. In addition, by adding 1% wt. of PEDOT:PSS to PDMS (30:1), the further increment of sensitivity from 0.72 0.23 to 1.44 0.17 kPa-1 (+100%) and the shorter response time from 1.59 0.02 to 0.45 0.03 s (-72%) are observed. The mechanical and electrical studies reveal that the change of PDMS (elastomer:curing agent) ratio and the adding of PEDOT:PSS to PDMS layer result in the modification of PDMS's deformability and the increase of charge transportation, leading to the enhancement of sensing characteristics of the sensors. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Growth and characterization of novel optoelectronic materials. Based on II-VI inorganic/organic heterostructures(2006-01-01); ;Keawprajak, Anusit; ; Novel optoelectronic materials based on II-VI inorganic/organic low-dimensional heterostructure were successfully grown by electron beam evaporator. The structures were based on ZnSe, tris(8-hydroxyquinoline) aluminum (Alq<inf>3</inf>) and N,N'-bis(3-methylphenyl)-N,N'-diphenyl-benzidine (TPD). The surface morphology of the structures was investigated by atomic force microscopy and field emission scanning electron microscope. The optical and electronic properties were examined by photoluminescence, photocurrent and electroreflectance spectroscopy. Photoluminescence spectra of the ZnSe/Alq <inf>3</inf>/ZnSe structure attributed to the change of exciton energy as a result of quantum confinement showed the formation of single quantum well structure. The luminescence color can be varied by changing the thickness of the Alq<inf>3</inf> layer. The other heterostructure of ZnSe/Alq<inf>3</inf>/TPD was grown on silicon substrate. The wavelength response of this structure shown by photocurrent signal ranged from 450 nm to 1100 nm. Electroreflectance features due to optical transition energy of the single quantum well of this structure were also observed. Under applied voltage, electroreflectance signals showed significant shift due to the quantum confined Stark effect. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Annealed zno/al2o3 core-shell nanowire as a platform to capture rna in blood plasma(2021-07-01) ;Takahashi, Hiromi ;Yasui, Takao ;Klamchuen, Annop; Wuthikhun, TuksadonRNA analytical platforms gained extensive attention recently for RNA-based molecular analysis. However, the major challenge for analyzing RNAs is their low concentration in blood plasma samples, hindering the use of RNAs for diagnostics. Platforms that can enrich RNAs are essential to enhance molecular detection. Here, we developed the annealed ZnO/Al<inf>2</inf>O<inf>3</inf> core-shell nanowire device as a platform to capture RNAs. We showed that the annealed ZnO/Al<inf>2</inf>O<inf>3</inf> core-shell nanowire could capture RNAs with high efficiency compared to that of other circulating nucleic acids, including genomic DNA (gDNA) and cell-free DNA (cfDNA). Moreover, the nanowire was considered to be biocompatible with blood plasma samples due to the crystalline structure of the Al<inf>2</inf>O<inf>3</inf> shell which serves as a protective layer to prevent nanowire degradation. Our developed device has the potential to be a platform for RNA-based extraction and detection. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Electroreflectance and photocurrent measurement of ZnSe/Alq 3/TPD heterostructure on Si-substrate(2005-11-20); ;Keawprajak, A.; ; The optical transition energy in ZnSe/tris(8-hydroxyquinoline) aluminum (Alq<inf>3</inf>)/N,N′-bis(3-methylphenyl)-N,N′-diphenyl-benzidine (TPD) heterostructure were investigated by room-temperature electroreflectance (ER) and photocurrent (PC) measurements. PC signal showed wavelength response of the device in the range of 450-1100 nm. ER features due to optical transition energy of the single quantum well of this structure were observed. The transition energies were determined by fitting the ER spectra to the theoretical line-shape expression. The subband transition energy decreased with increasing well thickness. Under applied voltage, both ER signals show significant shift due to the quantum confined Stark effect. © 2005 Elsevier B.V. All rights reserved. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Influence of Dragon Fruit Peels on the Synthesis of Antibacterial Nano Zinc Oxide (Nano-ZnO) via Green Synthesis Method(2026-05-20) ;Sakulpeeb, Natchayaporn ;Koetniyom, Wantana; ; This research focused on adding value to dragon fruit peel waste by utilizing it in the synthesis of antibacterial nano zinc oxide (Nano-ZnO) through a green synthesis process. In this study, all the dragon fruit peels were extracted using the solvent extraction technique with three different solvents (deionized water, ethanol, and methanol) for 1, 2, 3, 4, and 5 h, respectively. The amount of flavonoids from the extract was determined using UV-Vis spectrophotometer to obtain the optimum extraction time, which was 4 h for DI water as the solvent. Moreover, antibacterial Nano-ZnO was synthesized successfully by a green synthesis process using zinc nitrate Zn(NO3)2 and the extracts. The molecular vibrations as well as the crystal structure and morphology were investigated by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy (Raman), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM), respectively. Additionally, the antibacterial efficacy of the nano-zinc oxide samples was evaluated using disc diffusion method. Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli) were the test agents. The research shows that the X-ray diffraction patterns of all synthesized ZnO nanoparticles (NPs) exhibited a wurtzite (hexagonal) crystal structure. FT-IR spectroscopy confirmed the presence of Zn-O stretching vibrations at approximately 500 cm⁻¹. Furthermore, the FE-SEM reveals that ZnO-yellow particles displayed spherical morphologies with an average particle size of 145 nm. At the same time, ZnO-White and ZnO-Red nanoparticles exhibited a combination of rod-like and elliptical morphologies, with average particle sizes of 168 nm and 321 nm, respectively. In addition, the antibacterial activity demonstrates effective inhibition against S. aureus and E. coli in all three ZnO nanoparticle conditions. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Unveiling massive numbers of cancer-related urinary-microRNA candidates via nanowires(2017-12-01) ;Yasui, Takao ;Yanagida, Takeshi ;Ito, Satoru ;Konakade, YukiTakeshita, DaikiAnalyzing microRNAs (miRNAs) within urine extracellular vesicles (EVs) is important for realizing miRNA-based, simple, and noninvasive early disease diagnoses and timely medical checkups. However, the inherent difficulty in collecting dilute concentrations of EVs (<0.01 volume %) from urine has hindered the development of these diagnoses and medical checkups. We propose a device composed of nanowires anchored into a microfluidic substrate. This device enables EV collections at high efficiency and in situ extractions of various miRNAs of different sequences (around 1000 types) that significantly exceed the number of species being extracted by the conventional ultracentrifugation method. The mechanical stability of nanowires anchored into substrates during buffer flow and the electrostatic collection of EVs onto the nanowires are the two key mechanisms that ensure the success of the proposed device. In addition, we use our methodology to identify urinary miRNAs that could potentially serve as biomarkers for cancer not only for urologic malignancies (bladder and prostate) but also for nonurologic ones (lung, pancreas, and liver). The present device concept will provide a foundation for work toward the long-term goal of urine-based early diagnoses and medical checkups for cancer. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Mutation detection of urinary cell-free DNA via catch-and-release isolation on nanowires for liquid biopsy(2023-08-15) ;Takahashi, Hiromi ;Yasui, Takao ;Hirano, Masaki ;Shinjo, KeikoMiyazaki, YusukeCell-free DNA (cfDNA) and extracellular vesicles (EVs) are molecular biomarkers in liquid biopsies that can be applied for cancer detection, which are known to carry information on the necessary conditions for oncogenesis and cancer cell-specific activities after oncogenesis, respectively. Analyses for both cfDNA and EVs from the same body fluid can provide insights into screening and identifying the molecular subtypes of cancer; however, a major bottleneck is the lack of efficient and standardized techniques for the isolation of cfDNA and EVs from clinical specimens. Here, we achieved catch-and-release isolation by hydrogen bond-mediated binding of cfDNA in urine to zinc oxide (ZnO) nanowires, which also capture EVs by surface charge, and subsequently we identified genetic mutations in urinary cfDNA. The binding strength of hydrogen bonds between single-crystal ZnO nanowires and DNA was found to be equal to or larger than that of conventional hydrophobic interactions, suggesting the possibility of isolating trace amounts of cfDNA. Our results demonstrated that nanowire-based cancer screening assay can screen cancer and can identify the molecular subtypes of cancer in urine from brain tumor patients through EV analysis and cfDNA mutation analysis. We anticipate our method to be a starting point for more sophisticated diagnostic models of cancer screening and identification. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Modification of a photoanode by means of localized surface plasmon resonance from Au nanoparticles decorated on ZnO nanorods for photoelectrochemical applications(2019-01-01); ;Soyeux, Nathan ;Rattanawarinchai, Prapakorn ;Jessadaluk, SukittiyaKlamchuen, AnnopPhotoelectrochemical (PEC) activity is possibly enhanced by an increase in photocurrent generated from the photoanode. In this work, a modified photoanode that consists of zinc oxide nanorods (ZnO-NRs) decorated with gold nanoparticles (Au-NPs) is proposed to improve the generation of photocurrent. X-ray diffraction and scanning electron microscopy are employed to confirm the decoration of Au-NPs on well-aligned ZnO-NRs. A significant enhancement (∼4 times) in photocurrent density is obtained from the ZnO-NR photoanode decorated with Au-NPs compared to the bare ZnO-NR photoanode. Photoluminescence and UV-visible spectroscopy reveal that the improvement in photocurrent density results from (i) the decrease in charge recombination in the ZnO-NRs due to charge dissociation and (ii) the additional injection of charge from Au-NPs owing to localized surface plasmon resonance. This research presents the idea of taking the benefit from Au-NPs to enhance the photocurrent density in PEC applications through the decrease in charge recombination and the increase in charge injection.
