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Tailoring ZnO Nanostructures through Precursor Concentration and Hydrothermal Duration: A Pathway to Efficient Solar Water Splitting
(2026-11-10)
Borklom, Phanlapa
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Khemasiri, Narathon
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Jessadaluk, Sukittaya
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Rattanawarinchai, Prapakorn
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Kayunkid, Navaphun
This work investigated the formation of ZnO nanostructures on ITO substrates prepared by self-seeding hydrothermal synthesis for photoelectrochemical ( PEC) water splitting applications. The hydrothermal parameters, precursor concentration and hydrothermal time, were varied to explore their influences on ZnO crystallinity, morphology, and PEC performance. The combinations of X-ray diffraction and field emission scanning electron microscopy revealed highly oriented ZnO nanostructures with diverse morphologies, including small granules, nanorods, dense films, and hexagonal platelets. Topographic profiling of the morphological parameters revealed complex relationships between synthesis conditions and nanostructure characteristics, highlighting the importance of considering aggregation phenomena in substrate-based growth. This aggregation led to deviations from conventional crystal growth theory predictions, particularly for grain density and diameter evolution. PEC performance evaluation identified ZnO nanorods as the optimal morphology, exhibiting a photocurrent density of 0.182 mA/cm² at 0 V vs. Ag/AgCl. Further enhancement was achieved by decorating ZnO nanorods with CdS nanoparticles, resulting in a six-fold increase in photocurrent density (1.2 mA/cm²). This improvement is attributed to expanded light absorption and improved charge separation at the CdS/ ZnO interface. Our findings demonstrate the potential of rationally designed ZnO-based nanostructures in the advancement of solar-driven water splitting technologies and provide valuable insights for optimizing PEC systems through precise control of hydrothermal synthesis parameters, consideration of substrate-induced aggregation, and strategies for photoelectrochemical (PEC) water splitting applications.
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A microfluidic dermal fibroblast–macrophage co-culture on a chip linking inflammatory signalling to barrier-associated function
(2026-06-16)
Larpthavee, Preeda
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Chomthong, Thitikorn
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Pormrungruang, Pareesa
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Surassmo, Suvimol
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Rahong, Sakon
Here, we report a microfluidic dermal fibroblast–macrophage co-culture on-chip that directly links macrophage-driven inflammatory signalling to dermal barrier function within a three-dimensional collagen microenvironment. The platform integrates spatially compartmentalized co-culture of dermal fibroblasts and macrophages separated by a micropillar-confined collagen type I matrix, enabling non-contact paracrine communication while preserving extracellular matrix (ECM) architecture. Upon lipopolysaccharide stimulation, the system rapidly reproduced of acute inflammation within 6 h and 12 h, including elevated nitric oxide (NO) and tumor necrosis factor-alpha (TNF-α) secretion, increased permeability to both 10 kDa and 70 kDa FITC–dextran, and disruption of fibronectin organization. The measured permeability coefficient closely matched reported in vivo skin values, supporting physiological relevance. Suppression of inflammatory mediators using a nanostructured lipid carrier encapsulating Zingiber cassumunar and Kaempferia parviflora extracts resulted in dose-dependent reductions in NO and TNF-α, accompanied by restoration of dermal thickness and ECM integrity. Importantly, biochemical inhibition of macrophage activation translated into structural recovery of the fibroblast-embedded matrix, demonstrating a clear coupling between immune signalling and tissue-level remodeling. This microfluidic platform provides a rapid, physiologically relevant, and animal-free system for mechanistic investigation of dermal inflammation and evaluation of anti-inflammatory therapeutics.
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Influence of Dragon Fruit Peels on the Synthesis of Antibacterial Nano Zinc Oxide (Nano-ZnO) via Green Synthesis Method
(2026-05-20)
Sakulpeeb, Natchayaporn
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Koetniyom, Wantana
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Chutipaijit, Sutee
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Rahong, Sakon
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Kayunkid, Navaphun
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.
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Growth window and metal-insulator transition behavior of VO2 thin films deposited by pulsed laser deposition for thermal switch applications
(2026-05-01)
Jessadaluk, Sukittaya
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Rahong, Sakon
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Kayunkid, Navaphun
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Khemasiri, Narathon
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Rangkasikorn, Adirek
Vanadium dioxide (VO<inf>2</inf>) is a strongly correlated transition metal oxide that exhibits a sharp and reversible metal-insulator transition (MIT) near room temperature, making it a promising material for thermal switching and adaptive electronic applications. In this study, VO<inf>2</inf> thin films were deposited on single-crystalline Si, thermally grown SiO<inf>2</inf>, and fused quartz substrates by pulsed laser deposition, and the influence of substrate temperature and oxygen partial pressure on phase formation, structural properties, and MIT behavior was systematically investigated. By optimizing deposition conditions within a narrow oxygen pressure window, phase-pure monoclinic VO<inf>2</inf>(M) thin films with high crystalline quality were achieved while suppressing the formation of over-oxidized vanadium oxide phases. Structural and chemical analyses using X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy confirmed the stabilization of the V4+ oxidation state and uniform film stoichiometry. Temperature-dependent electrical measurements revealed a pronounced and reproducible MIT characterized by an abrupt change in resistance and a clear thermal hysteresis. In-situ temperature-dependent X-ray diffraction further demonstrated a direct correlation between the monoclinic-rutile structural transformation and the electronic transition. Importantly, the MIT behavior was consistently observed across all investigated substrates, indicating robust film growth and substrate tolerance. These results provide insight into the structure-property relationships governing VO<inf>2</inf> thin films and highlight their potential for integration into thermal switch and thermally adaptive device architectures.
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Enterocyte Culture on a Hybrid Transwell-Inserted Gut-on-a-Chip for Liquid–Liquid and Air–Liquid Interface Conditions
(2025-11-18)
Charoensri, Tidaporn
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Kulthong, Kornphimol
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Pormrungruang, Pareesa
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Wongwanakul, Ratjika
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Kunyanee, Chanikarn
Intestinal models have been studied extensively using in vitro microfluidic platforms, often called gut-on-a-chip devices, which replicate the physiological environment and functions of the human intestine. The role of fabrication techniques in developing these microfluidic systems is increasingly significant. Photolithography has traditionally been used for microchannel preparation, oxygen-plasma surface treatment, and conventional bonding methods that attach microchannels to surfaces. However, photolithography is limited to perfectly flat surfaces, is costly, requires specialized equipment, and must be conducted in controlled environments free from contaminants, making the process slow and labor-intensive. Consequently, there is a need for a fabrication method that enables rapid prototyping and is easy to use, cost-effective, and suitable for mass production. In this study, a hybrid chip was developed using an uncured poly(dimethylsiloxane) (PDMS) bonding technique, which provides strong adhesion. This hybrid chip incorporates a transwell insert and a PDMS fluid channel, which can be used to culture human intestinal cells (Caco-2 cells) at a flow rate of 30 μL/h over 5 days without removing the fluid channel. Furthermore, the hybrid chip enables the cultivation of Caco-2 cells under both the liquid–liquid interface (LLI) and air–liquid interface (ALI) conditions. Evaluations of cell viability, morphology, and gene expression of Caco-2 cells grown on the hybrid chip demonstrated improved cell viability, clear expression of ZO-1, and a significant increase in MUC2 expression in both LLI and ALI cultures, along with GLUT2 expression in the ALI culture, indicating that this fabricated hybrid chip is a viable in vitro fluid flow system for culturing Caco-2 cells.
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Selective formations of antimony-dopant for highly sensitive nitrogen dioxide responsive behavior of tin oxide-based chemiresistive sensor
(2025-02-15)
Rattanawarinchai, Prapakorn
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Khemasiri, Narathon
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Rahong, Sakon
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Rangkasikorn, Adirek
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Kayunkid, Navaphun
Here, selective formation of antimony (Sb) dopant species responsible for highly sensitive gas sensors based on tin oxide (SnO<inf>2</inf>) film grown via pulsed laser deposition is presented. By elevating a forming energy through controlling substrate temperature, not only crystallinity of Sb-SnO<inf>2</inf> (ATO) is notably enhanced but the Sb5 + also predominantly replace at Sn4+ site rather than Sb3+ counterpart. Such Sb-species selection plays a crucial role on the density of oxygen vacancy and free electron enabling to rationally design conductive behaviour of ATO film from insulative to degenerated semiconductor. As a practical example, detection of nitrogen dioxide (NO<inf>2</inf>) gas is selected as an application model. We found a narrow window for high NO<inf>2</inf> sensing performance of ATO film which strongly corresponds with the amount of carrier density. At certain window, ATO film exhibits high NO<inf>2</inf> response of 24.65 (10 ppm) and low limit of detection of 0.5 ppm, which is 5-fold higher and 10-fold lower than that of undoped-SnO<inf>2</inf>, respectively. Our finding demonstrates a facile approach to design over the chemical state, defect, and conductivity of the active sensing layer, allowing us to achieve an excellent sensing performance of functional materials conjugated to a nano-electronic platform.
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Urinary dengue NS1 detection on Au-decorated ZnO nanowire platform
(2024-06-15)
Sitthisuwannakul, Kannika
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Sukthai, Ratchanon
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Zhu, Zetao
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Nagashima, Kazuki
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Chattrairat, Kunanon
Biodetection for non-invasive diagnostics of fluids, especially urine, remains a challenge to scientists due to low target concentrations. And biological complexes of the detection target may contain contaminants that also interfere with any assay. Dengue non-structural 1 protein (Dengue NS1) is an important biomarker for dengue hemorrhagic fever and dengue shock syndrome. Here, we developed an Au-decorated nanowire platform and applied it with a sandwich fluorophore-linked immunosorbent well plate assay (FLISA) to detect Dengue NS1 in urine. For the platform, we fabricated zinc oxide (ZnO) nanowires to provide a high surface area and then coated them with gold nanoparticles (ZnO/Au nanowires) to simply modify the Dengue NS1 antibody and enhance the fluorescence intensity. Our platform employs a sandwich FLISA that exhibits high sensitivity, specifically detecting Dengue NS1 with a limit of detection (LOD) of 1.35 pg/mL. This LOD was 4500-fold lower than the LOD of a commercially available kit for Dengue NS1 enzyme-linked immunosorbent assay. We believe that our ZnO/Au nanowire platform has the potential to revolutionize the field of non-invasive diagnostics for dengue.
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Metal Oxide Nanostructures Enhanced Microfluidic Platform for Efficient and Sensitive Immunofluorescence Detection of Dengue Virus
(2023-11-01)
Pormrungruang, Pareesa
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Phanthanawiboon, Supranee
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Jessadaluk, Sukittaya
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Larpthavee, Preeda
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Thaosing, Jiraphon
Rapid 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 × 10−4 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.
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Mutation detection of urinary cell-free DNA via catch-and-release isolation on nanowires for liquid biopsy
(2023-08-15)
Takahashi, Hiromi
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Yasui, Takao
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Hirano, Masaki
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Shinjo, Keiko
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Miyazaki, Yusuke
Cell-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.
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Influence of Antimony Species on Electrical Properties of Sb-Doped Zinc Oxide Thin Films Prepared by Pulsed Laser Deposition
(2023-06-01)
Jessadaluk, Sukittaya
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Khemasiri, Narathon
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Kayunkid, Navaphun
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Rangkasikorn, Adirek
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Wirunchit, Supamas
This study systematically investigates the influence of antimony (Sb) species on the electrical properties of Sb-doped zinc oxide (SZO) thin films prepared by pulsed laser deposition in an oxygen-rich environment. The Sb species-related defects were controlled through a qualitative change in energy per atom by increasing the Sb content in the Sb<inf>2</inf>O<inf>3</inf>:ZnO-ablating target. By increasing the content of Sb<inf>2</inf>O<inf>3</inf> (wt.%) in the target, Sb3+ became the dominant Sb ablation species in the plasma plume. Consequently, n-type conductivity was converted to p-type conductivity in the SZO thin films prepared using the ablating target containing 2 wt.% Sb<inf>2</inf>O<inf>3</inf>. The substituted Sb species in the Zn site (Sb<inf>Zn</inf>3+ and Sb<inf>Zn</inf>+) were responsible for forming n-type conductivity at low-level Sb doping. On the other hand, the Sb–Zn complex defects (Sb<inf>Zn</inf>–2V<inf>Zn</inf>) contributed to the formation of p-type conductivity at high-level doping. The increase in Sb<inf>2</inf>O<inf>3</inf> content in the ablating target, leading to a qualitative change in energy per Sb ion, offers a new pathway to achieve high-performing optoelectronics using ZnO-based p–n junctions.

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