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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
;
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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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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Second-order nonlinear optical response of metal nanostructures
(2014-01-08)
Locharoenrat, Kitsakorn
The second-order responses depend on the structural symmetry of the metal nanostructures, which can give rise to interesting polarization dependences in the responses. We also show that the sensitivity of second-order processes to the symmetry provides important information about plasmonic effects in the nonlinear properties of the structures. © (2014) Trans Tech Publications, Switzerland.
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Review article: Mechanism of resonant enhancement of gold- and copper-nanowires arrays
(2014-01-01)
Locharoenrat, Kitsakorn
Although second harmonic generations from gold- and copper-nanowires have been the subject of extensive studies, a complete understanding of the mechanism of the enhancement is still missing. The aim of review article is to address these issues by performing systemic studies of mechanism of the resonant enhancements between gold- and copper-nanowires in terms of surface reconstruction and relativistic effect, and implements these types of candidate for the potential applications in optical communications and optical devices. © (2014) Trans Tech Publications, Switzerland.
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Second harmonic generation based on strong field enhancement in metallic nanostructured surface
(2014-01-01)
Locharoenrat, Kitsakorn
Although absorption is still the primary optical property of interest, other spectroscopic techniques including optical second harmonic generation (SHG) are also used to understand anisotropic nature of nanomaterials. Benefit of SHG technique as compared with linear optical approach is that SH response is the most sensitive to surface potential changes and SH intensity mainly comes from surface/interface layers. This article reports that optical absorption spectra due to surface plasmon modes of metallic nanowires exhibit strong anisotropic absorption. Maxwell-Garnett simulation cannot fit with experimental results because of wire sizes much larger than wavelength of light, whereas finite-difference timedomain calculation can fit well with experimental findings in terms of position of photon energy of absorption peak with respect to polarization conditions.
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Copper nanowires on NaCl (110) template
(2013-04-29)
Locharoenrat, Kitsakorn
We studied optical properties of copper nanowires fabricated by a shadow deposition method. We found that the optical absorption spectra of thinner nanowires exhibited stronger anisotropic absorption than thickner nanowires. Absorption maxima are located at lower photon energy when incident field is parallel to the wire axes than they are perpendicular to each other. They also shift to lower energy when the widths of nanowires are increased. © (2013) Trans Tech Publications, Switzerland.
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Nonlinear optical properties of controlled fabrication of copper nanowires by a shadow deposition
(2013-01-28)
Locharoenrat, Kitsakorn
The strongly geometrical shape, high aspect ratios, and nanoscale cross-section of nanowires is expected to affect optical properties through confinement effects. Herein we have investigated optical properties of Cu nanowires with studies of second harmonic generation (SHG) spectra. These optical properties of Cu nanowires will be one of the most important issues when considering the types of materials used in current applications and development of new applications. © (2013) Trans Tech Publications, Switzerland.
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Characterization, optical, and theoretical investigation of arrays of the metallic nanowires fabricated by a shadow deposition method
(2013-01-28)
Locharoenrat, Kitsakorn
;
Mizutani, Goro
We have fabricated Au, Cu, and Pt nanowires by using a shadow deposition technique. We have then investigated optical properties of these nanowires by studying the second harmonic generation (SHG) spectra. With experimental and theoretical studies, we have discovered that the surface plasmon resonance was served as an origin of the enhancement of the SH response from the metallic nanowires. © (2013) Trans Tech Publications, Switzerland.
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Characterization of flower-like titanate and titania nanowires on titanium plate substrate
(2013-01-01)
Pavasupree, Sorapong
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Onoda, Kinji
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Yoshikawa, Susumu
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Simpraditpan, Athapon
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Pecharapa, Wisanu
Flower-like structure titanate and titania on titanium plate substrate composed of nanowires were synthesized by hydrothermal method at 150 oC for 2 h using titanium plate substrate as the starting material. The crystalline structure, shape and size of the prepared sample were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). SEM images showed flower-like structure with uniform size about 2 ?m. The flower-like structure composed of nanowires with diameter about 20-50 nm. Titanate and titania could be controlled by washing process and calcination temperature. This synthesis method provides a simple route to fabricate nanostructured titanate and titania on titanium plate substrate for dye-sensitized solar cell and photocatalytic activity applications. © 2013 The Authors. Published by Elsevier B.V.

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