405-nm Laser Diode Research Articles

Portable FRET-Based Biosensor Device for On-Site Lead Detection.

Most methods for measuring environmental lead (Pb) content are time consuming, expensive, hazardous, and restricted to specific analytical systems. To provide a facile, safe tool to detect Pb, we created pMet-lead, a portable fluorescence resonance energy transfer (FRET)-based Pb-biosensor. The pMet-lead device comprises a 3D-printed frame housing a 405-nm laser diode—an excitation source for fluorescence emission images (YFP and CFP)—accompanied by optical filters, a customized sample holder with a Met-lead 1.44 M1 (the most recent version)-embedded biochip, and an optical lens aligned for smartphone compatibility. Measuring the emission ratios (Y/C) of the FRET components enabled Pb detection with a dynamic range of nearly 2 (1.96), a pMet-lead/Pb dissociation constant (Kd) 45.62 nM, and a limit of detection 24 nM (0.474 μg/dL, 4.74 ppb). To mitigate earlier problems with a lack of selectivity for Pb vs. zinc, we preincubated samples with tricine, a low-affinity zinc chelator. We validated the pMet-lead measurements of the characterized laboratory samples and unknown samples from six regions in Taiwan by inductively coupled plasma mass spectrometry (ICP-MS). Notably, two unknown samples had Y/C ratios significantly higher than that of the control (3.48 ± 0.08 and 3.74 ± 0.12 vs. 2.79 ± 0.02), along with Pb concentrations (10.6 ppb and 15.24 ppb) above the WHO-permitted level of 10 ppb in tap water, while the remaining four unknowns showed no detectable Pb upon ICP-MS. These results demonstrate that pMet-lead provides a rapid, sensitive means for on-site Pb detection in water from the environment and in living/drinking supply systems to prevent potential Pb poisoning.

BMeS-p-A succinimidyl ester as a sulfonyl aniline dye labeling reagent

Here, we describe the synthesis and properties of BMeS-p-A-NHS as a sulfonylaniline-based fluorescent labeling reagent. Introduction of a carboxyl group into the amino group of the sulfonylaniline skeleton was achieved by the ring-opening reaction of β-propiolactone. This small labeling reagent was water-soluble, photostable, solid-state emissive, and suitable for excitation with a versatile 405-nm laser diode, emitting green fluorescence with a large Stokes shift at 527 nm. The succinimidyl ester reactive group facilitated conjugation with substrates containing amino groups.

Abstract 3022: Lymph node metastasis in solid tumors: A marker or driver of disease progression

Abstract Background: The presence of lymph node metastasis in patients with solid tumors is associated with tumor aggressiveness, poorer prognosis and the recommendation for systemic therapy. However, whether tumor cells exit the lymph node and contribute to distant metastases remains controversial. Methods: In this study, we used syngeneic murine cell lines representing breast and melanoma cancer that spontaneously metastasize to the lymph node. We engineered these cells to express Dendra2, a photoconvertable protein. Dendra2 is a green-fluorescent protein that can be converted to emit red light by exposure to 405nm light. Once tumor cells spontaneously metastasized to the lymph node from the primary site, a 405nm laser diode was used on 5 consecutive days to convert Dendra2-cancer cells from green to red fluorescence, restricting the light exposure only to the metastatic lymph node. This technology allowed us to specifically trace the fate of cancer cells in the lymph node and beyond to other organs. Results: We show that spontaneous lymph node metastasis from breast cancer and melanoma mouse models can leave the lymph node and enter the blood circulation. We identified micrometastatic disease in the lung that originated from the lymph node in both models. We hypothesized that cancer cells escape the lymph node by directly invading lymph node blood vessels, as opposed to draining through the efferent lymphatic vessel. Immunohistochemical analysis of metastatic lymph nodes revealed isolated cancer cells in close association with CD31+ blood vessels, within high endothelial venules (HEVs) and breaching the vascular basement membrane. Quantitative analysis showed that 23±2% of isolated cancer cells were within 5μm of a blood vessel, compared to only 11±1% using a predictive model of randomly distributed cells in the lymph node (p<0.05). Further, 6±2% of the cancer cells were inside blood vessels defined as cells within the lumen of blood vessels and having cell centroids more than 3μm from the blood vessel endothelium. To further confirm that metastatic cancer cells in a lymph node have affinity for lymph node blood vessels, we used multiphoton intravital microscopy to measure cancer cell migration in an optical lymph node window in mice. Dendra2 expressing metastatic cancer cells are first seen in the subcapsular sinus of the lymph node and later invade the cortex of the lymph node where they accumulate around rhodamine-dextran labeled blood vessels. Cancer cells can be observed in directed migration toward blood vessels as well as moving inside blood vessels. Finally, we analyzed lymph nodes with metastatic lesions from patients with head and neck cancer and identified cancer cells that were closely associated with and inside blood vessels. Conclusions: Together, our data show for the first time that in spontaneous breast and melanoma mouse models, tumor cells in the lymph node can invade blood vessels, exit the node and colonize the lung. Citation Format: Ethel R. Pereira, Dmitriy Kedrin, Giorgio Seano, Olivia Gautier, Eelco F. Meijer, Dennis Jones, Shan-Min Chin, Shuji Kitahara, Echoe M. Bouta, Jonathan Chang, Elizabeth Beech, Han-Sin Jeong, Michael C. Carroll, Alphonse G. Taghian, Timothy P. Padera. Lymph node metastasis in solid tumors: A marker or driver of disease progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3022.

Spectroscopic properties of Sm3+-doped NaGd(MoO4)2 crystal for visible laser application

A NaGd(MoO4)2 crystal doped with 2at.% Sm3+ was grown by the Czochralski method. Polarized absorption and fluorescence spectra of the crystal were measured at room temperature. Spectroscopic parameters, including absorption and emission cross sections, Judd-Ofelt intensity parameters, radiative transition rates, fluorescence branching ratios, and fluorescence lifetime of the 4G5/2 multiplet, were obtained and compared with other Sm3+-doped crystals. The main fluorescence band around 646nm is related to the 4G5/2→6H9/2 transition, which has a branching ratio of 45.4% and peak emission cross sections of 1.73×10–21 and 3.13×10–21cm2 for π and σ polarizations, respectively. The results indicate that the Sm3+:NaGd(MoO4)2 crystal may be a potential gain medium of red visible laser pumped directly by commercially available 405nm laser diode.

Design of Projection Lithography Objective Lens with Sub-Ten Micrometer Line-Width and its MTF Experimental Measurements

Double fold reduction projection lithography objective lens with bi-telecentric configuration, consists of 6 lenses and the number aperture , is designed based on the optical design software Zemax. It uses the 405nm laser diode (LD) as light source. The spatial resolving capacity approaches to 5um. In a field of view of , its wave-front aberration is less than a quarter of wave-length and the distortion ratio is not more than. The imaging performance, in particular, the accurate modulation transfer function (MTF) value of the projection objective lens being fabricated by experiments is determined in this paper. Through analyzing the noise disturbance law in MTF tests, the result show that the projection objective lens has sub ten micrometer resolving ability.

Antibacterial and Antifungal Effect of 405 nm Monochromatic Laser on Endodontopathogenic Microorganisms

The purpose of this study is to evaluate the usefulness of 405 nm monochromatic laser irradiation as an alternative management for prevention and/or treatment of endodontic infections. A monochromatic laser-emitting device equipped with a 405-nm laser diode was developed. Using this device, the effect of 405 nm laser irradiation on the growth ofPorphyromonas gingivalis, Prevotella intermedia, Enterococcus faecalis, andCandida albicans, which are microorganisms associated with persistent endodontic infections, was evaluated by viable colony counting. As a result, the irradiation with a 405 nm laser had a significant bactericidal/fungicidal effect onP. gingivalis, P. intermedia, andC. albicans, whereas the growth ofE. faecaliswas not affected by the irradiation. The inhibition rate inP. gingivalisandP. intermediawas ~60% and ~80%, respectively, following irradiation at 0.2 W for 300 sec. The inhibition rate inC. albicanswas ~90% following irradiation at 0.2 W for 1200 sec. These results indicate that 405 nm monochromatic laser irradiation exerts a bactericidal/fungicidal effect on these microorganisms. The present study clearly demonstrates that 405 nm laser irradiation is a promising alternative management strategy for prevention and/or treatment of endodontic infections.

Physical properties of an oxide photoresist film for submicron pattern lithography

The minimum etched pits of 300nm diameter and the trenches of 300nm width with a 50nm depth for both geometries are prepared in the GeSbSn oxide photoresist on the silicon substrates. The lithographic patterns are recorded by direct laser writing, using a 405nm laser diode and 0.9 numerical aperture media disc mastering system. The developed pit diameters in an inorganic oxide photoresist are smaller than the exposed laser beam spot diameter due to thermal lithography. The crystal structures of the as-sputtered and the annealed powder samples scraped from the sputtered films are examined by X-ray diffractometer. The effect of the heating rate on the crystallization temperatures is evaluated by a differential scanning calorimeter and the crystallization activation energy is determined from Kissinger's plot. The optical and absorption characteristics of the oxides are strongly dependent on the oxygen flow rate during the reactive magnetron sputtering process. The transmittance of the deposited films increases and the absorption decreases with increasing oxygen flow rate, which implies that at high oxygen flow rate, the film resembles dielectric material. The oxygen flow rate during the deposition process is defined within a limited range to obtain the proper extinction coefficient. The working extinction coefficients of the films ranging from 0.5 to 0.8 are applied in this study to achieve the sharp and vertical edge of the etched pits and trenches of 50nm depth.

Phase-stable source of polarization-entangled photons in a linear double-pass configuration

We demonstrate a compact, robust, and highly efficient source of polarization-entangled photons, based on linear bi-directional down-conversion in a novel 'folded sandwich' configuration. Bi-directionally pumping a single periodically poled KTiOPO(4) (ppKTP) crystal with a 405-nm laser diode, we generate entangled photon pairs at the non-degenerate wavelengths 784 nm (signal) and 839 nm (idler), and achieve an unprecedented detection rate of 11.8 kcps for 10.4 μW of pump power (1.1 million pairs / mW), in a 2.9-nm bandwidth, while maintaining a very high two-photon entanglement quality, with a Bell-state fidelity of 99.3 ± 0.3%.

Formation and removal of multi-layered fluorescence patterns in gold-ion doped glass

We report the formation of fluorescence patterns inside gold-doped glass medium by femtosecond-laser fabrication. Strong fluorescence images appeared from the irradiated multi-layered region after low temperature annealing. We removed the images by exposing the glass to an electric furnace or a CO 2 laser beam for high temperature annealing. The method was also applied to recording, reading, and erasing of fluorescence data by a femtosecond laser, a 405-nm laser diode, and a CO 2 laser respectively.

The C-terminal Region of Human Adipose Triglyceride Lipase Affects Enzyme Activity and Lipid Droplet Binding

Adipose triglyceride lipase (ATGL) catalyzes the first step in the hydrolysis of triacylglycerol (TG) generating diacylglycerol and free fatty acids. The enzyme requires the activator protein CGI-58 (or ABHD5) for full enzymatic activity. Defective ATGL function causes a recessively inherited disorder named neutral lipid storage disease that is characterized by systemic TG accumulation and myopathy. In this study, we investigated the functional defects associated with mutations in the ATGL gene that cause neutral lipid storage disease. We show that these mutations lead to the expression of either inactive enzymes localizing to lipid droplets (LDs) or enzymatically active lipases with defective LD binding. Additionally, our studies assign important regulatory functions to the C-terminal part of ATGL. Truncated mutant ATGL variants lacking approximately 220 amino acids of the C-terminal protein region do not localize to LDs. Interestingly, however, these mutants exhibit substantially increased TG hydrolase activity in vitro (up to 20-fold) compared with the wild-type enzyme, indicating that the C-terminal region suppresses enzyme activity. Protein-protein interaction studies revealed an increased binding of truncated ATGL to CGI-58, suggesting that the C-terminal part interferes with CGI-58 interaction and enzyme activation. Compared with the human enzyme, the C-terminal region of mouse ATGL is much less effective in suppressing enzyme activity, implicating species-dependent differences in enzyme regulation. Together, our results demonstrate that the C-terminal region of ATGL is essential for proper localization of the enzyme and suppresses enzyme activity.

Digital Exposure System with 405nm Laser Diode for Printed Circuit Board Manufacturing Industry

We have developed an advanced digital exposure system for the printed circuit board manufacturing industry. This system has DMD based optics combined with 405nm laser units designed using Fuji Film original technology so as to achieve both high productivity and high precision at the same time. Fuji Film has experience packing plural laser modules into a single unit for high power output. The laser source is led into the optical systems through optical fibers. The exposure engine has plural optics covering a width of 510 mm that enables scanning of the panel in a shuttle motion. As a result, the exposure time is only 10 seconds for 510×610mm-sized imaging in the case of 10 mJ sensitivity materials. The system can produce over 160 panels per hour, making it suitable for mass production in the industry.

Near infrared broadband emission of bismuth-doped aluminophosphate glass

Near infrared broadband emission characteristics of bismuth-doped aluminophosphate glass have been investigated. Broad infrared emissions peaking at 1210nm, 1173nm and 1300nm were observed when the glass was pumped by 405nm laser diode (LD), 514nm Ar+ laser and 808nm LD, respectively. The full widths at half maximum (FWHMs) are 235nm, 207nm and 300nm for the emissions at 1210nm, 1173nm and 1300nm, respectively. Based on the energy matching conditions, it is suggested that the infrared emission may be ascribed to 3P1? 3P0 transition of Bi+. The broadband infrared luminescent characteristics of the glasses indicate that they are promising for broadband optical fiber amplifiers and tunable lasers.