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Infrared laser

Satoru Muramatsu, Xuan Wu, Mohua Chen, Mingfei Zhou, Tatsuya Tsukuda
Infrared spectroscopy and density functional theory calculations showed that gold complexes [CH3-Au-I] and [(CH3)2-Au-I2], in which one and two CH3I molecule(s), respectively, are oxidatively adsorbed on the Au atoms, are formed in a solid neon matrix via the reactions between the laser-ablated gold atoms (Au) and methyl iodide (CH3I). Global reaction route mapping calculations revealed that the heights of the activation barriers for the sequential oxidative addition to produce [CH3-Au-I] and [(CH3)2-Au-I2] are 0...
October 17, 2017: Journal of Physical Chemistry. A
Mingting Zhu, Zonghai Sheng, Yali Jia, Dehong Hu, Xin Liu, Xianyuan Xia, Chengbo Liu, Pan Wang, Xiaobing Wang, Hairong Zheng
Active-targeted cancer imaging and therapy of glioma has attracted much attention in theranostic nanomedicine. As a promising tumor-targeting ligand, holo-transferrin (holo-Tf) has been applied for enhancing delivery of nanotheranostics. However, holo-Tf-based nanoassemblies for active targeting mediated multi-modal imaging and therapeutics have not been previously reported. Here, we develop a one-step method for the preparation of holo-Tf-indocyanine green (holo-Tf-ICG) nanoassemblies for fluorescence (FL) and photoacoustic (PA) dual-modal imaging and photothermal therapy (PTT) of glioma...
October 17, 2017: ACS Applied Materials & Interfaces
Yeran Bai, Delong Zhang, Chen Li, Cheng Liu, Ji-Xin Cheng
Using a visible beam to probe the thermal effect induced by infrared absorption, mid-infrared photothermal (MIP) microscopy allows bond-selective chemical imaging at submicron spatial resolution. Current MIP microscopes cannot reach the high wavenumber region due to the limited tunability of the existing quantum cascade laser source. We extend the spectral range of MIP microscopy by difference frequency generation (DFG) from two chirped femtosecond pulses. Flexible wavelength tuning in both C-D and C-H regions was achieved with mid-infrared power up to 22...
October 16, 2017: Journal of Physical Chemistry. B
Pieter Geiregat, Arjan J Houtepen, Laxmi Kishore Sagar, Ivan Infante, Felipe Zapata, Valeriia Grigel, Guy Allan, Christophe Delerue, Dries Van Thourhout, Zeger Hens
Colloidal quantum dots (QDs) raise more and more interest as solution-processable and tunable optical gain materials. However, especially for infrared active QDs, optical gain remains inefficient. Since stimulated emission involves multifold degenerate band-edge states, population inversion can be attained only at high pump power and must compete with efficient multi-exciton recombination. Here, we show that mercury telluride (HgTe) QDs exhibit size-tunable stimulated emission throughout the near-infrared telecom window at thresholds unmatched by any QD studied before...
October 9, 2017: Nature Materials
Theodore A Henderson, Larry D Morries
BACKGROUND: The treatment of depression has been hampered by low efficacy of antidepressant medications and safety concerns with alternative modalities. Recent work demonstrated that multi-Watt transcranial near-infrared light therapy (NILT) can effectively treat traumatic brain injury (TBI). The current objective is to explore multi-Watt NILT efficacy in a proof-of-concept study as a treatment for depression. METHODS: Thirty-nine sequential patients treated for TBI between March 2013 and May 2017 provided depression self-assessment data and/or were administered the Hamilton depression rating scale...
2017: Frontiers in Psychiatry
Giorgia Sciutto, Silvia Prati, Irene Bonacini, Lucio Litti, Moreno Meneghetti, Rocco Mazzeo
The present research is focused on the setting up of an advanced analytical system for the detection of synthetic dyes. The system is based on the combination of an innovative thin layer chromatography (TLC) plate coupled with enhanced infrared (MU-ATR, metal underlayer attenuated total reflection) and Surface Enhanced Raman (SERS) spectroscopy. In particular, a TLC plate made of silver iodide (AgI) applied onto a gold coated glass slide (AgI@Au) is proposed as an efficient stationary phase for the separation of dyes mixtures...
October 23, 2017: Analytica Chimica Acta
Guoyong Zhou, Hong Xiao, Xiaoxia Li, Yi Huang, Wei Song, Liang Song, Meiwan Chen, Du Cheng, Xintao Shuai
A pH-sensitive copolymer PAsp(DIP)-b-PAsp(MEA) (PDPM) was synthesized and self-assembled to micelle loading chemotherapeutic drug doxorubicin (DOX) and introducing a gold nanocage structure for photothermo-chemotherapy and photoacoustic imaging. After further surface modification with polyethylene glycol (PEG), the DOX-loaded pH-sensitive gold nanocage (D-PGNC) around 100 nm possessed a uniform spherical structure with a pH-sensitive core of PAsp(DIP) incorporating DOX, an interlayer crosslinked via disulfide bonds and decorated with discontinuous gold shell, and a PEG corona...
October 10, 2017: Acta Biomaterialia
Olga Bibikova, Julian Haas, Ángela I López-Lorente, Alexey Popov, Matti Kinnunen, Yury Ryabchikov, Andrei Kabashin, Igor Meglinski, Boris Mizaikoff
Plasmonic anisotropic nanoparticles possess a number of hot spots on their surface due to the presence of sharp edges, tips or vertices, leading to a high electric field strength surrounding the nanostructures. In this paper, we explore different plasmonic nanostructures, including anisotropic gold nanostars (AuNSts) and spherical gold nanoparticles, in surface-enhanced infrared absorption spectroscopy (SEIRAS) in an attenuated total reflection (ATR) configuration. In our experiments, we observed up to 10-times enhancement of the infrared (IR) absorption of thioglycolic acid (TGA) and up to 2-times enhancement of signals for bovine serum albumin (BSA) protein on plasmonic nanostructure-based films deposited on a silicon (Si) internal reflection element (IRE) compared to bare Si IRE...
October 16, 2017: Analytica Chimica Acta
Shuo Yang, Di Hu, Anbo Wang
The Letter reports the inscription of fiber Bragg gratings (FBGs) in a single-crystal sapphire optical fiber via a point-by-point method by 780 nm infrared-femtosecond laser pulses. Compared to phase mask exposure, the use of the point-by-point method for the inscription provides a flexible way to fabricate sapphire FBGs and to make wavelength division multiplexing in sapphire fiber more practicable. The multiplexing of three cascade gratings is demonstrated, and their performance up to 1400°C is tested. The permanent enhancement of reflectivity by a factor of about 5 after heat treatment and the nearly linear temperature response with a slope of 25...
October 15, 2017: Optics Letters
M Gebhardt, C Gaida, T Heuermann, F Stutzki, C Jauregui, J Antonio-Lopez, A Schulzgen, R Amezcua-Correa, J Limpert, A Tünnermann
High-average power laser sources delivering intense few-cycle pulses in wavelength regions beyond the near infrared are promising tools for driving the next generation of high-flux strong-field experiments. In this work, we report on nonlinear pulse compression to 34.4 μJ-, 2.1-cycle pulses with 1.4 GW peak power at a central wavelength of 1.82 μm and an average power of 43 W. This performance level was enabled by the combination of a high-repetition-rate ultrafast thulium-doped fiber laser system and a gas-filled antiresonant hollow-core fiber...
October 15, 2017: Optics Letters
Mengrong Xu, Fei Yu, Jonathan Knight
We report the characteristics of a 1 W hollow-core fiber gas laser emitting CW in the mid-IR. Our system is based on an acetylene-filled hollow-core optical fiber guiding with low losses at both the pump and laser wavelengths and operating in the single-pass amplified spontaneous emission regime. Through systematic characterization of the pump absorption and output power dependence on gas pressure, fiber length, and pump intensity, we determine that the reduction of pump absorption at high pump flux and the degradation of gain performance at high gas pressure necessitate the use of increased gain fiber length for efficient lasing at higher powers...
October 15, 2017: Optics Letters
Yu Sun, Tian-Yi Shi, Ling-Yun Zhou, Yu-Yan Zhou, Bai-Wang Sun, Xiao-Ping Liu
Platinum-based drugs are used to treat a variety of cancers but have many side effects such as nephrotoxicity and neurotoxicity. A folate-decorated nanoparticles system with a good drug payload can selectively deliver drugs into folate receptor (FR)-overexpressing cancer cells to prevent the shortcomings of platinum-based chemotherapy. Here, folate-decorated and near-infrared (NIR) laser-activated nanoparticles (abbreviated as Pt(IV)-FINPs) were prepared via ultrasonic self-assembling of platinum(IV) prodrug c,c,t-Pt(NH3)2Cl2(OOCCH2CH2COOH)2, folic acid (FA)-functionalized lipid DSPE-PEG-FA and NIR fluorescent dye indocyanine green (ICG)...
October 13, 2017: Journal of Microencapsulation
Abhishek Sahu, Manse Kim, Jooyeon Ryu, Joon-Gon Son, Eunji Lee, Do Young Noh, Giyoong Tae
The application of pulsed and continuous wave (CW) lasers in nanomedicine has increased significantly over the last decade. Near infrared (NIR) lasers can be used for the precise control of drug release at the target site in a non-invasive manner. In this study, we have prepared nanographene oxide (nGO, size ~40nm) integrated liposomes (size ~900nm). The nGOs were not simply adsorbed onto the liposome surface but was embedded inside the liposomes as characterized by cryo-TEM, selected area electron diffraction (SAED), and fluorescence quenching studies...
January 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
Mengmeng Ma, Nan Gao, Yuhuan Sun, Jinsong Ren, Xiaogang Qu
Polyphenol compounds, such as curcumin, rutin, rifampicin, can inhibit Aβ aggregation and decrease reactive oxygen species (ROS), and have received much attention in recent years for Alzheimer's disease (AD) treatment. However, the excess metal ions in amyloid plaque can chelate to polyphenol compounds. It significantly declines the efficacy of polyphenol compounds when used in the clinic. In this report, a near-infrared (NIR)-caged upconversion responsive system UCNP@SiO2 @Cur/CQ is designed and synthesized to control drug sequential release by regulating NIR laser...
October 12, 2017: Small
Sergio Brossi Botta, Patricia Aparecida Ana, Marcela Leticia Leal Gonçalves, Kristianne Porta Santos Fernandes, Raquel Agnelli Mesquita-Ferrari, Renato de Araújo Prates, Aldo Brugnera Junior, Sandra Kalil Bussadori
OBJECTIVE: The aim of this in vitro study was to evaluate the degradation of type I collagen fibers after treatment with a papain-based gel associated with a blue dye (PapaMBlue™) for use in antimicrobial photodynamic therapy. MATERIALS AND METHODS: For such, 60 bioabsorbable membrane sponge discs were used. Group 1 was the negative control group. In groups 2, 3, and 4, the papain-based gel PapaMBlue gel was applied all over the samples for 4 min and irradiated using red laser (660 ± 10 nm) with 15, 30, and 40 J/cm(2), respectively...
October 12, 2017: Photomedicine and Laser Surgery
Ayanjeet Ghosh, Prabuddha Mukherjee, Sanghamitra Deb, Rohit Bhargava
We report here the first mesoscale characterization of solvent environments in the metal-organic framework (MOF) Cu3(BTC)2 using infrared imaging. Two characteristic populations of the MOF structures corresponding to the carboxylate binding to the Cu(II) (metal) ions were observed, which reflect a regular solvated MOF structure with axial solvents in the binuclear copper paddlewheel and an unsolvated defect mode that lacks axial solvent coordination. Infrared imaging also shows strong correlation between solvent localization and the spatial distribution of the solvated population within the MOF...
October 18, 2017: Journal of Physical Chemistry Letters
Lei Zhao, Xiaoqian Ge, Guihua Yan, Xiao Wang, Pengfei Hu, Liyi Shi, Otto S Wolfbeis, Hongjie Zhang, Lining Sun
A double-mesoporous nanosystem was synthesized for treating as well as imaging cancer cells by using a simple and mild method. The mesoporous platinum (Pt) nanoparticles acting as a core show excellent photothermal effect under illumination with an 808 nm near infrared (NIR) laser. The mesoporous silica linked with a lanthanide (Gd) complex acting as a shell displays potential applications as a contrast agent for magnetic resonance imaging (MRI). The final mPt@mSiO2-GdDTPA nanosystems exhibit good biocompatibility in vitro and in vivo, when investigated by methyl thiazolyl tetrazolium assay and histological and serum biochemistry analysis...
October 12, 2017: Nanoscale
Henry L Feng, Sumit Sharma, Sandra Stinnett, Sanjay Asrani, Prithvi Mruthyunjaya
BACKGROUND AND OBJECTIVE: To characterize the appearance of three types of artifacts observed on multicolor confocal scanning laser ophthalmoscopy (cSLO). PATIENTS AND METHODS: Retrospective review of 159 eyes of 96 consecutive patients from the Duke Eye Center who underwent multicolor cSLO with spectral-domain optical coherence tomography (SD-OCT). Infrared (IR), green, blue, and multicolor reflectance images were evaluated for artifacts with corresponding SD-OCT scans available for reference...
October 1, 2017: Ophthalmic Surgery, Lasers & Imaging Retina
Yalun Wang, Ming Chen, Nuernisha Alifu, Shiwu Li, Wei Qin, Anjun Qin, Ben Zhong Tang, Jun Qian
Imaging the brain with high integrity is of great importance to neuroscience and related applications. X-ray computed tomography (CT) and magnetic resonance imaging (MRI) are two clinically used modalities for deep-penetration brain imaging. However, their spatial resolution is quite limited. Two-photon fluorescence microscopic (2PFM) imaging with its femtosecond (fs) excitation wavelength in the traditional near-infrared (NIR) region (700-1000 nm) is able to realize deep-tissue and high-resolution brain imaging...
October 12, 2017: ACS Nano
Da-Peng Yang, Xuan Liu, Choon Peng Teng, Cally Owh, Khin Yin Win, Ming Lin, Xian Jun Loh, Yun-Long Wu, Zibiao Li, Enyi Ye
Star fruit (Averrhoa carambola) juice rich in vitamin C and polyphenolic antioxidants was used to synthesize branched gold nanoflowers. These biocompatible and stable gold nanoflowers show strong near-infrared absorption. They are successfully demonstrated to be highly efficient for both in vitro and in vivo photothermal therapy by using an 808 nm laser.
October 10, 2017: Nanoscale
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