Low infra red laser light irradiation on cultured neural cells: effects on mitochondria and cell viability after oxidative stress.
BMC Complement Altern Med. 2009;9:8. Epub 2009 Apr 15. PMID: 19368718
Alessandro Giuliani, Luca Lorenzini, Michele Gallamini, Alessandro Massella, Luciana Giardino, Laura Calzà
BACKGROUND: Considerable interest has been aroused in recent years by the well-known notion that biological systems are sensitive to visible light. With clinical applications of visible radiation in the far-red to near-infrared region of the spectrum in mind, we explored the effect of coherent red light irradiation with extremely low energy transfer on a neural cell line derived from rat pheochromocytoma. We focused on the effect of pulsed light laser irradiation vis-à-vis two distinct biological effects: neurite elongation under NGF stimulus on laminin-collagen substrate and cell viability during oxidative stress. METHODS: We used a 670 nm laser, with extremely low peak power output (3 mW/cm2) and at an extremely low dose (0.45 mJ/cm2). Neurite elongation wasmeasured over three days in culture. The effect of coherent red light irradiation on cell reaction to oxidative stress was evaluated through live-recording of mitochondria membrane potential (MMP) using JC1 vital dye and laser-confocal microscopy, in the absence (photo bleaching) and in the presence(oxidative stress) of H2O2, and by means of the MTT cell viability assay. RESULTS: We found that laser irradiation stimulates NGF-induced neurite elongation on a laminin-collagen coated substrate and protects PC12 cells against oxidative stress. CONCLUSION: These data suggest that red light radiation protects the viability of cell culture in case of oxidative stress, as indicated by MMP measurement and MTT assay. It also stimulates neurite outgrowth, and this effect could also have positive implications for axonal protection.
Article Published Date : Jan 01, 2009
Wide spectrum photocatalytic activity in lanthanide-doped upconversion nanophosphors coated with porous TiO2 and Ag-Cu bimetallic nanoparticles.
J Hazard Mater. 2019 Jan 03;367:694-705
Authors: Reddy KL, Kumar S, Kumar A, Krishnan V
Approaches towards maximum utilization of solar light spectrum for photocatalysis have currently attracted great interest. The combination of profoundly different properties, such as, upconversion, semiconducting and plasmonic properties can produce a favorable path in efficient utilization of the different regions of solar light reaching to earth. In this regard, design and fabrication of microstructures consisting of upconverting lanthanide doped nanophosphors coated with porous semiconducting material, TiO2 and decorated with plasmonic Ag-Cu bimetallic nanoparticles is presented in this work. These microstructures display great stability and exceptional photocatalytic activity by absorbing wide spectrum from ultraviolet to near infrared. The photocatalytic activity could be attributed to the synergistic effects between the different components and the efficient energy transfer between them. The development of such sort of hybrid microstructures could pave way for the development of new materials for the efficient utilization of the wide spectrum of sunlight.
PMID: 30654287 [PubMed - as supplied by publisher]
Therapeutic application of light emitting diode: Photo-oncomic approach.
J Photochem Photobiol B. 2019 Jan 09;192:1-7
Authors: Oh PS, Jeong HJ
As a new light source, light emitting diode (LED) with high brightness and lower cost has been rapidly developed in medical application and light therapy. LED phototherapy can activate target cells with appropriate power and adequate energy density. This review provides general information on therapeutic applications of blue, green, yellow, red, and infrared LED in medical treatments for various physical abnormalities and on bio-imaging. The bio-imaging system is improved by decreasing the number of microscopes apparatuses including neutral-density filter, excitation filters and mechanical shutters. The numbers of excitation photons are increased and the fluorescent excitation efficiency is improved at cellular level. In the target tissue, the therapeutic effect of LEDs is dependent on incident photons irrespective of the system used to generate these photons. Photomodulated light from LED device is delivered in pulsed mode with specific pulse sequences and time. Too low or too high dose of energy may be ineffective at all. Clinical applications of LED light depending on different wavelengths are summarized. The author's photo-oncomic experiments using a specific blue light emitting diode were introduced, showing that blue LED possessed anti-proliferative and anti-metastatic abilities in cancer cells and mice. As a promising light source, photo-oncomic approach of blue LED could be applied to treat cancers and inflammatory diseases.
PMID: 30654264 [PubMed - as supplied by publisher]
Perfluoroheptane-Loaded Hollow Gold Nanoshells Reduce Nanobubble Threshold Flux.
Small. 2019 Jan 17;:e1804476
Authors: Shin JE, Ogunyankin MO, Zasadzinski JA
The threshold flux for nanobubble formation and liposome rupture is reduced by 50-60% by adding a liquid mixture of tetradecanol and perfluoroheptane to the interior cavity of 40 nm diameter hollow gold nanoshells (HGN), and allowing the tetradecanol to solidify to hold the perfluoroheptane in place. On absorption of picosecond pulses of near-infrared light, the perfluoroheptane vaporizes to initiate cavitation-like nanobubbles as the HGN temperature increases. The lower spinodal temperature and heat capacity of perfluoroheptane relative to water causes the threshold flux for nanobubble formation to decrease. The perfluoroheptane-containing HGN can be linked via thiol-PEG-lipid tethers to carboxyfluorescein-containing liposomes and shows a similar decreased flux necessary for liposome contents release.
PMID: 30653279 [PubMed - as supplied by publisher]
Photoredox catalysis using infrared light via triplet fusion upconversion.
Nature. 2019 Jan;565(7739):343-346
Authors: Ravetz BD, Pun AB, Churchill EM, Congreve DN, Rovis T, Campos LM
Recent advances in photoredox catalysis have made it possible to achieve various challenging synthetic transformations, polymerizations and surface modifications1-3. All of these reactions require ultraviolet- or visible-light stimuli; however, the use of visible-light irradiation has intrinsic challenges. For example, the penetration of visible light through most reaction media is very low, leading to problems in large-scale reactions. Moreover, reactants can compete with photocatalysts for the absorption of incident light, limiting the scope of the reactions. These problems can be overcome by the use of near-infrared light, which has a much higher penetration depth through various media, notably biological tissue4. Here we demonstrate various photoredox transformations under infrared radiation by utilizing the photophysical process of triplet fusion upconversion, a mechanism by which two low-energy photons are converted into a higher-energy photon. We show that this is a general strategy applicable to a wide range of photoredox reactions. We tune the upconversion components to adjust the output light, accessing both orange light and blue light from low-energy infrared light, by pairwise manipulation of the sensitizer and annihilator. We further demonstrate that the annihilator itself can be used as a photocatalyst, thus simplifying the reaction. This approach enables catalysis of high-energy transformations through several opaque barriers using low-energy infrared light.
PMID: 30651612 [PubMed - in process]
Direct thermo-optical tuning of silicon microresonators for the mid-infrared.
Opt Express. 2018 Dec 24;26(26):34965-34976
Authors: Koehler L, Chevalier P, Shim E, Desiatov B, Shams-Ansari A, Piccardo M, Okawachi Y, Yu M, Loncar M, Lipson M, Gaeta AL, Capasso F
We use light from a visible laser diode to directly tune silicon-on-chip microresonators by thermo-optical effect. We show that this direct tuning is local, non invasive and has a much smaller time constant than global temperature tuning methods. Such an approach could prove to be highly effective for Kerr comb generation in microresonators pumped by quantum cascade lasers, which cannot be easily tuned to achieve comb generation and soliton-mode locked states.
PMID: 30650912 [PubMed]
Broadband efficient modulation of light transmission with high contrast using reconfigurable VO2 diffraction grating.
Opt Express. 2018 Dec 24;26(26):34641-34654
Authors: Kim SJ, Choi S, Choi C, Lee Y, Sung J, Yun H, Jeong J, Mun SE, Lee YW, Lee B
Ultra-compact dynamically reconfigurable modulation of optical transmission has been widely studied by using subwavelength-spaced resonant metasurface structures containing reconfigurable optical materials. However, it has been difficult to achieve high transmissivity, large modulation depth, and broad bandwidth simultaneously with the conventional resonance-based metasurface schemes. Here, we propose a reconfigurable phase-transition diffractive grating, made of thick VO2 ridge waveguides, for achieving the above-mentioned three goals simultaneously in the near-infrared range. Based on the large dielectric-to-plasmonic transition characteristic of VO2 in the near-infrared range, diffraction directivity of dual-VO2 ridge waveguide is designed to be tuned by thermally driven phase transition of VO2 for transverse electrically polarized illumination. Then, the diffractive VO2 ridge waveguide grating composed of the periodically arranged dual VO2 ridge waveguides is designed with on-state efficiency around 0.3 and minimum modulation depth about 0.35 over a broad bandwidth of 550 nm (1100-1650 nm). The working principle and excellent modulation performance are thoroughly verified through numerical and experimental studies.
PMID: 30650885 [PubMed]
Mid-to-far infrared tunable perfect absorption by a sub - λ/100 nanofilm in a fractal phasor resonant cavity.
Opt Express. 2018 Dec 24;26(26):34043-34059
Authors: Toudert J, Serna R, Pardo MG, Ramos N, Peláez RJ, Maté B
Integrating an absorbing thin film into a resonant cavity is the most practical way to achieve perfect absorption of light at a selected wavelength in the mid-to-far infrared, as required to target blackbody radiation or molecular fingerprints. The cavity is designed to resonate and enable perfect absorption in the film at the chosen wavelength λ. However, in current state-of-the-art designs, a still large absorbing film thickness (∼λ/50) is needed and tuning the perfect absorption wavelength over a broad range requires changing the cavity materials. Here, we introduce a new resonant cavity concept to achieve perfect absorption of infrared light in much thinner and thus, really nanoscale films, with a broad wavelength tenability by using a single set of cavity materials. It requires a nanofilm with giant refractive index and small extinction coefficient (found in emerging semi-metals, semi-conductors and topological insulators) backed by a transparent spacer and a metal mirror. The nanofilm acts both as absorber and multiple reflector for the internal cavity waves, which after escaping follow a fractal phasor trajectory. This enables a totally destructive optical interference for a nanofilm thickness more than 2 orders of magnitude smaller than λ. With this remarkable effect, we demonstrate angle-insensitive perfect absorption in sub - λ/100 bismuth nanofilms, at a wavelength tunable from 3 to 20 μm.
PMID: 30650834 [PubMed]
Broadband and wide-angle antireflective subwavelength microstructures on zinc sulfide fabricated by femtosecond laser parallel multi-beam.
Opt Express. 2018 Dec 24;26(26):34016-34030
Authors: Zhang F, Duan J, Zhou X, Wang C
The subwavelength microstructures (SWMS) on the surface of ZnS for antireflection in an infrared band have been theoretically designed and experimentally fabricated. The finite difference time domain (FDTD) simulation has been utilized to optimize geometry for obtaining high transmittance of SWMS. Then, during simulation for light field intensity distribution, the inner of SWMS emerges location and wavelength dependent light resonant region, which can be explained by Wood-Rayleigh (WR) law. Furthermore, according to refractive index gradient formation and light field coupling effect, the grating period and height are capable of regulating the band selection of antireflection and value of the transmittance, respectively. In addition, a rapid facile approach based on femtosecond laser parallel multi-beam has been proposed to experimentally realize the designed and optimal structures. The depth, period, and embedded nano-gratings of fabricated SWMS are tunable by controlling laser-processing parameters for antireflection in the wavelength of 8 μm-12 μm. Finally, the broadband and wide-angle antireflective SWMS on ZnS as well as robust mechanical strength and hydrophobicity have been achieved, expecting to be of great potential in an optoelectronic device application.
PMID: 30650832 [PubMed]
Electrically tunable multifunctional metasurface for integrating phase and amplitude modulation based on hyperbolic metamaterial substrate.
Opt Express. 2018 Nov 26;26(24):32063-32073
Authors: Lee Y, Kim SJ, Yun JG, Kim C, Lee SY, Lee B
Active metasurfaces, which are tunable and reconfigurable nanophotonic structures with active materials, have been in spotlight as a versatile platform to control the profiles of scattered light. These nanoscale structures show surpassing functionalities compared to the conventional metasurfaces. They also play an important role in a wide range of applications for imaging, sensing, and data storage. Hence, the expansion of functionalities has been highly desired, in order to overcome the limited space constraints and realize the integration of several optical devices on a single compact platform. In this context, an electrically tunable metasurface that enables respective modulation of the phase and amplitude of reflected light, depending on the angle of incidence at the targeted wavelength, is proposed. This resonance-based device with hyperbolic metamaterial substrate excites different kinds of highly confined modes, according to the incident angle. Indium tin oxide is employed to offer electrically tunable optical properties in the near-infrared regime. At the wavelength of 1450 nm, the proposed device modulates the phase of reflected light with ~207 degrees of modulation depth for normal incidence, whereas it shows ~86% of relative reflectance change for oblique incidence of 60 degrees. In principle, the proposed scheme might provide a path to applications for the next-generation ultracompact integrated systems.
PMID: 30650785 [PubMed]
Near-infrared chiral plasmonic metasurface absorbers.
Opt Express. 2018 Nov 26;26(24):31484-31489
Authors: Ouyang L, Wang W, Rosenmann D, Czaplewski DA, Gao J, Yang X
Chirality plays an essential role in the fields of biology, medicine and physics. However, natural materials exhibit very weak chiroptical response. In this paper, near-infrared chiral plasmonic metasurface absorbers are demonstrated to selectively absorb either the left-handed or right-handed circularly polarized light for achieving large circular dichroism (CD) across the wavelength range from 1.3 µm to 1.8 µm. It is shown that the maximum chiral absorption can reach to 0.87 and that the maximum CD in absorption is around 0.70. The current chiral metasurface design is able to achieve strong chiroptical response, which also leads to high thermal CD for the local temperature increase. The high-contrast reflective chiral images are also realized with the designed metasurface absorbers. The demonstrated chiral metasurface absorbers can be applied in many areas, such as optical filters, thermal energy harvesting, optical communication, and chiral imaging.
PMID: 30650733 [PubMed]
Cascaded-Microrings Biosensors Fabricated on a Polymer Platform.
Sensors (Basel). 2019 Jan 06;19(1):
Authors: Liang Y, Liu Q, Wu Z, Morthier G, Zhao M
Polymer-based single-microring biosensors usually have a small free spectral range (FSR) that hampers the tracing of the spectrum shifting in the measurement. A cascade of two microring resonators based on the Vernier effect, is applied in this article in order to make up for this defect. A small FSR difference between the reference microring and the sensing microring is designed, in order to superpose the periodic envelope signal onto the constituent peaks, which makes it possible to continuously track the spectrum of the sensor. The optical polymer material, Ormocore, which has a large transparent window, is used in the fabrication. The biosensor is fabricated by using an UV-based soft imprint technique, which is considered to be cost-effective and suitable for mass production. By optimizing the volume ratio of Ormocore and the maT thinner, the device can be fabricated almost without a residual layer. The device works at a wavelength of 840 nm, where water absorption loss is much lower than at the infrared wavelengths. A two-step fitting method, including single-peak fitting and whole-envelope fitting, is applied in order to trace the spectral shift accurately. Finally, the two-cascaded-microrings biosensor is characterized, and the obtained FSR is 4.6 nm, which is 16 times larger than the FSR of the single microring biosensor demonstrated in our previous work. Moreover, the sensitivity can also be amplified by 16-fold, thanks to the Vernier effect.
PMID: 30621353 [PubMed - indexed for MEDLINE]
Optimization of the ultrafiltration-assisted extraction of Chinese yam polysaccharide using response surface methodology and its biological activity.
Int J Biol Macromol. 2019 Jan;121:1186-1193
Authors: Xue HY, Li JR, Liu YG, Gao Q, Wang XW, Zhang JW, Tanokura M, Xue YL
Ultrafiltration is a separation process for purifying and concentrating macromolecular solutions. Using Baiyu yam (Dioscorea opposita Thunb) as the raw material, single-factor experiments, Box-Behnken design (BBD) and response surface methodology (RSM) were employed to investigate the effects of the ultrafiltration pH, temperature and pressure on the extraction rate of Chinese yam polysaccharide (CYP). The constructed regression model is highly significant, and the optimal ultrafiltration-assisted extraction conditions were determined to be the following: pH 6.5, 20 °C and 0.03 MPa. Under these optimal conditions, a CYP extraction rate of 88.7% was achieved. After purification with anion exchange (DE-52) and size-exclusion (Sephadex G-100) columns, the monosaccharide composition of CYP was determined to be 50.8% glucose, 24.2% mannose and 11.8% galactose. Fourier transform infrared (FT-IR) spectroscopy characterization of CYP confirmed the characteristic absorption peaks of the polysaccharides. The microstructure of CYP exhibited characteristics typical of amorphous powders. CYP also exhibited antioxidant activities, including the scavenging of DPPH radicals, hydroxyl radicals and superoxide anion radicals. Moreover, CYP exhibited a relatively strong inhibitory effect on BGC-823 cell growth.
PMID: 30342144 [PubMed - indexed for MEDLINE]
Highlighting IR Spectrochemical Imaging of the Retina.
Trends Biochem Sci. 2018 09;43(9):650-653
Authors: Aboualizadeh E, Hirschmugl CJ
An emerging application of mid-IR spectrochemical imaging of the retina is its utility in studying the highly localized biomolecular alterations in the chemistry of retinal cell layers associated with several pathological conditions. Spatially resolved IR images highlight simultaneous chemical composition of the entire span of the retina in a label-free manner.
PMID: 29729937 [PubMed - indexed for MEDLINE]