Small-molecule-mediated OGG1 inhibition attenuates pulmonary inflammation and lung fibrosis in a murine lung fibrosis model

Interstitial lung diseases such as idiopathic pulmonary fibrosis (IPF) are caused by persistent micro-injuries to alveolar epithelial tissues accompanied by aberrant repair processes. IPF is currently treated with pirfenidone and nintedanib, compounds which slow the rate of disease progression but fail to target underlying pathophysiological mechanisms. The DNA repair protein 8-oxoguanine DNA glycosylase-1 (OGG1) has significant roles in the modulation of inflammation and metabolic syndromes. Currently, no pharmaceutical solutions targeting OGG1 have been utilized in the treatment of IPF. In this study we show Ogg1-targeting siRNA mitigates bleomycin-induced pulmonary fibrosis in male mice, highlighting OGG1 as a tractable target in lung fibrosis. The small molecule OGG1 inhibitor, TH5487, decreases myofibroblast transition and associated pro-fibrotic gene expressions in fibroblast cells. In addition, TH5487 decreases levels of pro-inflammatory mediators, inflammatory cell infiltration, and lung remodeling in a murine model of bleomycin-induced pulmonary fibrosis conducted in male C57BL6/J mice. OGG1 and SMAD7 interact to induce fibroblast proliferation and differentiation and display roles in fibrotic murine and IPF patient lung tissue. Taken together, these data suggest that TH5487 is a potentially clinically relevant treatment for IPF but further study in human trials is required.

Investigation of Swift Heavy Ion Irradiated Reduced Graphene Oxide (rGO)/Molybdenum Disulfide (MoS₂) Nanocomposite Using Raman Spectroscopy

In this work, a few layer molybdenum disulfide (MoS₂) and reduced graphene oxide (rGO) nanocomposite have been synthesized by liquid exfoliation method. The morphological and structural properties are analyzed using scanning electron microscopy and X-ray diffraction technique. The optical properties are also investigated using absorption and Raman spectroscopy. This report presents quantification of swift heavy ion irradiation induced defects using Raman spectroscopy. We found both Raman mode E¹_2g and A_1g corresponding to MoS₂ and Raman modes of rGO are strongly affected by increasing ions doses. The defect induced lattice strain in the rGO/MoS₂ nanocomposite is also estimated from Raman spectroscopy. MoS₂ layers are found to be much more sensitive than rGO in the rGO/MoS₂ nanocomposite. These types of study further used in device based application of rGO/MoS₂ nanocomposite system.

Investigating the Energy Transfer from Dye Molecules to DNA Stabilized Au Nanoparticles

Double-stranded DNA stabilized gold nanoparticles (Au NPs) are synthesized by chemical reduction method and characterized with different spectroscopic techniques such as UV-Visible absorption, Fourier transform infrared (FTIR), & circular-dichroism (CD) as well as transmission electron microscopy (TEM). These NPs show absorption maximum at 520 nm and size of most of the particles are of the order of 3.5 ± 1.0 nm. These Au NPs show crystalline nature as confirmed from electron diffraction pattern. The effect of formation of Au NPs on the macromolecule has been studied using infrared and circular dichroism spectroscopy. Formation of NPs causes conformational changes in the DNA molecules. These Au NPs are further used as resonant energy acceptor of fluorescence emission from dye molecules (Rhodamine 6G). The fluorescence intensity of Rhodamine 6G (R6G) is quenched in presence of Au NPs. The effect of DNA molecules on the fluorescence quenching and the rate of energy transfer from R6G molecules to Au NPs have been explored.

Photoreduction altered work function of Au-TiO2 nanoparticles measured by scanning Kelvin probe microscopy

The present study investigates the systematic changes observed in work function (WF) of Au-nanoparticles supported on TiO2 as a result of variation in surface plasmon resonance induced absorption intensity. Synthesis of hybrid Au-TiO2 nanoparticles was carried out by sol-gel process followed by photoreduction of gold (III) chloride trihydrate in presence of UV light. Surface Plasmon resonance appearing at 540 nm in the UV/Vis absorption spectra, confirms the formation of Au nanoparticles. The composition of these hybrid Au-TiO2 nanoparticles was determined from Rutherford back scattering studies. Transmission electron microscopy measurements reveal the size of synthesized Au nanoparticles to be 15 +/- 2 nm with well defined lattice fringes. With increase in photoreduction time, the concentration of Au nanoparticles increases, size remaining the same. To observe the efficiency of these hybrid nanoparticles towards photo-assisted applications, their work function was measured using scanning Kelvin probe microscope. The detail analysis of variation of their WF values with photoreduction time reveals that a plateau or saturation behavior of Au-TiO2 nanoparticles close to that of pure Au is achieved after a photoreduction time of 6 hours due to occurrence of maximum Au loading on TiO2 surface.

Synthesis of nanodimensional TiO2 thin films

Nanodimensional TiO2 has wide application in the field of photocatalysis, photovoltaic and photochromic devices. In present investigation TiO2 thin films deposited by pulsed laser deposition method are irradiated by 100 MeV Ag ion beam to achieve growth of nanophases. The nanostructure evolution is characterized by atomic force microscopy (AFM). The phases of TiO2 formed after irradiation are identified by glancing angle X-ray diffraction and Raman spectroscopy. The particle radius estimated by AFM varies from 10-13 nm. Anatase phase of TiO2 is formed after irradiation. The blue shift observed in UV-VIS absorption spectra indicates the nanostructure formation. The shape and size of nanoparticles formed due to high electronic excitation depend upon thickness of the film.

Nanocrystalline SnO2 formation using energetic ion beam

Nanocrystalline tin oxide (SnO2) thin films grown by RF magnetron sputtering technique were characterized by UV-Visible absorption spectroscopy and Photoluminescence spectroscopy. From atomic force microscopic (AFM) and Glancing angle X-ray diffraction (GAXRD) measurements, the radius of grains was found to be approximately 6+/-2 nm. The thin films were bombarded with 250 keV Xe2+ ion beam to observe the stability of nanophases against radiation. For ion bombarded films, optical absorption band edge is shifted towards red region. Atomic force microscopy studies show that the radius of the grains was increased to approximately 8 +/- 1 nm and the grains were nearly uniform in size. The size of the grains has been reduced after ion bombardment in the case of films grown on Si. During this process, defects such as vacancies, voids were generated in the films as well as in the substrates. Ion bombardment induces local temperature increase of thin films causing melting of films. Ion beam induced defects enhances the diffusion of atoms leading to uniformity in size of grains. The role of matrix on ion beam induced grain growth is discussed.

Synthesis of nanocrystalline tin oxide thin film by swift heavy ion irradiation

Nanocrystals of tin oxide were formed in e-beam evaporated films by swift heavy ion (SHI) irradiation. The nucleation of nanocrystals occurred due to electronic excitation by swift heavy ion. Nanophase thin films are characterized systematically by HRTEM, GAXRD, EDX, and UV/NIS absorption techniques. Nanocrystals having size of 8 nm radius are synthesized in different substrates during swift heavy ion irradiation and without subsequent annealing. SHI induced nanocrystallization could be achieved in both crystalline and non-crystalline substrates.