Analysis of the molecular alterations in cancer cells following nanotechnology-assisted targeted radiotherapy using Raman spectroscopy.

The study unveiled an innovative strategy for precise radiation targeting in cancer treatment, along with the monitoring of molecular changes induced by this therapeutic approach. In this research, we explored the impact of administering anti-HER2-AgNPs nanoconjugates either individually or in conjunction with gamma irradiation on the viability of SKBR3 breast cancer cells. The utilization of nanoconjugates resulted in an enhancement of cellular sensitivity toward radiation. The viability of the cells exhibited a decline as the dose of irradiation increased, and this decrease was further exacerbated by the passage of time following irradiation. The analysis of RS revealed distinct cellular responses in varying conditions. The observed increase in SERS intensity, resulting from the increment in dose from 0 to 2 Gy, can be attributed to the probable upregulation of HER2 expression induced by irradiation. The observed decrease in SERS intensity at doses of 4 and 6 Gy can be attributed to the likely reduction in HER2 expression. It was illustrated that the analysis of Raman spectroscopy data can aid in the identification of radiation-induced biochemical alterations in cancer cells during the application of nanoconjugates-based radiotherapy. The findings revealed that nanoconjugates have the potential to enhance cellular sensitivity to radiation along with facilitating the detection of radiation-induced biochemical alterations within cancer cells.

Enhancement of third order nonlinear optical responses via alteration of the density of states of electrons: VS2-NiS2 hybrid nanostructure.

We successfully synthesized VS2-NiS2 hybrid nanostructures via a one-pot hydrothermal technique. Microstructural characterizations were carried out by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), UV-visible spectroscopy, and Fourier transform infrared spectroscopy (FTIR). The optical indexes such as n, k, and ε were assessed based on the reflectance spectra data and Kramers-Kronig method. By adding varying amounts of the NiS2 phase in the hybrid nanostructure, the morphology of the hybrid nanostructures is altered to produce microflowers, nanoflakes, and nanoflowers. These changes affect the nonlinear optical properties. The third order nonlinear optical parameters (n 2, ß) were analyzed via a simple and accurate Z-scan technique using different laser powers. The two-photon absorption phenomenon has a significant enhancement effect on the nonlinear absorption process, but the nonlinear refractive behaviour of the different hybrid nanostructures changes from self-defocusing to self-focusing due to the alteration of the electronic state alignment and morphology. The magnitudes of n 2 and ß are in the order of 10-9 cm2 W-1 and 10-3 cm W-1, respectively. The increasing of the density of states of electrons leads to the improvement of the nonlinear optical responses of the VS2-NiS2 hybrid nanostructures in comparison with the pure VS2 structure. This study demonstrates the great potential of this hybrid nanostructure for optical limiters and modulators as well as photonic devices.

Surface-Enhanced Raman scattering of methylene blue on titanium nitride nanoparticles synthesized by laser ablation in organic solvents.

Suspensions of titanium nitride (TiN) nanoparticles (NPs) were prepared using nanosecond Ce:Nd:YAG pulsed laser ablation (λ = 1064 nm) of a TiN target immersed in various solvents such as Toluene (C6H5CH3), Acetonitrile (CH3CN), and N, N-dimethylformamide (C3H7NO). The synthesized NPs were characterized by applying a range of spectroscopic, structural, and compositional analysis techniques. The obtained TiN NPs in N, N-dimethylformamide (DMF-TiN NPs) solvent showed strong optical absorption in the near-infrared (NIR) range; Whereas, the obtained TiN NPs in toluene (T-TiN NPs) and acetonitrile (AN-TiN NPs) solvents were covered with a carbon matrix layer that quenched their surface plasmon resonance (SPR). The carbon matrix on the NPs was removed by thermal oxidation to obtain carbon-free TiN NPs. All the prepared carbon-free TiN NPs were employed as substrates for the surface-enhanced Raman scattering (SERS) spectroscopy of methylene blue (MB) molecules as a probe molecule adsorbed on the surface. All substrates indicated nearly the same order of enhancement factors (EFs) (~103) for MB.

VUV photochemistry and nuclear spin conversion of water and water-orthohydrogen complexes in parahydrogen crystals at 4 K.

Samples of H2O, HDO, and D2O were isolated in solid parahydrogen (pH2) matrices and irradiated by vacuum ultraviolet (VUV) radiation at 147 nm. Fourier-Transform Infrared (FTIR) spectra showed a clear depletion of D2O and an enrichment of both HDO and H2O by 147 nm irradiation. These irradiation-dependent changes are attributed to the production of OH and/or OD radicals through photodissociations of H2O, HDO, and D2O. The radicals subsequently react with the hydrogen matrix, leading to the observed enrichment of H2O. No trace of isolated OH or OD was detected in the FTIR spectra, indicating that the OH/OD radicals react with the surrounding matrix hydrogen molecules via quantum tunneling within our experimental timescale. The observed temporal changes in concentrations, especially the increase of HDO concentration during VUV irradiation, can be interpreted by a model with a rapid conversion from orthohydrogen (oH2) to pH2 in water-oH2 complexes upon VUV photodissociation, indicating either the acceleration of the nuclear spin conversion (NSC) of H2 due to the magnetic moment of the intermediate OH/OD radical, or the preferential reaction of the OH/OD radical with a nearby oH2 molecule over other pH2 molecules. We have also identified and quantified an anomalously slow NSC of H2O and D2O complexed with oH2 in solid pH2.

Core-Double-Shell Fe2O3@SiO2@Jarosite Hybrid Nanoparticles Synthesized by Laser Ablation of Turquoise in Ethanol.

This work highlights a facile green route for the one-step synthesis of iron oxide core-double-shell nanoparticles (NPs) and aluminum phosphide (AlP) nanosheets by pulsed laser ablation of the mineral turquoise target from Nishapur in the presence of an ethanol solvent. High-resolution transmission electron microscopy, selected-area electron diffraction pattern, and field emission scanning electron microscopy (FESEM) in combination with energy-dispersive X-ray mapping revealed the formation of NPs with a typical core@double-shell structure in which crystalline α-Fe2O3 (iron oxide) formed the core, while SiO2 (quartz) and (K, H3O)Fe3(SO4)2(OH6) (jarosite) participated as the inner and outer shell, respectively. However, the application of laser ablation on the turquoise phase of the target led to the formation of AlP nanosheets which was confirmed by the X-ray diffraction patterns and FESEM images. Strong absorption of the vein-ablated species in the UV region (250-360 nm) was the characteristic feature of α-Fe2O3 and jarosite phases, while the absorption band at 250-300 nm for the turquoise-ablated species was related to the presence of Cu compound species and also the α-Fe2O3 phase in the sample. Photoluminescence emission spectra for the vein-ablated species depicted a peak centered at 370 nm, while a peak located at 364 nm was ascribed to the turquoise-ablated species. In particular, these hybrid NPs with high purity and stability may offer new opportunities for bio-applications such as anticancer agents and water/wastewater applications.

SERS-Active Cu Nanoparticles on Carbon Nitride Support Fabricated Using Pulsed Laser Ablation.

We report a single-step route to co-deposit Cu nanoparticles with a graphitic carbon nitride (gCN) support using nanosecond Ce:Nd:YAG pulsed laser ablation from a Cu metal target coated using acetonitrile (CH3CN). The resulting Cu/gCN hybrids showed strong optical absorption in the visible to near-IR range and exhibited surface-enhanced Raman or resonance Raman scattering (SERS or SERRS) enhancement for crystal violet (CV), methylene blue (MB), and rhodamine 6G (R6G) used as probe analyte molecules adsorbed on the surface. We have characterized the Cu nanoparticles and the nature of the gCN support materials using a range of spectroscopic, structural, and compositional analysis techniques.

Nanohybrids of Two-Dimensional Transition-Metal Dichalcogenides and Titanium Dioxide for Photocatalytic Applications.

The ever increasing need for renewable and clean energy resources as well as environmental concerns are considered as two serious challenges of today's society. Photocatalysis has proved to be a reliable and effective technology to overcome these issues. However, to bring the full potential of this approach into reality, two main hurdles of fast charge recombination and the limited visible light absorption should be tackled. To address these obstacles, nanocomposites based on titanium dioxide nanostructures and semiconducting two-dimensional transition-metal dichalcogenides have been developed and proven to be excellent photocatalysts. In this review, we will overview the recent developments on the fabrication and rational design of these nanocomposites both for hydrogen production and photocatalytic degradation of pollutants with emphasis on those appealing structures.

Enhanced thermoelectric properties of hydrothermally synthesized Bi0.88-x Zn x Sb0.12 nanoalloys below the semiconductor-semimetal transition temperature.

Bi0.88-x Zn x Sb0.12 alloys with x = 0.00, 0.05, 0.10, and 0.15 were prepared using hydrothermal synthesis in combination with evacuating-and-encapsulating sintering. The effects of partial Zn substitution for Bi and different sintering temperatures on the thermoelectric properties of Bi0.88-x Zn x Sb0.12 alloys were investigated between 25 K and 425 K. Both the electrical conductivity and absolute thermopower are enhanced for the set of alloys sintered at 250 °C. The maximum power factor of 57.60 µW cm-1 K-2 is attained for the x = 0.05 alloy sintered at 250 °C. As compared with Zn-free Bi0.88Sb0.12, both the total thermal conductivity and lattice component are reduced upon Zn doping. Bipolar conduction is observed in both electronic and thermal transport. The maximum zT of 0.47 is attained at 275 K for the x = 0.05 alloy sintered at 250 °C.

Mesoporous plasmonic nanocomposites based on Au/Ag-TiO2 aerogels as SERS substrates.

Au/Ag-TiO2 mesoporous nanocomposite aerogels are special materials that can be applied as efficient surface-enhanced Raman spectroscopy (SERS) substrates, in order to detect low concentration of analytes from aqueous environments. At the same time, they benefit from structural and intrinsic properties of aerogels and TiO2, respectively, and also the plasmonic effects of Au/Ag nanoparticles. Here, several composites of TiO2 aerogel modified with various concentrations of Au, Ag, and a mixture of Au-Ag nanoparticles were prepared by applying two different methods of synthesis. The SERS detection efficiency of the nanocomposites was established by using the dye crystal violate (CV) as the test molecule. The lowest concentration of CV detectable by SERS, which was 10-10 M, was found to depend on the method of synthesis, size, and type of the nanoparticles that were used in the nanocomposite structure. In addition, the morphological and structural characterizations of the nanocomposites were investigated through Brunauer-Emmet-Teller results, field emission scanning electron microscopy (FESEM), and transmission electron microscope images.

High-Performance and Stable Gel-State Dye-Sensitized Solar Cells Using Anodic TiO2 Nanotube Arrays and Polymer-Based Gel Electrolytes.

Highly ordered and vertically oriented TiO2 nanotube (NT) arrays were synthesized with potentiostatic anodization of Ti foil and applied to fabricate gel-state dye-sensitized solar cells (DSSCs). The open structure of the TiO2 NT facilitates the infiltration of the gel-state electrolyte; their one-dimensional structural feature provides effective charge transport. TiO2 NTs of length L=15-35 µm were produced on anodization for periods of t=5-15 h at a constant voltage of 60 V, and sensitized with N719 for photovoltaic characterization. A commercially available copolymer, poly(methyl methacrylate-co-ethyl acrylate) (PMMA-EA), served as a gelling agent to prepare a polymer-gel electrolyte (PGE) for DSSC applications. The PGE as prepared exhibited a maximum conductivity of 4.58 mS cm(-1) with PMMA-EA (7 wt %). The phase transition temperature (Tp) of the PGE containing PMMA-EA at varied concentrations was determined on the basis of the viscosities measured at varied temperatures. Tp increased with increasing concentration of PMMA-EA. An NT-DSSC with L=30 µm assembled using a PGE containing PMMA-EA (7 wt %) exhibited an overall power conversion efficiency (PCE) of 6.9%, which is comparable with that of a corresponding liquid-type device, PCE=7.1%. Moreover, the gel-state NT-DSSC exhibited excellent thermal and light-soaking enduring stability: the best device retained ∼90% of its initial efficiency after 1000 h under 1 sun of illumination at 50 °C, whereas its liquid-state counterpart decayed appreciably after light soaking for 500 h.