The effect of 2D tungsten disulfide nanoparticles on Lewis lung carcinoma cells in vitro.

The unique physicochemical properties of modern two-dimensional (2D) nanomaterials with graphene-like structures make them promising candidates for biology and medicine purposes. In this article, we investigate the influence of the two-dimensional tungsten disulfide (2D WS2) water suspension nanoparticles obtained by an improved mechanochemical method from powdered WS2 on morphological and structural characteristics of Lewis lung carcinoma cells using FT-IR, Raman spectroscopy, and confocal microscopy. The characterization of the 2D WS2 nanoparticles by different physical methods is given also. We have highlighted that 2D WS2 does not exert cytotoxic activity in the case of 1 day incubation with tumor cells. Prolongation of the incubation period up to 2 days has caused a statistically significant (p < 0.05) concentration-dependent decrease of the number of viable cells by more than 30% with the maximum cytotoxic effect at concentrations of 2D WS2 close to 2 µg ml-1. In the Raman spectra of 2D WS2 treated cells the bands centered at 354 cm-1 and 419 cm-1, which are assigned to characteristics and modes of WS2 nanoparticles were observed. The obtained data indicate, that the cytotoxic effect of 2D WS2 on tumor cells in the case of long-term incubation is realized particularly through the ability of 2D WS2 to enter tumor cells and/or accumulate on their surface, which gives a rationale to conduct further studies of their antitumor efficacy in vitro and in vivo when combined with chemotherapeutic drugs.

Dual effect of 2D WS2 nanoparticles on the lysozyme conformation.

In the present work we studied the effect of 2D WS2 nanoparticles on the conformational changes in lysozyme protein at different pH values (2.0-11.5). The contributions of various structural conformations (α-helix, ß-sheets parallel and antiparallel, unordered structure and side groups) were determined by decomposition of Amid I absorbance bands. The 2D WS2 were shown to have different impact on secondary structure depending on pH of the solution and protein concentration. The amyloid fibril presence was confirmed with confocal microscopy enhanced by gold support, and fluorescent spectroscopy with amyloid-sensitive dye Thioflavin T. Our data show that WS2 can both inhibit and stimulate amyloid formation. Additionally, we have also reported an unusual spectroscopic behavior displayed by lysozyme, indicated by narrowing of Amide I and Amide II bands at pH 2.5 and 3.5 when incubated with 2D WS2 nanoparticles.

Vibrational spectra of DNA in the confined interglobular volume of photonic crystal.

The impact of confinement of DNA molecules in a limited volume of the cavity of photonic crystals (PC) on the vibrational properties of the DNA molecule and its conformation is studied. According to our preliminary study, the aqueous shell is removed when the DNA molecules are infiltrated into the PC cavities. Raman scattering (RS) DNA marker lines showed a dramatic conformational change of DNA in the PC cavities and the appearance of new unknown conformational states. We observed the enhancement of vibrational modes of DNA in the PC in comparison with free DNA of about tenfold and the absence of vibrational modes in DNA bases in a region of 1450-1700 cm-1. The observed features in the RS spectra of DNA are explained by the impact of confined interglobular volume and strong localization of the electromagnetic field. Namely, FDTD simulations in linear regime demonstrate the localization of light in cavities of PC with an approximately ninefold enhancement of the electric field within the photonic stop-band, which is the main reason for RS amplification.

2D-BN nanoparticles as a spectroscopic marker and drug delivery system with protection properties.

An application of 2D-BN nanoparticles as a spectroscopic marker, weak luminescent marker and anticancer drug (doxorubicin, DOX) delivery system with protection properties was studied for the LNCaP strains of cancer cells using FTIR and Raman spectroscopy for analysing the cancer cells, cells with BN, the cancer cells with DOX, and the cancer cells with BN nanoparticles loaded by DOX. Study of IR absorption and Raman spectra of the LNCaP strains of cancer cells incubated with 2D-BN nanoparticles for 1 hour showed that the 2D-BN nanoparticles could pass through the cell membrane and localize inside the membrane or close to the membrane in the cytoplasm of the cells. We registered the spectra of the disturbed lipids during the DOX-2D-BN passing through the membrane. After incubation for 2 hours and more, spectral changes in other structural components of the cell (nuclei, cytoplasm, mitochondria) can be registered. Confocal microscopy showed that a gold nanostructured support enhances the fluorescence of the cancer cells with 2D-BN as well as that with DOX, however the double action of 2D-BN and DOX on the cancer cells aggravates the emission property of the studied system. An MTT test showed that the toxicity of DOX on the 2D-BN nanoparticles is less than that on the reference cells, and at the same time the efficiency of the DOX action on the cancer cells does not change.

Surface enhanced IR absorption of nucleic acids from tumor cells: FTIR reflectance study.

The data on surface enhanced IR absorption (SEIRA) of nucleic acids deposited on a metal substrate were obtained using FTIR in reflectance mode. A 200-400 A thick gold film on a glass plate was the metal substrate. The approximate enhancement factors of the SEIRA for different vibrations of nucleic acids in our experimental conditions were 3-5. The roughness of the Au surface was about 50 A. Application of this method to nucleic acids isolated from tumor cells revealed some possible peculiarities of their structural organization, namely, the appearance of unusual sugar and base conformations, modification of the phosphate backbone, redistribution of the H-bond net, and so forth. This method enhanced a set of the bands, which is impossible to observe in conventional IR geometry. The SEIRA spectra of the RNA from tumor cells showed more sensitivity to the grade of tumor malignancy than the spectra of the DNA. After application of the anticancer drug doxorubicin to sensitive and resistant strains, the DNA isolated from these strains had different spectral features, especially in the region of the phosphate I and II bands. As induced by anticancer drugs, the conformational changes in the DNA from resistant and sensitive cancer strains could be characterized with different levels of structure disordering.

The SEIRA spectroscopy data of nucleic acids and phospholipids from sensitive- and drug-resistant rat tumours.

It is known that tumour progression towards drug resistance is one of the main factors resulting in the failure of cancer treatment. As tumour progression is based on the genetic instability, the study of the structure of nucleic acid from tumour cells is of great importance both for basic knowledge and for biomedical application. We applied surface enhanced infrared absorption spectroscopy (SEIRA) of nucleic acids on gold substrate and essentially increased the sensitivity of IR spectroscopy. We observed numerous changes in infrared spectra of DNA from sensitive and resistant cells that reflect drastic changes in molecular structure of DNA from tumour cells. The DNA from resistant cancer cells could be characterised as rigid structure, the structure of DNA from sensitive cancer strain seems to be flexible and after application of anticancer drugs drastically changes and approaches to the structure of helix forms. The molecular structure of lipids from resistant and sensitive cancers after application of anti-tumour drugs is also modified. Thus, we observed a disordering in the lipid chain packing from resistant cells after application of cisplatin and, in some cases, formation of phospholipid-Pt complex.

FTIR spectroscopy studies of nucleic acid damage.

Fourier transform infrared (FTIR) spectra of RNA isolated from tumour brain (glioma) and DNA isolated from low-dose gamma-irradiated epididymis cells of rats from the Chernobyl accident zone have been investigated in the 700-4000 cm(-1) region. The total absorbed radiation doses were equal to or less than 57 cGy. Observed changes in the FTIR spectra represent the damage in the primary, secondary and tertiary structure of nucleic acid, which seem to be connected with modification of bases and sugars, and redistribution of the H-bond network. FTIR data for tumour and gamma-irradiated nucleic acid show some similar features. A great amount of statistical data and good mathematical approaches are needed for the use of these data as diagnostic criteria.

[Visualization of the effects of millimeter radiation on blood plasma]. / Vizualizatsiia deistviia millimetrovogo izlucheniia na plazmu krovi.

Experiments on millimeter wave radiation (range 37.5-78.5 Ghz incident radiation power density 1-10 mVt/cm2) upon index refraction of 2-10% water solution of human blood plasma are presented. Investigations were carried out by holographic interferometry with sufficient sensitivity for estimating the index refraction -10(-6). Index refraction variations in 2% water solution of human blood plasma are detected to be equal to 10(-4). Such index refraction variations upon millimeter wave is one order greater than that of the temperature effect and two order greater than the sensitivity of settlement. The mechanism of these phenomena is discussed.