Formation of self-trapping waveguides in bulk PMMA media doped with Phenanthrenequinone.

Experimental and theoretical investigations of light self-trapping waveguides in a bulk polymeric medium based on polymethylmethacrylate (PMMA) with photosensitive phenanthrenequinone (PQ)-molecules are examined. Self-channeling was generated for the first time in this nonlinear bulk PQ-PMMA media with a thickness up to several millimeters and 0.1 mol. % PQ-concentration. The experimental formation of volume waveguide structures with a length of 2 - 3 cm at different laser wavelengths (405 nm, 488 nm, and 514.5 nm) was demonstrated. The calculations based on a model for the laser beam propagation in the bulk PQ-PMMA medium with competitive nonlinearities are in a good agreement with the experiments.

Raman and fluorescence micro-spectroscopy applied for the monitoring of sunitinib-loaded porous silicon nanocontainers in cardiac cells.

Nanomaterials are a central pillar in modern medicine. They are thought to optimize drug delivery, enhance therapeutic efficacy, and reduce side-effects. To foster this technology, analytical methods are needed to validate not only the localization and distribution of these nanomaterials, but also their compatibility with cells, drugs, and drug release. In the present work, we assessed nanoparticles based on porous silicon (pSiNPs) loaded with the clinically used tyrosine kinase inhibitor sunitinib for their effectiveness of drug delivery, release, and toxicity in colon cancer cells (HCT 116 cells) and cardiac myoblast cells (H9c2) using Raman micro-spectroscopy, high-resolution fluorescence microscopy, along with biological methods for toxicological effects. We produced pSiNPs with a size of about 100 nm by grinding mesoporous silicon layers. pSiNPs allowed an effective loading of sunitinib due to their high porosity. Photoluminescence properties of the nanoparticles within the visible spectrum allowed the visualization of their uptake in cardiac cells. Raman micro-spectroscopy allowed not only the detection of the uptake and distribution of pSiNPs within the cells via a characteristic silicon Raman band at about 518-520 cm-1, but also the localization of the drug based on its characteristic molecular fingerprints. Cytotoxicity studies by Western blot analyses of apoptotic marker proteins such as caspase-3, and the detection of apoptosis by subG1-positive cell fractions in HCT 116 and MTT analyses in H9c2 cells, suggest a sustained release of sunitinib from pSiNPs and delayed cytotoxicity of sunitinib in HCT 116 cells. The analyses in cardiac cells revealed that pSiNPs are well tolerated and that they may even protect from toxic effects in these cells to some extent. Analyses of the integrity of mitochondrial networks as an early indicator for apoptotic cellular effects seem to validate these observations. Our study suggests pSiNPs-based nanocontainers for efficient and safe drug delivery and Raman micro-spectroscopy as a reliable method for their detection and monitoring. Thus, the herein presented nanocontainers and analytical methods have the potential to allow an efficient advancement of nanoparticles for targeted and sustained intracellular drug release that is of need, e.g., in chronic diseases and for the prevention of cardiac toxicity.

Broadening of the light self-trapping due to thermal defocusing in PQ-PMMA polymeric layers.

The channel formation by the self-trapping of a (1 + 1)D beam in polymeric media based on a polymethylmethacrylate (PMMA) matrix containing phenanthrenequinone (PQ) molecules is predicted theoretically and observed experimentally for the first time. Particular attention is paid to the effect of thermal beam expansion, which in conjunction with the photorefractive nonlinearity of the medium results in the possibility to control optically the geometrical parameters of the generated channel.

Non-local response in glass-like polymer storage materials based on poly (methylmethacrylate) with distributed phenanthrenequinone.

The development of volume phase gratings written by two-wave-mixing in glass-like polymer storage materials based on poly (methylmethacrylate) and its thermostable derivative (copolymer with acrylic acid) with distributed phenanthrenequinone is investigated experimentally and theoretically. The maximal diffraction efficiency is considered in dependence on the grating period. The redistribution processes of the molecules are described with a one-dimensional diffusion model yielding the existence of a non-local response in the photopolymer layer, and the corresponding non-local response length of phenanthrenequinone is found experimentally.