Synthesis, characterisation and in vitro investigation of photodynamic activity of 5-(4-octadecanamidophenyl)-10,15,20-tris(N-methylpyridinium-3-yl)porphyrin trichloride on HeLa cells using low light fluence rate.

Photodynamic therapy (PDT) is a treatment that aims to kill cancer cells by reactive oxygen species, mainly singlet oxygen, produced through light activation of a photosensitiser (PS). Amongst photosensitisers that attracted the most attention in the last decade are cationic and amphiphilic molecules based on porphyrin, chlorin and phthalocyanine structures. Our aim was to join this search for more optimal balance of the lipophilic and hydrophilic moieties in a PS.

Comparison of two techniques for reliable characterization of thin metal-dielectric films.

In the present study we determine the optical parameters of thin metal-dielectric films using two different characterization techniques based on nonparametric and multiple oscillator models. We consider four series of thin metal-dielectric films produced under various deposition conditions with different optical properties. We compare characterization results obtained by nonparametric and multiple oscillator techniques and demonstrate that the results are consistent.

Use of gold island films in design of reflectors with high luminosity.

We describe the optical properties of gold island films embedded between SiO2 and/or TiO2 layers. Plasmonic properties of gold films have been characterized using spectrometry and variable angle spectroscopic ellipsometry for various combinations of the embedding media. The obtained refractive indices of embedded gold island films have been used in the design of several types of multilayer reflectors.

Gradient silver nanoparticle layers in absorbing coatings--experimental study.

Metal island films show a characteristic absorption peak related to the surface plasmon resonance of free electrons. This kind of film can be used in absorbing coatings, together with dielectric layers. Such absorbing multilayer coatings, with and without the gradient of the silver mass thickness in metal island films throughout the coating, have been deposited by electron beam evaporation.

General approach to reliable characterization of thin metal films.

Optical constants of thin metal films are strongly dependent on deposition conditions, growth mode, and thickness. We propose a universal characterization approach that allows reliable determination of thin metal film optical constants as functions of wavelength and thickness. We apply this approach to determination of refractive index dispersion of silver island films embedded between silica layers.

On the dielectric function tuning of random metal-dielectric nanocomposites for metamaterial applications.

The potential of random metal-dielectric nanocomposites as constituent elements of metamaterial structures is explored. Classical effective medium theories indicate that these composites can provide a tunable negative dielectric function with small absorption losses. However, the tuning potential of real random composites is significantly lower than the one predicted by classical theories, due to the underestimation of the spectral range where topological resonances take place.

Fractionated illumination improves the outcome in the treatment of precancerous lesions with photodynamic therapy.

Photodynamic therapy (PDT) is a noninvasive therapy for non-melanoma skin cancer. The aim of this study was comparison of efficacy between fractioned versus single dose illumination in photodynamic therapy (PDT) of actinic keratosis (AK) and Bowen's disease (BD). Fifty-one patients (36 AK and 15 BD) were treated with PDT They were randomly arranged in two treatment groups.

Visualization of basal cell carcinoma by fluorescence diagnosis and independent component analysis.

Photodynamic detection (PDD) of skin tumours is based on the visualization of a fluorophores, with the ability to accumulate in tumour tissue, by the use of fluorescence imaging. Of particular importance is the application of δ-5-aminolaevulinic acid (ALA) that, through the process of biosynthesis causes formation of the protoporphyrin IX (PpIX). The PpIX has the ability of selective fluorescence after basal cell carcinoma (BCC) has been treated with ALA.