POLYELECTROLYTE NANOCARRIERS LOADED WITH CAYNINE-TYPE PHOTOSENSITISERS FOR PHOTODYNAMIC THERAPY; CELLULAR LOCALIZATION AND EFFICACY

Abstract

The photodynamic therapy (PDT) is a promising anticancer strategy that may be safer or more beneficial in cases where extensive surgery, chemotherapy or radiotherapy may be limited due to risk of cosmetic and functional tissue damage. A major advantage of PDT is that both the PS itself is minimally toxic in the absence of light and hence PS accumulation in non-specific tissues confers minimal systemic toxicity. As a result, PDT has the potential to be repeated safely if needed without the risk of harming neighboring healthy tissue [1]. However, some difficulty for intravenous administration of PS is high hydrophobic properties of most these compounds. Searching for photodynamic therapy effective nanocarriers which enable a photosensitizer to be selectively delivered to tumor cells with enhanced bioavailability and diminished dark cytotoxicity is of current interest. Among various nanotransporter systems an important role is played some polymeric nanocarriers with ability to incorporate many hydrophobic molecules of drug thereby enhancing their solubility and permeation The previous our works has been carried out to explore the biological potential of the polymeric nanocapsules loaded with hydrophobic cyanines as effective delivery system of photosensitizer in photodynamic therapy of cancer cells [2,3]. In this report we presented usefulness of multilayer nanocapsules for delivering of cyanine-type photosensitizers to the cancer cells (lung A549 and colon MC38 cell lines). Intercellular visualization of delivered PS fluorescence emission after light excitation (cytofluorimetric and confocal microscopy method) allow to evaluation of cellular uptake. The reactive oxygen species (ROS) generation confirmed high PDT efficacy in the studied cancer cells. The multilayer nanocapsules were prepared by subsequent adsorption of opposite charged polyelectrolyte layers (dextran and chitosan sulfate sodium salt) on the nanoemulsion liquid core (layer-by-layer (L-b-L) approach). The L-b-L nanocapsules based on o/w nanoemulsion droplets stabilized by new generation of biocompatible saccharide-derived surfactants, i.e. linear 2-(dodecyldimethylammonio)-ethylgluco-heptonamide bromide (D2GHA-12) or dicephalic N,N-bis[3,3’(trimethylammonio)propyl] dodecanamide dimethylsulfate (C12(TAPAMS)2) and loaded with hydrophobic cyanine-type photosensitizers: zinc phtalocyanine ZnPc or cyanine IR-780. Dynamic light scattering (DLS) and atomic force microscopy (AFM) confirmed that almost monodisperse, sphere-shaped and nanosized carriers were developed. We characterized biocompatibility of obtained nanocapsules for evaluate their suitability for use in support of anticancer therapy. Nanocapsules were subjected to in vitro biological analysis of cytotoxic effect on target cancer cells as well as by estimation of hemolytic activity against human erythrocytes. Additionally, we determined the cytotoxicity of nanocapsules against control normal cells – macrophages and endhotelial cells. The low hemolytic potential and insignificant dark cytotoxicity against target cancer cells and macrophages as well as endothelial cells indicate good biocompatibility of obtained nanocarriers. Visualization of delivered cyanines in the cytoplasm of cancer cells and increase of their cellular uptake (related to free cyanine internalization) indicate attractiveness of multilayer nanocapsules based on o/w nanoemulsion liquid core as effective nanonocarriers of hydrophobic cyanines as photosensitizers with potential application for PDT.