Synthesis of imidazolium-terminated carbosilane dendrimers and dendrons and study of their interactions with a cell membrane model

Abstract

A new family of imidazolium-terminated carbosilane dendrimers and dendrons was synthesized and characterized as a nanotechnological alternative to current therapies. The aim of this research was the study of the interacting process of nano-structures with a cell membrane model (lecithin liposomes), with the final ambitious purpose to use these nano-structures for biomedical applications, e.g. as anticancer drug. The interactions occurring over time between the dendrimers, at different generations (from G1 to G3) and different concentrations (1 mM, 10 mM and 20 mM), and cell membrane models were investigated using a computer-aided analysis of the electron paramagnetic resonance (EPR) spectra of selected spin probes, able to enter the liposome membrane, mimicking the phospholipid behavior. The EPR analysis provided structural and dynamical information on the systems indicating that the increase in generation and concentration produced an increased perturbation of the liposome structure. The dendrons and G1 dendrimers poorly interacted and this interaction was almost independent on dendrimer concentration and decreased over time. Conversely, G3 dendrimers showed a significant variation of the interacting process in respect of concentration. A fast kinetics of internalization was proposed at low dendrimer concentration, while accumulation of dendrimers at the liposome surface slowed down the internalization process. The cytotoxic effect of the dendrimers and the dendrons was verified by an in vitro screening in a selection of tumor cell lines, in parallel with the EPR results.