from the conferences organized by TANGER Ltd.
Several experimental strategies have been formulated to develop theranostic liposomes by incorporating both drugs and various imaging contrast agents.in last decades. Liposome kinetics and cracking could be potentiated by external forces (ultrasound, electro-magnetic, laser induced). Gadolinium is used in many contrast entities, and they could be detectable by various methods of electron microscopy and tomography if the concentration is within a good range of values. Our workplace is working with a wide range of extracellular vesicles, which are natural transporters of regenerative factors. In order to evaluate the Gd-label effectiveness for some specific extracellular vesicles (specific exosomes derived from mesenchymal stromal cells), experimental labeling methods were prepared. We prepared original conjugation methods for Gd-DSPS binding to the surface lipid layer of extracellular vesicles, and evaluation by electron microscopy and DLS methods was conducted. To reveal possible adverse effects of Gd-vesicles that may be initiated after contact with living cells, we also evaluated basic cytotoxicity tests, and we conducted a statistical survey for metal distribution from dermal dressing into different tissues. Results of tests revealed that vesicles before and after Gd-labeling had very similar sizes (115 versus 122 nm) and similar zeta potential. It has been demonstrated that Gd-vesicles are stable particles in the dermis and subdermal region, still detectable after 12 days as compact nanobodies with high contrast under electron microscopy in dermal tissue. A simple dose of 20 µg per 1 cm² on dermal tissue (mixed in a hydrogel drop) showed very good diffusion into the tissues over the next 6 days. The diffused concentration of vesicles is sufficient for the quantification of particles with mass spectrometry after taking a biopsy, but not yet sufficient for the quantification of particles by traditional X-ray or MRI tomography. Gd-release had no adverse toxicity. A modified variant, “Gd + extra sono-stimul,” was evaluated at the end of the experiment. There is evidence that sono-stimulation could accelerate the penetration of healing vesicles into the target dermal tissue.
Keywords: Nanovesicles, metal toxicity, medical device, tissue model, liposome kinetic© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.