New method to trace nanoparticles in skin will contribute to replacing animals in tests
Researchers from Sechenov University together with their colleagues from Australia conducted a series of experiments with upconversion luminescent nanoparticles and various models of human skin to determine how many nanoparticles penetrated the skin and how quickly and deep they moved.
The experiment allowed to determine which compounds enhance and which, on the contrary, impede penetration through the stratum corneum. It turned out that under certain conditions particles can accumulate in live epidermis, under the stratum corneum, or even in deeper layers. To trace penetration, scientists used confocal laser-scanning microscope and mass spectrometry.
Now, knowing that upconversion nanoparticles can accumulate in the deep layers of epidermis and in the upper derma, scientists tried to determine how safe their medical application would be. Normally, to do this, researchers put nanoparticles on the skin of laboratory animals and after some time take samples in areas exposed to the impact.
The authors of the paper showed that this goal can be achieved without animal experiments. They cultivated multilayer living human epidermis and proved that in the three-dimensional structure upconversion nanoparticles are not toxic.