LA-ICP-MS mapping of the silver distribution in skin during wound healing

Silver nanoparticles (AgNPs) –containing dressings are increasingly being used in the treatment of wounds and skin burns. Recently we demonstrated that AgNPs can be massively released as agglomerates onto the skin, penetrate deeply into the dermis, enter into the fibroblasts by endocytosis, and accumulate to a remarkable amount into the cytoplasm. In this work skin biopsies were collected from three different patients treated with AgNPs dressings. The samples, taken during the healing process, were analyzed by laser ablation coupled to inductively coupled plasma mass spectrometry (LAICP- MS) to map the distribution of carbon, phosphorus, sulphur and silver with a spatial resolution ranging from 5μm-100μm. The analyses confirm that silver is released in the dermis during treatment. After the new epidermis is formed, silver released by the applied dressing does not seem able to cross the new epidermis and remains on the surface of the skin. No silver was observed in the subcutaneous adipose tissue. For the first time silver was detected in the vessel walls. We concluded that silver is not able to cross the epidermis and the adipose tissue, and it is distributed to the organs via the blood stream due to its ability to penetrate into the vessels after release directly onto the dermis.