Evidence for the phagocytosis of intact oligolamellar liposomes by human keratinocytes in vitro and consecutive intracellular disintegration.

While there is evidence for the use of liposomes as drug carriers upon topical application to the skin, the underlying mechanisms are far from being clear. Therefore human keratinocytes grown in vitro were exposed to large oligolamellar liposomes. After attachment and invagination these particles can be found unchanged within the cytoplasm both inside and outside of lysosomes. If incorporated into lysosomes the structural lipids can be disintegrated and spread within the entire phagolysosome. Gold labeling adds further to the hypothesis of intact uptake of liposomes by the living cells of the human epidermis.