Scanning electron microscopic observations on photodynamic effects in cells in vitro

This paper reports an ultrastructural study of cell surfaces in normal (PTK₂) and malignant (Hela) cells in vitro using the scanning electron microscope. The study describes cells treated by haematoporphyrin derivatives (HPDs) from different sources as well as the destruction of cells which have taken up HPD in combination with laser microirradiation of single cells. The results indicate that an HPD effect on cell surface structure occurred: in general the microvilli were markedly reduced and some of the filopodia broken, shortened and thickened. The effects of different HPD drugs on cell surface structure differed to a certain extent within the limits of normal variation. In addition ultrastructural observations following HPD treatment plus laser microirradiation showed remarkable photodynamic cell damage identifiable within seconds after treatment.