Fluorescence Lifetime Imaging Microscopy Tracks Nanocarrier Penetration Into Human Cell-Based Non-Melanoma Skin Cancer Models

P SCHILRREFF ; C ZOSCHKE; A BOREHAM; R BRODWOLF; P VOLZ; M SCHÄFER-KORTING; U ALEXIEV; MJ MORILLA

Workshop; Imaging Techniques for Biotechnology and Biomedical Applications; 2016

Fluorescence Lifetime Imaging Microscopy (FLIM) reveal characteristic fluorescent lifetime signatures of nanocarrier bound dye and provide novel insights into the uptake of different nanocarriers into human skin ex vivo and organotypic non-melanoma skin cancer models. FLIM uses excited-state fluorescence decay curves of the fluorescing molecules in each image pixel and thereby allows the identification of unique fluorescence lifetime species, being specific for a certain dye and its environment [1].We found striking interactions between dendritic core-multishell nanocarriers or tecto-dendrimers and the stratum corneum of normal tissues due to altered fluorescence lifetime signatures within the stratum corneum compared to the free nanocarrier solution. In normal tissues, nanocarrier penetration stops at the level of the stratum granulosum, whereas impaired skin barrier allows further penetration into the epidermis.This correlates to an impaired skin barrier function with altered stratum corneum lipids and tight junctions within the skin cancer models [2]. In conclusion, FLIM offers a versatile, efficient, and reliable method to unravel fluorophore-tissue interactions.