Methods and Models for the Investigation of the Uptake of Nanoparticles into Hair Follicles

This thesis established in vitro skin models and methods to investigate the follicular uptake of nanoparticles (NPs) for potential transfollicular vaccination. A method was developed to quantify NP deposition in hair follicles, showing excellent correlation between in vitro pig ear models and in vivo human forearm models. Surface modifications, such as phospholipid coatings on poly(lactide-co-glycolide) (PLGA) NPs, affected penetration into hair follicles, while massage increased penetration depth but not the amount of NPs. A proof of concept study demonstrated that PLGA and chitosan-PLGA NPs with ovalbumin (OVA) stimulated CD4+ and CD8+ T-cells more effectively than OVA in solution, and an adoptive transfer experiment in mice confirmed the feasibility of transfollicular vaccination without prior skin treatment.