Figure 1. Schematic overview of targeted delivery of polystyrene beads of varying sizes

Schematic overview of targeted delivery of polystyrene beads of varying sizes. Beads with diameters greater than 10 microns do not penetrate the stratum corneum (left), whereas beads smaller than 3 microns penetrate the skin by both the intercellular spaces between the corneocytes as well as via the infundibulum (right). When beads are between 3 and 10 microns in diameter, targeted delivery to the sebaceous gland and the follicular unit can be achieved. (Figure modified from Reference 8.)