Fig. 3
From: Recent advances in transdermal drug delivery systems: a review
A SEM images of the prepared ALA-ES gels. B TEM images of ALA-ES in human HS tissue dermis. ALA-ES is indicated using black arrows. C TEM image of OA-UCNP. The nanoparticles show near-spherical shape with an average diameter around 25 nm. D Microscopy images of a section of a sample pig ear skin under 980 nm excitation laser. E Schematic illustration of W/O/W emulsification of HA-PLGA. F Fluorescence microscopic images of histological sections of rat skin at 4 and 12 h after topical application of Rho B-encapsulated HA-PLGA NPs. Scale bar, 100 μm. A, B Reproduced from [63], copyright permission by American Chemical Society 2018. C, D Reproduced from [67], copyright permission by IOP Publishing Ltd. 2020. E, F, G Reproduced from [68], copyright permission by BioMed Central Ltd. 2019