*2.1. Materials*

DEX (Fagron Ibérica, Barcelona, Spain), ethyl cellulose (EC) (Ashaland Industries Europe GmbH, Rheinweg, Switzerland), Tween 80 and Span 60 (Croda Iberica S.A., Spain), benzalkonium chloride (Sigma Aldrich, Madrid, Spain), medium chain triglycerides (MCT) (Oxi-Med Expres S.A., Barcelona, Spain), ethanol absolute (ET) and ethyl acetate (EA) (Scharlab S.L., Barcelona, Spain), and purified water (Inhouse) were used to formulate the LPNCs. Coumarin 6 (C6) (Sigma Aldrich, St. Louis, MO, USA) and 1,2-dioleoyl-3- [16-N-(lissamine rhodamine B sulfonyl) amino]palmitoyl-sn-glycerol (LRB) (Avanti Polar

Lipids, Alabaster, AL, USA) were used as fluorochromes. Paraformaldehyde (Scharlab S.L., Barcelona, Spain), Sucrose (Acor, Valladolid, Spain), optimal cutting temperature compound (OCT) (Tissue-Tek Sakura Finetek, Torrance, CA, USA), rabbit anti-DEX IgG (Abcam, Cambridge, UK), Alexa Fluor 488 goat anti rabbit (Life Technologies, Carlsbad, CA, USA), ProlongTM Gold Antifade mounting medium (Thermo Fisher Scientific, Barcelona, Spain), and Tween 20 (Sigma-Aldrich, St. Louis, MO, USA) were used to prepare samples for microscopic visualization.
