*Article* **Antifungal Encapsulated into Ligand-Functionalized Nanoparticles with High Specificity for Macrophages**

**Susana P. Mejía 1,2,†, Daniela López 2,†, Luz Elena Cano 2, Tonny W. Naranjo 2,3 and Jahir Orozco 1,\***


**Abstract:** Infectious diseases caused by intracellular microorganisms such as *Histoplasma capsulatum* represent a significant challenge worldwide. Drug encapsulation into functionalized nanoparticles (NPs) is a valuable alternative to improving drug solubility and bioavailability, preventing undesirable interactions and drug degradation, and reaching the specific therapeutic target with lower doses. This work reports on Itraconazole (ITZ) encapsulated into core-shell-like polymeric NPs and functionalized with anti-F4/80 antibodies for their targeted and controlled release into macrophages. Uptake assay on co-culture showed significant differences between the uptake of functionalized and bare NPs, higher with functionalized NPs. In vitro assays showed that F4/80-NPs with 0.007 μg/mL of encapsulated ITZ eliminated the *H. capsulatum* fungus in co-culture with macrophages effectively compared to the bare NPs, without any cytotoxic effect on macrophages after 24 h interaction. Furthermore, encapsulated ITZ modulated the gene expression of anti and pro-inflammatory cytokines (IL-1, INF-Y, IL-6 and IL-10) on macrophages. Additionally, the anti-F4/80 antibody-coating enhanced natural and adequate antifungal response in the cells, exerting a synergistic effect that prevented the growth of the fungus at the intracellular level. Functionalized NPs can potentially improve macrophage-targeted therapy, increasing NPs endocytosis and intracellular drug concentration.

**Keywords:** *Histoplasma capsulatum*; PLGA; Itraconazole; macrophage; functionalized nanoparticle; F4/80 receptor
