Macrophage\nMembrane-Coated Nanoparticles for the Delivery\nof Natamycin Exhibit Increased Antifungal and Anti-Inflammatory Activities\nin Fungal Keratitis

This\nstudy aims to explore the efficacy and safety of macrophage\nmembrane-coated nanoparticles for the delivery of natamycin (NAT)\nin the therapy of fungal keratitis (FK). Macrophage membranes were\nisolated and identified by immunofluorescence staining (IFS). NAT\nwas encapsulated into poly(lactic-<i>co</i>-glycolic acid)\n(PLGA). Fungal stimulated macrophage membranes (M1) or unstimulated\nmembranes (M) were separately mixed and sonicated with PLGA nanoparticles.\nThe biocompatible nanoparticles (PLGA-NAT, PLGA-NAT@M, and PLGA-NAT@M1)\nwere characterized with zeta-sizer analysis, transmission electron\nmicroscopy (TEM), and Western blot. Drug encapsulation and loading\nefficiency and the release of NAT in the nanoparticles were detected\nby ultraviolet spectrophotometry. The cytotoxicity, ocular surface\ntoxicity and irritability, and systemic safety of nanoparticles with\ndifferent concentrations were assessed. In vitro, we examined the\nantifungal properties of the nanoparticles. The eye surface retention\ntime, drug release, and curative effects on FK were evaluated in vitro\nand in vivo. IFS results showed the separation of the macrophage membrane\nand nucleus. The prepared nanoparticles had a typical “core–shell”\nstructure and uniform nanometer size, and the membrane proteins were\nretained on the membrane allowing to exert functional effects of macrophage.\nThe loading efficiencies of PLGA-NAT@M and PLGA-NAT@M1 were 7.6 and\n6.7%, respectively. The encapsulation efficiencies of PLGA-NAT@M and\nPLGA-NAT@M1 were 51.2 and 41.5%, respectively. PLGA-NAT@M and PLGA-NAT@M1\ncould gradually release NAT and reduce the clearance of the ocular\nsurface. Macrophage membranes enhanced the antifungal activity of\nPLGA-NAT. Furthermore, the membrane coated with macrophage increased\nthe biocompatibility and decreased the corneal toxicity of nanoparticles.\nIn vivo, PLGA-NAT@M1 significantly alleviated the severity of FK.\nIn vitro, PLGA@M and PLGA@M1 reduced the protein levels of inflammatory\ncytokines after fungal stimulation. The prepared PLGA-NAT@M1 has good\nphysical properties and biosafety. It could evade ocular surface clearance,\nrelease NAT gradually, and achieve high antifungal and anti-inflammatory\nefficiencies to FK. Macrophage membrane-coated nanoparticles clinically\nhave high application potential to the treatment of FK.