Multimodal evaluation of mannose engineered poly lactic glycolic acid nanoparticles with granulocyte colony stimulating factor focused delivery to bone marrow for neutropenia

Neutropenia, characterized by a critical reduction in neutrophils, demands targeted therapeutic strategies to enhance the delivery efficiency of granulocyte colony-stimulating factor (G-CSF) specifically to bone marrow macrophages. This study focused on engineering mannose-modified poly(D, L-lactide-co-glycolide) (PLGA) nanoparticles (NPs) to achieve ligand-directed delivery of G-CSF. Mannose anchoring was achieved via Ethylenediamine (EDA)-mediated chemical ligation using N-hydroxysulfosuccinimide (NHS) and dicyclocarbodiimide as coupling agents, resulting in Mn-EDA-PLGA NPs. G-CSF-loaded and placebo NPs were fabricated through a multiple emulsion solvent evaporation method and subjected to comprehensive physicochemical characterization. The developed placebo Mn-EDA-PLGA NPs measured 199 ± 12 nm, while G-CSF-loaded Mn-EDA-PLGA NPs measured 153 ± 12.2 nm, both exhibiting a negative surface charge of − 40.07 ± 1.1 mV and − 34.9 ± 1.9 mV, respectively. Polydispersity index values were low (0.34 and 0.41), indicating uniform particle distribution. Entrapment efficiencies were significant, with the optimized G-CSF-loaded formulation achieving 72.6% drug encapsulation efficiency and drug loadings of 5 µg and 3 µg for placebo and active NPs, respectively. Scanning electron microscopy confirmed spherical morphology with smooth surfaces. Biological evaluation using scintigraphy and flow cytometry in J774.2 macrophage cells validated the targeting efficiency of mannose-modified NPs. Furthermore, molecular docking and molecular dynamics simulations substantiated the stability and interaction profile of G-CSF within the nanocarrier system. The convergence of in vitro, in vivo, and silico findings underscores the potential of Mn-EDA-PLGA NPs as a robust delivery vehicle for G-CSF, offering enhanced bone marrow macrophage targeting. This targeted approach holds promise for improving therapeutic outcomes in neutropenia by maximising drug localization and minimising systemic exposure.