Controlling ligand surface density optimizes nanoparticle binding to ICAM-1

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Cell Biology

Background:

• Pathogen entry into cells often involves surface receptor-ligand interactions.
• Multivalent ligand binding enhances pathogen internalization, but ligand density effects are less understood.

Purpose of the Study:

• To investigate the impact of ligand density on nanoparticle cellular uptake.
• To explore methods for modulating ligand density on poly(DL-lactic-co-glycolic acid) nanoparticles (PLGA NPs).

Main Methods:

• Utilized poly(DL-lactic-co-glycolic acid) nanoparticles (PLGA NPs) functionalized with a cyclic peptide (cLABL) targeting intercellular cell adhesion molecule-1 (ICAM-1).
• Modified Pluronic surfactants were combined in varying ratios to control the number of reactive sites on NP surfaces.
• Analyzed particle charge and reactive sites, then conjugated cLABL to modulate surface density.
• Assessed cellular uptake in A549 cells (carcinomic human alveolar basal epithelial cells).

Main Results:

• The ratio of modified Pluronic surfactants influenced NP surface charge and reactive site availability.
• Increased relative amounts of reactive Pluronic led to higher surface density of cLABL.
• Cellular uptake studies indicated an optimal cLABL density for enhanced internalization by A549 cells.

Conclusions:

• Surface ligand density is a critical parameter for optimizing nanoparticle-based cell targeting.
• Tailoring ligand density on NPs can significantly enhance their efficacy in cellular uptake.
• Findings support the consideration of surface density in the design of targeted nanodelivery systems.