Ligand Separation on Nanoconstructs Affects Targeting Selectivity to Protein Dimers on Cell Membranes

Area of Science:

• Nanotechnology
• Biophysics
• Molecular Biology

Background:

• Cell membrane receptors play crucial roles in cellular processes.
• Understanding nanoparticle-cell interactions is key for targeted drug delivery and diagnostics.
• Ligand presentation on nanoparticles influences their biological interactions.

Purpose of the Study:

• To investigate how ligand density on nanoparticles affects their binding selectivity to cell membrane receptors.
• To determine the impact of ligand spacing on nanoparticle-receptor interactions in live cells.

Main Methods:

• Utilized gold nanostars functionalized with DNA aptamers at varying densities.
• Employed single-particle tracking to analyze nanoparticle dynamics (rotational and translational) on cancer cells.
• Differentiated between cells expressing dimeric (dimer+) and monomeric (dimer-) forms of target receptors.

Main Results:

• Matched density (MD) nanoparticles, with ligand spacing similar to receptor dimer binding sites, showed enhanced selectivity for dimeric receptors.
• MD nanoparticles exhibited slower rotation and larger translational footprints on dimer+ cells compared to dimer- cells.
• Non-matched density (ND) nanoparticles (NDlow and NDhigh) displayed minimal changes in dynamics across cell types.

Conclusions:

• Nanoparticle ligand density is a critical factor for achieving selective targeting of membrane receptors.
• Real-time single-particle analysis provides insights into the dynamics of nanoconstruct-cell interactions.
• Tailoring ligand spacing on nanoparticles can lead to improved specificity for therapeutic applications.