Nanoparticle Ligand Exchange and Its Effects at the Nanoparticle-Cell Membrane Interface

Area of Science:

• Nanomaterial science
• Biomedical engineering
• Surface chemistry

Background:

• The nanoparticle-cell membrane interface is critical for nanoparticle fate and biological responses.
• Understanding ligand exchange mechanisms at this interface is crucial for designing effective nanomaterials.
• Current knowledge gaps exist regarding how ligand properties impact nanoparticle-membrane interactions.

Purpose of the Study:

• To investigate the effects of different surface ligands on gold nanoparticle (AuNP) interactions with lipid bilayers and cell membranes.
• To elucidate the role of ligand exchange in governing nanoparticle interfacial phenomena.
• To correlate ligand properties (molecular weight, charge, bonding) with observed effects on nanoparticle behavior and cellular uptake.

Main Methods:

• Synthesis of gold nanoparticles (AuNPs) with a consistent core size (~13 nm).
• Modification of AuNPs with 12 distinct surface ligands, categorized by molecular weight, charge, and adsorption mode (physisorption/chemisorption).
• Evaluation of ligand exchange dynamics at nanoparticle-supported lipid bilayers (SLBs) and natural cell membranes.

Main Results:

• Physisorbed ligands on AuNPs can be exchanged with lipid molecules, dependent on ligand adsorption affinity and size.
• Ligand exchange drives AuNP aggregation into ordered monolayers within lipid bilayers.
• Altered nanoparticle aggregation impacts cell membrane integrity, nanoparticle uptake efficiency, and endocytosis pathways.

Conclusions:

• Ligand exchange is a key mechanism governing nanoparticle-cell membrane interactions.
• Nanoparticle aggregation and subsequent biological effects are tunable via surface ligand properties.
• Findings provide insights for designing safer and more effective nanomaterials for biomedical applications, particularly in theranostics.