Using engineered single-chain antibodies to correlate molecular binding properties and nanoparticle adhesion dynamics

Area of Science:

• Biomedical Engineering
• Materials Science
• Nanotechnology

Background:

• Optimizing nanocarrier design requires understanding how molecular interactions influence adhesion.
• Therapeutic and diagnostic nanocarriers rely on targeted binding for efficacy.

Purpose of the Study:

• To investigate the relationship between molecular binding properties and nanocarrier adhesion under fluid flow.
• To evaluate the impact of molecular size, valency, and binding kinetics on nanoparticle attachment and detachment.

Main Methods:

• Studied 200-nm nanoparticles with various molecular interactions: single-chain variable fragments (scFvs), full antibodies, and avidin/biotin.
• Utilized scFv mutants with varying binding kinetics and explored effects of molecular size via linkers.
• Employed computational models to extract multivalent kinetic rate constants for attachment and detachment.

Main Results:

• Nanoparticle attachment rate increased with adhesion molecule valency and size.
• Bond kinetics did not affect scFv-mediated attachment but influenced antibody/antigen and avidin/biotin adhesion.
• Nanoparticle detachment probability correlated with valency, size, and binding affinity.

Conclusions:

• Single-chain variable fragments (scFvs) show potential as nanoparticle targeting receptors.
• Multivalent binding and bond mechanical strength are key factors in nanoparticle adhesion.
• Enhancing scFv mechanical strength could improve nanoparticle targeting efficiency and tunable kinetic properties.