Inter-particle biomolecular reactivity tuned by surface crowders.

Area of Science:

• Colloid and Surface Science
• Biomolecular Engineering
• Nanotechnology

Background:

• The kinetics of biomolecular bond formation on colloidal particles are critical for applications like biosensing, drug delivery, and colloidal assembly.
• Understanding how particle surface composition influences these binding rates is essential for optimizing such technologies.

Purpose of the Study:

• To investigate the relationship between particle surface molecular composition and the rate of biomolecular bond formation.
• To quantify how specific interactions and passive surface modifiers affect inter-particle aggregation kinetics.

Main Methods:

• Utilized an optomagnetic cluster experiment to measure the inter-particle rate of aggregation.
• Functionalized particles with DNA or proteins for specific binding and polyethylene glycol (PEG) as a passive surface crowder.
• Interpreted experimental data using model simulations.

Main Results:

• Inter-particle binding kinetics were found to be primarily governed by specific interactions.
• Surprisingly, passive crowder molecules (PEG) significantly tuned the binding kinetics for both DNA- and protein-functionalized particles.
• Model simulations indicated that crowders reduce particle surface reactivity by decreasing the reactivity of specific binder molecules.

Conclusions:

• The molecular composition of particle surfaces, including passive modifiers, plays a crucial role in controlling biomolecular binding kinetics.
• Passive surface crowders can effectively modulate the reactivity of specific binding molecules on particle surfaces.
• These findings offer insights for designing and controlling particle-based systems for various applications.