On the Assembly of Actin Polymerization-Powered Motors

Area of Science:

• Colloid and Surface Science
• Biomimetic Engineering
• Nanotechnology

Background:

• Active colloids and micromotors exhibit self-propulsion exceeding Brownian motion.
• Natural systems utilize biopolymerization for microorganism and organelle locomotion.
• Existing synthetic propulsion methods are often limited by reaction conditions.

Purpose of the Study:

• To explore the propulsion mechanism of Listeria monocytogenes for engineered motors.
• To integrate natural locomotion strategies into synthetic active particles.
• To investigate the effect of ActA immobilization strategies on motor propulsion.

Main Methods:

• Synthesized silica particles as motor platforms.
• Immobilized the actin-recruiting protein ActA using homogeneous, Janus-type, and polymer brush coatings.
• Compared locomotion efficiency against Brownian motion and analyzed particle behavior in response to pH and clustering.

Main Results:

• Janus-type ActA-coated motors showed up to a 5-fold increase in propulsion compared to Brownian motion.
• Motor locomotion, orbiting, and docking behavior were influenced by environmental pH and particle aggregation.
• Different ActA immobilization strategies yielded varying propulsion efficiencies.

Conclusions:

• Engineered micromotors can effectively mimic natural actin-based propulsion.
• Janus-type coatings represent a promising strategy for enhancing synthetic motor performance.
• These biomimetic motors offer a platform for studying active matter and developing novel engineered units.