Engineering Motile Coacervate Droplets via Nanomotor Stabilization

Coacervate-based artificial cells have gained significant attraction in synthetic biology for their ability to mimic life-like functions such as compartmentalization, selective molecular uptake, and the hosting of biochemical reactions. However, the incorporation of motility, a key feature of natural cells, remains underexplored. This is mainly caused by the dynamic character of coacervates, which hampers their stability and limits control over functional motile components within the structure. In this contribution, we have been able to address this gap by physically anchoring gold nanoparticles (AuNPs)-coated nanomotors at the coacervate interface in combination with a terpolymer membrane. The positively charged coacervates promoted the assembly of negatively charged nanomotors on their surfaces via electrostatic interactions. By costabilizing the coacervates with a terpolymer membrane, patches of nanomotors were firmly immobilized on the coacervates' surface and the stability of coacervates was preserved during motion performance. The distribution of nanomotors shifted from spotted distribution, patchy distribution, to almost full coverage upon increasing nanomotors concentration. Optimal motile behavior was found when achieving a patchy coverage of nanomotors at the interface, which enabled the system to become a light-driven micromotor platform through the surface plasmon thermal effect of the AuNPs. Remarkably, the motion dynamics of these coacervate droplets could be modulated by tuning nanomotors' density on the surface, coacervates' size, and laser light intensity. This study provides a first example of a coacervate system, which is stabilized by a combination of nanoparticles and a terpolymer membrane, of which their motility is effectively transferred to the artificial cell structure.