Micro- and nanomotors and their use for biomedical applications have recently received increased attention. However, most designs use top-down methods to construct inorganic motors, which are labour-intensive and not suitable for biomedical use. Herein, we report a high-throughput design of an asymmetric hydrogel microparticle with autonomous movement by using a microfluidic chip to generate asymmetric, aqueous, two-phase-separating droplets consisting of poly(ethylene glycol) diacrylate (PEGDA) and dextran, with the biocatalyst placed in the PEGDA phase. The motor is propelled by enzyme-mediated decomposition of fuel. The speed of the motors is influenced by the roughness of the PEGDA surface after diffusion of dextran and was tuned by using higher molecular weight dextran. This roughness allows for easier pinning of oxygen bubbles and thus higher speeds of the motors. Pinning of bubbles occurs repeatedly at the same location, thereby resulting in constant circular or linear motion.

Microfluidics is an ideal tool for the design of self‐assembled micromotors. It allows for easy change of solutions, catalysts, and flow rates, which affect shape, structure, and motion of the resulting micromotors. A microfluidic tool generating aqueous‐two‐phase‐separating droplets of UV‐polymerizable poly(ethylene glycol)diacrylate (PEGDA) and an inert phase, salt, or polysaccharide, is utilized to fabricate asymmetric microbeads. Different molecular weights and branching of polysaccharides are used to study the effect on shape, surface roughness, and motion of the particles. The molecular weight of the polysaccharide determines the roughness of the motors inner surface. Smooth openings are obtained by low molecular weight dextran, while high surface roughness is obtained with a high molecular weight branched polysaccharide. Since roughness plays an important role in bubble pinning, it influences both speed and trajectory. Increasing speeds are obtained with increasing roughness and trajectories ranging from linear, circular to tumble‐and‐run depending on the nature of bubble pinning. This microfluidic tool allows for fine‐tuning shape, structure, and motion by easy change of solutions, catalysts, and flow rates.

Covalent and non-covalent molecular binding are two strategies to tailor surface properties and functions. However, the lack of responsiveness and requirement for specific binding groups makes spatiotemporal control challenging. Here, we report the adaptive insertion of a hydrophobic anchor into a poly(ethylene glycol) (PEG) host as a non-covalent binding strategy for surface functionalization. By using polycyclic aromatic hydrocarbons as the hydrophobic anchor, hydrophilic charged and non-charged functional modules were spontaneously loaded onto PEG corona in 2 min without the assistance of any catalysts and binding groups. The thermodynamically favourable insertion of the hydrophobic anchor can be reversed by pulling the functional module, enabling programmable surface functionalization. We anticipate that the adaptive molecular recognition between the hydrophobic anchor and the PEG host will challenge the hydrophilic understanding of PEG and enhance the progress in nanomedicine, advanced materials and nanotechnology.

Micro‐ and nanomotors and their use for biomedical applications have recently received increased attention. However, most designs use top‐down methods to construct inorganic motors, which are labour‐intensive and not suitable for biomedical use. Herein, we report a high‐throughput design of an asymmetric hydrogel microparticle with autonomous movement by using a microfluidic chip to generate asymmetric, aqueous, two‐phase‐separating droplets consisting of poly(ethylene glycol) diacrylate (PEGDA) and dextran, with the biocatalyst placed in the PEGDA phase. The motor is propelled by enzyme‐mediated decomposition of fuel. The speed of the motors is influenced by the roughness of the PEGDA surface after diffusion of dextran and was tuned by using higher molecular weight dextran. This roughness allows for easier pinning of oxygen bubbles and thus higher speeds of the motors. Pinning of bubbles occurs repeatedly at the same location, thereby resulting in constant circular or linear motion.