Enzymatic Janus Liposome Micromotors

Abstract

A liposome-based micromotor system that utilizes regional enzymatic conversion and gas generation to achieve directional motion in water is presented. Constituted mainly of a low-melting lipid and a high-melting lipid together with cholesterol, these liposomes maintain stable Janus configuration at room temperature as a result of lipid liquid−liquid phase separation. Local placement of enzymes such as horseradish peroxidase is realized via affinity binding between avidin and biotin, the latter as a lipid conjugate sorted specifically into one domain of these Janus liposomes as a minor component. In the presence of the substrate, hydrogen peroxide, these enzyme-decorated Janus liposomes undergo directional motion, yielding velocities exceeding thermal diffusion by three folds in some cases. Experimental details on liposome size control, motor assembly, and substrate distribution are presented; effects of key experimental factors on liposome motion, such as substrate concentration and liposome Janus ratio, are also examined. This work thus provides a viable approach to building asymmetrical lipidassembled, enzyme-attached colloids and, in addition, stresses the importance of asymmetry in achieving particle directional motion.

Lipid vesicle-based molecular robots

“…In 2019, Ghosh et al showed that GUVs with ATPase-tagged lipid membranes exhibited enhanced mobility in the presence of ATP. 286 In 2023, Jin et al demonstrated that horseradish peroxidase (HRP)-decorated Janus GUVs undergo directional motion in the presence of H 2 O 2 , while such enhanced mobility is absent from homogeneously enzyme-decorated GUVs 287 ( Fig. 11(c) ).…”

Free‐Standing Janus Nanosheets: Ultrafast Self‐Assembly and Versatile Biphase‐Application

“…[8] Additionally, Janus architectures with asymmetric magnetic properties can give rise to notable performances in drug delivery, [9,10] biological imaging and probes, [11,12] and directional motion. [13,14] Aside from the traditional spherical Janus particles, 1D Janus rods and 2D Janus nanosheets are also feasible, albeit typically more challenging to prepare. [15][16][17] Notably, 2D Janus nanosheets have been the subject of significant interest due to their high aspect ratio, highly anisotropic shape and chemistry, as well as the highly confined rotation at interfaces.…”

Chemomechanical Communication between Liposomes Based on Enzyme Cascades

“…We used different populations of enzyme-functionalized liposomes and/or solid particles that are part of catalytic reaction cascades. The addition of the substrate for the first population results in the enhanced motility of those particles. ,− At the same time, the chemical product formed serves as the substrate for the second population and enhances their motility. The process continues in populations involving three enzymes, resulting in enhanced motility of the third population.…”