(691e) Autonomous Motion of Mixed Polymer Janus Particles Driven By Enzymatic Catalysis

Cellular motion is a dynamic process that plays a critical role in immunology, tissue assembly, and physiological homeostasis. Cell-like motility of artificial cells, or protocells, has the potential to enhance biologist’s understanding of complex cellular processes and to develop new technologies related to drug delivery, biochemical sensing, and cell-to-cell signaling. Understanding the fundamental requirements for protocell motion would provide insights into cellular motion and lead to the development of new technologies for building responsive protocells that could sense and respond to environmental stimuli. In this work, we use the notion that enzymes, when converting substrates to products, can exert forces. Our group recently used this idea to illustrate the enzyme-driven motion of cell-sized, urease-functionalized poly(lactic-co-glycolic acid) (PLGA) microcapsules. These capsules were intentionally developed with a non-uniform enzyme distribution on their shell; enzyme asymmetry has been hypothesized to be the driving force for enhanced motion. In our current work, we have made asymmetric Janus microparticles using microfluidic assembly to test whether asymmetric particles can display enhanced motion. We fabricated Janus microparticles using a mixed polymer system, blending the polymers PLGA and polycaprolactone (PCL). These two polymers partially phase separate during dewetting. Protein conjugation via 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) targets carboxylic acid functional groups which are only present on one lobe of the Janus particle, creating an inherent asymmetry in both shape and enzyme functionalization. This asymmetry can propel Janus particles functionalized with urease. Active motion of these particles provides direct measurements of the relationship between direction of motion and the axis of asymmetry of the Janus particles. We are exploring the relationship between capsule size, capsule asymmetry, enzyme density and enzyme type and the avidity of capsule motion.