Nanoseminar dr. Rao Vutukuri
Speaker: dr. Rao Vutukuri, University of Twente/ TNW/ Nanobiophysics)
Title:Designer active matter: from self-propelled particles to active vesicles
Abstract: Active matter systems present us with exciting possibilities for designing novel bio-inspired materials and devices, yet they also introduce scientific and technological challenges. Active matter systems consume internal or extract energy from their local environment in order to generate their own motion. Designing simple synthetic active model systems such as self-propelled particles (SPPs) or artificial microswimmers is currently a topic of substantial interest in the active soft matter for a variety of reasons. First, their collective motion bears a striking resemblance with their more complex natural counterparts. Second, they serve as model systems to study intrinsically out-of-equilibrium systems and display rich collective phenomena such as active clustering, segregation, and anomalous density fluctuations . In this talk, I will present some designing strategies to develop novel self-propelled and biomimetic systems. In the first part of my talk, I introduce three systems: rotators, artificial flagella-like swimmers , and particles whose propulsion direction can be controlled by light modulation . Using the direction-reversible particles, I demonstrate that the reversibility of the disturbance velocity fields around the particles can be used to drive processes mimicking the “fusion-fission” of cellular systems. In the second part of my talk, I present a simplified biomimetic system to investigate how the lipid membrane responds to highly localized point forces from within, such as those exerted by the cytoskeleton. In our system, the cell membrane is mimicked by giant unilamellar vesicles of lipid bilayers, and the local internal forces are generated by enclosing self-propelled particles . I demonstrate that the propulsion forces of individual self-propelled particles, as small as ~ 0.1 pN, are sufficient to dramatically distort vesicle shapes and lead to active membrane fluctuations. Our study paves the way for understanding the interplay between local active forces and dynamic vesicle shape deformations. Our results may also aid in understanding the conditions under which cells change their shape either locally or globally and advance the design of artificial systems, such as micron-sized soft robotic system and synthetic cells.
1. Bechinger, et al., Active particles in complex and crowded environments, Rev. Mod. Phys, 88, 2016.
2. H. R. Vutukuri, et al., Rational design and dynamics of self-propelled colloidal bead chains: from rotators to flagella, Scientific Reports, 7, 16758 (2017). https://www.nature.com/articles/s41598-017-16731-5
3. H. R. Vutukuri, et al., Light-switchable propulsion of active particles with reversible interactions, Nat. Communi. 11, 2628(2020). https://www.nature.com/articles/s41467-020-15764-1
4. H. R. Vutukuri, et al., Active particles induce large shape deformations in giant lipid vesicles, Nature, 586, 52 (2020). https://www.nature.com/articles/s41586-020-2730-x