Autonomous Matter Symposium

Daan Frenkel

Viruses: not “alive”, yet autonomous

One characteristic of autonomy is that the concept is only meaningful for objects that exist in a variable environment: a rock in deep space does neither influence, nor adjust to its environment. But neither is a pre-programmed robot autonomous. I shall argue that strains of viruses behave in time as autonomous systems, even though individual viruses do not. But, of course, in the end, it is all down to evolution and, as we have all seen during the past few years, viruses are the ultimate evolution machines.

Daan Frenkel received his PhD in Physical Chemistry from the University of Amsterdam in 1977. Subsequently, he was a postdoc at UCLA and worked at Shell Research (Amsterdam), the Universities of Utrecht and Amsterdam and at the FOM Institute AMOLF.
In 2007, he was appointed 1968 Chair of Chemistry (Cambridge), where he was Head of Department (2011-2015).
He has published over 500 papers. His book “Understanding Molecular Simulations” (with B Smit) has over 20 000 citations.
Daan Frenkel’s research interests focus on numerical simulations of many-body systems, with an emphasis on problems relating to ordering and self-assembly in soft matter.

Metin Sitti

Physical Intelligence of Small-scale Machines

Intelligence of physical agents is not only enabled by their computational intelligence in their brain, but also by their physical intelligence encoded in their body. This presentation reports bioinspired and abstract physical intelligence methods designed and implemented in small-scale robots from insect scale down to cell-size scale. Light-powered phototactic and bacteria-driven chemo/magnetotactic microswimmers are presented at the cell-size scale. At the milliscale, bioinspired soft-bodied robots with shape and stiffness programming capability, physical adaptation in confined spaces, and multifunctionality are presented. Liquid crystal elastomer type of stimuli-responsive materials are integrated with magneto-elastic composites towards self-sensing and self-adapting millirobots. Finally, mechanical computing systems using bistable metastructures are proposed to encode physical computing in millimachines.

Metin Sitti is the director of Physical Intelligence Department at Max Planck Institute for Intelligent Systems in Stuttgart, Germany. He is also a professor at ETH Zurich, professor at Koç University, and honorary professor at University of Stuttgart. He was a professor at Carnegie Mellon University (2002-2014) and a research scientist at UC Berkeley (1999-2002) in USA. He received BSc and MSc degrees (1994) from Boğaziçi University, Turkey, and PhD degree from University of Tokyo, Japan (1999). His research interests include physical intelligence, small-scale mobile robotics, bio-inspiration, and wireless medical devices. He received the Breakthrough of the Year Award in Falling Walls World Science Summit 2020, ERC Advanced Grant in 2019, Rahmi Koç Science Medal in 2018, SPIE Nanoengineering Pioneer Award in 2011, and NSF CAREER Award in 2005.

Birte Höcker

On the design of protein folds and functions

Protein design aims to build new proteins with novel functions. Methods range from generating and screening mutant libraries via repurposing of active sites or binding pockets all the way to de novo design. I will discuss advantages and difficulties of the different approaches and show some highlights from our recent applications that range from the repurposing of a repressor to a plant sensor via evolution-guided design by chimeragenesis to the de novo design of TIM-barrel proteins. As the rapidly developing AI-based methods also have a great potential for protein design, I will also touch on the use of natural language processing for protein design.

Birte Höcker is a full professor at the department of biochemistry at Bayreuth University. After studying biology at the University of Göttingen and Carleton University in Ottawa, she received her PhD in biochemistry from the University of Cologne. She then worked as a postdoctoral fellow on computational protein design at Duke University in Durham, NC. In 2006 she started her independent research group at the MPI for Developmental Biology in Tübingen. In 2016 the group relocated to Bayreuth where they continue their work on the evolution and design of protein folds and functions.

Eduard Hannezo

Mechano-chemical models of collective cell migration

Living tissues are characterized by an intrinsically mechano-chemical interplay of active physical forces and complex biochemical signalling pathways. Either type of feature alone can give rise to complex emergent phenomena at the tissue scale, for example mechanically driven flocking or rigidity transitions, or chemically driven reaction-diffusion instabilities. An important question is thus how to quantitatively assess the contribution of these different cues to the large-scale dynamics of biological materials in cases where multiple phenomena are present or even coupled. In this talk, I will present a few examples that we have worked on in the context of collective cell migration.

Lauren Zarzar

Chemically programmable active oil droplets

Understanding the chemo-mechanical mechanisms that direct the motion and interactions of self-propulsive colloids is a growing interest area in the field of active matter. An important consideration when designing chemotactic active colloids, such as self-propelled droplets, is the mechanism by which asymmetric forces will be generated and applied to direct the colloid motion. In the case of active droplets, motion is often driven by interfacial tension gradients and Marangoni flows induced by micelle-mediated solubilization, a process wherein the droplet contents are transferred into the continuous micellar phase. However, it is still not well understood how the chemical compositions and dynamics of these gradients can be harnessed to influence droplet activity. In this presentation, I will discuss chemomechanical frameworks for generating oil-in-water droplet behaviors like self-propulsion, attraction/repulsion, and non-reciprocal interactions (e.g. chasing) of tunable strength and directionality with a special focus on chemical composition of the emulsions. I will describe how the adsorption of solid nanoparticles on the surface of solubilizing oil droplets can further influence the droplets’ self-propulsion speeds, proposing possible mechanisms. The interfaces present in the emulsion, and the structure of complex droplets, is observed to be critical to active behaviors, and I will propose ideas for how the non-equilibrium transport at liquid interfaces may play a role in governing the active behaviors of solubilizing droplets.

Lauren Zarzar is an associate professor at Penn State with appointments in the Department of Chemistry and the Department of Materials Science and Engineering. Prior to Penn State, Lauren earned a B.A. in chemistry and a B.S. in economics from the University of Pennsylvania, a Ph.D. in chemistry from Harvard University, and completed a postdoc at MIT. Her group’s research interests include the study of responsive systems and active matter, laser direct writing for synthesis and patterning of nanomaterials, and micro-optics.