Direct measurements of collective swimming forces at the mesoscale

Projektinformationen

SWARM

ID Finanzhilfevereinbarung: 101115076

DOI

10.3030/101115076

EK-Unterschriftsdatum 31 Oktober 2023

Startdatum 1 Januar 2024

Enddatum 31 Dezember 2028

Finanziert unter

• European Research Council (ERC)

Gesamtkosten

€ 1 500 000,00

EU-Beitrag

€ 1 500 000,00

Koordiniert durch

AALTO KORKEAKOULUSAATIO SR
Finland

Periodic Reporting for period 1 - SWARM (Direct measurements of collective swimming forces at the mesoscale)

Berichtszeitraum: 2024-01-01 bis 2026-06-30

Zusammenfassung vom Kontext und den Gesamtzielen des Projekts

The collective, coherent swimming of many organisms is commonly observed in nature and important to many biological processes. The physics of this phenomenon has been studied in detail at the viscous microscale and inertial macroscale, where simplifications can be made to theoretical models to describe the swimming of simply shaped objects. However, the development of such an analytical approache is not straightforward for actively swimming organisms with real-life shapes. Furthermore, the physics is heavily complicated at the so-called mesoscale, where both viscous and inertial forces are of similar importance. This mesoscale is full of living organisms, such as small larvae, shrimps, and jellyfish, and the physics behind their swimming and hydrodynamic interactions is strongly complicated by non-linear and time-dependent effects at increasing swimming speeds and organism sizes. A breakthrough in our understanding of mesoscale collective swimming dynamics is hindered by an absence of force-based experiments on living meso-organisms. The main scientific goal of SWARM is to resolve several major questions on mesoscale motility and swimming interactions, with the grand goal to discover new insights into how and why swarms of mesoswimmers are formed in nature. We aim to provide sensitive and important force and fluid dynamics data for theorists to use in their future models and for engineers to use in their biomimicry design of new mesorobots.

Arbeit, die ab Beginn des Projekts bis zum Ende des durch den Bericht erfassten Berichtszeitraums geleistet wurde, und die wichtigsten bis dahin erzielten Ergebnisse

In this SWARM project, we study the swimming dynamics of living meso-scale organisms through direct force measurements. In the first part of the project, we have further developed the micropipette force sensor to allow for measurements in the highly dynamic regime of mesoswimmers. We have successfully probed the swimming forces of the model meso-swimmer Artemia across several life stages. By observing the swimmer motion simultaneously with the direct force measurements, we have been able to correlate the intricate mesoswimming kinematics with the dynamics. We have discovered what type of swimming motion produces the best propulsion. Our work furthermore shows that there is a universal law of how micro- to meso-organisms swim and we can now estimate the swimming forces based on the size of the organism and the frequency of its motion. This significantly advances our understanding of biological meso-swimming dynamics.

We have also studied how groups of Artemia swimmers behave when confined in a small sphere. This represents a landmark in mesoscale living matter physics and capillary phenomena. We showcase a simplistic approach to capture the core physics of an intricate many-body system by measuring the swimmer-induced oscillations of the “living” droplets. In this work, we derive a new scaling law describing how crowding affects the swimming speed of the swimmers and compare our results with directly tracked swimmers in quasi-2D droplets.

Fortschritte, die über den aktuellen Stand der Technik hinausgehen und voraussichtliche potenzielle Auswirkungen (einschließlich der bis dato erzielten sozioökonomischen Auswirkungen und weiter gefassten gesellschaftlichen Auswirkungen des Projekts)

The first results of SWARM include quantitative information of how to swim at the mesoscale in order to achieve the best propulsion and thus provides guidance for future biomimicking meso-robot designs. Based on our work, such meso-robots can now be programmed to move in the most efficient way. Our work on confined swimmers is important for future work on bio-inspired droplet actuation with implications for mesoscale robotics, fluidics, and sensing. These research projects build the foundation needed for the rest of this SWARM project, where we will start to understand collective swimming dynamics at the mesoscale. This is important in the creation of new biomedical and engineering applications at the mesoscale, such as swallowable surgery with swarming meso-robots capable of optimising their swarm geometry to minimise power consumption in different environments.