Direct measurements of collective swimming forces at the mesoscale

Informazioni relative al progetto

SWARM

ID dell’accordo di sovvenzione: 101115076

DOI

10.3030/101115076

Data della firma CE 31 Ottobre 2023

Data di avvio 1 Gennaio 2024

Data di completamento 31 Dicembre 2028

Finanziato da

• European Research Council (ERC)

Costo totale

€ 1 500 000,00

Contributo UE

€ 1 500 000,00

Coordinato da

AALTO KORKEAKOULUSAATIO SR
Finland

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

Periodo di rendicontazione: 2024-01-01 al 2026-06-30

Sintesi del contesto e degli obiettivi generali del progetto

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.

Lavoro eseguito dall’inizio del progetto fino alla fine del periodo coperto dalla relazione e principali risultati finora ottenuti

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.

Progressi oltre lo stato dell’arte e potenziale impatto previsto (incluso l’impatto socioeconomico e le implicazioni sociali più ampie del progetto fino ad ora)

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.