News

New multi-million euro projects design magnetic tweezers to explore interaction and swarming dynamics of moving particles

Professor Jaakko Timonen's five-year research projects will design a new kind of magnetic tweezers with which to control and study the interaction of moving active particles. The tweezers could be used in microbiological research, for example, to separate and differentiate between various types of cells.

A flock of birds is a group of active particles. The birds fly independently, but the sum of their interactions moves the flock more or less in the same direction. Microscopically small ”flocks”, such as bacteria populations, behave in a somewhat similar way.

In physics, autonomously moving—or self-propelled—particles from microbes to larger animals and synthetic particles are called agents or active particles. The new extensive research projects led by Professor Jaakko Timonen seek a breakthrough in controlling microscopic active particles with magnetic tweezers. The research focuses on particles that move in different ways: bacteria, microalgae, and synthetic active particles.

The aim is to develop a new type of magnetic tweezers to manipulate rapidly moving active particles in real-time and also to study the mechanisms underlying the interaction between the particles. Professor Timonen’s projects are funded by both the Academy of Finland and the European Research Council (ERC) Starting Grant.

In the first phase, Timonen’s team will examine the framework, or the room for manoeuvre, of a single active particle: how can it affect the collective action of a larger group of particles. The study involves mixing chemically synthesized magnetic nanoparticles with the active particles and seeing how their motion could be controlled with an external magnetic field. This micromanipulation technique based on magnetic forces is called magnetic tweezing.

We turn one actively moving agent to a different direction than the others and monitor in real-time how that changes the collective motion.

Jaakko Timonen

‘We turn one actively moving agent to a different direction than the others and monitor in real-time how that changes the collective motion. If you compare this phenomenon to a flock of birds, we are looking for the smallest change in direction and amount of movement needed from a single bird to make the entire flock formation react and change course,’ says Jaakko Timonen.

Active particles move rapidly and unpredictably, however, making it difficult to manipulate them. These “intelligent” magnetic particles controlled with magnetic tweezers could be programmed to differentiate various types of microscopic objects, such as different cell types in microbiological research.

In the next phase of the project, active particles will be placed in magnetic fluid. The goal now is to control not individual particles, but the entire flock at the same time—indirectly through the magnetic fluid. The fluid acts as magnetic tweezers creating potential wells of energy to trap a large number of active particles.

We want to study this interesting competitive situation where the particles try to move even though they are running out of space.

Jaakko Timonen

‘When we have previously conducted similar studies on passive colloidal particles, they have ended up in simple formations at the bottom of the potential well. In our new study design, we replace passive particles with active ones. When the potential well becomes deeper, the particle density grows and there is less and less room to move. We want to study this interesting competitive situation where the particles try to move even though they are running out of space,’ says Timonen.

Further information:

Jaakko Timonen
Assistant Professor
Aalto University
[email protected]
tel. +358 44 230 5820

  • Published:
  • Updated:
Share
URL copied!

Read more news

Etualalla seisovan naisen taustalla abstrakti taustakuva, ja kuvan päällä keltaisella ohjelmointitekstiä
Press releases Published:

Finnish universities join forces to train 5G experts

FITech universities, and the University of Helsinki are using a million euros in funding from the Ministry of Education and Culture to launch expert training in 5G technology. The courses will be open to all, and free of charge. Training will also be available as a minor subject for university students.
QS-ranking tulos 2021
Press releases, Research & Art Published:

Aalto University’s Art & Design now ranked 6th in the world

Six of Aalto’s fields reached the top 100 in the prestigious QS ranking
Leffateatterin akustiikka tallennettiin erikoismikrofonilla. Kuva: Janne Riionheimo / Aalto-yliopisto
Press releases Published:

Cinema acoustics can modify substantially the soundscape of a movie

Carefully mixed music can sound stuffy or the clarity of speech may suffer, noticed researchers of Acoustics at Aalto University.
dox release from dna nanostructure aalto university
Press releases Published:

Researchers watch anti-cancer drug release from DNA nanostructures in real time

Findings provide insights into tunable drug delivery and new design paradigms of DNA-based drug-carriers