Scientists Uncover How Microswimmers Move Faster in Groups – Paving the Way for Tiny Drug-delivering Robots
Scientists have revealed how tiny swimming cells – such as sperm and bacteria – are able to move faster when travelling as a group, and the research could accelerate the development of microscopic robots that deliver drugs to specific regions of the body.
The work, conducted by researchers from Loughborough University and the Indian Institute of Science, shows that when 'microswimmers' move together through enclosed environments, they change the properties of the fluid around them, reducing resistance and increasing their speed compared to swimming alone.
The findings could be key to designing artificial microswimmers – tiny, controllable, swimming robots – that could be used for a variety of medical applications, such as IVF, parasite treatment, and targeted medical drug delivery that replaces traditional, less precise interventions.
“Imagine if we could create artificial microswimmers that can be injected into the bloodstream and controlled from the outside. We could navigate them to specific areas of the body, for example, cancer cells, and have them deliver drugs only to these areas”, says Dr Marco Mazza, the study’s senior author.
“To do this, we first need to understand how naturally occurring microswimmers navigate different fluid environments and our study has made significant progress in this area.”
The research, published in Physical Review Letters, focuses on a theoretical model for Paramecium – tiny single-celled organisms that live in water and propel themselves by beating hair-like structures called cilia. Their movement is similar to that of sperm and other microswimmers, which also use appendages to generate motion and navigate fluid environments.
Using computer simulations and theoretical models, the researchers analysed how an individual microswimmer and groups of up to 10 move through a confined liquid crystal environment – a unique type of fluid that flows like a liquid but has molecules that line-up in an ordered way. These structured fluids naturally occur in nature and biological systems, including cell membranes and tissues.
The key findings are:
Microswimmers moving in groups create flow fields – movements in the surrounding liquid – that help them swim more efficiently by reducing resistance and enhancing propulsion
As more swimmers join, their average speed increases, allowing them to move faster than they could alone
Liquid crystal environments help guide and direct microswimmers, influencing their movement
There are two types of microswimmers – ‘pushers’ and ‘pullers’. Pushers benefit from collective movement, while pullers hinder each other, showing the effect depends on swimmer type.
The next step is to expand the research, moving from small-scale simulations to those that replicate how hundreds of microswimmers move through different enclosed liquid environments.
The scientists also hope to collaborate with experimental researchers working with Paramecium and other types of microswimmers to compare real-world behaviour with their theoretical models. This will provide deeper insights into collective swimming dynamics, which could inform the design of artificial microswimmers.
Professor Tony Croft, one of the study authors and Emeritus Professor of Mathematics Education at Loughborough University, hopes the impact of this research will be felt beyond the academic realm.
“This work has the power to ignite curiosity in young minds, inspiring new generations of learners to explore the fascinating intersection of mathematics, physics and biology”, he said.
“Too often, students perceive mathematics as dry and irrelevant; our work challenges that notion, revealing its deep connections to the real world and its potential to unlock exciting new discoveries.”
Read the original article on Loughborough University.