Researchers at the Max Planck Institute for Intelligent Systems, the Institute for Bioengineering of Catalonia (IBEC) and the University of Stuttgart have revealed in an article in Nature Communications that micromotors can be guided using tiny topographical patterns on the surfaces over which they swim.
Samuel Sánchez and Mykola Tasinkevych's ‘microswimmers’ are usually guided through fluids using specially engineered magnetic multilayer coatings, which combined with external magnetic fields, helps to control their trajectory.
An active particle approaches a micro-fabricated step and orients along it due to chemical activity and hydrodynamic interactions.
MPI for Intelligent Systems, Stuttgart
This new study, the result of a collaboration between experimental research and theory, demonstrates that the particles can use the features of the surfaces over which they swim to change their direction of motion.
“Micromotors tend to settle and move near surfaces, and we’ve seen that this tends to interfere with their swimming behaviour,” says group leader and ICREA research professor Samuel, who heads the Smart Nano-Bio-Devices group at IBEC and Stuttgart’s MPI-IS. “This led us to explore new methods to guide micromotors using surface alterations.”
Using a microfabrication process, the researchers modified surfaces to create a series of indentations or steps, several times smaller than the radius of the particle, which a specific type of micromotors – Janus particles, whose surfaces have two or more distinct physical properties – can use as signals to follow a particular path. This strategy is inspired by the one used by molecular motors in natural systems, where inside the cell, motor proteins bind to the cytoskeleton filaments to achieve directional motion.
The Janus particles are prepared by coating half of a silica particle with platinum. While the platinum face acts as a catalyst in hydrogen peroxide, the silica side remains inert, an asymmetry in chemical properties that leads to a self-propelled motion of these colloids.
The researchers noticed that the particles tend to have a stable orientation parallel to the surface, and exploited this phenomenon to guide the particles along sub-micron sized steps. They were able to demonstrate that the chemical activity of the particles and the associated hydrodynamic interactions with the nearby surfaces are responsible for the observed phenomenon.
“This finding opens up the possibility of guiding these particles along complex pathways using small changes in the surface,” explains Samuel. “This can have significant implications for the design of new artificial micromotors for a variety of applications.”
Simmchen, J., Katuri, J., Uspal, W.E., Popescu, M.N., Tasinkevych, M., and Sanchez, S. (2016). Sculpted topographical pathways guide chemical microswimmers. Nature Communications Volume: 7, Article number: 10598, DOI:10.1038/ncomms10598
Annette Stumpf | Max-Planck-Institut für Intelligente Systeme
Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery
20.01.2017 | GSI Helmholtzzentrum für Schwerionenforschung GmbH
Seeking structure with metagenome sequences
20.01.2017 | DOE/Joint Genome Institute
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences