Credit: Patrick Hage
Self-assembly is the spontaneous organization of building blocks into disordered state structures or patterns. Some everyday examples include freezing liquids or crystallizing salts. These self-assembly processes also occur in many biological systems, such as protein folding or the formation of DNA helices, and there is a growing interest in studying these self-assembly processes. Researcher Patrick Hage created a new class of self-assembling microparticles that respond to temperature and light, allowing precise control of their assembly into structures.
Colloidal particles, which range in size from a few nanometers to a few micrometers, are often used to study self-assembly processes. Due to their small size, gravitational forces have a minimal influence on their motion. As a result, these particles tend to move randomly while at the same time interacting with each other.
“Despite their small size, these colloidal particles can be imaged using conventional microscopy techniques,” says Patrick Hage, a former doctor. researcher and now postdoctoral fellow in the Self-Organizing Soft Matter group. “The arrangement of these materials on this length scale can lead to materials with new mechanical and optical properties. A natural example of a colloidal ‘superstructure’ with unique optical properties is an opal, which is composed of crystals of small silica spheres. Superstructure control. could lead to new materials for photonic crystals, coatings and sensors “.
Importance of control
To create sensitive and reconfigurable colloidal materials, it is very important to have control over the interactions between particles and the ability to modulate these interactions through external indications.
One way to help modulate interactions is through surface functionalization, where small, simple DNA strands attach to the surface of particles. As you will find in the nucleus of a cell in the human body, these strands of DNA join together to form a DNA helix.
“It’s the formation of these DNA helices that holds the particles together,” says Hage. “Particles with DNA on their surface can be modulated using temperature as a trigger. This controls how the particles interact with each other and leads to complicated structures such as colloidal crystals.”
Multiple triggers
The goal of Hage’s doctorate. The research was to develop a system that would respond to multiple triggers: light and temperature in this case. “The use of multiple activators allows the growth of structures to be controlled in both space and time.”
Hage accomplished this by adding a light-sensitive molecule to the DNA strands responsible for colloidal assembly. This resulted in interactions of particles that responded to both light and temperature at the same time. The combination of these particles with a fluorescent microscope, a heating chamber and a digital micromirror device allowed the visualization of particles while giving precise control of temperature and the ability to apply light with specific patterns to the sample.
“I created a configuration that allows me to visualize the formation of superstructures (e.g., crystals) at specific temperatures, while gaining the ability to modify or remove unwanted structures by applying local light patterns,” says Hage. “In future processes, this dual control could be used to make self-assembled structures for a variety of applications such as advanced sensors or photonic crystals for photonic devices.”
Hage will now continue the work from his doctorate. as part of a 4-month postdoctoral fellowship in the same group. “I look forward to continuing to work to further optimize the system and then transfer the knowledge to other members of the group.”
X-rays help scientists use design DNA to discover new forms of material More information: Synthesis, functionalization and self-assembly of isotropic and irregular microparticles. research.tue.nl/en/publication… -of-isotropic-and-pa Provided by Eindhoven University of Technology
Citation: activation of the self-assembly to microscale with light and heat (2022, June 7) recovered on June 7, 2022 of
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