Home > Press > Reversible Writing with Light: Self-assembling nanoparticles take their cues from their surroundings
Nanoparticles in a light-sensitive medium scatter in the light (left) and aggregate in the dark (right). This method could be the basis of future-quot; re-writable paper-quot. CREDIT: Weizmann Institute of Science |
Abstract:
The medium is the message. Dr. Rafal Klajn of the Weizmann Institute's Organic Chemistry Department and his group have given new meaning to this maxim: An innovative method they have now demonstrated for getting nanoparticles to self-assemble focuses on the medium in which the particles are suspended; these assemblies can be used, among other things, for reversibly writing information.
This approach is an elegant alternative to present methods that require nanoparticles to be coated with light-sensitive molecules; these then switch the particles' state when light is shined on them. According to the group's research, which recently appeared in Nature Chemistry, putting regular, uncoated nanoparticles into a light-sensitive medium would be simpler, and the resulting system more efficient and durable than existing ones. The possible applications range from rewritable paper, to water decontamination, to the controlled delivery of drugs or other substances.
The medium, in this case, is made up of small "photo-switchable" (or "photoresponsive") molecules called spiropyrans. In the version of the photoresponsive molecule employed by Klajn and his group, absorbing light switches the molecule to a form that is more acidic. The nanoparticles then react to the change in acidity in their environment: It is this reaction that causes the particles to aggregate in the dark and disperse in the light. This means that any nanoparticles that respond to acid - a much larger group than those that respond to light - can now potentially be manipulated into self-assembly.
By using light - a favored means of generating nanoparticle self-assembly - to control the reaction, one can precisely govern when and where the nanoparticles will aggregate. And since nanoparticles tend to have different properties if they are floating freely or clustered together, the possibilities for creating new applications are nearly limitless.
Klajn points out that these molecules have a long history at the Weizmann Institute: "Two Institute scientists, Ernst Fischer and Yehuda Hirshberg, were the first to demonstrate the light-responsive behavior of spiropyrans in 1952. Later on, in the 1980s, Prof. Valeri Krongauz used these molecules to develop a variety of materials including photosensitive coatings for lenses. Now, 63 years after the first demonstration of its light-responsive properties, we are using the same simple molecule for another use, entirely," he says.
The advantages of the medium-based approach are clear. For one, the particles do not seem to degrade over time - a problem that plagues the coated nanoparticles. "We ran one hundred cycles of writing and rewriting with the nanoparticles in a gel-like medium - what we call reversible information storage - and there was no deterioration in the system. So you could use the same system over and over again," says Klajn. "And, although we used gold nanoparticles for our experiments, theoretically one could even use sand, as long as it was sensitive to changes in acidity."
In addition to durable "rewritable paper," Klajn suggests that future applications of this method might include removing pollutants from water - certain nanoparticles can aggregate around contaminants and release them later on demand - as well as the controlled delivery of tiny amounts of substances, for example, drugs, that could be released with light.
###
Dr. Rafal Klajn's research is supported by the Abramson Family Center for Young Scientists; the Rothschild Caesarea Foundation; the Mel and Joyce Eisenberg-Keefer Fund for New Scientists; the estate of Olga Klein Astrachan; and the European Research Council.
####
About Weizmann Institute of Science
The Weizmann Institute of Science in Rehovot, Israel, is one of the world's top-ranking multidisciplinary research institutions. Noted for its wide-ranging exploration of the natural and exact sciences, the Institute is home to scientists, students, technicians and supporting staff. Institute research efforts include the search for new ways of fighting disease and hunger, examining leading questions in mathematics and computer science, probing the physics of matter and the universe, creating novel materials and developing new strategies for protecting the environment.
For more information, please click here
Contacts:
Yael Edelman
Copyright © Weizmann Institute of Science
If you have a comment, please Contact us.Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Related News Press |
News and information
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Good as gold - improving infectious disease testing with gold nanoparticles April 5th, 2024
Display technology/LEDs/SS Lighting/OLEDs
Utilizing palladium for addressing contact issues of buried oxide thin film transistors April 5th, 2024
Light guide plate based on perovskite nanocomposites November 3rd, 2023
Simple ballpoint pen can write custom LEDs August 11th, 2023
Govt.-Legislation/Regulation/Funding/Policy
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Chemical reactions can scramble quantum information as well as black holes April 5th, 2024
Self Assembly
Liquid crystal templated chiral nanomaterials October 14th, 2022
Nanoclusters self-organize into centimeter-scale hierarchical assemblies April 22nd, 2022
Atom by atom: building precise smaller nanoparticles with templates March 4th, 2022
Nanostructures get complex with electron equivalents: Nanoparticles of two different sizes break away from symmetrical designs January 14th, 2022
Nanomedicine
New micromaterial releases nanoparticles that selectively destroy cancer cells April 5th, 2024
Good as gold - improving infectious disease testing with gold nanoparticles April 5th, 2024
Researchers develop artificial building blocks of life March 8th, 2024
Discoveries
Chemical reactions can scramble quantum information as well as black holes April 5th, 2024
New micromaterial releases nanoparticles that selectively destroy cancer cells April 5th, 2024
Utilizing palladium for addressing contact issues of buried oxide thin film transistors April 5th, 2024
Announcements
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Environment
Billions of nanoplastics released when microwaving baby food containers: Exposure to plastic particles kills up to 75% of cultured kidney cells July 21st, 2023
Water
Taking salt out of the water equation October 7th, 2022
Grants/Sponsored Research/Awards/Scholarships/Gifts/Contests/Honors/Records
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Chemical reactions can scramble quantum information as well as black holes April 5th, 2024
Photonics/Optics/Lasers
With VECSELs towards the quantum internet Fraunhofer: IAF achieves record output power with VECSEL for quantum frequency converters April 5th, 2024
Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024
Optically trapped quantum droplets of light can bind together to form macroscopic complexes March 8th, 2024
HKUST researchers develop new integration technique for efficient coupling of III-V and silicon February 16th, 2024
The latest news from around the world, FREE | ||
Premium Products | ||
Only the news you want to read!
Learn More |
||
Full-service, expert consulting
Learn More |
||