Chemists design molecule that responds to stimuli

November 23, 2010
A cartoon representation of reversible organization from synthetic lipid-like molecules to form cell-like structures (called vesicles) upon change in temperature. The cell like structures cluster together similar to toad eggs or Caviar-like morphologies upon maintaining a particular temperature.

( -- The venus flytrap plant captures its prey when it senses the presence of an insect on the tips of its leaves. An amphiphilic molecule designed by chemists at The City College of New York acts in a similar manner by changing its structure when heated slightly and, then, reverting to its original form when cooled.

The finding, reported in the journal , points toward the possibility of designing adaptive soft materials in the lab that take their cues from how nature responds to , said Dr. George John, associate professor and corresponding author.

Professor John and colleagues designed the molecule, which has both water-adhering and water-repelling ends, from cardanol, a naturally available material found in cashew nut shell liquid. When mixed with water, the molecules formed a self-assembled called a micelle with a water-adhering exterior and water-repelling interior.

Warming the micelles to 50 degrees Celsius caused them to take on a three-dimensional structure known as a vesicle that was larger – 200 – 300 nm in diameter – and viscous, much like oil. "The molecules would stick together, similar to caviar," Professor John said. "When we touched the material with a glass rod, we could draw it out in a thin strand, much like glue."

Allowing the material to cool resulted in the reverting to their original micellar structure. When they were reheated, they would again take on the viscous form.

The change in structure resulted because, while heating caused the micelles to rearrange, they began to interlock in a bi-layer arrangement and eventually undergo curvature. Directional hydrogen bonding of the amide linkages and stacking of the aromatic ring groups, further stabilized the assembly.

The objective of the research is to study responsive systems, Professor John said. "If we can understand the influence of saturation at the bi-layer stage, we can regulate the adaptive response to stimuli." This will require investigating the number of micelles needed in a mixture and where they need to be positioned.

Explore further: Nanoscale packaging could aid delivery of cancer-fighting drugs

Related Stories

A Venus flytrap for nuclear waste

January 26, 2010

Not every object is food to a Venus flytrap. Like the carnivorous plant, a new material developed at Northwestern University permanently traps only its desired prey, the radioactive ion cesium, and not other harmless ions ...

New nanoparticle could improve cancer detection, drug delivery

February 12, 2010

( -- University of Florida scientists have developed a new nanoparticle that could improve cancer detection and drug delivery. The particle, called a 'micelle' and made up of a cluster of molecules called aptamers, ...

Scientists make water-free liquid from blood protein

June 7, 2010

( -- Scientists at the University of Bristol have discovered a way to make a highly concentrated water-free liquid of a key blood protein, myoglobin, opening up the possibility of new types of biomedical materials.

Sugar battles oil spills

August 12, 2010

The environment has often suffered from the catastrophic effects of an oil spill, the most recent example being the oil spill in the Gulf of Mexico. The search for ways to remove oil from polluted water is therefore urgent. ...

Recommended for you

New approach for 'nanohoops' could energize future devices

October 12, 2015

When Ramesh Jasti began making tiny organic circular structures using carbon atoms, the idea was to improve carbon nanotubes being developed for use in electronics or optical devices. He quickly realized, however, that his ...

The universe's most miraculous molecule

October 9, 2015

It's the second most abundant substance in the universe. It dissolves more materials than any other solvent. It stores incredible amounts of energy. Life as we know it would not be possible without it. And although it covers ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.