Stunning Spring Flowers Self-Assemble in a Beaker as Crystals

It's definitely spring. Leaves are unfurling, birds are singing and chemists have created self-assembling flowers in a beaker. These micron-scaled, delicate structures are made of crystals, and show how scientists can manipulate chemical gradients in order to reveal what's possible in the environment.

The miniscule sculptures are curved and delicate--a sharp contrast to the cubic or jagged forms that crystals usually take. These formations seem to bloom from the surface of a submerged glass slide, assembling themselves one molecule at a time in order to create fields of carnations and marigolds.

"For at least 200 years, people have been intrigued by how complex shapes could have evolved in nature," said Wim L. Noorduin, a postdoctoral fellow at the Harvard School of Engineering and Applied Sciences, in a news release. "This work helps to demonstrate what's possible just through environmental, chemical changes."

The scientists accomplished this spectacular display through the use of compounds in a liquid solution. More specifically, the precipitation of crystals depends on a reaction of compounds that are diffusing through a liquid solution. The crystals grow forward or away from certain chemical gradients as the pH (how acidic or basic a solution is) of the reaction shifts back and forth. The conditions of the reaction dictate whether the structure resembles broad, radiating leaves, a thin stem or a rosette of petals.

This same sort of reaction can be seen in nature, though. For example, curved marine shells form from calcium carbonate underwater. In addition, gradients of signaling molecules in a human embryo help set up the plan for the body.

The final result from the most recent experiment shows that researchers can indeed manipulate the growth of these delicate structures. It also allows scientists further insight into biological systems, and allows them to understand exactly what processes happen in order to cause specific formations. More interestingly, though, the research has produced some fantastic-looking flowers.

"When you look through the electron microscope, it really feels a bit like you're diving in the ocean, seeing huge fields of coral and sponges," said Noorduin in a news release. "Sometimes I forget to take images because it's so nice to explore."

The findings were published in the journal Science.