• Microscopic crystal 'flowers' build themselves in a Harvard lab

    Wim Noorduin

    Researchers formed hierarchically complex structures by controlling the growth of crystals in a solution. Here, a coral shape was nucleated on top of a spiral. (The scanning electron microscope view is false-colored, but represents the actual color of the structure.)

    By Jillian Scharr, TechNewsDaily

    Imagine peering into a microscope and finding yourself in a garden.

    That's the case at Harvard School of Engineering and Applied Sciences, where researchers have found a way to shape microscopic crystals into complex and often beautiful structures.

    Inspired by coral reefs, seashells and other naturally occurring complex mineral structures, postdoctoral fellow Wim L. Noorduin and Harvard colleagues have been researching ways to create similar designs.

    These "flowers" were created by mixing barium chloride and sodium silicate, also known as waterglass, in a beaker of water. The resulting reaction combines with carbon dioxide in the air to create crystals made of barium carbonate in the water.

    Noorduin found that as the crystals self-assembled, he could control their shape, size and direction of growth by altering the temperature, the amount of carbon dioxide allowed into the reaction and the acidity of the water.

    Increasing the carbon dioxide levels creates the broad, flat leaves of those mineral flowers, for example. Fluctuating the acidity level creates the ruffled wave in the petals.

    Wim Noorduin

    This false-colored photomicrograph shows a red coral structure with green "stems" grown inside the cavities of the coral. While the stems are growing, researchers opened them with a pulse of carbon dioxide to produce the purple structure.

    Wim Noorduin

    A field of microscopic tulips takes shape in this false-colored scanning electron microscope image.

    Laura Hendriks / Wim Noorduin

    This complex microscopic bouquet was formed by first nucleating green stems inside purple vases, after which the stems were opened during growth to form the blue part.

    The curved petals, slender stems and jagged thorns, formed by the carbonate-silica crystals as they grew, demonstrate the effectiveness of Noorduin's technique. The team was able to create the structures on glass slides and metal plates as well, and even grew a "garden" of flowers in front of the Lincoln Memorial that's imprinted on the back of a penny.

    The images were taken with a scanning electron microscope, which uses electrons to create images of microscopic images. The color was added digitally.

    "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 … Sometimes I forget to take images because it's so nice to explore," Noorduin said in Harvard's press release.

    Crystal manipulation has more applications than just the aesthetic. Aside from the valuable insight into the way silicon-based structures are formed in nature, this technique can be used in nanotechnology fields such as optics and electronics.

    Noorduin's findings follow a similar discovery from Harvard biologist Howard Berg, who found that certain bacterial colonies take intricate geometric shapes in response to concentrations of chemicals around them.

    Noorduin's paper, "Rationally Designed Complex, Hierarchical Microarchitectures," was published in the journal Science on May 17.

    Email jscharr@technewsdaily.com or follow her @JillScharr. Follow us @TechNewsDaily, on Facebook or on Google+.

    Copyright 2012 TechNewsDaily

  • Tiny sensors that measure amplitude are big step

    Vijay Kumar / Purdue University

    Researchers have learned how to improve the performance of sensors that use tiny vibrating "microcantilevers," like the one pictured here, to detect chemical and biological agents for applications from national security to food processing.

    By John Roach, Contributing Writer, NBC News

    Anyone who watched the recent X-Games coverage heard commentators obsess about "amplitude" — how high snowboarders such as Shaun White soar above the lip of the superpipe to perform aerial tricks.

    Scientists more concerned with using vibrating sensors to detect harmful chemicals in the air we breathe and food we eat than White's frontside double cork 1260 share the love for amplitude.

    In their case, they've found that a change in the amplitude of a tiny sensor's vibration is a reliable indication that a chemical of interest has glommed onto it. 

    Sensors that measure shifts in frequency — how often a vibrating motion repeats itself — when a chemical of interest sticks to it have been around for a while, noted Jeffrey Rhoads, a mechanical engineer at Purdue University in West Lafayette, Indiana.

    "But when the devices get smaller, that can be harder to do due to noise," he explained to me Tuesday. That is, at small scales, scientists have a hard time detecting changes in frequency that are due to the chemical of interest from changes because of other factors.

    To get around this, Rhoads and colleagues found that they can measure changes in amplitude instead. The breakthrough, he said, could lead to applications everywhere from food safety and national security to, eventually, biomedical research.

    Proof-of-concept experiments showed that change in amplitude was a more reliable way to detect the presence of small quantities of methanol gas than the frequency approach.

    Applied to other gases this could be useful, for example, when attempting to determine the safety of food, Rhoads said. "If there's a little bit of something bad, the whole thing is shot."

    Looking to the future, the team hopes to apply these sensors to things like detecting the concentration of certain cells in a person's blood, for example.

    To get there will require improvements to measure not just the presence of a chemical, but also its concentration. Doing so will require better understanding of the chemistry of the chemicals of interest.

    Findings are detailed a paper appearing online this week in the Journal of Microelectromechancial Systems.

    More on sensor technology:

    John Roach is a contributing writer for msnbc.com. To learn more about him, check out his website. For more of our Future of Technology series, watch the featured video below.

    The modernist kitchens of Grant Achatz are known for using experimental equipment to produce unusual cuisine, thanks to an unusual partnership with PolyScience, a lab equipment.