February, that cruelest of months, has shown up bearing snow; I am not amused. However, lucky for us, we can distract ourselves from the horrible weather by reading about some interesting research-type sensor projects that I present for your edification and amusement. This month we've got sensors for wood quality for the timber industry, tiny biosensors that can monitor single bacteria, and a lab-on-a-chip made of paper.
Tailoring Wood Production
Not every tree cut down is destined to be the same thing; variations in a log's moisture content and density determine what it is best used for—pulp and paper, furniture, or construction—but these qualities aren't particularly easy, cheap, or convenient to measure. Canadian researcher Brigitte Leblon, professor of remote sensing at the University of New Brunswick in Fredericton, Canada, wants to develop a real-time monitoring system capable of monitoring the moisture content and density of wood, from its beginning as a log, all the way through to processing. Working in collaboration with researchers from the University's magnetic resonance imaging research centre, along with scientists from FP Innovations, the University of Toronto, and Nagoya University in Japan, the team is applying a number of different technologies: NIR spectroscopy (which is already successfully used in agriculture to monitor the moisture content of grain and hay), ground-penetrating radar, and magnetic resonance imaging. The general idea, as explained in the news article, "Professor works on wood sensors", is to attach a sensor to each log or piece of wood product and thus continuously monitor its qualities in a way that's robust, accurate, and won't break the bank. Leblon is already working to adapt the NIR spectroscopy sensors to work for the application.
Treating With the Most Effective Antibiotic
Bacteria are sneaky and in the battle between bacterium and antibiotic, it's not always clear exactly which antibiotic will be most effective against a given bacterial infection. Now, researchers at the University of Michigan, led by professor Raoul Kopelman, have created a biosensor that lets them assess individual bacterial cells for their speed of growth and their susceptibility to a given antibiotic. The asynchronous magnetic bead rotation (AMBR) sensor measures the speed at which a tiny, spherical magnetic bead (asynchronously) rotates in a magnetic field. Attaching a bacterium to the bead will alter the rate at which it rotates. If the bacterium grows, that rate of rotation decreases. Exposing the bacterium to an effective antibiotic stops the growth and thus stops the decrease in rotation rate. The neat bit (well, of many neat bits) is that the effect is measurable within minutes. While the technology is nowhere near ready to visit a hospital lab near you, it holds immense promise. You can read more in Nancy Ross-Flanigan's article, "See how they grow: Monitoring single bacteria without a microscope."
A Makeover for Test Strips
We've talked a great deal about lab-on-chip technology and developments. The ability to perform rapid assays for multiple chemicals or disease markers is incredibly attractive and potentially useful, but some of the systems are anything but cheap. Purdue University researchers have used microfluidics to create paper test strips that can perform more complex assays. Rather than etching microfluidic channels into glass or plastic, the researchers used absorbent paper, coated with a hydrophobic layer. By selectively removing some of that hydrophobic top layer with a laser to expose the absorbent underlayer, they created patterned areas that enable an applied fluid to wick through the paper to react with various reagents. Because the researchers are using commercially available paper, they hope to create cheap, effective, disposable test strips that can test a given sample for multiple things.