Microcantilevers: "Silkmoth inspires novel explosive detector"
What are microcantilevers?
A microcantilever is a nanoscale, flexible platform that responds to various signals by resonating (flexing) as a result of the stimulus (Vashist, 2007). This system is commonly found in spring joints, cars and other applications where flex is common. To give you an idea of how the cantilevers work, the following video clip provides a nice, brief visual of the basics of this phenomenon.
The antennae of the silkmoth, Bombyx mori, provide the inspiration for this type of sensing system. The antenne themselves resemble a comb-like cantilever system, with each section of the antenna acting as an individual, flexible lever. Not only can the lever respond to the pressure created by air currents, chemo-receptors, magnetic receptors and light receptors at the end of each "lever" can also respond to changes. The motion of the lever in response to the signal is used to "translate" the signal to the rest of the organism. Artificial microcantilevers have been developed that mimic the shape and flexibiltiy of the moth's antennae. The high surface area of the levers sample the environment for clues. The most recent application of the moth cantilever is in the detection explosive material. Microcantilevers can be designed to respond to a variety of signals:
- Real silkmoth "antennae" microcantilevers(See figure below):
- Artificial microcantilevers "mimics" produced from titanium/carbon nanofibers:
- The purpose of the sensor is to create a super-sensitive monitors with a high surface area to volume ratio. The highly convoluted receptor surface allows for quick analysis of the surroundings. The cantilevers can be coated with a variety of materials to allow them to sample a variety of signals (magnetic, light, chemical, pressure).
- Example video of an artificial microcantilve system, similar to a moth's antennae, that records signals on a surface below the flexing levers:
Description of current status of the engineered technology:
- There are many applications of microcantilever technology including explosive detections, drug therapy, in-vivo biosensors for blood nutrient analysis, pressure sensors, magnetic sensors and more. The list is truly exhaustive (see link for full list) but here are a few:
- humidiy levels
- metal ion detection
- glucose, hormone, drug levels in blood stream
- cancer cell markers
- DNA chips for polymorphisms and more.....
- Here are a few pictures illustrating the application of microcantilever technology:
- ALL IMAGES: http://www.frontbiosci.org/2013/v5s/af/357/fulltext.php?bframe=figures.htm
- Microcantilevers have got potential applications in every field of science ranging from physical and chemical sensing to biological disease diagnosis. (Vishat). The major advantages of microcantilevers as sensing mechanisms over the conventional sensors include their high sensitivity, low cost, super-low detection requirement (the molecule that is being tested for can be present only in nanoliters and STILL GET A POSITIVE TEST), non-hazardous procedure with fewer steps (obviating the need for labels), quick response and low power requirement. Most important is the fact that an array of microcantilevers can be employed for the diagnosis of large numbers of various disease biomarkers of a single disease in a single go thus having tremendously high analysis capabilities. The technology holds the key to the next generation of highly sensitive sensors. With the development of the technology for nanocantilevers, sensors have achieved attogram sensitivity, which has until recently only been a dream for researchers. Further increases in sensitivity will allow researchers the ability to count the numbers of molecules. (See Source: Vishat, 2007 and Vasan, 2013).
- This is absolutely a societal win, mainly because lives can be saved in the detection of harmful substancse such as poisons and explosives AND there is a huge reduction in the amount of materials required to perform an exponentially better detection method (higher accuracy).
- Ha ha.. I still have trouble with this one..but I am going with bioinspiration. Althougth the entire scaffolding (microcantilever) system mimics the function of the moth antennae, the materials used to create the structure as well ans the tupe of signals received and transmitted are not the same as the moth, so this is definitely design by inspiration from nature.
“Bio-Inspired Nanostructured Sensor for the Detection of Ultralow Concentrations of Explosives.” D. Spitzer, T. Cottineau, N. Piazzon, S. Josset, F. Schnell, S. N. Pronkin, E. R. Savinova, and V. Keller. Angewandte Chemie. 29 mai 2012.
“Point of Care Biosensor-systems.” Arvind, Sai. Vasan, S. Frontiers in Bioscience S5, 39-71, January 1, 2013
“A Review of Microcantilevers for Sensing Applications.” Vasish, Kumar, S. OARS, May 2007. DOI : 10.2240/azojono0115
appliations of cantilever in the “millipede” arrangment to detect forces of external field: