1. Nobuo Misawaa,b,1,
2. Hidefumi Mitsunob,c,1,
3. Ryohei Kanzakic, and
4. Shoji Takeuchia,b,2
+ Author Affiliations
1.
a Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan;
2.
b Life Bio Electro-mechanical Autonomous Nano Systems (Life BEANS) Center, The BEANS Project, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan; and
3.
c Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
1.
Edited by Katepalli R. Sreenivasan, New York University, New York, NY, and approved July 20, 2010 (received for review March 31, 2010)
2.
.1N.M. and H.M. contributed equally to this work.
Abstract
This paper describes a highly sensitive and selective chemical sensor using living cells (Xenopus laevis oocytes) within a portable fluidic device. We constructed an odorant sensor whose sensitivity is a few parts per billion in solution and can simultaneously distinguish different types of chemicals that have only a slight difference in double bond isomerism or functional group such as .OH, .CHO and .C(.O).. We developed a semiautomatic method to install cells to the fluidic device and achieved stable and reproducible odorant sensing. In addition, we found that the sensor worked for multiple-target chemicals and can be integrated with a robotic system without any noise reduction systems. Our developed sensor is compact and easy to replace in the system. We believe that the sensor can potentially be incorporated into a portable system for monitoring environmental and physical conditions.
Hebrides olfactory machinery
Matthias Gräbner 25/08/2010
Researchers combine living cells with evaluation electronics,
creating an olfactory-machine whose performance technically
not be reached so far is
Technical devices are better than man.
Whether in the universe or in the nano world,
much remains hidden from the eye, can make the technology visible.
The same goes for listening: Machines take sound true
in areas that we do not remain closed for reasons of age.
But when it comes to smell, not even the comparatively
poor man is now equipped to fight from the electronics.
Not to mention many of us far superior animals.
Even individual cells can register chemicals - say,
smelling. The sperm, for example, is based on the search
for the egg to lily of the valley fragrance, as researchers
have found. The fact that the olfactory perception is probably
the worst so far investigated has meaning for several reasons.
First, it has historically been given less attention - smells
long regarded as something that aroused than unpleasant associations.
Painting and music refer to visual and auditory senses,
but how popular are odor-art?
The fact is, however, that the olfactory sense is also not easy to tap. It is not enough to understand the basis. It depends on more than wavelengths and amplitudes: odors are mediated by different chemical substances. When we found out what makes Lily of the Valley Sun smell how we perceive it in the spring, then we know for a long time not see why violets smell of violets. Even the man has over 400 different receptors that are distributed to the olfactory mucosa in an area of five square centimeters. They allow up to 10,000 different smells. As a rule, have to dock only a few molecules of the substance at the receptors to produce an impression.
Oocytes of the African clawed frog as a chemical sensor for a machine
How can this potential best use of technology? One way would be to replicate the mechanism that has the nature as conceived. Another way to show Japanese researchers in the current issue of the Publications of the U.S. Academy of Sciences (PNAS). In their [external] Paper describing how eggs of the African clawed frog [external] Xenopus laevis may act as a chemical sensor for a machine.
The researchers calculated that chose this egg is on their mobile application for the practical size of about one millimeter in diameter. Genetically, the scientists took cells for receptors for a variety of training materials that have been borrowed from various insects. Then docks to a corresponding molecule on the receptors of the cell, creating a tiny current - which it will have to enhance and evaluate. The researchers succeeded in surprisingly good
The eggs were found to be very robust in the experiment. At the same time they were able to distinguish between the different, chemically very similar substances. The conventional way you would for a gas chromatograph must try. Since so far about 50 receptors of insects in the required manner are known, it would be a based on the claw frog egg system quite well. Therefore it is not even necessary to understand the detailed operation of the receptors. The microfluidic apparatus, the researchers have constructed is, while just 5 x 30 x 45 millimeters in size. It could, so the idea, well suited as a portable sensor for example for environmental monitoring. In a typical Japanese experiment, the researchers built their device in a robot-head: whenever the sensor is then registered a certain smell, led the head of defined movements.
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