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Odor Sensors Fabrication - Self-assembled Sensing Materials

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Self-assembling

Our group has been actively pursuing new methods and strategies for fabrication of acoustic-wave-based odor sensors. The methods should ideally yield sensors who would significantly contribute to disrimination among odorants/odors/flavors, at low levels of odorants' concentration - possibly below concentration of the human detection threshold. An important matter here is also that the sensors be obtained in a relatively simple and cost-effective way. One of the well-known methods for relatively efortless modification of surfaces is self-assembling. In our case, the self-assembling technique is used to form hybrid sensing films of lipid-derivatives, directly on the surface of sensor. Either lipopolymers or lipopolymers and lipids terminated with disulphide groups are used for self-assembling here. The figure below shows an idealized schematic view of the concept used in our laboratory. The diagram (A) depicts a first variation of the method that utilizes lipopolymers as a chemisorbed support.

Note, that the lipid moieties are extending on the top of the lipid-derivative phase. This is utlized to promote a hydrophobic interaction between the chemisorbed species and any kind of amphiphilic molecules (i.e. ones with hydrophilic head-groups and hydrophobic tails). Another variation of the method is shown below in diagram (B). The lipopolymers are accompanied there with chemisorbed lipids who are intended to act as "spacers" - separating the long lipopolymers and creating structure even more porous than the one seen in diagram (A).

As before, the amphiphilic molecules can be used to form a physisorbed phase on top of the chemisorbed supports. The fabrication process relies on simple immersion of sensors in appropriately prepared solutions. So far, we have been able to use the method for fabrication of planar Quartz Crystal Microbalance (QCM) and spherical Surface Acoustic Wave (Ball-SAW) devices. More...

Last update: Fri, April 17, 2009 16:23

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