Chemisorption based sensors

The sensing mechanisms of the tin oxide based sensors have been discussed in many publications (9,10,11). The most widely accepted model for tin oxide based sensors operated at temperatures <400°C is based on the modulation of the depletion layer width in the semiconductor (sensor) due to chemisorption as illustrated schematically in Figure 6. For C2H 0H and Sn0x (or PdAu/Sn0x) interaction, the possible reaction steps may be expressed by the following equations ... 

Tabk 5.6 Chemisorption>Based Acoustic Wave Sensors... 

In this part we will describe recent achievements in the development of biosensors based on DNA/RNA aptamers. These biosensors are usually prepared by immobilization of aptamer onto a solid support by various methods using chemisorption (aptamer is modified by thiol group) or by avidin-biotin technology (aptamer is modified by biotin) or by covalent attachment of amino group-labeled aptamer to a surface of self-assembly monolayer of 11-mercaptoundecanoic acid (11-MUA). Apart from the method of aptamer immobilization, the biosensors differ in the signal generation. To date, most extensively studied were the biosensors based on optical methods (fluorescence, SPR) and acoustic sensors based mostly on thickness shear mode (TSM) method. However, recently several investigators reported electrochemical sensors based on enzyme-labeled aptamers, electrochemical indicators and impedance spectroscopy methods of detection. 

Bowker M, Bowker LJ, Bennett RA, Stone P, Ramirez-Cuesta A (2000) In consideration of precursor states, spillover and Boudart s collection zone and of their role in catalytic processes. J Mol Cat A Chem 163 221-232 Brinzari V, Korotcenkov G, Schwank J, Boris Y (2002) Chemisorptional approach to kinetic analysis of SnOj Pd-based thin film gas sensors (TFGS). J Optoelect Adv Mater (Romania) 4(1) 147-150 Bultel L, Vemoux P, Gaillard E, Roux C, Siebert E (2005) Electrochemical and catalytic properties of porous Pt-YSZ composites. Solid State Ionics 176 793-801... 

Du D, Ding J, Tao Y, Chen X (2008) Application of chemisorption/desorption process of thiocholine for pesticide detection based on acetylcholinesterase biosensor. Sensor Actuat B 134 908-912... 

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