Nanostructures

Nanostructures are synthesized using MEMS technology. Some examples are:

• Nanowires [1]
• Nanorods [2]
• Nanoparticles [4]
• Nanobelts [5]
• Nanosheets [6]
• Nanotubes [7]
• Porous materials [8]

Each has its own advantages and disadvantages, the main idea of nanostructures is to increase the surface area ratio

Surface area ratio increase when the surface has irregularities at the surface. In the schematic from above, the addition of irregularities onto the surface tends to create more free places for the recognition bio molecules to attach.

Many different nanostructures can be deposited on the sensor working area. Nanowires or nanotubes can be aligned, nanorods and nano particles usually enhance the sensitivity by attaching themselves to biomolecules and thus enhancing electrical conductivity, nanobelts as well as Nanosheets can provide several new layers for adhesion, and finally porous materials (like porous Silicon) can also act like a filter by only letting the correct size particles through it. The decision on how to use a certain nanostructure depends entirely on creativity and experience.

[1] Fabrication of nanowires of multicomponent oxides: Review of recent advances, Shankar K. S, Raychaudhuri A. K, Materials science and engineering C, 25, 738-751(2005)
[2] Gold nanorods: Synthesis, characterization and applications, Pérez-Juste J, Pastoriza-Santos I, Liz-Marzán L. M, Mulvaney P, Coordination Chemistry reviews, 249, 1870-1901(2005)
[3] Manufactured nanoparticles: An overview of their chemistry, interactions and potential environmental implications, Ju-Nam Y, Lead J. R, Science of the total environment, 400, 396-414(2008)
[4] Nanobelts of Semiconducting Oxides, Pan Z. W, Dai Z. R, Wang Z. L, Science, 291, 1947-1949(2001)
[5] Preparation and characterization of graphite nanosheets from ultrasonic powdering technique, Chen G, Weng W, Wu D, Wu C, Lu J, Wang P, Chen X, Carbon, 42, 753-759(2004)
[6] Nanostructuring electrode with carbon nanotubes: A review on electrochemistry and applications for sensing, Gooding J. J, Electrochimica Acta, 50, 3049-3060(2005)
[7] Properties of porous silicon nano-explosive devices, du Plessis M, Sensors and Actuators A, 135, 666-674(2007)
 
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