Fiber-based microchip

Figure 10.15 (a) Photograph of a typical fiber-based microchip, (b) SEM image of the cross-section of a fiberglass-packed microchannel in the PMMA substrate, and (c) immobilization... 

Biosensors based on optical fibers as transduction element have been recently reviewed by Wolfbeis [97]. Optical biosensors based on miniattaized SPR or on evanescent field monitoring are not as often found in miniaturized biosensors, especially in comparison to miniaturized electrochemical transducers, yet. Two examples will be given here a miniaturized SPR biosensor by Cullen and co-workers [98] and an evanescent based microchip biosensor by Borchers and co-workers [99]. The best-known SPR biosensor is the BIAcore device from Pharmacia Company, Sweden. It has been on the market for over a decade and is routinely used for hybridization kinetic analyses, specificity analyses, etc. Cullen and co-workers have incorporated a commercially available miniaturized SPR transducer into a field analyzer and developed a competition and inhibition assay for an estrogenic compound in water samples that function as endocrine disrupting compounds (EDCs). 

Malcik, N., Ferrance, J. P, Landers, J. P, and Caglar, P, The performance of a microchip-based fiber optic detection technique for the determination of Ca ions in urine. Sens. Act. B-Chem., 107, 24, 2005. 

These pyrolyzed photoresist three-dimensional electrodes have applications in batteries, but they are also applicative to microchip bioanalysis systems. Fischer et al. have used pyrolyzed photoresist to make three-dimensional electrodes for dual amperometric detection for microchip electrophoresis [8]. However, it is important to note that many electrodes for microchip electrophoresis are three-dimensional electrodes and can be fabricated from a number of sources including carbon-based screen printing inks, precious metal-based screen printing inks, carbon fibers, electroplating of metallic electrodes, vapor deposition of metallic electrodes, etc. The choice of material is usually a function of... 

Boron-reinfixced aluminum is a technologically mature continuous-fiber MMC (Fig. 2). Applications for this composite include tubular truss members in the mid-fiiselage structure of the space shuttle orbiter and cold plates in electronic microchip carrier multilayer boards. Fabrication processes for boron/aluminum composites are based on hot-press diffusion bonding of alternating layers of aluminum foil and boron fiber mats (foil-fiber-foil processing) or plasma-spraying methods. 

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