Multichannel chip

Recently, the fabrication of a sensor array in a chip by covalent attachment of fluorescent monolayers on the walls of glass microchannels has been demonstrated. The monolayer array (confined in a multichannel chip) is prepared by parallel synthesis of monolayers functionalized with different fluorophore-ligand pairs, resulting in a sensing chip, which is able to generate a fingerprint of the network with a single fluorescence snapshot for different analytes.63... 

To automate the process of SAM synthesis in the microchannels for the generation of sensing arrays, a multichannel chip suitable for continuous flow of reagents was designed. A microchannel chip (4 x 2.2 cm2) with five parallel channels confined in an area of 200 pm was fabricated. Each channel can be individually addressed and... 

Figure 4.17 depicts the protocol for the parallel synthesis of five sensing SAMs in the multichannel chip. After the activation with piranha and the formation of the amino-terminated TPEDA SAM, the unique functionalisation of each monolayer can be achieved by introducing consecutively different fluorophores fl (, x = 1-5) and ligands (L, y = 1-5) in each channel. As a result an array of five fluorescent SAMs (F l. ) confined to a single chip can be achieved. The result is a chip with an array of five fluorescent SAMs. 

Fig. 4.18 Overlay image of the multichannel chip functionalized with an array of five different fluorescent monolayers filled with acetonitrile (a), Ca2+ (perchlorate salt, 10 4 M, acetonitrile) (b), and Cu2+ (perchlorate salt, 10 4 M, acetonitrile) (c) 68...

At the University of Twente in the Netherlands, a multichannel chip has been designed with an integrated NMR detection coil and has yielded promising results at low field... 

Fig. 13 Top-. Overlay image of the multichannel chip with an array of five different sensing fluorescent sensing reporters filled with (a) MeCN, (b) (perchlorate salt 10 M in MeCN), (c) (perchlorate salt 10 M in MeCN). Bottom Corresponding fluorescence intensity...

Xue, Q., Dunayevskiy, Y. M., Foret, F., and Karger, B. L. (1997). Integrated multichannel microchip electrospray ionization mass spectrometry analysis of peptides from on-chip tryptic digestion of melittin. Rapid Commun. Mass Spectrom. 11, 1253 — 1256. 

Bromberg, A. and R. A. Mathies. Multichannel homogeneous immunoassay for detection of 2,4,6-trinitrotoluene (TNT) using a microfabricated capillary array electrophoresis chip. Electrophoresis 25, 1895-1900 (2004). 

The advent of microfabrication greatly improved pHPLC design and will eventually provide the ultimate lab-on-a-chip. Shintani et al. built a multichanneled pHPLC for the separation of... 

Custom chips. Because of the computational demand of multichannel or multivoice audio processing, custom silicon has been proposed as one way to solve this basically intractable problem. Also, going to custom silicon provides a manufacturer with a not-so-subtle way to hide proprietary algorithms - it s harder to reverse engineer a chip than it is a program for a commercially available processor. 

Other than protein, histamine in human blood samples was determined by the immunoassay method. It was detected by its binding with anti-histamine IgG, which was coupled to ferrocene (Fc-IgG). Separation of histamine and its complex with antibody was based on p/ differences, and it was achieved in a PMMA chip consisting of a multichannel matrix column coated with a cation-exchange resin (Nation). Histamine was detected electrochemically a decrease in the current due to Fc-IgG occurred after its binding to histamine [1012],... 

Homogeneous immunoassay for TNT and its analogues was also achieved in a multichannel format using a 96-lane CAE chip [1013]. 

Badal, M.Y., Wong, M., Chiem, N., Salimi-Moosavi, H., Harrison, D.J., Developing a routine coating method for multichannel flow networks on a chip using pyrolyzed poly(dimethylsiloxane). Micro Total Analysis Systems, Proceedings 5th pZAS Symposium, Monterey, CA, Oct. 21-25, 2001, 535-536. 

Figure 11 Simultaneous determination setup using branched multichannel immunoassay chip.

These solid state detectors are multichannel devices. They have large number of photon-detecting registers. The registers are semiconductor capacitors that have been formed on a silicon chip. These detectors, which can detect very low levels of light, are primarily used in probe-type, near-infrared, and visible spectrophotometers and in fluorometers. 

Implementation of fluidic functions inside a plate reader is however not a straightforward task. For short-term detection, the chip depicted in Fig. lOf [16] in the Chapter Perfusion Based Cell Culture Chips of this book could be amenable for use with a plate reader since its function does not require any external pump. However, for long- term real-time monitoring, this system is not suitable due to the need for a CO2 incubator. An alternative approach could be based on a multichannel pump, suitable for integration with a polymeric microfluidic cell culture chip independent of a CO2 incubator. The pump shown in Fig. 10b [17] in the Chapter Perfusion Based Cell Culture Chips of this book could function as the basis for such an approach. 

Fig. 9.7.15 First continuous sampling CE chip designed by Andrew Ewing s group at Pennsylvania State University, (a) Schematic of set-up and principle of operation for continuous flow CE chip used for on-line analysis. Capillary is rastered back and forth laterally at the gap entrance to a chip by linear translation stage actuated by stepper motors, where the analyte is pulled from a continuous flowing stream by EOF and continuously injected onto the chip. A multichannel detector is used to measure the migration of...

These multichannel detectors work by having hundreds of silicon photodiodes positioned side by side on a single collision crystal or chip. Each photodiode has an associated storage capacitor that collects and integrates the photocurrent generated when the photons strike the photodiode. Periodically, they are discharged and the current read. A spectrum cau be recorded if radiation dispersed into its different wavelengths falls on the surface of the diode array. 

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