Reagent delivery systems

Lemke and Hleftje [4] developed a computer-controlled pH-etat (Fig. 11.1) In which the reagent delivery system le based on a droplet generator, also computer-controlled, capable of selectively adding 0.06- L aliquots. This precise... 

Fig. 11.1 Block diagram of pH-stat with reagent delivery system. (Reproduced from [4] with permission of Elsevier).

The second type of enzyme application in microfluidics is protein interaction studies. In order to study interactions between enzymes and substrates, peptides, or other proteins, an alternative to microtiter plates is the microarray. These arrays are very often used in conjunction with microfluidic sample and reagent delivery systems alternatively, microchannels can be used to deposit spots in an array. By immobilizing substrates or inhibitors on the array, it is possible to screen large numbers of molecules for their relative abilities to bind a particular enzyme. This is typically accomplished by tagging the enzyme with a fluorescent molecule and using the intensity of the array spots to determine the amount of enzyme bound (Fig. 3a). This is a promising... 

Electrochemical immunoassays were pioneered in the 1980s by Heineman, Halsall, and coworkers.23-29 Early in their studies, they employed voltammetric and amperometric techniques to measure proteins and small biologically important molecules, such as hormones, via competitive and sandwich-type immunoassays. Heineman and Halsall and other researchers explored many different measurement techniques and incorporated microfluidics, - reagent delivery systems, interdigitated electrode arrays, b34-36 magnetic beads ° b33,35-37 various designs to improve... 

If the complete reagent delivery system can be kept pressurized with a constant liquid reagent composition, the delivery delay is negligible. 

Excipients manufacture The manufacture of novel excipients may be provided in an application or supporting DMF. Typically these excipients are noncompendial and are used in specialized dosage forms and drug delivery systems. CDER chemists are responsible for the scientific reviews and evaluation of the records and data associated with the manufacture of these novel excipients. The review will include starting materials, key intermediates, reagents, and solvents. cGMP inspections by the Field usually will be performed on request from CDER. 

The Reaction Vessel Enclosure stores solvents and common reagents in 250-mL to 4-L bottles. Reagent delivery is mediated by a valve system. The accuracy of delivery is under the control of optical sensors. The autosampler handles up to 176 different reagents. The Reaction Vessel Enclosure contains 24 reaction vessels, which are organized in three banks of eight. 

MultiSynTech produces a manual version of its SYRO II synthesizer, SYRO II O. S. Manual Block. It does not have a robotic delivery system or a computer. Reaction blocks can be used just like with the SYRO II synthesizer. Reagent delivery is manual. All reaction parameters can be set up by a separate control unit. The Manual Block is substantially less expensive and less space consuming than its robotic equivalent. 

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