Dialysis integrated with detection

Sensors based on integrated dialysis, reaction and detection differ from those described in Section 4.3.1 in the fact that a (bio)chemical reaction takes place after separation (simultaneously with detection). They thus fit the generic configuration depicted in Fig. 5.1. A. Some of the ingredients of such a reaction may be immobilized at the sensing microzone, even though the reaction may also take place in the solution passed through it. 

As with sensors based on a triply integrated process involving gas diffusion, there are few reported examples of sensors integrating dialysis, reaction and detection. There follows a description of die most salient examples based on the ingredient of the (bio)chemical reaction that is dialysed at the sensing micro2one. 

Therefore, this sensor integrates a biochemical and a chemical reaction with a prior separation (dialysis) and chemiluminescence detection. The process involves the following steps (a) dialysis of the enzyme (6) enzymatic oxidation of the reagent (c) derivatization of hydrogen peroxide and d) detection of the chemiluminescence produced. Such an original approach offers several advantages over similar methodologies, namely ... 

Integration of a dialysis membrane or coupling to a microdialysis probe can help to exclude many of the larger molecules such as proteins that are typically responsible for fouling the sensor elements of microchip analysis systems. The nature of the analysis will dictate whether coupling to a flowthrough or separation-based sensor must be achieved and the kind of detection elements to be employed (optical, electrochemical, etc.). One of the issues with microchip devices is the very small... 

Future developments will see the optimization of device design and the investigation of alternative materials for microchip, electrode, and membrane fabrication. It is envisioned that further advances in fabrication and integration procedures will allow the development of implantable/wearable micro-dialysis/microchip systems for personal or on-animal monitoring. Integration of the separation-based systems with powerful detection techniques such as MS will further improve the detection capability of these systems for biological, pharmaceutical, and environmental monitoring. 

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