Microchip laboratories

Microchip laboratories have many advantages. They require only tiny amounts of sample. This is especially advantageous for expensive, difficult-to-prepare materials or in cases such as criminal investigations, where only small amounts of evidence may exist. The chip laboratories also minimize contamination because they represent a closed system once the material has been introduced to the chip. The chips also can be made to be disposable to prevent cross-contamination of different samples. 

The contactless conductivity microchip detection system, developed in our laboratory [31], has been particularly useful for this task. Its popularity has grown rapidly in recent years. Conductivity is a universal detection technique for CE microchips, as it relies on the same property of the analyte as the separation itself, namely the mobility of ions under the influence of an electrical field. Such a detector can thus sense all ionic species having conductivity different from the background electrolyte. 

In our laboratory, polymer CE microchips in combination with EC detection have been successfully used as miniaturised devices for determination of clinically important analytes. As commented in Section 34.1.2, poly(methylmethacrylate) (PMMA) is one of the most used polymers for manufacturing microchips. Recently, cyclic olefin copolymers (COCs) such as Topas (thermoplastic olefin polymer of amorphous... 

A significant amount of work on microdevices has recently focused on proteins and peptides. Some of this was initiated as part of the larger proteomics effort, but currently the work is centered largely on the transfer of current analytical methods to microchips. This includes enzymatic assays and immunoassays, both of which are routinely utilized in clinical laboratories. We have included these... 

Other than the standard cross-t configurations, electrophoretic microchips are not currently commercially available and tend to be fabricated in the laboratories that use them. They can be constructed from glass (Pyrexlike or soda lime), silicon (as per microelectronic chips), or a variety of plastics, or cast from silicone-like materials (polydimethyl-siloxane). The first two of these constitute the vast majority of the electrophoretic devices described in the literature. 

From the perspective of the clinical laboratory, miniaturization has been a long-term trend in clinical diagnostics instrumentation. For example, capillary electrophoresis instruments (see Chapter 5) and mass spectrometers have been implemented on microchips of silicon, glass, or plastic. In actuality, however, these devices are not manufactured on a nanometer scale but rather on a micrometer scale. Consequently, this chapter will be concerned with microminiaturized devices whose key components (1) are approximately 100 micrometers in size, (2) are employed in analytical measurement, and (3) require special forms of fabrication designed for microdevices. Although this chapter does not attempt to discuss submicron or molecular structures at the nanometer scale, it should be noted that applications discussed later in it require only nanoliter (nL) quantities of a sample or deal with individual cells that may have cell volume in the picoHter (pL) to nL range. 

The scope of assays using microchips has also encompassed hpoproteins. Low-density lipoprotein analyses have been performed in an uncoated glass microchannel capillary electrophoresis chip. Analyses using mixtures of lipoproteins isolated from blood have been completed in under 25 seconds. However, no convenient method is yet available for the clinical laboratory,... 

Because the bulk of assays in the clinical chemistry laboratory stem from the various metabolites, the potential for microchip-based assays is extremely large. The possibility that multiple assays wiU be carried out using microsamples with minimal use of reagents has many implications for the... 

Kricka LJ. Microchips, microarrays, biochips and nanochips personal laboratories for the 21st century. Clinica Chimica Acta 2001 307 219-23. 

Recently, the research laboratories of the microchip producer AMD began to use TERS for characterizing patterned silicon surfaces. Metallized AFM tips that have been prepared by sputter deposition of thin Ag films onto quartz tips and sharpened by focused ion beam (FIB) miUmg were used. With a top-illumination set-up, line profiles of patterned samples were recorded and the influence of laser deflection at the tip and laser heating on silicon stress measurements were studied [44-46]. 

The patient calls family physician s office and is instructed to come in that afternoon. She arrives at physician s office, activates personal health card (e.g., a smart card is activated by the patient s thumb print), hands it over to the receptionist the RFID microchip in the health card is activated by the reader at the physician s office and the electronic patient record is open. The patient is shown to the examination room a nurse takes vital signs captured via an electronic data capture system including voice dictation. The family physician sees her and orders an ECG (electrocardiogram) test. The patient sees the receptionist the receptionist finds the laboratories nearest to her home gives her the addresses of two nearest laboratories. The patient goes to the nearest diagnostic laboratory. The RFID microchip in the health card is activated by the reader at the laboratory ECG (electrocardiogram) is performed, blood is drawn (test location records ECG results, notifies physician of ECG completion), and the specimen is sent to a second location. The patient waits at home for a call from her family physician. The blood sample arrives at the second... 

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