Fiber-optic bundle

Theory and Equipment. Many diseases of the human body can be identified by visual appearance. Tumors in the upper gastrointestinal (GI) tract, for example, possess a characteristic salmon pink color (3). The presence of such a color can be an indication of disease. Endoscopy is the medical imaging tool used to detect such colors in the inside of hoUow internal organs such as the rectum, urethra, urinary bladder, stomach, colon, etc. An endoscope is the instmment used to perform endoscopy. Endoscopic imaging involves the production of a tme color picture of the inside of the human body using lenses and either hoUow pipes, a fiber optic bundle, or a smaU CCD camera. AU three use a large field-of-view, sometimes referred to as a fish eye, lens to aUow a 180° field of view. 

Alternatively, a fiber optic bundle can be used in place of the pipe. In a fiber optic bundle, a matrix of smaU (50—100 -lm) fiber optic strands are arranged such that the ordering of the strands at one end is equivalent to that on the other end. Therefore an image focused on one end with lenses is transmitted to the other end. Light is typicaUy sent down some of the fibers not used for image transmission to provide illumination. 

Endoscopes containing a CCD camera replace the fiber optic bundle with a smaU monochrome CCD chip at the focal point of the fish eye lens (4). 

An x-ray area detector can be used to collect the intensities of many reflections at a time. The crystal must be oriented in many different settings with respect to the incident beam but the detector needs to be positioned at only a few positions to collect all of the data. A charge coupled device (CCD) is used as the area detector on the Siemens SMART single crystal diffractometer system. The SMART detector consists of a flat 6-cm circular phosphorescent screen that converts x-ray photons to visible light photons. The screen is coupled to a tapered fiber optics bundle which is then coupled to a one inch by one inch square CCD chip. The CCD chip has 1024 x 1024 pixels each of which stores an electrical charge proportional to the number of... 

FW = filter wheel FB = fiber optic bundle LS = light source PP = peristaltic pump. Tlie colorimetric reading stations are marked 1 through 9. 

Figure 13.2 Internally illuminated monolith reactor (IIMR) scheme with a detail of the cross section of the monolith channels and the fiber-optic bundle.

Figure 12. The high density biosensor based on a fiber optic bundle. Figure provided by Dr. David Walt (Tufts University, Boston, MA).

Fluorometers designed for research purposes(31) are typically equipped with a xenon arc lamp, monochromators, one or more photomultiplier tubes, cuvet holders, and a computer interface. Some research level fluorometers, such as the Perkin-Elmer LS50, have optional microtiter plate reading accessories with fiber optic bundles. This is convenient since 96-well microtiter plates are commonly used for immunoassay development, and many commercial immunoassays are based on the use of microtiter plates. Fluorometers designed for commercial immunoassay purposes are generally dedicated instruments with few, if any, data acquisition and reduction parameters that can be manipulated by the user. 

The extmders were monitored using a pair of custom-made transmission probes inserted into the extruder die just downstream from the screws. Each probe consisted of a sapphire window brazed into a metal body a quartz rod behind the window piped the light to the end of the probe low-OH silica fiber-optic bundles connected the probe to the NIR analyzer, an LT Quantum 12001. Optical path lengths were typically between 0.3 and 2.0 cm. 

Another unique approach to microarray technology uses fiber optic bundles to support an array of microbeads that are coated with DNA capture sequences. Each bead is individually associated with a single fiber in the bundle, and hybridization targets labeled with fluorescent dyes are hybridized to the beads. The one-to-one concordance of bead to fiber in the bundle permits every bead in the hybridization array to be addressed and reported individually/94,95)... 

Pogue BW, Burke G. Fiber-optic bundle design for quantitative fluorescence measurement from tissue. Applied Optics 1998, 37, 7429-7436. 

FIGURE 7 Illumina BeadArrays. The Sentrix Array Matrix contains 96 1.4-mm fiber-optic bundles (bottom left). Each bundle is an individual array consisting of 50,000 5-pm fiber-optic strands, each of which is chemically etched to create a microwell for a single bead (top left). The Sentrix BeadChips can assay 1-16 samples at a time on a silicon slide (bottom right) that has been processed to provide microwells for individual beads (top right). Both BeadArray platforms rely on 3-pm silica beads that randomly self-assemble (center and top). 

Fuh et al. (1988) devised an enzyme optrode for penicillin. (5-Lactamase was immobilized on a fluorescein isothiocyanate-labeled porous glass particle which was glued to the tip of a fiber optic bundle. Excitation was carried out by an argon laser. pH changes resulting from the enzyme reaction led to changes of the fluorescence intensity. The response time of the sensor was 20-45 s, the detection limit being 0.1 mmol/1 penicillin. 

Fig. 6. Schematic of Technicon CHEA1 I analyzer where P = aspiration MV = metering valves CT = capillary Teflon tube M = reagent mixing zone FW = filter wheel FB = fiber optic bundle LS = light source PP = peristaltic pump. The colorimetric reading stations are marked 1 through 9.

Fluoresceinamine immobilized into polyfvinyl alcohol) membranes using cyanuric chloride and glutaraldehyde on fiber optic bundles pH [41]... 

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