Immobilization oligonucleotides

In a similar way, the use of oligonucleotide-immobilized beads enabled the realization of DNA sensitive biochips that could be used to detect biotin labelled sequence as 5.108 molecules59. 

Figure 10.14 (a) Schematic representation of hybridization between ferrocene-conjugated oligonucleotide immobilized on gold electrode and its complementary strand, (b) Cyclic voltammograms recorded at v — 2(X) V/s and dependence of the anodic peak current on scan rate, normalized versus v1/2. Reprinted with permission from Ref. 76. Copyright 2003 American Chemical Society. 

Fig. i Matrix isolation method of surface immobilization of probe oligonucleotide/poly-electrolyte mixed film for enhanced selectivity. Phase 1 Photolabile dimethoxybenzoin (DMB) protecting groups are selectively exposed to electromagnetic radiation of appropriate wavelength to provide reactive sites in which polyelectrolyte spacers can be immobilized. Phase 2 The remaining DMB-protected sites are photo-deprotected to expose sites for probe oligonucleotide immobilization onto the solid surface... 

Retention of oligonucleotides immobilized beads was also achieved on a slit-type filter chamber fabricated on Si. The three different designs are shown in Figure 8.3 [829-831]. Although the flow rate decreased when the chamber was filled with beads, clogging of the filter was rare and reversible, especially with the design shown in Figure 8.3c [831]. 

Figure 2 Minisequencing reaction on with extension primers immobilized on the microarray surface. The multiplex PCR products of the regions containing the SNPs are allowed to hybridize to the oligonucleotides immobilized on the microarray (A). The primers are extended with fluorescently labelled ddNTPs complementary to the nucleotide at the SNP position. Four different fluorophores, one for each nucleotide is used allowing for a simultaneous detection of the four nucleotides in one single reaction (B). After washing the slide with sodium hydroxide and salt buffers, only the extended primers covalently attached to the surface remains and the fluorescence is measured (C) and the genotypes assigned.

A scheme of oligonucleotide immobilization by electrochemical adsorption is shown in Fig. 3. 

Zhou XC, Huang LQ, Li SFY (2001) Microgravimetric DNA sensor based on quartz crystal microbalance comparison of oligonucleotide immobilization methods and the application in genetic diagnosis. Biosens Bioelectron 16 85-95... 

Y. Okahata, M. Kawase, K. Niikura, F. Ohtake, H. Fmusawa, Y. Ebara, Kinetic Measurements of DNA Hybridisation on an Oligonucleotide-Immobilized 27-MHz Quartz Crystal Microbalance , Anal. Chem., 70, 1288 (1998)... 

Watterson, J.H., et al. Effects of oligonucleotide immobilization density on selectivity of quantitative transduction of hybridization of immobilized DNA. Langmuir, 2000, 16, p. 4984-4992. 

Figure 5-14. Schematic illustration of DNA detection based on the direct measurement of conductivity using nanoscale electrical leads. The binding of a target sequence to a pair of probe oligonucleotides immobilized on opposing nanoscale electrodes would provide a means to detect DNA sequences using direct conductivity measurements.

Ogura M., Koo K. and Mitsuhashi M. (1994) Use of the fluorescent dye YOYO-I to quantify oligonucleotides immobilized on plastic plates. Biotechniques, 16, 1032-1033. 

Advances in microarray technology, with the use of cDNA or oligonucleotides immobilized in a predefined organization on a solid phase, have led to measurements of mRNA expression levels on a genome-wide scale (see chapter 3). The results of the measurements can be displayed on a plot (fig. 13.1) on which a row represents one gene at various times, a column the whole set of genes, and the time of gene expression... 

Zeng J, Ahnadidy A, Watterson J, Krull UJ (2002) Interfacial hybridization kinetics of oligonucleotides immobilized onto fused silica surfaces. Sens Actuators B 90 68-75... 

Figure 44 Two examples of specific interaction on structured star PEG layers, (a) Specific adsorption of streptavidin onto biotin-patterned surfaces, (b) fluorescentiy labeled oligonucleotides immobilized onto freshly prepared surfaces with existing NCO functionality. Reprinted from Heyes, C. D., Groll, J., Moller, M. Nienhaus, G. U. Mol. BioSyst. 2007,3,419. ...

Another interesting approach to fiber-optic sensor development has been reported by Walt and co-workers [114,115], who have created multiplexed extrinsicmode fiber optic microarray biosensor. The sensor employed fiber optic bundles (2-3 feet in length) composed of many optical fibers each 200-350 Lun in diameter. The microarray was fabricated by immobilizing a different oligonucleotide probe sequence onto the distal end of each fiber. Individual fibers within the bundle were made reactive for oligonucleotide immobilization by immersing the bundle in a solution of... 

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