Oligo immobilized

Fig. 9 Surface modification of cells with ssDNA-PEG-lipid. (a) Real-time monitoring of PEG-lipid incorporation into a supported lipid membrane by SPR. (r) A suspension of small unilamellar vesicles (SUV) of egg yolk lecithin (70 pg/mL) was applied to a CH3-SAM surface. A PEG-lipid solution (100 pg/mL) was then applied, (ii) Three types of PEG-lipids were compared PEG-DMPE (C14), PEG-DPPE (C16), and PEG-DSPE (C18) with acyl chains of 14, 16, and 18 carbons, respectively, (b) Confocal laser scanning microscopic image of an CCRF-CEM cell displays immobilized FITC-oligo(dA)2o hybridized to membrane-incorporated oligo(dT)20-PEG-lipid. (c) SPR sensorigrams of interaction between oligo(dA)2o-urokinase and the oligo (dT)2o-PEG-lipid incorporated into the cell surface, (i) BSA solution was applied to block nonspecific sites on the oligo(dT)20-incorporated substrate, (ii) Oligo(dA)20-urokinase (solid line) or oligo(dT)20-urokinase (dotted line) was applied...

Fig. 10 Confocal laser scanning microscope images of islets with urokinase (UK) immobilized on the membrane. The green fluorescence indicates positive immunostaining for UK. (a) Islets were modified with oligo(dT)2o-PEG-lipid (C16) or (b) oligo(dT)2o-PEG-lipid (C18) then, oligo (dA)2o-UK was added to the media, (c) Unmodified islets with (left) and without (right) oligo (dT)20-PEG-lipids added to the solution. Insets. Bright field images. Scale bars 100 pm...

Fig. 11 Islets with immobilized urokinase (UK-islets) were tested for the ability to dissolve fibrin, (a) Fibrin in the plate gel medium was dissolved by UK-islets (clear areas). Fifty islets were applied to each spot, and the plate was observed after incubation at 37 °C for 14 h. (1) untreated islets (2) UK-islets treated with oligo(dT)2o-PEG-lipid (C16), just after preparation (3) UK-islets treated with oligo(dT)2o-PEG-lipid (C16) lost activity after 2 days in culture (4) UK-islets treated with oligo(dT)20-PEG-lipid (C18), just after preparation and (5) UK-islets treated with oligo (dT)20-PEG-lipid (C16) lost activity after 2 days in culture, (b) Morphology of UK-islets after 1 and 7 days of culture...

With the development of enzymatic polymerization in solution, also first accounts for SIP appeared. Loos et al. [350] reported on enzymatic surface polymerization of glucose-l-phosphate with potato phosphorylase as the catalyst resulting in oligo- or poly-(a,l- 4)-D-glucopyranose. As initiator sites, immobilized malto-heptaose was used. Enzymatic grafting of hexyloxyphenol onto chitosan is reported by Payne and coworkers [351]. 

Hamaguchi, Y, Aso, Y, Shimada, H., and Mitsuhashi, M., Direct reverse transcrip-tion-PGR on oligo(dT)-immobilized polypropylene microplates after capturing total mRNA from crude cell lysates, Clin. Chem., 44, 2256-2263, 1998. 

An array of oligonucleotide which is composed of 20 80-mer oligos, or peptide nucleic acid probes, is synthesized either in situ (i.e., on-chip) or using conventional synthesis followed by on-chip immobilization. The resultant DNA array is then exposed to the labeled sample of DNA, hybridized, and the identity/abundance of complementary sequences determined. This method was developed at Affymetrix, Inc. and called DNA chips. Today, oligonucleotide-based chips are manufactured by many companies using alternative in situ synthesis or depositioning technologies. 

The choice of DNA array depends on cost, density, accuracy, and the type of DNA to be immobilized on the surface. The first criteria should be whether the chips contain immobilized cDNAs or shorter oligonucleotide sequences. The former must be spotted on the chips as complete molecules, but oligos can either be spotted or synthesized on the surface of a chip. The final criteria to select a chip should be whether the user makes or purchases the chip. Homemade systems offer limited number of spotting samples. 

Fig. 6. Measurement of the relative amount of ligand bound to each protein in the array. (A) Schematic of on-chip binding assay in which a fluorescently labeled interaction partner binds to the functional, arrayed protein immobilized to the streptavidin-coated surface via the biotinylated BCCP tag. (B) p53 protein function microarray probed with Cy3-labeled GADD45 duplex oligo. Quantification of the signal intensity from each spot allows the effect of polymorphic and functional variation on the DNA binding function of p53 to be determined.

Total RNA or (polyA+)RNA (mRNA) can be used for experiments. In the latter case, a purification step is necessary, as mRNA is isolated from total cellular RNA by affinity chromatography on oligo-dT immobilized to a solid support. The amount of the purified RNA is determined by its dual wavelength absorbance at 260 nm and 280 nm and the quality checked by agarose gel or capillary electrophoresis. 

Due to the presence of an immobilized oligo(ethyleneglycol) fragment in 394 and 395 and a crown ether moiety in 396-398, these SAMs have been evaluated by cyclic voltammetry for their alkali cation-recognition properties with a potential to be utilized as thin-film ion sensors. 

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