Dendritic complexation agents

Selective dendritic complexation agents for heavy metal ions... 

All plastics are permeable to moisture, and this can lead to failures caused by (i) electrochemical corrosion of aluminium metallisation (ii) dendritic growths between gold metallisation tracks and (iii) the corrosion of gold if suitable complexing agents are present. The rate of degradation is affected by many factors but two of the most important are the amount of ionic contamination which can be leached from the plastic and the quality of the passivation layer which is now present on the surface of all ICs. 

Bonding Agents. These materials are generally only used in wire cable coat compounds. They are basically organic complexes of cobalt and cobalt—boron. In wire coat compounds they are used at very low levels of active cobalt to aid in the copper sulfide complex formation that is the primary adherance stmcture. The copper sulfide stmcture builds up at the brass mbber interface through copper in the brass and sulfur from the compound. The dendrites of copper sulfide formed entrap the polymer chains before the compound is vulcanized thus hoi ding the mbber firmly to the wire. 

A similar type of biotin-dendritic multimer also was used to boost sensitivity in DNA microarray detection by 100-fold over that obtainable using traditional avidin-biotin reagent systems (Stears, 2000 Striebel et al., 2004). With this system, a polyvalent biotin dendrimer is able to bind many labeled avidin or streptavidin molecules, which may carry enzymes or fluorescent probes for assay detection. In addition, if the biotinylated dendrimer and the streptavidin detection agent is added at the same time, then at the site of a captured analyte, the biotin-dendrimer conjugates can form huge multi-dendrimer complexes wherein avidin or streptavidin detection reagents bridge between more than one dendrimer. Thus, the use of multivalent biotin-dendrimers can become universal enhancers of DNA hybridization assays or immunoassay procedures. 

A PAMAM-PEG-PAMAM dendritic triblock copolymer has also been shown to be an efficient gene delivery agent [40 ]. Plasmid DNA was found to assemble with the copolymer forming compact nanosized particles with a narrow size distribution. The resulting complex exhibited high solubility when compared to PAMAM dendrimers, low-cytotoxidty... 

Another two types of supported dendrons used for generation of dendritic gene delivery devices are the polystyrene-bound polyurea and peptoid dendrons developed by Bradley and coworkers. They demonstrated that these dendrons, once cleaved from the support, complex efficiently plasmid DNA and transfect it successfully into cells. The highest efficiency (comparable or better than that displayed by the commercial transfection agent Superfect) was observed for bis-G3 dendrons capped with lysine. In general, the efficiency increased with the dendron generation (positive effect). 

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