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Synthesis of DNA-encapsulated silica elaborated by sol-gel routes

2013-01-01
Kapusuz, Derya
Durucan, Caner
The highly specific functions of DNA can be used for designing novel functional materials. However, aqueous solubility and biochemical instability of DNA impede its direct utilization as a functional component. Herein, preparation of a hybrid material encapsulating the DNA molecules (double-stranded salmon sperm, 50-5000 base pairs) in robust host-sol-gel-derived silica-has been described. The encapsulation was carried out in two steps: hydrolysis of an acidic tetraethylorthosilicate [Si(OC2H5)(4)] sol and was followed by condensation near physiological pH upon addition of alkaline DNA-containing solutions. The gelation behavior and structural properties of the DNA-silica hybrids were investigated by Si-29 nuclear magnetic resonance and by nitrogen adsorption. The selective adsorption of a DNA-interactive reagent molecule (ethidium bromide) in their diluted aqueous solutions on DNA-silica hybrids confirmed that the DNA molecules remained entrapped within the silica host without any deterioration. A DNA encapsulation mechanism correlating the silica microstructure and DNA holding efficiency has been proposed.