Encapsulation of nucleotides and DNA into Mg-Al layered double hydroxide

Abstract

The encapsulation of mononucleotides and DNA into Mg-Al layered double hydroxide (LDH, also known as hydrotalcite) by intercalation reaction, and release profile of mononucleotides and DNA was examined. Screening of the intercalation conditions (mononucleotide concentration, reaction temperature, reaction time, and pH) was carried out in order to determine precisely the optimal conditions. Intercalation of all examined mononucleotides and DNA into the chloride form of LDH was found to be possible using the ion-exchange method. The amount of mononucleotide taken up was 0.6-1.5 mmol per 1 g LDH. Intercalation compounds were examined using XRD and solid-state NMR. The interlayer distance of 5'-mononucleotide-intercalated LDH was found to be 14.0-15.3A, while that of 3'-mononucleotide-intercalated LDH was 17.4-17.7A. Intercalation of double-helix DNA of less than 500 base pairs was verified, with an uptake of 1.8 mmol per 1 g LDH (based on mononucleotide units). The intercalation mechanism and release profile in aqueous K(2)CO(3) solution were also investigated. Complete release of the nucleotides was found to take place. The encapsulation makes possible to protect mononucleotides and DNA, and promise the carrier of them to gene.