Cellular uptake behavior of [γ-32P] labeled ATP-LDH nanohybrids

The inorganic layered double hydroxide support, Mg4Al2(OH)(12)(NO3)(2). mH(2)O, could be obtained by coprecipitation in aqueous solution; the interlayered NO3- anions can be replaced by biomolecules such as cytidine 5'-monophosphate, adenosine 5'-monophosphate, guanosine 5'-monophosphate and adenosine 5'-triphosphate to form new biomolecule-LDH hybrids. Upon intercalating these biomolecules into hydroxide layers, the interlayer distance increases from 8.7 Angstrom (for NO3-) to 14.5 Angstrom, 16.9 epsilon Angstrom, 18.4 Angstrom, and 19.4 Angstrom, respectively. According to spectroscopic analysis, it is also found that the intercalated biomolecules maintain their chemical properties unchanged in the interlayer space of the layered double hydroxide. Furthermore, the isotope dilution test for the transfer efficiency of [gamma-P-32] ATP-LDH hybrid into eucaryotic cells verifies reproducibly much higher transfer efficiency of the hybrid than for ATP molecules alone due to the charge neutralization of anionic phosphate molecules by cationic hydroxide layers in the hybrid. These experimental data suggest the potential usefulness of LDHs as innovative inorganic reservoirs and delivery carriers for genes, drugs, and other biomolecules.