Mössbauer, XRD and TEM Study on the Intercalation and the Release of Drugs in/from Layered Double Hydroxides

Layered double hydroxides (LDHs) are one of the very important nano-carriers for drug delivery, due to their many advantageous features, such as the ease and low-cost of preparation, low cytotoxicity, good biocompatibility, protection for the intercalated drugs, and the capacity to facilitate the uptake of the loaded drug in the cells. In our previous studies, Mössbauer spectroscopy was applied to monitor structural changes occurring during the incorporation of Fe(III) in MgFe- and CaFe-LDHs, and the intercalation of various organic compounds in anionic form. Recently, we have successfully elaborated a protocol for the intercalation and release of indol-2-carboxylate and L-cysteinate in CaFe-LDH. The corresponding structural changes in the LDH samples were studied by XRD, HR-TEM and 57Fe Mössbauer spectroscopy. The Mössbauer spectra reflected small but significant changes upon both the intercalation and the release of drugs. The changes in the basal distances could be followed by XRD measurements, and HR-TEM images made these changes visible

Design of nucleic acid-layered double hydroxide nanohybrids

We report here on the design of inorganic–organic hybrid materials, which consist of layered double hydroxides (LDHs) as inorganic carrier and short single-stranded nucleic acids (ssDNA) as organic molecules. LDHs were prepared by the co-precipitation method followed by hydrothermal treatment. A model 12-nucleotide-long sequence was immobilized either by ion exchange or covalent grafting. Both the LDH composition and the nucleic acid-to-particle ratio were opti- mized throughout the synthesis to develop highly stable sus- pensions of the hybrid materials. Structural characterization revealed that the covalent attachment of the ssDNA was suc- cessfully achieved via silanization of the LDHs in aqueous suspension. Covalent linkage of the nucleic acids confers to this model nanoparticulate system promising properties and potential for applications as therapeutic agents. Fragments of nucleic acids could be introduced into living cells without release during the delivery process since LDHs slowly dis- solve in the slightly acidic intracellular space