This is a copy of the slides presented at the meeting but not formally written up for the volume.
New biomolecular-inorganic nanohybrids with two different functions, one from inorganic moiety and the other from biological one were realized by soft chemical methods such as intercalation, coprecipitation and exfoliation-reassembling reactions. Recently we have been focusing on two-dimensional inorganic compounds like layered double hydroxides (LDHs), since they are biocompatible and can be used as gene or drug delivery inorganic nanovehicles. To the best of our knowledge, such inorganic drug delivery vectors are quite different from conventionally developed ones such as viral based vectors, naked DNA, biodegradable polymers,liposomes, and etc, those which are however limitedly used due to their toxicity, immunogenecity, poor integration, and etc. But we found that such disadvantages can be overcome by immobilizing genes or drug molecules into these new inorganic vectors, which consist of non-toxic metal ions with biological compatibility. Since LDHs are anion exchangeable, negatively charged functional biomolecules can be easily intercalated into hydroxide layers of LDHs by soft chemical reaction methods to form bio-LDHs nanohybrids. In such a way they can gain extra stabilization energy due to the electrostatic interaction between inorganic layers, whatever they are anionic or cationic, and counter-charged biomolecules or drugs. We also found that the hydroxide layers of LDHs could protect the intercalated molecules very efficiently. If necessary, inorganic materials, as reservoir and delivery carrier, can be intentionally removed by dissolving them in an acidic or basic media, which offer a way of recovering the encapsulated biomolecules or drugs. The possible roles of inorganic lattice as the gene and drug delivery carrier will be shown by demonstrating the cellular uptake experiments of FITC, fluorophore, with laser scanning confocal fluorescence microscopy as well as of radioactive isotope-labeled ATP-LDH hybrid. As the typical examples for gene and drug delivery systems, As-myc-LDH and MTX-LDH nanohybrids will be demonstrated along with their endocytic mechanism. In addition, nanotoxicity of LDH and other inorganic nanoparticles will be also discussed in detail.