Biological hybrid materials for drug delivery system

We have attempted to realize new biomolecular-inorganic nanohybrids with two different functions, one from inorganic moiety and the other from biological one. Recently we were quite successful in demonstrating that a two-dimensional inorganic compound like layered double hydroxide (LDH) can be used as gene or drug delivery carriers. Such inorganic vectors are completely new and different from conventionally developed ones such as viral-based, naked, and cationic liposomes, those which are limited in certain cases of applications due to their toxicity, immunogenecity, poor integration, and etc. But the mentioned problems can be overcome by synthesizing inorganic vectors properly with non-toxic metal ions having biological compatibility. Since LDHs with positive layer charge have an anion exchange capacity, functional biomolecules with a negative charge can be intercalated into hydroxide layers of LDH by a simple ion-exchange reaction to form a bio-LDH nanohybrid. 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 it in an acidic which offer a way of recovering the encapsulated biomolecules. 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 the typical example for gene and drug delivery system, MTX-LDH will be demonstrated in detail.