1. Nanotechnology in Medicine Krešimir Pavelić, Marijeta Kralj and Damir Kralj Division of Molecular Medicine and Division of Material Chemistry Ruđer Bošković Institute Zagreb, Croatia

2. Nanotechnology Antisense therapy gene therapy
conventional drug delivery

3. Antisense Therapy
The aim is to interface with gene expression by preventing the translation of proteins from mRNA.
Mechanisms of mRNA interactions:
sterical blocking of mRNA by antisense binding and destruction antisense mRNA hybrids by RnaseH enzyme
formation of triple helix between genomic double-stranded DNA and oligonucleotides
the cleavage of target RNA by ribozymes.

4. Antisense Therapy and Nanoparticles
Problems: poor stability of antisense oligonucleotides versus nuclease activity in vitro and in vivo, and their low intracellular penetration have limited their use in therapeutics. Solutions: to increase antisense stability, to improve cell penetration and also to avoid non-specific aptameric effects (leading to non-specific binding of antisense oligonucleotides) the use of particulate carriers such as nanoparticles, has been considered. (The size of nanocapsules nm).

5. Gene Therapy
Method for treatment or prevention of genetic disorders based on delivery of repaired or the replacement of incorrect genes. Aimed at treating or eliminating the cause of disease.

6. Gene Therapy and Nanoparticles
Problems: gene delivery, vector immunogenicity, stability. Solutions: nanotechnology in gene therapy would be able to replace the currently used viral vectors by potentially less immunogenic nanosize gene carriers. Vector based on nanoparticles (50 to 500 nm in size) were developed to transport plazmid DNA.

7. Conventional Drugs and Nanoparticles
Problems: delivery by oral route can not be used with most proteins due to both the degradation of these molecules within the intestine and their poor uptake across the intestinal wall. Solutions: pharmaceuticals can be incorporated within biodegradable nanoparticles. This has advantages of protecting the pharmaceuticals from proteolysis within the intestine, or amplifying the uptake capacity of the oral delivery system.

8. Soluble Inorganic Vector
Layered double hydroxides (LDHs)
cationic brucite-like layers
exchangeable interlayer anions

9. Hypothesis
The unique anion exchange capability of LDHs meet the requirement of inorganic matrices for encapsulating functional biomolecules with negative charge in aqueous media.
Such biomolecules can be incorporated between hydroxide layers by a simple ion-exchange reaction to form bio-LDH nanohybrids.

10. Soluble Inorganic Vector
The negatively charged biomolecules intercalated in the gallery spaces would gain extra stabilization energy due to the electrostatic interaction between cationic brucite
layers and anionic DNA
molecule.

11. Soluble Inorganic Vector
Hydroxide layers can play role of a reservoir to protect intercalated DNA from DNase degradation If desired, the hydroxide layers can be intentionally removed by dissolving in an acidic media, which offers a way of recovering the encapsulated biomolecules.

12. LDH
Interlayer
ion
Ion exchange
Nanohybridization
DNA-LDH
hybrid
Recognition
and uptake
Schematic illustration
of the hybridization and
transfer mechanism of the
DNA-LDH hybrid into a cell

13. Conclusions
Inorganic supramolecules, such as nanoscale LDHs, can act as biomolecule reservoirs and gene/drug carriers
LDH itself is nontoxic
Cellular uptake experiments reveal that the FITC-LDH hybrid is effectively transferred into NIH3T3 cells.
Antisense myc-LDH hybrid cause strong antitumor effect in vitro.
LDHs can act as new inorganic carrier, completely different from existing nonviral vectors in terms of its chemical nature.