Transcript Nanotechnology in Medicine Krešimir Pavelić Division of Molecular

Nanotechnology
in Medicine
Krešimir Pavelić, Marijeta Kralj and Damir Kralj
Division of Molecular Medicine and
Division of Material Chemistry
Ruđer Bošković Institute
Zagreb, Croatia
Nanotechnology
• Antisense therapy
• gene therapy
• conventional drug
delivery
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.
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 nonspecific aptameric effects (leading to nonspecific binding of antisense oligonucleotides)
the use of particulate carriers such as
nanoparticles, has been considered. (The size of
nanocapsules - 350 + 100 nm).
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.
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.
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.
Soluble Inorganic Vector
Layered double hydroxides
(LDHs)
• cationic brucite-like layers
• exchangeable interlayer
anions
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.
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.
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.
Interlayer
ion
LDH
Ion exchange
Nanohybridization
Recognition
and uptake
Schematic illustration
of the hybridization and
transfer mechanism of the
DNA-LDH hybrid into a cell
DNA-LDH
hybrid
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.