3. Dendrimers are the new artificial macromolecules which have the structure like a tree. consist of a
series of chemical shells built on a small core molecule. Each shell consists of two chemicals, always in the
same order and is called a generation
Fig. A: Schematic 2D presentation of dendrimer
Fig. B: 3D presentation of dendrimer
4. Properties
Structure
Compact and Globular
synthesis
Careful and stepwise growth
Structure control
Very high
Shape
spherical
Crystallinitty
Non crystalline, amorphous material, lower glas
temperature
Nonpolar solubility
high
Aqueous solubility
high
viscosity
Non liner relationship with molecular weight
reactivity
high
5. Dendrimer Components
- Dendrimers consist of three main components…
Interior
Surface: functional peripheral group
Interior: affects host-guest properties
Core: affects 3D shape of dendrimer
Core
Surface
6. - Count branching points as the “generation”
This is a “G2 dendrimer.”
Higher generation dendrimers form more dense, dimensional shape.
7.
8.
9. How do we make a dendrimer?
We make the nanodevice by modeling it first. Modeling then drives synthesis, which produces materials for testing. Test
results, in turn, drive further modeling and synthesis.
12. convergent strategy
Lee J. W., Kim J.H., Kim Byung-Ku. Synthesis of azide-functionalized PAMAM dendrons at the focal point and their application for synthesis of PAMAM-like dendrimers,
Tetrahedron Letters, 2006. 47:2683–2686
13. Organic Synthesis
Dendrimers have been prepared via click chemistry, employing Diels-Alder reactions,thiol-yne reactions and
azide-alkyne reactions.An example is the synthesis of certain polyphenylene dendrimers is shown in this figure
http://en.wikipedia.org/wiki/Dendrimer
14. Supramolecular
Dendrimers
Supramolecular systems are rarely designed from first
principles. Rather, chemists have a range of wellstudied structural and functional building blocks that
they are able to use to build up larger functional
architectures. Many of these exist as whole families of
similar units, from which the analog with the exact
desired properties can be chosen. The molecule shown
here is a combination of traditional organic synthetic
compounds using significant steric hinderence to
achieve a particular shape/conformation
17. Size scale of Dendrimers of different generations vs. Biological
Proteins
18. Dendrimers vs. Proteins
Similarities
Size
Weight
Well defined chemical structure (known bonding
structure)
3 dimensional position of each atom is difficult to
determine - yet a consistent specific 3 dimensional
structure exists
Difficult to perform chemical analysis
Easy for cell to uptake
Main Difference
Proteins are polymers made from
20 different monomers, while
dendrimers are polymers made
from two monomers.
19. Dendrimer Applications
This light-harvesting dendrimer performs some functions of artificial photosynthesis.
White light is gathered through chain-ends that behave like antennae and funneled
into a chromophore in the dendrimer's core that then emits a single color of amplified
light
20. 1- Bioactive Dendrimers
Dendrimers can be functionalized for surface
activity., such as attaching to cells, and using a
quantum dot interior core for imaging.
Dendrimers can contain metal atoms including
gold which can absorb radiation at a particular
wavelength, and used in cancer treatment. The
relatively short lifetime of a dendrimer enures
that it won’t bioaccumulate in the body, or
concentrate potentially toxic cadmium (CdS
quantum dots).
Dendrimer
21. 2- Dendrimer as magnetic resonance imaging contrast agents
Dendrimer based metal chelates act as a magnetic resonance imaging contrast
agent. Dendrimers are highly suited and used as image contrast media because of
their properties. Many tests carried on dendrimers have shown that dendrimers are
stronger contrast agent than conventional ones.
The effect of sepsis on dendrimer-enhanced magnetic resonance imaging (MRI) of the kidney. MRI scans 1, 9,
and 17 minutes after intravenous injection of G4 dendrimer. (A) Sham-operated mouse 20 hours after surgery. (B)
Cecal ligation and puncture (CLP)-operated mouse 20 hours after surgery.
22. 3- Dendrimers in Antitumor Therapy
Dendrimers molecule has found use
as diagnostic reagent for tumour
imaging by magnetic resonance
imaging and as contrast agent; by
varying the size and hydrophilicity
and by combining with tumour
targeting antibodies, these
compounds can be used for a range
of specific imaging purpose The
drug used should be non-toxic,
under non- irradiative condition,
thus acting as prodrug when not
irradiated.
23. 4- Dendrimers as Gene Transfer agents
Dendrimers as Gene Transfer agents
because
• Unmodified PAMAM and PPI
dendeimers an form complexes with
DNA.
• Partially degraded or fragmented (
activated) dendrumers help
transfection efficiency
• Slight excess of primaryamines is
benefiocail
24. 5- Dendrimers in targeted drug delivery
Dendrimers have multifunctionality and
high potential for drug delivery
applications as they possess high
density and wide variety of functional
groups on its surface 9-11. Its well
defined molecular structure, segmental
spherical construction of dendrimers
offers an interesting architecture for
dendrimers. If one of these segments is
attached with active drug molecule, the
other can be highlighted as targeting
group. Due to this double functional
group, the plasma level of the drugs will
stay at desired level for longer time
period and increase its Pharmaceutical
efficiency.
25. 6- Dendrimers in drug delivery
Dendrimers in drug delivery because
• Enhance the aqueous solubility
• Increase circulation half life
• Target certain tissue.
• Improve transit across biological
barrier .
• Slow drug metabolism
26. 7- Dendrimers in transdermal drug delivery
Transdermal drug delivery has come into existence long back. To improve the effectiveness of the drug
transdermal drug delivery system was emerged. Drug delivery through skin to achieve a systematic effect of
drug is known as transdermal drug delivery.
27. 8- Dendrimers in oral drug delivery
Oral drug delivery is the most popular and has received more attention in the pharmaceutical field because of ease
of production, low cost, convenience of ease of administration and flexibility in designing of dosage. The oral drug
delivery depends on various factors such as type of delivery system, the disease being treated, and the patient, the
length of the therapy and properties of the drug.
29. 10- Dendrimers Fighting the Spread of Diseases
The dendrimers (blue and red) in VivaGel interact with
The dendrimer (blue and red) attaches to multiple receptors
protein structures (yellow) on the surface of HIV, blocking
(pink) on cell membranes or other biological structures such
the interaction of HIV (purple) with healthy human cells
as a virus.
(pink) that results in HIV infection.
30. 11-Dendrimers used for enhancing the solubility
PAMAM dendrimers are expected to have potential applications in
enhancing the solubility for drug delivery systems 1, 2. Dendrimers
have hydrophilic exteriors and hydrophilic interiors, which are
responsible for its unimolecular micelle nature.
31. 12- Dendrimers for additives, printing inks and paints
Dendrimers can be used in toners material with additives which require less material
than their liquid counterparts. Xerox Corp. Patented a dry toner compound
dendrimers as charge enhancing species in the form of an additive
34. 15- Supramolecular Architectures
A schematic illustration of supramolecular architectures
of self-assembled extended amphiphilic dendrons,
developed at Cornell by Ulrich Wiesner, professor of
materials science and engineering , and his research
team. The illustration shows (A) cubic micelles,
(B) two-dimensional lamellar layers, (C) hexagonally
arranged cylindrical columns and (D) three-dimensional
continuous cubic structures.
35. 16- Dendrimers as a separating agent
A study of variety of compounds synthesized to determine suitability for enhancing boron
rejection by reverse osmosis and nanofilteration membrane to separate born from sea water
has been developed. For separation, compound must have amphiphile chemical structure and
form micelle in aqueous solution. As a new compound dendrimers with a high density of
functional moiety, is able to form micelle structure which can be easily separated and
recovered by ultra filtration membrane.
36. Dendrimer Superstructures
Dendrimers are repetitively branched molecules. [1] [2]
The name comes from the Greek word "δένδρον"
(pronounced dendron), which translates to "tree".
Synonymous terms for dendrimer include arborols
and cascade molecules. However, dendrimer is
currently the internationally accepted term. A
dendrimer is typically symmetric around the core, and
often adopts a spherical three-dimensional
morphology. The word dendron is also encountered
frequently. A dendron usually contains a single
chemically addressable group called the focal point.
The difference between dendrons and dendrimers is
illustrated in figure one, but the terms are typically
encountered interchangeably.[3]
38. Re f e r
e n c e s
• http://www.nature.com/ki/journal/v67/n6/full/4495293a.html#fig1
• http://www.chemistry.ohio-state.edu/cgi-bin/brochure?Faculty=parquett
• http://nano.med.umich.edu/Dendrimers.html#dendrimer_introduction
• http://nano.med.umich.edu/Dendrimers.html
•
http://www3.interscience.wiley.com/cgi-bin/fulltext/106558159/PDFSTART
•
http://www.lbl.gov/Science-Articles/Research-Review/Magazine/2001/Fall/features/02Dendrimers.html
• http://perceco2.chem.upenn.edu/~percec/inthenews/denx.html
• http://www.gade.uni-hd.de/research.php
•
http://www.fda.gov/nanotechnology/powerpoint_conversions .com
• http://www.news.cornell.edu/releases/Sept04/Wiesner.supermolecules.deb.html
• http://en.wikipedia.org/wiki/Dendrimers
http://pubs.acs.org/doi/abs/10.1021/nl202220q
• http://www.ncbi.nlm.nih.gov/pubmed/21864902
