Dendrimers are synthetic, highly branched polymers with three distinct components: a core, interior layers, and an exterior surface. They are synthesized using either a divergent or convergent method. Dendrimers have many potential applications including as drug delivery systems, solubility enhancers, and in gene therapy due to their highly branched structure which allows encapsulation of bioactive molecules in their interior. They are characterized using techniques like spectroscopy, scattering, chromatography and microscopy. Common uses include delivery of anticancer drugs, enhancing drug solubility, and cellular delivery of therapeutic agents.
2. CONTENTS:-
1. INTRODUCTION
2. HISTORY
3. COMPONENTS OF DENDRIMERS
4. NEED OF DENDRIMERS
5. METHODS OF SYNTHESIS
6. TYPES OF DENDRIMERS
7. CHARACTERIZATION OF DENDRIMERS POLYMERS
8. APPLICATIONS
3. INTRODUCTION:-
The word “ Dendrimer” originated from two Greek words
Dendron :- meaning tree
meros :- meaning part or segment
Dendrimers are a new class of Polymeric materials. They are highly branched
monodispers , Artificial macromolecules.
Dendrimers may be defined as Synthetic three – dimensional hyper branched
globular macromolecules , which is characterized by its highly branched 3D
structure that provides a high degree of surface functionality .
4. HISTORY :-
In 1978 Vogtle and Co – workers was First introduced chemistry of
Dendrimers.
In 1980 , Donald Tomalia and Co – workers discovered these hyper branched
molecules were called dendrimers .
In 1985 , Vogtle synthesized the first family of Dendrimers the First “ Cascade
molecules”.
At the same time , Newkame’s group independently reported synthesis of
similar molecules.
They called them arborols from the Latin word ( arbor also means “a tree”)
5. COMPONENTS OF DENDRIMERS:-
Dendrimers contain three different components
1. An Initiator core :-
2. Interior layers :- Composed of repeating unit’s , radically attached to the
interior core (generation).
3. Exterior layer :- Attached to the outermost interior generation ( Terminal
functionality)
7. NEED OF DENDRIMERS:-
Nano particles , drug delivery systems are most popular one.
However reticuloendothelial system (RES ) Uptake , drug leakage ,
immunogenicity, haemolytic toxicity, cytotoxicity, restrict the use of
nanostructures.
These are overcome by surface engineering the Dendrimer such as Polyester
Dendrimer, Glyco – Dendrimers , PEGylated Dendrimers etc.
The bioactive Agent Can be easily encapsulated into the interior of the
Dendrimers.
8. METHOD OF SYNTHESIS:-
1. Divergent method
2. Convergent method
3. Hypercores & branched monomers method
4. Double Exponential and Mixed growth
5. Other accelerated growth techniques
9. DIVERGENT METHOD:-
Dendrimers Starts from the central core and extends towards the surface i.e.
Diverging into space .
Two step process .
Activation of functional surface groups.
Addition of branching monomer units .
Divergent approach is successful for the production of large quantities of
Dendrimers
It causes some difficulties in the purification of the final product
10. CONVERGENT METHOD:-
Dendrimer starting from the end groups and progression inwards.
When the growing wedges are enough large , attached to a suitable core to
give a complete Dendrimer.
The convergent methodology also suffers from low yields in the synthesis of
large structures.
11.
12. HYPERCORES & BRANCHED MONOMERS
TECHNIQUE :-
Freechet group continued their efforts on research of hypercore & branched
monomers .
This method involves the pre assembly of oilgomeric species, which can then
be linked together to give Dendrimer.
These monomers allow to the design synthesis strategies that are more
convergent in classical synthesis sense of world.
13. DOUBLE EXPONENTIAL AND MIXED
GROWTH METHOD:-
Double Exponential growth similar to a rapid growth technique for linear
polymers , involves an AB2 monomers with orthogonal protecting groups for
the A and B functionalities .
This approach allows the preparation of monomers for both convergent and
divergent growth from a single starting material .
These two products are reacts together to give an orthogonally protected
trimer, which may be used to repeat the growth process again .
14.
15. OTHER ACCELERATED GROWTH
TECHNIQUES:-
This is two step approach designed by fretchet .
In this approach two different monomers are used so as to avoid the need of
an activation step between growth steps .
The two monomeric units are AB2 & CD2 . Where A&D react to form bond
under required conditions while B&C are stable , Where B&C React to form
bond while A&D remain stable .
In this technique the hindrance likely to be experienced is that difficulty of
Finding a set of reactions , Which conform to above criteria.