Thermoresponsive polymers for biomedical applications

1. Course:advance polymers
Dilshad bajwa
Roll#11

2. Introduction
“Smart polymer” materials that have the ability to
respond to external stimuli, represent one of the most
exciting and immerging class of materials
They are cheaper and more easily handled than metals
or ceramics.
Stimulus-responsive or ‘smart’
polymers
Smart polymers and hydrogels undergo fast,
reversible changes in microstructure from a
hydrophilic to a hydrophobic state with change in
(pH, temperature, ionic strength) etc.

3. Temperature-responsive polymers
Respond to temperature changes
Types of thermo responsive polymer:
TRP which shows LCST
TRP which shows UCST
e.g poly(acrylonitrile-co-butadiene)

4. Temperature responsive polymer
The first established LCST is 32oC for poly(N-
isopropylacrylamide) (PNIPAAm) in water solution
At this temp:
•Undergoes a sharp coil-globule transition
•Changes from hydrophilic state to hydrophobic
state as temperature is increases
•In aqueous solutions, it is soluble below LCST
and less soluble above it

5. Gene Therapy:
Gene therapy aims at the treatment of many
genetic diseases .
Delivery of therapeutic gene (DNA) into the
cells that will replace, repair or regulate the
defective gene.
Gene therapy aims at the treatment of many
genetic diseases .
Delivery of therapeutic gene (DNA) into the
cells that will replace, repair or regulate the
defective gene.
The main steps of gene delivery
using a cationic polymer:
(1) DNA complexation formation
(polyarginine polymer AND PNIPAAm
)above LCST

6. (2) Complex traversing through cell
membrane to the cytoplasm at 37 °C
(3) DNA release into the cytoplasm below
LCST
(4) DNA transfer into nucleus

7. Tissue Engineering
To regenerate or replace biological
damaged or diseased tissue or
generate replacement organs
for a wide range of medical
conditions such as heart diseases,
diabetes, and spinal cord injury .

8. Thermoresponsive polymer is mixed at
room temperature with cells and then
injected into the body.Upon injection due
to the temperature increase (to 37 °C)
that is above the polymer’s LCST, the
polymer forms a physical gel.

9. Drug delivery through Micelles
The thermoresponsive properties of terpolymers
of PEGMA-b-(DMAEMA-co-MMA)
The formation of thermoresponsive
micelles with sustained drug release in vitro

10. Cross Linked Micelles
The formation of micelles above the LCST
of PEG-b-PPG-b-PEG triblock copolymers
By incorporating a methacrylate group
onto each end of the block copolymers
crosslinking.
crosslinked layer slowed the release of
drug by entrapment but allowed an
increase in the release with increased
temperature

11. Formation of nanocages from polymers of PEG
(blue) PPG (red) and methacrylate groups
(green)

12. Polymer bilayer film entraps particles
and cells.

13. Conclusion:
Thermoresponsive polymers
and their uses in gene therapy
,genetic engineering .drug delivery
etc. have a definite impact in the
medical field.

14. THANKS FOR LISTENING