2. Outline
Fun Fact
Introduction
Hydrogel
Nanocomposite hydrogels (NCHs)
Types / Classification of NCHs
Synthesis of NCHs
Characterization Techniques
NCHs for Biomedical Applications
Conclusion
Future directions
3. Fun Fact
• In the early 1950s Otto and Lím from the Prague(Czechoslovakia) Institute of Chemical
Technology initiated a research program to design polymers for medical use (shape-
chemical-biochemical stability, high permeability & tissue mimicry).
• Lím worked tirelessly using Polyvinylalcohol and after about a year, Lím by chance
identified a novel hydrogel material while synthesizing the tri ethylene glycol di
methacrylate monomer by acid catalyzed trans-esterification of methyl methacrylate with tri
ethylene glycol.
• One day Lím had to catch the train to his home, so he stopped the reaction early, and
managed to add water to separate the layers before leaving. In the morning, he noticed that
the water layer turned into a clear hydrogel overnight
4. Introduction
Since then, the use of hydrogels has extended to various biomedical and
pharmaceutical applications.
Hydrogels resemble living tissues closely in their physical properties because
of their relatively high water content , soft and rubbery consistency.
In an attempt to increase physical, chemical, electrical, biological, and
swelling/de-swelling/ (porosıty and adhesion)
We (You and I) researchers incorporate carbon-based, polymeric, ceramic
and/or metallic nanomaterials to give these hydrogels superior characteristics
like optical, mechanical, magnetic and stimulus-sensitive properties.
Very helpful to medical (especially drug delivery, regenerative medicine,
molecular imaging, stem cell engineering, implants e.t.c)
Wichterle O. Encyclopedia of Polymer Science and Technology.
5. According to ISI Web of Science (data obtained November 2013). A steady increase in the
number of publication indicates growing interest in the field of nancomposite hydrogels.
6. Hydrogel
Water-swollen polymeric materials that maintain a distinct
three-dimensional structure.
Due to their high water content, most hydrogel structures
possess excellent biocompatibility.
Classification
natural, synthetic, hybrid hydrogels.
on the basis of nature of the crosslinking:
covalent or non-covalent (physical) gels;
homopolymer, copolymer, interpenetrating, or double networks
nanowerk.com
7. Nanocomposite Hydrogels
Nanomaterials have particles of size in order of few nanometers.
The properties of particles vary significantly in nanoscale sizes making it interesting for
various uses.
Inspired by flexible biological tissues, Nanomaterial-filled, hydrated, polymeric networks that
exhibit superior properties such as optical, electrical, magnetic, elasticity and strength,
compared to traditionally made hydrogels.
Increased Biocompatability, of various fields such as: drug delivery and stem cell engineering,
medical implants, regenerative medicine, medical imaging, medical therapy etc..
8. Types of Hydrogel Nanocomposite
Carbon-based Nanomaterials
The electrical conducting property of these hydrogels allow them to mimic the
characteristic of nerve, muscle, and cardiac tissues.
Polymeric Nanoparticles
Tailored for drug delivery and tissue engineering with the presence
Inorganic Nanoparticles
Most inorganic nanoparticles used for nanocomposite hydrogels are already
present in and necessary for the body and therefore do not present any negative
impacts on the body.
Metal and Metal-Oxide Nanoparticles
The electrical and thermal conductivity and magnetic property of metals
enhance the electrical conductivity and antibacterial property of nanocomposite
hydrogels when incorporated.
https://en.wikipedia.org/wiki/Nanocomposite_hydrogels
9. Hydrogel polymer synthesis
Firstly, monomers were dissolved in deionized water at the desired mole ratios in
cylindrical glass tubes and PEG (5% w/w of total monomer weight) was added to this
aqueous monomer solution.
Then, initiator (1% w/w of total monomer weight) and crosslinking agent (5% w/w of
total monomer weight) were also directly added.
After sealing the mouth of these tubes with rubber caps, the solution was purged with
nitrogen gas for 30 min and the polymerization reaction was performed at 80 °C for 3 h.
At the end of the reaction, the glass tubes were carefully broken and hydrogels were cut
into discs 10 mm in length.
These hydrogel discs were immersed in deionized water at room temperature for 72 h.
During this time, the water was replaced once a day with fresh distilled water in order to
remove residual monomer.
Afterwards, hydrogels were dried in an oven at 50 °C. Dried pure hydrogels were used
for preparation of hydrogel-silver nanocomposites.
Bali A. Et all
PEG polymer as an example
10. Hydrogel Nanocomposite Synthesis
Firstly, dry pure hydrogel discs (50 mg) were completely swollen in distilled water for 2
days
Then the freshly swollen hydrogels were equilibrated in 30 mL of aqueous AgNO3
solution (2g/L, 0.012 mol/L) for 24 hours.
After removing the excess of AgNO3 solution from the surface of the swollen hydrogels
with filter paper,
The silver salt loaded hydrogels (HS) were immersed in 50 mL of NaBH4 solution
(2g/L, 0.053 mol/L) for 24 hours to reduce the absorbed silver ion (Ag+) in the hydrogel
structure to metallic silver nanoparticles (Ago).
The formation of the silver nanoparticles in the hydrogel structure was observed by the
appearance of a brown color
Silver Nanocomposite as an example
Bali A. Et all
20. Conclusion
The introduction of nanocomposites into hydrogel polymers
allows mimicking of the complex tissues and hopefuly organ.
Vast diverstiy of applications requires a perfect combination
of techniques to achieve desired novel material.
Read more see more…
21. Future Persperctive
Integration of suitable biological cues within the hydrogel at the
nano scales may provide them with biological features, thus
leading to an increasingly detailed design of the biomaterial to
be used in the field of cell/drug delivery and tissue engineering.
Stem cell engineering especially at the embryo level is a
promising field of regenerative medicine that will greatly aid the
succes of Nanocomposite hydrogel.
23. List of References
http://www.nanowerk.com/spotlight/spotid=35162.php
https://en.wikipedia.org/wiki/Nanocomposite_hydrogels
Wichterle O. Encyclopedia of Polymer Science and Technology. In: Mark HF, Gaylord NG, Bikales N, editors. Interscience.
Vol. 15. New York, NY: 1971. pp. 273–291.
Song, Fangfang; Li, Xiaoqiong; Wang, Qun; Liao, Liqiong; Zhang, Chao. "Nanocomposite Hydrogels and Their Applications
in Drug Delivery and Tissue Engineering“. Journal of Biomedical Nanotechnology 11 (1): 40–52. doi:10.1166/jbn.2015.1962
https://en.wikipedia.org/wiki/Nanocomposite_hydrogels
The swelling behaviour of thermoresponsive hydrogel/silica nanoparticle composites
Ilke Anac, Robert F. Roskamp, Markus Retsch, Ulrich Jonas, Bernhard Menges and Jon A. Preece
Gaharwar A.K., Arpanaei A., Andresen T.L., Dolatshahi-Pirouz A.*, “3D Biomaterial Microarrays for Regenerative Medicine:
Current state-of-the-art, Emerging Directions and Future Trends”, Advanced Materials,DOI: 10.1002/adma.201503918 2016
http://people.tamu.edu/~gaharwar/Publications.html
Dr. Nermin Seda Kehr, Eko Ai Prasetyantoi Kathrin Benson, Bahar Ergün, anzhela Galstyani Prof. Hans –Joachim Galla;
Periodic Mesoporous Organosilica-Based Nanocomposite Hydrogels as Three Dimensional Scaffolds
http://link.springer.com/article/10.1007/s00396-008-1949-0#page-1