HYDROGEL NANOCOMPOSTIES

THE BIOMEDICAL APPLICATIONS

OMOYAYI IBRAHIM O. 20142575

OutlineFun FactIntroductionHydrogelNanocomposite hydrogels (NCHs)Types / Classification of NCHsSynthesis of NCHsCharacterization TechniquesNCHs for Biomedical ApplicationsConclusionFuture directions

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

IntroductionSince 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.

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.

HydrogelWater-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

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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..

Types of Hydrogel Nanocomposite

Carbon-based NanomaterialsThe electrical conducting property of these hydrogels allow them to mimic the characteristic of nerve, muscle, and cardiac tissues.

Polymeric NanoparticlesTailored for drug delivery and tissue engineering with the presence Inorganic NanoparticlesMost 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 NanoparticlesThe 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

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

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

General Synthesis of Hydrogel Nanocomposite

R. V Coenraad    Et all

Hydrogel Nanocomposite Characterization

• Swelling study• X-ray diffraction• UV- Visible Spectroscopy• Atomic Force Microscopy• Fourier Transmission Infra red Microscopy

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• Google Images

• Intrısic Properties of Nanocomposites

• Google Images

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ConclusionThe 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…

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.

Thank You

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