Keyworkers:

Dr. Katerina Polakova        kacka.polakova@email.cz
Dr. Libor Machala               libor.machala@upol.cz
Dr. Zdenka Markova           zdeni.markova@gmail.com

Examples of bioapplications of magnetic micro/nanoparticles:

1) Immobilization and magnetic separation of biological active compounds such as proteins, enzymes, cytokinines, antibodies, antigens etc.

Advances:

• Extremely short process time
• Magnetic micro- or nanospheres can be separated easily and quickly by magnetic forces and will be used together with bioaffine ligands, e.g. antibodies or proteins with a high affinity to the target. The targets can be cells, bacteria or DNA/RNA.
• The special advantages of magnetic separation techniques are the fast and simple handling of a sample vial and the opportunity to deal with large sample volumes without the need for time-consuming centrifugation steps.
• This also makes biomagnetic separation ideal for automated assay / analysis systems which will play a very important role in the near future
• Immobilized enzymes (such as trypsin, lipase) show higher thermostability, time stability, operational stability and storage stability

2) Magnetofection: novel, simple and highly efficient method to transfect cells in culture. It exploits magnetic force exerted upon gene vectors associated with magnetic particles to draw the vectors towards, possibly even into, the target cells. In this manner, the full vector dose applied gets concentrated on the cells within a few minutes so that 100% of the cells get in contact with a significant vector dose

Conjugation of magnetic iron oxide particles with the biological active compound:

• Covalently by using active agent such as Glutaraledyhe (GA) or 1-ethyl-3-(3- dimethylaminepropyle) carbodiimide (EDC)
• Electrostatically, where magnetic particles play a role as cationic exchangers

Product:

 A) Mag (magnetite-Fe₃O₄)

Magnetic core: magnetite (Fe₃O₄), prepared by thermally induced solid state reaction

Physico-chemical characteristics:

• Size: 30-50 nm
• Character of aggregates in micrometers scale
• Fast magnetic separation by external magnet
• Specific surface area: 15 m²/g
• Powder or aques dispersion

 

 

 

 

 

 

 

 

 

Mag : surface functionalization of Mag nanoparticles for bioapplications:

1)Mag/chitosan (adsorption of chitosan, free functional groups for conjugation of biological active substances: -NH₂, -OH)

Note: chitosan is soluble under pH 6.5, therefore the higher pH is recommended for the experiments with Mag/chitosan particles

 

2) Mag/NH₂ covalently bounded surface shell by TEOS and APTES Functional groups: NH₂ (35 nmol per 1 mg of nanoparticles)

 

3) Mag/ COOH 

 

4) Mag/cellulose (magnetic microbeads encapsulated into cellulose shell bearing high density of free -OH functional groups on the surface)

• Stable in various pH and for a long time in water suspension
• resistant to high pressures
• fast magnetic separation
• the size of microbeads can be tuned from 50 to 300μm
• we offer also modified cellulose of magnetic microbeads by -COOH,

-CHO and -SO₃H functional groups

 

B) Maghemite (γ-Fe₂O₃)

• Magnetic core: ferrimagnetic spinel of cubic symetry,
• orange powder
• stable dispersion in water
• colloidal character
• size: 20-50nm

 

Maghemite : surface functionalization for bioapplications:

1)    Maghemite/NH2

2) Maghemite/COOH     

3) Maghemite/CHO      

                         

 

Note: We can also determine the adsorption capacity and the amount of functional groups on the surface of all offer nanoparticles