Stem cell targeting and activation using magnetic particles
The present invention provides a method of selectively activating and/or targeting stem cells which enables the cells to then be manipulated mechanically in a remote manner wherein the method comprises magnetically manipulating a stem cell in vivo or in vitro by the association of a magnetisable particle within the stem cell.
1. An in vitro method for the differentiation of an adult stem cell, the method comprising the steps of:
(i) contacting, in vitro, an adult stem cell with a magnetizable particle so as to associate the adult stem cell and the magnetizable particle; and
(ii) magnetically manipulating the associated adult stem cell and magnetizable particle by applying a magnetic field so that the adult stem cell differentiates.
2. The method of claim 1 , wherein the adult stem is a mesenchymal stem cell or a bone marrow stromal cell.
3. The method of claim 1 , wherein the method is for the differentiation of a. mesenchymal stem cell or a bone marrow stromal cell into connective tissue.
4. The method of claim 3 , wherein the connective tissue is bone tissue, cartilage tissue, ligament or tendon.
5. The method of claim 1 , wherein the magnetizable particle is tagged with at least one antibody or protein binding motif that recognizes an element of the adult stem cell.
6. The method of claim 1 , wherein the magnetizable particle is tagged with at least one integrin, cadherin, selectin, immunoglobulin or RGD molecule.
7. The method of claim 1 , wherein the adult stem cell expressed a mechano-activated transmembrane ion channel and the magnetizable particle is tagged with at least one antibody that recognizes the ion channel.
8. The method of claim 7 , wherein the transmembrane ion channel is a potassium ion channel.
9. The method of claim 7 , wherein the transmembrane ion channel is a TREK potassium ion channel.
10. The method of claim 7 , wherein the transmembrane ion channel is the TREK-1 ion Channel.
11. The method of claim 1 , wherein the magnetizable particle is magnetic or reacts in a magnetic field.
12. The method of claim 1 , wherein the magnetizable particle comprises elemental iron (Fe) or a compound thereof, or a chromium compound.
13. The method of claim 1 , wherein the magnetizable particle comprises an iron salt selected from the group consisting of: magnetite (Fe 3 O 4 ),maghemite (γFe 2 O 3 ), greigite (Fe 3 S 4 ) and combinations thereof.
14. The method of claim 1 , wherein the magnetizable particle has a size of from 1 nm to 10 μm.
15. The method of claim 1 comprising contacting a plurality of adult stem cells with a plurality of magnetizable particles and wherein the magnetizable particles have a mean size of 5000 nm or less.
16. The method of claim 1 , wherein the applied magnetic field is a variable magnetic field.
17. The method of claim 1 , wherein the applied magnetic field is a variable magnetic field which has a frequency of from 0.1 to 10 Hz.
18. The method of claim 1 , wherein the magnetic field has a flux density of from 10 mT to 1400 mT.