Manganese comprising nanostructures
Disclosed herein are nanostructures comprising a polymeric framework comprising at least five geminal bisphosphonate groups, wherein the geminal bisphosphonate groups independently of each other are incorporated as —R 3 R 4 C(P═O(OR 1 )(OR 2 )) 2 , wherein R 1 and R 2 are independently selected from the group consisting of a negative charge, H, alkyl and aryl, and wherein at least one of R 3 and R 4 is a group connected to the polymeric framework with the proviso that when only one of R 3 and R 4 is such a connected group, the other of R 3 and R 4 is either a group being able to connect to the polymeric framework, or the residue of such a group, or selected from the group consisting of H, OH, OR 5 and R 5 , wherein R 5 is a lower alkyl. The polymeric framework may comprise manganese ions. Disclosed are also methods for producing such manganese containing nanostructures, compositions comprising such manganese containing nanostructures and use of such manganese containing nanostructures, i.a. as MRI contrasting agents.
1. A nanostructure comprising manganese ions incorporated in a polymeric framework comprising at least five geminal bisphosphonate groups, wherein the geminal bisphosphonate groups independently of each other are incorporated as
—R 3 R 4 C(P═O(OR 1 )(OR 2 )) 2
wherein:
R 1 and R 2 are independently selected from the group consisting of a negative charge, H, alkyl and aryl, and
at least one of R 3 and R 4 is a group connected to the polymeric framework, or forming part of the polymeric framework, with the proviso that when only one of R 3 and R 4 is such a connected group, the other of R 3 and R 4 is either a group being able to connect to the polymeric framework, or the residue of such a group, or selected from the group consisting of H, OH, OR 5 and R 5 , wherein R 5 is a lower alkyl.
2. A nanostructure according to claim 1 , wherein the group connected to the polymeric framework, and/or the group being able to connect to the polymeric framework or the residue of such a group is selected from the group consisting of:
(CH 2 ) n Si(R x ) 3 wherein R x independently is a lower alkyl, OH, O − , or O—, — denotes a bond to the polymeric framework, and n is 1-5,
(CH 2 ) n COR y wherein R y is O—, NH 2 , NHR z , NR z 2 , or a bond to the polymeric framework, R z is a lower alkyl and n is 1-5, and — denotes a bond to the polymeric framework, and
(CH 2 ) n SO 2 R y wherein R y is O—, NH 2 , NHR z , NR z 2 , or a bond to the polymeric framework, R z is a lower alkyl and n is 1-5 and — denotes a bond to the polymeric framework.
3. A nanostructure according to claim 1 , which comprises silicon atoms.
4. A nanostructure according to claim 3 , wherein the Si/Mn molar ratio is 5-20.
5. A nanostructure according to claim 1 , wherein R 3 and/or R 4 are/is selected from the group consisting of —(CH 2 ) n —Si(R x ) 3 , wherein R x independently is a lower alkyl, OH, O − , or O—, — denotes a bond to the polymeric framework, and n is 1-5.
6. A nanostructure according to claim 1 , wherein the hydrodynamic diameter of the nanostructures is 3-7 nm.
7. A nanostructure according to claim 1 , wherein the hydrodynamic diameter of the nanostructure is 10-20 nm.
8. A nanostructure according to claim 1 , wherein the polymeric framework comprises monomer residues containing a geminal bisphosphonate group and two organo-oxysilane groups.
9. A nanostructure according to claim 1 , wherein the polymeric framework is derived from polyethyleneimine.
10. A nanostructure according to claim 1 , wherein the P/Mn molar ratio is 7-20.
11. A nanostructure according to claim 1 , wherein said nanostructure further comprises hydrophilic groups attached to the outer parts.
12. A nanostructure according to claim 11 , wherein the hydrophilic groups comprise —(CH 2 CH 2 O) n CH 3 moieties wherein n=4-50.
13. A pharmaceutical composition comprising a nanostructure according to claim 1 .
14. An MRI contrast agent comprising a pharmaceutical composition according to claim 13 .
15. A method for obtaining a nanostructure according to claim 1 , comprising:
obtaining nanostructures of a polymeric framework comprising geminal bisphosphonates, and
contacting said nanostructures with manganese ions.
16. An MRI contrast agent comprising a nanostructure according to claim 1 .