68Ga-NOTA-CHSg and 99mTc-CHSg Labeled Microspheres for Lung Perfusion and Liver Radio microspheres Therapy Planning

Alejandro Amor-Coarasa et al., Hindawi Publishing Corporation. International Journal of Molecular Imaging. Volume 2013, Article ID 279872, 9 pages http://dx.doi.org/10.1155/2013/279872

An emulsion method was used to create 30.1 ± 4.8 micro-m size range microspheres with biodegradable Chitosan glycol (CHSg).Microspheres were characterized and labeled with 99mTc or 68Ga as an alternative to MAA in perfusion PET and SPECT studies. Surface decoration of CHSg microspheres with p-SCN-Bn-NOTA was performed to increase 68Ga in vivo stability. 99mTc was labeled directly to the CHSg microspheres.

I think CHSg microspheres with p-SCN-Bn-NOTA can also be used for indirect labeling of Tc-99m

To be honest, there is no other group that can be easily used to either chelate the metal directly or to modify the surface for chelation. However, you must realize that even when you use some of those groups for chelation/modification the vast majority of the available amine groups remain free. 

I agree with Alejandro. For radioiodines you can use the Bolton-Hunter reagent or some of the newer  stannylated benzoic acid activated ester derivatives and for radiometals some of the bifunctional ligands from macrocyclics.

Dr Ahmad has summaries the answer and excellent explanations were added by both Alejandro and Jacek..

Let us know your results and thoughts...

Good luck 

Dear all, thank you for your contributions.

The reason that I would prefer using other groups except the amines is because I also crosslink my particles using the amine groups. Given that I need some free amine groups for other purposes, I want to use them for chitosan labeling as least as possible.