Radiolabeling of folic acid-modified chitosan with 99mTc as potential agents for folate-receptor-mediated targeting

The feasibility of chitosan (CS) as a backbone for the design of 99mTc-labeled targeting agent was evaluated in this study. Chitosan–folate conjugate (CSFA) and chitosan–folate dithiocarbamate (CSFADTC) were synthesized, characterized and radiolabeled with 99mTc as model compounds for folate-receptor (FR) targeting. 99mTc-complexes were prepared with high radiochemical purity and high stability. The hydrophilicities of these 99mTc-complexes were determined by partition coefficient experiments. The results of biodistribution in normal mice showed that the folic-acid modified agents (99mTc-CSFA and 99mTcN-CSFADTC) had obviously higher uptake in FR-positive kidney and much lower liver and spleen uptakes than that of non-folic-acid modified 99mTc-agent, and the kidney uptakes of FA-modified agents could be blocked significantly by the corresponding cold ligand. Furthermore in vitro and in vivo specific studies will be done in cell line and tumor bearing mice to confirm the usefulness of this chitosan backbone for FR targeting agent design.

Graphical abstractFolic-acid modified chitosan conjugates (CSFA and CSFADTC) were synthesized and radiolabeled with 99mTc as model compound for folate-receptor (FR) targeting.Figure optionsDownload full-size imageDownload as PowerPoint slide