Preparation of 131I-Collagen-Chitosan Microspheres for Interventional Radionuclide Therapy

Objectives Objective: Radionuclide-labeled microspheres have been used for interventional radionuclide cancer therapy, but microspheres comprised of non-biodegradable materials, such as glass beads, are not suitable for repetitive treatment. On the other hand, it is important to choose degradable biomaterials matched with radionuclide decay half-life for development of radionuclide-labeled microspheres which can be used for repetitive treatment. The objective of this study is to develop a novel iodine-131-radiolabeled, biodegradable microsphere for interventional radionuclide cancer therapy.

Methods Methods: The collagen-chitosan microspheres were prepared with type-I collagen and chitosan cross-linked by glutaraldehyde, using an emulsification-chemical crosslinking method. 131I-radiolabelling of collagen-chitosan microspheres was achieved using Chloramine-T or N- bromosuccinimide. The size of the microspheres was determined using scanning electron microscope (SEM). The in vitro stability of 131I-collagen-chitosan microspheres was evaluated by incubation of the microspheres in saline or human blood serum for 8 days, respectively. To test in vivo stability of 131I microspheres, 131I-microspheres were directly injected into HepG2 tumor xenograft in mice, and its stability in tissues was assessed by histological analysis.

Results Results: The microspheres comprised of collagen-chitosan were synthesized and further prepared by centrifuge and filtration through a 100 μm strainer and centrifuge after reaction. Desirable shape and particle size of 20-30 μm were confirmed by SEM scanning (Fig.1 A). A successful 92.10% 131I radiolabeling of the microspheres was achieved and radiolabeling of the microspheres was quite stable with 87.70% of the original 131I radioactivity remained with the microspheres after incubation in serum for 8 days. Furthermore, stable and prolonged presence of the microspheres in the tumor tissues were demonstrated by histological analysis tumor tissues injected with the 131I-microspheres (Fig.1 B).

Conclusions Conclusion: The biodegradable collagen-chitosan microspheres were successfully prepared using emulsification-chemical crosslinking method and radiolabeled with 131I radionuclide. 131I-radiolabeled collagen-chitosan microspheres exhibited stability in vitro and in vivo desirable for interventional radionuclide therapy. The results of this study support further development of the 131I-radiolabelled collagen-chitosan microspheres for interventional radionuclide cancer therapy.

• Download figure
• Open in new tab
• Download powerpoint