Development of Alginate-Based Biodegradable Radioactive Microspheres Labeled with Positron Emitter through Click...

Area of Science:

• Biomaterials Science
• Radiochemistry
• Nuclear Medicine

Background:

• Biodegradable radioactive microspheres are promising for cancer diagnostics and therapeutics.
• Alginate-based microspheres offer biocompatibility, biodegradability, and stability for clinical use.

Purpose of the Study:

• To develop novel positron emission tomography (PET) microspheres using alginate radiolabeled with gallium-68 (Ga-68).
• To evaluate the radiolabeling efficiency, stability, and in vivo behavior of the developed PET microspheres.

Main Methods:

• Fabrication of polyethylenimine (PEI)-decorated calcium alginate microspheres (PEI-CAMSs).
• Modification of PEI-CAMSs with azadibenzocyclooctyne-N-hydroxysuccinimide ester (ADIBO-NHS).
• Radiolabeling of azide-functionalized NOTA chelator (N3-NOTA) with Ga-68 and subsequent conjugation to PEI-CAMSs via strain-promoted alkyne-azide cycloaddition (SPAAC).
• Assessment of radiolabeling efficiency and stability using radio-instant thin-layer chromatography-silica gel (radio-ITLC-SG) and human blood serum.
• In vivo PET imaging in mice to evaluate biodistribution and stability.

Main Results:

• The developed [Ga-68]Ga-NOTA-PEI-CAMSs achieved over 99% radiolabeling efficiency.
• The microspheres demonstrated high stability (92%) in human blood serum.
• In vivo PET imaging confirmed the stability and biodistribution of the microspheres in mice for up to 2 hours post-injection.

Conclusions:

• Novel biodegradable PET microspheres ([Ga-68]Ga-NOTA-PEI-CAMSs) were successfully developed using a straightforward method.
• These microspheres exhibit excellent radiolabeling efficiency and stability, highlighting their potential for preoperative imaging and targeted radionuclide therapy.
• The developed platform is promising for theranostic applications using various radionuclides.