An indium:calcium phosphate colloid that specifically targets fibrin

Area of Science:

• Radiochemistry
• Biomaterials Science
• Biomedical Imaging

Background:

• Fibrin is a key component of blood clots and atherosclerotic plaques.
• Targeted delivery of radionuclides to fibrin could enable diagnostic imaging of vascular diseases.
• Indium-114m is a radionuclide with potential for medical applications.

Purpose of the Study:

• To evaluate the in vitro fibrin-targeting capabilities of different indium-114m preparations.
• To compare the fibrin binding affinity of soluble indium-114m, colloidal indium-114m, and indium-114m calcium phosphate colloid.
• To explore the potential of indium-114m calcium phosphate as an imaging agent for vascular stenosis.

Main Methods:

• Preparation of soluble, colloidal, and indium-114m calcium phosphate (In:CaP) colloid forms.
• Incubation of indium-114m preparations with human plasma and induction of fibrin polymerization.
• Quantification of fibrin uptake of indium-114m via gamma counting and SDS-PAGE analysis.

Main Results:

• Soluble indium-114m bound to transferrin, not fibrin.
• Both colloidal indium-114m and In:CaP colloid bound fibrin.
• In:CaP colloid exhibited approximately twofold higher fibrin binding compared to colloidal indium-114m.
• Indium binding specificity to fibrin, not fibrinogen, was confirmed.
• Fibrin binding of In:CaP was dependent on phosphate concentration.

Conclusions:

• Indium-114m calcium phosphate colloid demonstrates superior fibrin targeting compared to other indium preparations.
• The specific binding to fibrin, independent of fibrinogen, highlights its potential.
• In:CaP's biocompatibility and fibrin-targeting ability suggest its utility in diagnostic imaging for vascular stenosis detection.