Actinium chelation and crystallization in a macromolecular scaffold.

Area of Science:

• Radiochemistry
• Nuclear Medicine
• Coordination Chemistry

Background:

• Targeted alpha therapy (TAT) utilizes alpha-emitting radioisotopes for cancer treatment.
• Actinium-225 (²²⁵Ac) is a key radioisotope for next-generation TAT, but its coordination chemistry is poorly understood.
• Limited availability and lack of stable isotopes hinder the study of Actinium's chemical behavior.

Purpose of the Study:

• To characterize the solution and solid-state behavior of Actinium.
• To establish a platform for probing the coordination chemistry of Actinium isotopes.
• To inform the development of ²²⁵Ac-based radiopharmaceuticals for TAT.

Main Methods:

• Utilized the longest-lived Actinium isotope, Actinium-227 (²²⁷Ac).
• Employed a combined system of an 8-coordinate synthetic ligand and a mammalian protein.
• Characterized solution and solid-state chemical behavior.

Main Results:

• Successfully characterized the chemical behavior of ²²⁷Ac in solution and solid-state.
• Demonstrated a viable platform for studying Actinium coordination chemistry.
• Provided insights into Actinium's coordination relative to lanthanides and actinides.

Conclusions:

• The developed platform enables fundamental studies of Actinium coordination chemistry.
• Results are expected to advance ²²⁵Ac-based TAT development.
• This work positions Actinium within the broader context of the Periodic Table and +3 actinide/lanthanide chemistry.