Researchers at the University of Warwick have developed a groundbreaking cancer treatment using iridium, a rare heavy metal abundant in meteorites but scarce on Earth's surface.
Iridium occurs in trace amounts on Earth, mostly concentrated near the planet's core. Elevated levels in soil layers signal past meteorite impacts, providing key evidence for the asteroid linked to dinosaur extinction.
Known for its corrosion resistance at high temperatures, iridium has long been used in X-rays and brachytherapy for cancer. However, traditional brachytherapy irradiates tumor areas, risking damage to surrounding healthy tissues.
Led by Dr. Peter Sadler at the University of Warwick, scientists created a non-radioactive iridium complex that kills cancer cells selectively.
Under light activation, the complex generates reactive oxygen species, which cancer cells are far more vulnerable to than healthy ones.
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To precisely target tumor nuclei, the team pairs the iridium complex with albumin, a protein that cancer cells avidly uptake and transport into their nuclei via optical fiber illumination, sparing healthy tissue.
"It's fascinating to see how albumin delivers our photosensitizer directly to the nucleus," says Dr. Cinzia Imberti, co-author of the study.
This approach offers dual benefits: the complex preferentially homes to the nucleus over other cell parts, and its strong luminescence enables real-time monitoring of cancer cell destruction.
Tests so far are in vitro; animal trials are next, with promising potential for human application.
Iridium's crustal rarity poses a challenge, but therapeutic doses are minimal—and asteroid mining sites could supply more if needed.
Source: Angewandte Chemie International Edition
