Iodine-loaded microgels reduced keloid size by about 70% in mice

A small, irregular scar can be hard to treat without touching the healthy skin around it. At Pusan National University, researchers led by Seung Yun Yang have tested an injectable system that places radiation inside keloid tissue itself: keloid size fell by about 70% after two weeks in mice carrying patient-derived tissue.

The material is a freeze-dried microgel made from hyaluronic acid, or HA, a biodegradable substance. Using microfluidic technology, the team produced uniform, porous particles that rapidly absorb a solution of radioactive iodine-131. Once injected into the keloid, the particles act as a form of microbrachytherapy—local radiation delivered from within the tissue—rather than relying on an external beam aimed at an uneven surface.

Preparation was fast. The microgels achieved more than 90% labeling efficiency in less than 10 minutes, according to Yang. After injection, they stayed localized in keloid tissue for up to 14 days. In laboratory tests using patient-derived keloid fibroblasts, doses of at least 10 MBq—megabecquerels, a unit of radioactivity—caused more than 80% of the cells to die within 48 hours, mainly through apoptosis, a form of programmed cell death.

And so what, concretely? If the approach survives further testing, clinicians could have a minimally invasive way to expose a small keloid to radiation while limiting delivery beyond the lesion. The researchers also say on-site radiolabeling could reduce radioactive waste and logistical demands, while allowing treatment to be tailored to individual lesions. The work could potentially extend to other localized tumors, but that application has not been established.

For now, the evidence stops before human treatment. The study found no significant abnormalities in thyroid function, blood parameters or major organs in the mice, and no detected off-target biodistribution or damage to nearby healthy tissue. Longer-term studies still need to examine recurrence, immune responses, dose distribution and clinical safety; the results were published in the Journal of Controlled Release.