Keloids are a special type of pathological scar caused by overactive fibroblasts after skin injury, producing large amounts of collagen. This leads to scar tissue extending beyond the original wound boundary, accompanied by itching, pain, and tenderness. Current treatments include surgical excision, corticosteroid injections, laser therapy, and radiation therapy, but these often require long-term, multiple treatments and carry a certain risk of recurrence. While radiation therapy can inhibit keloid growth, traditional external beam radiation is difficult to precisely cover small and irregularly shaped lesions and can easily damage surrounding healthy tissue.

To address this issue, a research team at Pusan National University, led by Professor Yang Seung-yoon, has developed an injectable hyaluronic acid microgel system for the direct delivery of radioactive materials into keloid tissue. Professor Yang also serves as the CEO of SNVIA Ltd. The research findings were published online on August 10, 2026, and will be featured in Volume 398 of the *Journal of Controlled Release*.

The research team used microfluidics and freeze-drying to prepare uniformly sized, biodegradable hyaluronic acid microgels. Freeze-drying created a porous structure in the microgels, enabling them to rapidly absorb radioactive solutions. Subsequently, the researchers labeled the microgels with radioactive iodine-131 and evaluated their cytotoxicity and apoptosis-inducing effects in patient-derived keloid fibroblasts. Animal experiments were conducted using a mouse model carrying patient-derived keloid tissue to observe the therapeutic effects, radioactivity retention, in vivo distribution, and safety of the microgels.

Labeling efficiency is a key parameter of this system. Yang Chengyun explained that through absorption-mediated rapid radiolabeling, the lyophilized microgels can achieve an iodine-131 labeling efficiency of over 90% within less than 10 minutes. After injection, the microgels can remain within keloid tissue for up to 14 days. In vitro experiments showed that iodine-131-labeled microgels at doses of at least 10 MBq induced the death of over 80% of keloid fibroblasts within 48 hours, primarily through apoptosis. In a xenograft model, two weeks after intralesional injection, the keloid volume decreased by approximately 70%, and no distribution of radioactive material to non-target tissues or damage to surrounding healthy tissues was observed. No significant abnormalities were observed in thyroid function, hematological parameters, or major organs.

The practical significance of this platform lies in simplifying the preparation and implementation process for local brachytherapy. On-site radiolabeling reduces the logistical burden of radioactive waste generation, transportation, and storage, while also facilitating dose adjustments based on the specific lesion. The research team believes this method has the potential to be applied to other types of localized tumors in the future, but further research is needed to evaluate its broader applicability.

Yang Chengyun stated that this technology provides a minimally invasive and precise local radiotherapy approach, overcoming to some extent the limitations of traditional external beam radiation therapy in targeting small, irregular lesions. This study provides preliminary preclinical evidence for targeted microradiotherapy for keloid treatment. Further long-term follow-up studies are needed to assess recurrence, immune response, dose distribution, and clinical safety.