Pusan National University Develops Injectable Microgels for Targeted Keloid Radiotherapy

Injectable hyaluronic acid microgels offer a promising new strategy for targeted, minimally invasive keloid radiotherapy

BUSAN, South Korea, Aug. 27, 2026 /PRNewswire/ -- Researchers in Korea are developing a new approach to localized brachytherapy that could improve the treatment of keloid scars. The strategy uses injectable, biodegradable hyaluronic acid microgels that act as tiny radiation reservoirs within target tissue. By combining rapid radiolabeling with localized delivery, the platform aims to overcome limitations of conventional radiation treatment while offering greater flexibility and precision. The study highlights a promising step toward targeted, minimally invasive microbrachytherapy.

Keloids are abnormal, fibroproliferative scars that form when overactive fibroblasts produce excessive collagen after skin injury. Unlike ordinary scars, they can extend beyond the original wound and cause itching, pain, and tenderness. Current treatments, including surgery, corticosteroid injections, lasers, and radiotherapy, may require prolonged treatment and can be associated with recurrence. Although radiotherapy can suppress keloid growth, conventional external-beam approaches struggle to precisely target small, irregular lesions while sparing surrounding healthy tissue.

To address this challenge, researchers from Pusan National University, led by Prof. Seung Yun Yang, who also serves as CEO of SNVIA Co., Ltd., developed an injectable system designed to deliver radiation directly within keloid tissue. Prof. Yang explains, "We developed an "off-the-shelf" microbrachytherapy approach using injectable, biodegradable hyaluronic acid (HA) microgels for keloid treatment." The researchers investigated whether freeze-dried HA microgels could provide rapid and sustained local delivery of radioactive iodine-131 (¹³¹I) while minimizing systemic exposure. This paper was made available online on August 10, 2026 and will be published in Volume 398 of the Journal of Controlled Release on October 10, 2026.

The researchers fabricated uniform, biodegradable HA microgels using microfluidic technology and freeze-drying, creating a porous structure that could rapidly absorb radioactive solution. The microgels were then labeled with ¹³¹I and evaluated using patient-derived keloid fibroblasts to assess cytotoxicity and apoptosis. Their therapeutic efficacy, radioactive retention, biodistribution, and safety were subsequently evaluated in mice carrying patient-derived keloid tissue.

The microgels enabled rapid and efficient radiolabeling. "Through absorption-mediated rapid radiolabeling, our freeze-dried microgels achieve high labeling efficiency (>90%) of iodine-131 in less than 10 minutes," shares Prof. Yang. Following injection, the microgels remained localized within keloid tissue for up to 14 days. In vitro, ¹³¹I-HA microgels at doses ≥10 MBq induced more than 80% keloid fibroblast death within 48 hours, primarily through apoptosis. Intralesional injection also reduced keloid size by about 70% after 2 weeks in a xenograft model, without off-target biodistribution or damage to surrounding healthy tissues. No significant abnormalities were observed in thyroid function, blood parameters, or major organs.

The team believes the platform could simplify the preparation and delivery of localized brachytherapy. On-site radiolabeling may reduce radioactive waste and logistical demands while allowing treatment to be tailored to individual lesions. The approach could potentially be adapted for other localized tumors, although further studies are needed to assess its broader applications.

Finally, Prof. Yang concludes, "This technology provides a minimally invasive approach to deliver precise local radiotherapy, overcoming the targeting limitations of conventional external beam radiation for small, irregular lesions." Overall, the findings provide a promising preclinical foundation for targeted microbrachytherapy for keloids. Longer-term studies are still needed to evaluate recurrence, immune responses, dose distribution, and clinical safety.

Reference
Title of original paper: Off-the-shelf microbrachytherapy using on-site fast radiolabeling for keloid treatment
Journal: Journal of Controlled Release
DOI: 10.1016/j.jconrel.2026.115239

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Website: https://www.pusan.ac.kr/eng/Main.do

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SOURCE Pusan National University