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.
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Reference
DOI: 10.1016/j.jconrel.2026.115239
About Pusan National University
Pusan National University, located in Busan, South Korea, was founded in 1946 and is now the No. 1 national university of South Korea in research and educational competency. The multi-campus university also has other smaller campuses in Yangsan, Miryang, and Ami. The university prides itself on the principles of truth, freedom, and service and has approximately 30,000 students, 1,200 professors, and 750 faculty members. The university comprises 14 colleges (schools) and one independent division, with 103 departments in all.
Website: https://www.pusan.ac.kr/eng/Main.do
About SNvia Co., Ltd.
SNvia is a biotechnology company and a subsidiary of Pusan National University, focused on the manufacture of innovative medical products based on microneedle technologies and photocurable polymers, with more than nine years of experience in the field. SNvia’s photocurable therapeutic polymers (PhotoQ-HA®) are hyaluronic acid (HA)–based, medical-grade biomaterials produced in qualified manufacturing facilities. The development of photocurable HA is guided by principles of safety and biocompatibility, enabling a wide range of biomedical applications, including tissue adhesives, hemostatic agents, tissue-engineering scaffolds, bioinks for 3D printing, and drug-delivery carriers for long-term therapy.
Website: https://www.snvia.com
About the Author
Prof. Seung Yun Yang is a Professor of Biomaterials Science at Pusan National University (PNU) and a polymer engineer specializing in functional biomaterials for drug delivery and tissue regeneration. He earned his PhD in Polymer Engineering from POSTECH in 2010 and completed postdoctoral training at Brigham and Women’s Hospital, Harvard Medical School. Since joining PNU, he has developed innovative medical devices using photocurable polymers and microneedle technologies to enhance drug delivery and promote tissue regeneration. He is also the founder of SNVIA Co., Ltd., where he leads research expansion and clinical translation and oversees global collaborations.
Lab: https://sites.google.com/site/syanglabpnu/
ORCID id: 0000-0002-1233-8960
Journal of Controlled Release
Experimental study
Animals
Off-the-shelf microbrachytherapy using on-site fast radiolabeling for keloid treatment
10-Aug-2026
S. K. and S. Y. Y. are inventors of patent applications (PCT/KR2022/012398) held by Pusan National University. The authors declare no competing interests.