A technology has been developed that can suppress the biggest challenge in organ transplantation, "immune rejection," without systemic side effects. Professor Cha Hyeong-jun of the Department of Chemical Engineering at Pohang University of Science and Technology POSTECH and Professor Joo Gye-il of the Department of Chemical and Biomedical Engineering at Ewha Womans University said on the 9th, "We developed an 'immune shield (Immune-Shield)' technology that directly sprays an immunosuppressant onto the surface of the transplanted organ using an adhesive material derived from mussels." The findings were recently published in the international journal Journal of Controlled Release in the field of pharmacology and drug delivery.
Organ transplantation is the most effective treatment to restore organs damaged by accidents or disease. However, there is a global shortage of transplantable organs, and xenotransplantation, which transplants animal organs into humans, is drawing attention as an alternative. Yet immune rejection, in which the human immune system recognizes the transplanted organ as an external invader, has been a major problem not only for animal-to-human transplants but also for transplants from other people.
To prevent this, patients must continuously take immunosuppressants. But oral or injectable administration delivers the drug systemically throughout the body, which can cause serious side effects such as kidney toxicity and increased risk of infection. It creates a paradox in which a drug intended to save the organ instead weakens the patient's immunity.
The research team focused on delivering the drug not to the "whole body" but only to the "transplanted organ." Using the principle that mussels adhere strongly even underwater, the team developed a technology to attach tiny hydrogel particles containing immunosuppressants directly to the organ surface. The method coats the surface of biological tissue using adhesive microgels, and the team named it the "immune shield."
The "immune shield" is applied like a spray. It coats stably even on the moist surface of organs, and the microgels remain on the organ surface while slowly releasing the immunosuppressant. By forming an invisible protective layer on the organ surface, the drug is delivered only to the transplant site instead of spreading systemically through the bloodstream.
In xenotransplantation experiments, applying the "immune shield" markedly reduced the infiltration of immune cells and inflammatory responses, and significantly extended the survival of the transplanted tissue. It is significant in that it showed more than double the immunosuppressive effect compared with existing drug delivery methods.
Professor Cha Hyeong-jun said, "We have proposed a new strategy to solve the long-standing challenge of immune suppression using mussel-derived adhesive protein, a source material from Korea," adding, "Because it is a spray, it can be easily applied to the complex surfaces of organs and will serve as a key technology to increase the success rate of xenotransplantation going forward."
The research team included doctoral candidates Lee Sang-min and Woo Hyeon-taek of the Department of Chemical Engineering and the Graduate School of Convergence Science and Technology (medical science major) at Pohang University of Science and Technology POSTECH, and Dr. Choi Geun-ho.
References
Journal of Controlled Release (2026), DOI: https://doi.org/10.1016/j.jconrel.2025.114468