Triple-negative breast cancer (TNBC) has earned its reputation as one of oncology’s most formidable challenges because it removes the molecular handles that make many other breast tumors vulnerable to targeted drugs. Representing roughly 15–20 percent of breast cancer cases, TNBC lacks meaningful expression of estrogen receptors, progesterone receptors, and human epidermal growth factor receptor 2, leaving chemotherapy as a central treatment option for many patients. Immunotherapy has opened a new therapeutic door, but its benefits remain limited to a minority of people with TNBC. A major reason is the tumor’s profoundly immunosuppressive microenvironment, where regulatory T cells, or Tregs, restrain the immune responses that might otherwise recognize and destroy malignant cells.
A team led by Professor Eijiro Miyako at Tohoku University’s Institute of Multidisciplinary Research for Advanced Materials has now developed a multifunctional nanomedicine designed to confront several of these biological obstacles at once. The platform, named B-LM-DMX-αCD25, combines gallium-based liquid-metal nanoparticles, a photothermal agent, a stimulator of interferon genes (STING) agonist, and an antibody directed against CD25, a surface marker highly expressed by Tregs. Rather than relying on a single mechanism, the system is engineered to coordinate tumor ablation, selective immune suppression reversal, and innate immune activation. In studies conducted in drug-resistant TNBC mouse models, the treatment produced complete regression of tumors, sharply reduced lung metastases, and extended survival, suggesting that the approach could transform a localized treatment into a systemic anticancer response.
At the center of the platform are liquid-metal nanoparticles based on gallium, a metal that remains liquid near room temperature and can be engineered into nanoscale structures with useful optical and chemical properties. The particles function as photothermal transducers: after absorbing near-infrared light, they convert electromagnetic energy into heat. The reported photothermal conversion efficiency exceeds 54 percent, allowing the nanoplatform to generate substantial temperatures under external laser irradiation. This property is especially valuable in cancer therapy because the particles can be activated at the tumor site rather than continuously exposing the entire body to a toxic drug. The researchers further coated the nanoparticles with components derived from whole blood, creating a biomimetic shell intended to make the construct appear more like a natural biological entity to the immune system.
This blood-cell camouflage is designed to reduce rapid clearance by the mononuclear phagocyte system, a network of immune cells in organs such as the liver and spleen that commonly captures intravenously administered nanoparticles. According to the researchers, the coating enabled the particles to accumulate in tumors at approximately five times the efficiency of conventional nanoparticles. Improved tumor localization is a crucial technical advantage because it can increase the concentration of therapeutic material where it is needed while limiting exposure in healthy tissues. The strategy also illustrates a broader direction in nanomedicine: instead of constructing completely artificial particles that the body immediately identifies as foreign, scientists are using biological membranes and blood-derived components to borrow the body’s own mechanisms of circulation and immune evasion.
Once the camouflaged nanoparticles reach a tumor, the treatment is activated with near-infrared laser light. In the mouse experiments, irradiation raised the tumor temperature to approximately 58 degrees Celsius within five minutes. This level of heating causes direct thermal destruction of malignant cells, but the researchers are also exploiting a second consequence: immunogenic cell death. Unlike ordinary cell death, which may leave the immune system largely unaware, immunogenic cell death releases tumor-associated antigens and danger-associated molecular patterns. These molecular signals can stimulate antigen-presenting cells and help them process tumor material, potentially turning the treated tumor into an in situ source of personalized cancer vaccines. In effect, the photothermal component does not merely burn cancer cells; it helps expose their molecular identity to the immune system.
The platform’s antibody component is intended to remove one of the most important immune restraints inside TNBC tumors. Tregs normally protect the body from excessive or misdirected immune activity, but tumors can recruit and exploit these cells to suppress cytotoxic T lymphocytes and maintain an immunologically “cold” environment. B-LM-DMX-αCD25 carries anti-CD25 antibodies on its surface, allowing it to target CD25-rich Tregs within the tumor. The selective depletion of these cells is designed to release what the researchers describe as an immunological brake. This approach differs from indiscriminate immune stimulation because it focuses immune-modulating activity at the disease site and aims to reduce suppressive cells before activating tumor-directed immunity.
The third mechanism is supplied by DMX, a STING agonist incorporated into the nanoplatform for laser-triggered release. The STING pathway is part of the innate immune system and responds to abnormal cytosolic DNA, a signal associated with infection and cellular damage. When activated in the tumor microenvironment, STING signaling can promote dendritic-cell maturation and stimulate production of type I interferons, including interferon-β. These cytokines help bridge innate and adaptive immunity by improving antigen presentation and supporting the expansion and function of tumor-specific cytotoxic T cells. In the B-LM-DMX-αCD25 design, photothermal heating therefore performs two coordinated tasks: it causes immunogenic tumor destruction and releases the STING agonist at the site of treatment.
The resulting sequence is intended to create a positive feedback loop. Anti-CD25 targeting reduces local immune suppression, while photothermal therapy supplies tumor antigens and danger signals. STING activation then enhances dendritic-cell activity and interferon signaling, helping the immune system convert those tumor-derived materials into a stronger adaptive response. The activated T cells can travel beyond the irradiated lesion, potentially recognizing and attacking cancer cells at distant sites. This systemic effect is particularly important in TNBC, which can spread aggressively to the lungs and other organs. The researchers’ results support that possibility: treatment suppressed pulmonary metastases by more than 90 percent in orthotopic mouse models, indicating that the therapy’s impact extended beyond the area directly exposed to the laser.
Molecular and cellular analyses of treated tumors showed extensive immune remodeling. The investigators reported more than a 13-fold increase in CD3-positive T cells and an approximately 11-fold increase in dendritic cells within the tumor tissue. CD3 is a component of the T-cell receptor complex and serves as a broad marker of T-cell presence, while dendritic cells are essential for capturing antigens and presenting them to T lymphocytes. Together, these findings suggest that the therapy changed the tumor from an immune-excluded environment into one with substantially greater immune-cell infiltration and antigen-presenting capacity. In the drug-resistant TNBC models, the treatment achieved complete tumor regression in all animals and extended median survival beyond 70 days. These results are striking, but they remain preclinical: responses in mice do not establish safety, dosing, or effectiveness in human patients.
The researchers are now considering how the platform could be adapted for other solid tumors characterized by strong immune suppression, including pancreatic and ovarian cancers. They are also developing formulations compatible with NIR-II light, which penetrates tissue more effectively than the near-infrared wavelengths commonly used in first-generation photothermal systems. Greater penetration could make it possible to treat tumors located deeper inside the body, although precise control of heating and protection of surrounding tissue will remain essential. At the same time, the team is preparing GLP-compliant repeat-dose toxicology studies, an important step toward evaluating biodistribution, immune reactions, organ toxicity, clearance, and the effects of repeated administration. The findings, published in Advanced Science, present B-LM-DMX-αCD25 as a highly integrated experimental strategy: a blood-camouflaged liquid-metal nanoplatform that combines targeted Treg depletion, laser-driven immunogenic tumor destruction, and STING-amplified systemic immunity in an effort to overcome the biological defenses of metastatic triple-negative breast cancer.
Subject of Research: A blood-cell-camouflaged liquid-metal nanoplatform for treating metastatic triple-negative breast cancer through Treg depletion, photothermal therapy, and STING pathway activation.
Article Title: Blood Cell-Camouflaged Liquid Metal Nanoconjugates Orchestrate Treg Depletion and STING-Amplified Photothermal Immunity for Metastatic Triple-Negative Breast Cancer Therapy
News Publication Date: 11 August 2026
Web References: https://doi.org/10.1002/advs.77069
References: Advanced Science, DOI: 10.1002/advs.77069
Image Credits: Eijiro Miyako
Keywords: Triple-negative breast cancer, cancer immunotherapy, nanomedicine, liquid-metal nanoparticles, photothermal therapy, STING agonist, regulatory T cells, dendritic cells, tumor immunogenicity, metastasis, biomimetic nanoparticles, Tohoku University
Tags: advanced nanomedicine platformsblood-camouflaged liquid metal nanoparticlesCD25 targeting Treg cellsgallium-based liquid-metal nanoparticlesimmune microenvironment modulationmultifunctional nanomedicine for cancer therapynanotechnology in breast cancerovercoming tumor immunosuppressionphotothermal therapy for cancerSTING agonist in cancer immunotherapytriple negative breast cancer treatmenttumor ablation and immune activation
