Visualization of Immune Rejection: Noninvasive Imaging/Efficacy Evaluation of Immune Rejection after Liver Transplantation via Stable NIR-II Scaffolds

Liver transplantation is the only definitive treatment to cure liver failure in the clinic. However, patients undergoing allogeneic liver transplantation often experience immune rejection, which can lead to significant liver damage or even recurrent liver failure. Currently, the clinically used method for evaluating immune rejection primarily depends on complex percutaneous needle aspiration biopsy (PNAB), which is invasive and cannot provide real-time in vivo information. Such limitations often lead to a great lag or even inaccurate assessments for doctors to treat patients. Herein, for the first time, we have achieved in vivo imaging of immune rejection after liver transplantation via a stable NIR-II scaffold and achieved efficacy evaluation of dexamethasone (DXM) in vivo in this way. The results showed that the probe NIR II-HD-B could clearly capture the increased reactive oxygen species (ROS) caused by immune rejection after liver transplantation, which was consistent with the results of DCFH-DA staining in vitro. More importantly, when the liver-transplanted mice were treated with DXM, the signal of NIR II-HD-B was obviously reduced, indicating the remission of immune rejection, which was lined with decreased CD4⁺ and CD8⁺ T cells (immune stress index). Impressively, NIR-II imaging-guided medication significantly reduced organ damage from immune rejection, while uninformed treatment (either by taking excessive doses or none at all) would cause substantial organ damage in mice. These findings highlighted that, compared to complex in vitro slice staining data (which requires euthanizing mice), noninvasive NIR-II imaging not only avoided invasive interventions but also provided real-time in vivo information to guide the treatment process.