Imbalanced redox homeostasis, involving either oxidative stress or  reductive stress, can profoundly impact cellular functions, contributing to  various diseases. While the implications of oxidative stress in the adverse  effects of nanoparticles have been extensively studied, our comprehension  of reductive stress within the context of nano-redox system interactions  remains limited. Here we illuminate a domino effect initiated by the  dehydrogenase-like activity of transition metal borides. Specifically, seven  transition metal borides were identified to emulate the enzymatic activity  of natural dehydrogenases, resulting in heightened levels of reductive  constituents within critical biological redox pairs in cells. Mass cytometry  analysis provides compelling evidence that reductive stress initiates an  immunosuppressive environment within lung tissues, promoting the  metastasis of breast cancer cells to the lungs. In summary, our study unveils  the chemical basis of nano-induced reductive stress and establishes a  mechanistic axis that interlinks dehydrogenase-like activity, reductive  stress, immunosuppression and tumour metastasis.

    This work has been published in Nature Nanotechnology with the titleof Intracellular dehydrogenation   catalysis leads to reductive stress   and immunosuppression.