Self‐Assembled Pt(II) Complexes Boost Up Stem Cell Proliferation and Accelerate Metamorphosis in Living Organisms

Self-assembly is a well-known phenomenon in nature, occurring at all scales, from small molecules to complex biomolecules, and it is the foundation for the formation of hierarchical biological structures. Pivotal is the requirement for precise organization through supramolecular interactions, which often trigger dramatic changes in reactivity, spectroscopic features and functional outcomes. Here, we demonstrate that the self-assembly of a Pt(II) complex not only gives rise to a superior imaging probe, but also to the emergence of redox-active features. Once in vivo, the self-assembled Pt(II) complex surprisingly acts as a potent promoter of stem cell proliferation and a modulator of key physiological functions. The assembled luminescent complexes finely tune reactive oxygen species (ROS) response in the transparent freshwater polyp Hydra vulgaris, enhancing the total antioxidant capacity and modulating the expression of key genes involved in antioxidant defenses and cell cycle progression. In addition, in the sea anemone Nematostella vectensis, the assembled complex accelerates the larvae-to-adult metamorphosis process, further underscoring its multifaceted role and species-specific action in diverse biological systems and ultimately paving the way for innovative theranostic strategies.