In Situ Lipid Interactions of an Anticancer Metal Complex

An integrated multimodal imaging workflow of cryogenic super-resolution fluorescence microscopy and soft X-ray tomography, Orbitrap secondary ion mass spectrometry, and inductively coupled plasma-mass spectrometry has revealed the unexpected targeting of a half-sandwich cyclopentadienyl Rh(III) phenylazopyridine anticancer complex to cellular lipid membranes and lipid droplets. The complex accumulates in plasma membranes with a surprisingly intense switch-on luminescence in living cancer cells, drives remodeling of lipid droplet architecture, and penetrates deeply into lipid-rich tissue environments. DFT modeling shows strong supramolecular interactions between the complex and glycerophosphorylcholine lipids.