Ratiometric two-photon microscopy reveals attomolar copper buffering in normal and Menkes mutant cells

Significance Impaired copper regulation has been implicated in a range of human diseases, yet the current mechanistic understanding of intracellular copper homeostasis remains incomplete. While Cu(I)-selective synthetic fluorescent probes could shed light on copper homeostasis within living cells by dynamically reporting intracellular Cu(I) availability, the affinity range of previously employed probes was insufficient to achieve significant...