Responsive fluorescence enhancement for in vivo Cu(II) monitoring in zebrafish larvae

Several neurodegenerative diseases are ascribed to disorders caused by the secretion of Cu ions. However, a majority of the current techniques for copper ion detection are restricted to in vivo monitoring and nonspecific interactions. Their methods are limited to the systematic analysis of Cu ions in living organisms. Thus, a synthetic molecular fluorophore, 5-amino 2,3-dihydroquinolinimine (NDQI), has been developed and successfully utilized in in vivo monitoring of the distribution of Cu(II) in zebrafish larvae. The reversible formation of the NDQI-Cu complex allows its use with high metal concentrations and in oxidative stress conditions. The NDQI-directed strategy developed here can quantitatively differentiate cells with different Cu(II) concentrations. Remarkably, dynamic distribution of Cu(II) in the intestine and liver can be observed.