Optical Monitoring of Labile Zinc inside Metastatic Cells with Plasmonic Chemonanosensors

We report the development and characterization of an optical nanosensor for the detection of labile zinc in biological environments. The readout is based on surface-enhanced Raman scattering promoted by a Raman reporter conjugated to the inner plasmonic cavity of hollow silica nanocapsules. We quantify Zn²⁺ by obtaining the ratio between a Zn²⁺-sensitive band and a Zn²⁺-insensitive band. The Raman reporter measures within the range from 10^-5 to 10^-11 M and exhibits a limit of detection of 10^-11.72 M. The nanosensor discriminates between intracellular and extracellular Zn²⁺ concentrations.