Detection of Nickel in Fish Organs with a Two-Photon Fluorescent Probe

Abstract

Molecular imaging by two-photon microscopy (TPM) has become indispensable to the study of biology/medicine owing to its capability of imaging deep inside intact tissues. To make TPM a more-versatile tool, a large variety of two-photon probes are needed. Herein, we report a new two-photon fluorescent probe (ANi2) that can be excited by 750 nm femtosecond pulses and detect Ni2+ ions in fresh fish organs at 90-175 mu m depth without interference from the pH value or from other biologically relevant species through the use of TPM. TPM images of fish organs labeled with ANi2 revealed that Ni2+ ions accumulate in fish organs in the order: kidney > heart > gill >= liver. Moreover, a linear relationship was found between the two-photon-excited fluorescence (TPEF) and the inductively coupled plasma mass spectrometry intensities (ICP-MS), thereby allowing the quantitative measurement of Ni2+ ions in live tissue.