In Vivo Chemoselective Photoacoustic Imaging of Copper(II) in Plant and Animal Subjects.

The detection of Cu2+ in living plants and animals is of great importance for environment monitoring and disease diagnosis. Here, a near-infrared (NIR) turn-on photoacoustic (PA) probe (denoted as LET-2) is developed for Cu2+ detection in living subjects, such as soybean sprouts and mice. The absorbance band of LET-2 shifts from 625 to 715 nm after the interaction with Cu2+ , thus producing strong PA signal output at 715 nm (PA715 ) as an indicator. The PA715 value is increased as a function of the concentration of Cu2+ (0 × 10-6 -20 × 10-6 m), with a calculated limit of detection of 10.8 × 10-9 m. More importantly, both in vitro and in vivo studies in soybean sprouts and mice indicate that the as-prepared LET-2 PA probe is highly sensitive and selective for Cu2+ detection. These findings provide a solution for in vivo detection of metal ions by using chemoselective PA probes.