Near-infrared fluorescence probe for the determination of acid phosphatase and imaging of prostate cancer cells

Abstract

In this paper, we developed a near-infrared mercaptopropionic acid (MPA)-capped CuInS₂ quantum dot (QD) fluorescence probe for the detection of acid phosphatases (ACP), which is an important biomarker and indicator of prostate cancer. The fluorescence of CuInS₂ QDs could be quenched by Cu²⁺, and then the addition of adenosine-5′-triphosphate (ATP) could effectively turn on the quenched fluorescence due to the strong interaction between Cu²⁺ and ATP. The ACP could catalyze the hydrolysis of ATP, which would disassemble the complex of Cu²⁺–ATP. Therefore, the recovered fluorescence could be quenched again by the addition of ACP. In our method, the limit of detection (LOD) is considerably low for ACP detection in solution. Using the CuInS₂ QDs fluorescence probe, we successfully performed in vitro imaging of human prostate cancer cells.