High-sensitivity fluorescent probe with a self-immolative spacer for real-time ratiometric detection and imaging of alkaline phosphatase activity

Alkaline phospholipase (ALP)—a hydrolase associated with many cancers and is widely distributed in human organs—has been recognized as an important biomarker in several medical and biological fields. In order to better detect and image ALP, we constructed a novel ratiometric fluorescent probe—APW—that can respond quickly (in less than 15 minutes) with high quantum yield (Φ = 0.6) and sensitivity (its detection limit is 0.46 U L−1) to ALP. Our study is significant in that it uses a new ratio response method that has rarely been reported, which greatly reduced the response time. Furthermore, we successfully applied the novel probe in cell imaging with satisfactory results.