Detection and Quantification of Tightly Bound Zn in Blood Serum Using a Photocaged Chelator and a DNAzyme Fluorescent Sensor.

DNAzymes have emerged as a powerful class of sensors for metal ions due to their high selectivity over a wide range of metal ions, allowing for on-site and real-time detection. Despite much progress made in this area, detecting and quantifying tightly bound metal ions, such as those in the blood serum, remain a challenge because the DNAzyme sensors reported so far can detect only mobile metal ions that are accessible to bind the DNAzymes. To overcome this major limitation, we report the use of a photocaged chelator, XDPAdeCage to extract the Zn from the blood serum and then release the chelated Zn into a buffer using 365 nm light for quantification by an 8-17 DNAzyme sensor.