Fluorescence-Quenching-Based Enzyme-Activity Assay by Using Photon Upconversion


  • This study was supported by the Academy of Finland (grant nos.: 114903 and 119497). The authors thank Pirjo Laaksonen (University of Turku) for blood sampling and Hidex Oy for technological support in the anti-Stokes photoluminescence measurements.


original image

Switch the lights off! A novel sensitive enzyme-activity assay combines the advantageous features of upconverting phosphors (UCPs) and fluorescence quenching. The new assay principle allows the use of fluorescent particulate labels in a quenching-based assay despite the fact that it is not possible to achieve adequate quenching efficiency of particle fluorescence directly. Infrared excitation enables even the use of colorful samples.