A chemical timer approach to delayed chemiluminescence

Although the onset time of chemical reactions can be manipulated by mechanical, elec-trical, and optical methods, its chemical control remains highly challenging. Herein, we report a chemical timer approach for manipulating the emission onset time of che-miluminescence (CL) reactions. A mixture of Mn2+, NaHCO3, and a luminol analog with H2O2 produced reactive oxygen species (ROS) radicals and other superoxo species (superoxide containing complex) with high efficiency, accompanied by strong and immedi-ate CL emission. Surprisingly, the addition of thiourea postponed CL emission in a concentration-dependent manner. The delay was attributed to a slow-generation-scavenging mechanism, which was found to be generally applicable not only to various types of CL reagents and ROS radical scavengers but also to popular chromogenic reactions. The precise regulation of CL kinetics was further utilized in dynamic chemical coding with improved coding density and security. This approach provides a powerful platform for engineering chemical reaction kinetics using chemical timers, which is of application potential in bio-assays, biosensors, CL microscopic imaging, microchips, array chips, and informatics.

Automated summary

This study presents a chemical timer approach for manipulating the emission onset time of chemiluminescence (CL) reactions. By adding thiourea, the delay of CL emission can be achieved through a slow-generation-scavenging mechanism, which is applicable not only to CL reactions but also to other common chromogenic reactions. The precise regulation of CL kinetics can be utilized in dynamic chemical coding with improved coding density and security.