The chemiluminescence (CL) reactions exhibit flash-type light emission which restrict its potential application in cold light sources, bioassays, biosensors and biological imaging. USTC Professor CUI Hua and Professor MA Mingming's team succeeded in developing firefly-mimicking intensive and long-lasting CL hydrogels, with Professor WANG Wei from Nanjing University. The light emission is visible even for naked eyes and lasts for over 150 hours when the hydrogels are mixed with H₂O₂. This work proposed slow-diffusion-controlled heterogeneous catalysis mechanism and offered a new approach to design high intensity, long duration CL materials.

(Image by Cui Hua)

This hydrogels consist of nature chitosan, CL reagent N-(4- aminobutyl)-N-ethylisoluminol (ABEI) and catalyst Co²⁺. The porous network structure possessed micro/nano-sized pores and acted as a water-absorbing sponge, which allowed high concentration of ABEI to be loaded into the pores of the hydrogels. The results demonstrated that 89.48% ABEI existed in aqueous phase and almost all of Co²⁺ (99.8%) was immobilized at the skeleton of the CL chitosan (CS) hydrogels. Co²⁺ located at the skeleton of CS hydrogels is active site of the CL reaction, which is surrounded by ABEI molecules in pores of the hydrogels. When H₂O₂ slowly diffuses to the active site, Co²⁺ as a catalyst would react with H₂O₂ to produce a highly reactive hydroxyl radical OH·, followed by the reaction with ABEI anion and HO^2- to facilitate the formation of ABEI radicals and O²·-. Finally, ABEI radicals react with O²·- to generate strong CL emission. Because of the slow diffusion rate of H₂O₂ in hydrogels with high micro/nano-sized pores, the CL reaction is a slow-diffusion-cotrolled process and could proceed for several days.

The team have demonstrated firefly-mimicking intensive and long-lasting CL ABEI/CO²⁺/CS hydrogels. Such CL emission with long-lasting mechanism is distinctly different from those of existing enzyme-involved CL and peroxyoxalate ester CL systems. The hydrogels can be used as cold light source in emergency situations, decorative entertainment, and underwater lighting and may also find future applications in biosensors, microchips, bioassays and bioimaging, due to the hydrogel’s excellent biocompability and intensive and long-lasting CL emission.

The paper was published at Nature Communications, entitled as “Firefly-mimicking intensive and long-lasting chemiluminescence hydrogels” (Nat. Commun., 2017, DOI:10.1038/s41467-017-01101-6) on 17th Oct. PhD candidate LIU Yazhi, PhD candidate LI Qi and Postdoc SHEN Wen at USTC contributed equally to this work. This project was supported by the National Key Research and Development Program of China (Grant No. 2016YFA0201300) and the National Natural Science Foundation of China (Grant No. 21527807 and 21475120)

The link of the paper: https://www.nature.com/articles/s41467-017-01101-6

Contact:

Prof. CUI Hua

hcui@ustc.tsg211.com

(DENG Weiting, USTC News Center)