Metal-to-ligand charge-transfer: Applications to visual detection of β-galactosidase activity and sandwich immunoassay.
In this work, we report a novel use of the distinctive metal-to-ligand charge-transfer (MLCT) absorption properties of the chromogenic Fe(BPDS)34-(BPDS=bathophenanthroline disulfonic acid) reporter for the visual detection of β-galactosidase (β-Gal) activity and sandwich immunoassay. The enzymatic hydrolysis of the substrate p-aminophenyl-β-D-galactopyranoside can switch on the reduction of Fe3+to Fe2+and the subsequent complexation of Fe2+with the BPDS ligand to generate the Fe(BPDS)34-reporter, leading to the appearance of the intense MLCT absorption band at 535nm and the colorless-to-red color change of the solution. Simply through a single step, the activity of β-Gal can be sensitively and selectively detected within the dynamic range of 0-220mUmL-1, with a limit of detection (LOD) of 1.69mUmL-1. This approach is applicable for the visual detection of β-Gal activities in the presence of complex human serum samples. Besides, when integrated with the sandwich immunoassay of carcinoembryonic antigen, a LOD of 1.16ngmL-1can be achieved. In light of its prominent simplicity and practicality, our MLCT-based approach holds great potential in diagnostic and analytical applications.
School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China.
Qiong
Q
Hu
School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China.
Kefeng
K
Ma
School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China.
Yaqi
Y
Mei
School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China.
Minhui
M
He
School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China. Electronic address: j.kong@njust.edu.cn.
Jinming
J
Kong
School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China; Chemistry Department, College of Arts and Sciences, University of South Florida, East Fowler Ave, Tampa, Florida 33620-4202, United States. Electronic address: xueji@usf.edu.
Xueji
X
Zhang
D003124:Colorimetry; D004579:Electron Transport; D057075:Enzyme Assays / Q000379:methods*; D007118:Immunoassay / Q000379:methods*; D007501:Iron / Q000737:chemistry*; D008024:Ligands; D010618:Phenanthrolines / Q000737:chemistry*; D001616:beta-Galactosidase / Q000378:metabolism*
D008024:Ligands; D010618:Phenanthrolines; C017049:bathophenanthroline disulfonic acid; D007501:Iron; D001616:beta-Galactosidase
Bathophenanthroline; Colorimetric; Density functional theory; Immunoassay; Metal-to-ligand charge-transfer; β-galactosidase