Multifunctional porphyrin-ionic liquid aggregate for highly sensitive electrochemical detection of protein.

Herein, this paper describes a novel label-free and extensibility electrochemical sensing platform based on porphyrin-ionic liquid (Por-IL) aggregate for the detection of antibody. The Por-IL was synthesized with water-soluble porphyrins Zn(II) meso -tetrakis (4-sulfonatophenyl)porphyrin (ZnTPPS)) and the ionic liquid 1-decyl-alkyl-3-methylimidazolium bromide (C 10 mimBr) under room temperature, which exhibited high singlet oxygen (1O 2) quantum yields and electrocatalytic activity toward hydrogen peroxide (H 2 O 2). In the presence of antibody, the antibody could be introduced on the surface of the electrode on the basis of antigen-antibody biorecognition. Under light illumination, the 1O 2 formed, then water and the formed 1O 2 could be catalyzed by antibody via the antibody catalyzed water oxidation pathway to produce H 2 O 2 which could be detected by the electrode, leading to the electrochemical signal for readout. Using anti -carcinoembryonic antigen (anti -CEA) as a model target, this method displayed a wide linear detection range and a lower detection limit. In particular, Por-IL demonstrated lower detection limit of 1.67 fg/mL. Furthermore, the Por-IL sensors were able to detect antibody in complex samples. The immunosensor platform has the features of label-free, sensitivity, only with air and on/off light switching and could be used to detect of a variety of antibody by using corresponding antigen, showing potential application in medical diagnosis. [Display omitted] • An electrochemical immunosensor platform based on porphyrin (Por)-ionic liquid (IL) aggregate was designed. • The Por-IL aggregate has high catalytic activity toward H 2 O 2 and singlet oxygen quantum yields. • The sensor has the extensibility. [ABSTRACT FROM AUTHOR]