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 watersoluble porphyrins Zn(II) meso-tetrakis (4-sulfonatophenyl)porphyrin (ZnTPPS)) and the ionic liquid 1-decylalkyl-3-methylimidazolium bromide (C10mimBr) under room temperature, which exhibited high singlet oxygen (O-1(2)) quantum yields and electrocatalytic activity toward hydrogen peroxide (H2O2). 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 O-1(2) formed, then water and the formed O-1(2) could be catalyzed by antibody via the antibody catalyzed water oxidation pathway to produce H2O2 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, PorIL 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.