3,4,9,10‐Perylenetetracarboxylic Acid/Hemin Nanocomposites Act as Redox Probes and Electrocatalysts for Constructing a Pseudobienzyme‐Channeling Amplified Electrochemical Aptasensor

A simple wet‐chemical strategy for the synthesis of 3,4,9,10‐perylenetetracarboxylic acid (PTCA)/hemin nanocomposites through π–π interactions is demonstrated. Significantly, the hemin successfully conciliates PTCA redox activity with a pair of well‐defined redox peaks and intrinsic peroxidase‐like activity, which provides potential application of the PTCA self‐derived redox activity as redox probes. Additionally, PTCA/hemin nanocomposites exhibit a good membrane‐forming property, which not only avoids the conventional fussy process for redox probe immobilization, but also reduces the participation of the membrane materials that act as a barrier of electron transfer. On the basis of these unique properties, a pseudobienzyme‐channeling amplified electrochemical aptasensor is developed that is coupled with glucose oxidase (GOx) for thrombin detection by using PTCA/hemin nanocomposites as redox probes and electrocatalysts. With the addition of glucose to the electrolytic cell, the GOx on the aptasensor surface bioelectrocatalyzed the reduction of glucose to produce H 2 O 2 , which in turn was electrocatalyzed by the PTCA/hemin nanocomposites. Cascade schemes, in which an enzyme is catalytically linked to another enzyme, can produce signal amplification and therefore increase the biosensor sensitivity. As a result, a linear relationship for thrombin from 0.005 to 20 n M and a detection limit of 0.001 n M were obtained.