Reusable Photo‐Electro‐Enzymatic Glucose Biosensor using dithienylethene mediators

In the development of enzymatic biosensors, the use of electrochromic mediators has been accepted and widely used during decades. The main drawback of this type of enzymatic substrates is the difficult recovery of the initial redox state of the molecule, which can be done electrochemically or by antioxidants addition, complicating the initially simple structure of the biosensor. Actually, those strategies are rarely followed; being the single-use biosensor configuration the most extended for this detection mechanisms. Alternatively, we propose the first reported use of a diacid dithienylethene 1,2-bis(5-carboxy-2-methylthien-3-yl)cyclopentene (DTE) photoelectrochromic compound as a substrate of the horseradish peroxidase (HRP). The photoisomerization between the open (DTEo) and closed (DTEc) forms of the molecule and the respective shift in the redox potential allowed the light-induced enzymatic detection of glucose in the glucose oxidase (GOx) - HRP cascade system. This fast and easy control over the enzymatic substrate availability by light pulses permits a gradually consumption and the light-regeneration of the biosensor for a number of cycles. We consider the presented results transcendent in the development of all-photonic, reusable and light-controlled photonic biosensing systems.