Smart and flexible bioelectronics on graphene have emerged as a new frontier in the field of biosensors and bioelectronics. Graphene has begun to be seen as an ideal signal transducer and a promising alternative for the production of low-cost bioelectronic devices.1-2 However, biological systems used in these devices suffer from a lack of control and regulation. There is an obvious need to develop “switchable” and “smart” interfaces for both fundamental and applied studies. Here, we report the fabrication of a stimuli-responsive graphene interface, which is used to regulate biomolecular reactions.
The present study aims to address the design and development of a novel auto-switchable graphene bio-interface that is capable of positively responding, by creating smart nanoarchitectures. The smart bio-interface consists of a two-dimensional graphene donor and a polymeric receptor, which are rationally assembled together based in a stoichiometric donor-receptor interaction. By changing the external conditions such as temperature, light and pH of the medium, we acheived control of the biochemical interactions. In the negative mode, access of an associated enzyme to its substrate is largely restricted, resulting in a decrease in the diffusion of reactants and the consequent activity of the system. In contrast, the biosubstrate could freely access the enzyme facilitating bioelectrocatalysis in a positive response. More importantly, this provides the first example of responsive bioelectronics being achieved on a two-dimensional graphene interface by controlling the various external stimuli in an on/off-switchable model.
Using electrochemical techniques, we demonstrated that interfacial bio-electrochemical properties can be tuned by modest changes in conditions. Such an ability to independently regulate the behaviour of the interface has important implications for the design of novel bioreactors, biofuel cells and biosensors with inbuilt self-control features.
 O. Parlak, A. P. F. Turner, A. Tiwari, Advanced Materials, 3 (2014), 482.
 O. Parlak, A. Tiwari, A. P. F. Turner, A. Tiwari, Biosensors and Bioelectronics 49 (2013), 53.
Biosensing and Nanomedicine-VIII at SPIE Optics and Photonics, San Diego, CA, 9-13 August 2015.