A Wearable and Deformable Graphene-Based Affinity Nanosensor for Monitoring of Cytokines in Biofluids

A wearable and deformable graphene-based field-effect transistor biosensor is presented that uses aptamer-modified graphene as the conducting channel, which is capable of the sensitive, consistent and time-resolved detection of cytokines in human biofluids. Based on an ultrathin substrate, the biosensor offers a high level of mechanical durability and consistent sensing responses, while conforming to non-planar surfaces such as the human body and withstanding large deformations (e.g., bending and stretching). Moreover, a nonionic surfactant is employed to minimize the nonspecific adsorption of the biosensor, hence enabling cytokine detection (TNF-alpha and IFN-gamma, significant inflammatory cytokines, are used as representatives) in artificial tears (used as a biofluid representative). The experimental results demonstrate that the biosensor very consistently and sensitively detects TNF-alpha and IFN-gamma, with limits of detection down to 2.75 and 2.89 pM, respectively. The biosensor, which undergoes large deformations, can thus potentially provide a consistent and sensitive detection of cytokines in the human body.