fig6

Figure 6. Saliva-based wearable electrochemical sensors for diabetes mellitus. (A) Optical image of the inkjet-printed glucose biosensors coated with the enzyme and the mediator (GO_X and Fc) and encapsulated with Nafion. Reproduced with permission^[232]. Copyright 2018, The Author(s); (B) Optical images of the screen-printed WE, RE and CE for electrochemical sensor on the mouthguard. Reproduced with permission^[233]. Copyright 2018, Elsevier B.V.; (C) Optical images showing the integration of the wireless mouthguard glucose sensor and its real-time response when installed in the human oral cavity. Reproduced with permission^[234]. Copyright 2020, American Chemical Society; (D) The overview of a non-invasive, wireless pacifier, inserted into a baby model and its Na⁺-to-K⁺ ion ratio. Reproduced with permission^[235]. Copyright 2022, Elsevier B.V.; (E) The overview images of glucose pacifier-biosensor sensing concept. Signal interpretation: a dry device (I), saliva reaches and starts to fill the electrochemical chamber (II), stabilization of the signal (III), glucose signal (IV), and saliva elimination from the pacifier (V). Reproduced with permission^[236]. Copyright 2019, American Chemical Society. GO_X: Glucose oxidase; Fc: ferrocene; WE: working electrode; RE: reference electrode; CE: counter electrode.