fig4

Figure 4. Glucose sensing mechanisms and MN-based electrochemical detection. (A) Enzymatic reaction scheme for glucose sensing. The catalytic oxidation of glucose involves redox cycling that generates a measurable electrochemical current; (B) Schematic illustration of multilayer MN-based glucose sensing; (C) Continuous monitoring performance obtained by CA, comparing MNs with and without a PU encapsulation layer; (D) Synthesis route and sensing mechanism of the GOx@ZIF-8(TiO₂) glucose sensor; (E) CV measured at pH 7 for varying glucose concentrations; the inset shows the calibration plot based on cathodic peak currents; (F) Schematic of glucose sensing using porous polymer MNs; (G) Chronoamperometric current responses demonstrating sensitivity variations as a function of MN surface porosity. The error bar in (G) represents the standard deviation. (B and C) Reproduced with permission Copyright 2024, Microchemical Journal^[114]. (D and E) Reproduced with permission Copyright 2018, ACS Omega^[126]. (F and G) Reproduced with permission Copyright 2021, Journal of Physics: Energy^[132]. MN: Microneedle; MNs: microneedles; PU: polyurethane; GOx: glucose oxidase; ZIF: zeolitic imidazolate framework; CV: cyclic voltammetry.