Fig. 6. (A) Schematic of the glucose-responsive colorimetric MN-sensing platform triggered by both pH decrease and H₂O₂ generation. (B) Scanned images of the colorimetric microneedle patches after ISF extraction from four mice with normoglycemia (100 mg dL⁻¹) and hyperglycemia (400 mg dL⁻¹). Scale bar, 4 mm. (C) Red Green Blue (RGB) mean – value of scanned images in (B) (reproduced from ref. 105 with the permission of Elsevier Inc, copyright 2020).