For glucose detection assay, TBHBA and 4-AAP were dissolved in
10 mM PBS buffer (pH 7.0) to get 5 mg/mL TBHBA and 20 mg/mL 4-
AAP stock solutions, respectively. The stock solutions were stored
at 4 ◦C in the dark environment. The detection solutions were a
mixture of gelatin, HRP, GOD and stock solutions which should be
avoided from light.