Highly sensitive electrochemiluminescence glucose sensor under alkaline conditions based on glucose oxidase@conductive metal-organic framework nanocapsules

Electrochemiluminescence (ECL) sensors based on luminol had been frequently coupled with enzymatic reactions to detect various targets. However, a major challenge arises from the conflict between the neutral environmental required for enzymatic activity and the higher luminescence efficiency of luminol under alkaline conditions. In this study, glucose oxidase (GOx)@Zn-HHTP (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene) was successfully synthesized, significantly enhancing the stability of encapsulated GOx. At pH 10.0, the enzyme retained 80 % of its catalytic activity compared to its performance under neutral conditions. To demonstrate its applicability, GOx@Zn-HHTP had been applied to construct an ECL glucose sensor. Operating under alkaline conditions, this sensor maintained a high luminescence efficiency of luminol, resulting in an 8.5-fold increase in sensitivity and a 25-fold reduction in the detection limit compared to the sensor operating under neutral environments. This sensor was successfully applied for detection of glucose in sweat, effectively mitigating interference from the complex matrix of sweat samples and enabling accurate detection of glucose at low concentrations.