This disclosure relates to a nanoporous composition including a number of clusters of nanoparticles dispersed in a liquid, a nanoporous layer formed of the nanoporous composition, a glucose-oxidation electrode including the nanoporous layer, and a glucose-sensing device and system including the glucose-oxidation electrode. This disclosure also relates to a method of making the nanoporous composition, the nanoporous layer, the glucose-oxidation electrode and the glucose-sensing device and system. Further, this disclosure also relates to devices, systems and methods for continuous glucose monitoring (CGM) and blood glucose monitoring (BGM).