Trehalose-based nanogels for stabilizing and controlled releasing biomolecules such as glucagons are disclosed. Specifically, trehalose-based nanogels comprise (a) a copolymer comprising first methacrylate units and second methacrylate units, wherein (i) the first methacrylate units comprise trehalose side chains; and (ii) the second methacrylate units comprise disulfide side chains; (b) dithiol cross-linkers; wherein the dithiol cross-linkers cross link the copolymer through the disulfide side chains of the second methacrylate units.