"Non-Naked" Gold with Glucose Oxidase-Like Activity: A Nanozyme for Tandem Catalysis.

It has been widely reported that "naked" gold nanoparticles (Au NPs) without protectors have glucose oxidase (GOx)-like activity, and the use of protectors can inhibit the GOx-like activity. Here, "non-naked" Au NPs with GOx-like activity are synthesized by using protein as protector. Although "naked" Au NPs have peroxidase-like activity and GOx-like activity, the optimal pH ranges of the both activities are obviously different. Fortunately, as-synthesized "non-naked" Au NPs show the dual enzyme-like activities at the same pH. So, "non-naked" Au NPs can be described as "tandem nanozyme." As another bonus, the participation of protein protector can stabilize the GOx-like activity and make Au NPs modifiable. Even though Au NPs are connected with graphene oxide (GO), the GOx-like activity is still not changed. Further, Au NPs-GO nanocomposites are applied on the one-pot nonenzymatic glucose colorimetric detection. The "non-naked" gold not only broadens the species of tandem nanozymes, but also facilitates the functionalization of nanozymes, which is promising for immunoassay, biosensor, and medical treatment.