Figure 1. Synthesis of metal@ZnO core-shell nanostructures using urease as a template.

Step 1: Synthesis of metallic nanoparticles using urease both as reducing as well as stabilizing agent. Step 2: hydrolysis of urea by the nanoparticle-enzyme composite led to the increase in pH around the enzyme due to production of ammonia that catalyzed the growth of ZnO shells around the metal nanoparticle-enzyme composite.