Enzyme complexes, ferritins, heat shock proteins, viruses and virus-like particles are typical natural bionanoparticles (BNPs). A characteristic feature of BNPs is that multiple proteins are organized through non-covalent interactions to form highly organized nanostructures. The unique advantages of BNPs for materials development rely on their molecular precision and intrinsic genetic programmability, where a specific codon modification translates to the corresponding change in amino acid residue with unsurpassed fidelity, consistency and spatial resolution. In addition, these particles exhibit distinctive structural symmetries and yet are stable enough to be extensively modified by bioconjugation chemistry, which allows for the presentation of functional units in a spatially selective manner. Owing to these valuable properties, BNPs have recently been employed as templates or building blocks to fabricate novel functional materials for a variety of applications.^1–4