Quantitative functionalization of biosynthetic caged protein materials

Background As one of the representative protein materials, protein nanocages (PNCs) are self‐assembled supramolecular structures with multiple advantages, such as good monodispersity, biocompatibility, structural addressability, and facile production. Precise quantitative functionalization is essential to the construction of PNCs with designed purposes. Results With three modifiable interfaces, the interior surface, outer surface, and interfaces between building blocks, PNCs can serve as an ideal platform for precise multi‐functionalization studies and applications. This review summarizes the currently available methods for precise quantitative functionalization of PNCs and highlights the significance of precise quantitative control in fabricating PNC‐based materials or devices. These methods can be categorized into three groups, genetic, chemical, and combined modification. Conclusion This review would be constructive for those who work with biosynthetic PNCs in diverse fields.