Apoferritin can act as a scaffold for functionalization in the inner and outer surfaces. However, traditional covalent modification methods have a risk of disrupting the structure and physicochemical properties of apoferritin. Herein, we report a method for designing versatile apoferritin-based nanosystems through noncovalent interaction between a PEGylated [FeFe]-hydrogenase mimic (FeFe-PEG-N3) and apoferritin. FeFe-PEG-N3 can be anchored into the threefold channels of apoferritin via program injection, at a number of ∼8 per protein. We also engineered apoferritin with an FeFe-PEG-N3/ATRP initiator conjugate for in situ and noninvasive atom transfer radical polymerization (ATRP) at the apoferritin surface. This "grafting-from" method for noncovalent apoferritin engineering has the advantages of simple preparation, good controllability, and high efficiency and affords opportunities for the construction of multifunctional apoferritin-based nanosystems for broad applications such as drug delivery and catalysis.
Keywords: apoferritin; atom transfer radical polymerization; click chemistry; grafting-from; in situ polymerization.