Accelerated Ring-Opening Polymerization of a-Amino Acid N-Carboxyanhydride via Inorganic Nano-initiators 

While the accelerated polymerization of N-carboxyanhydrides (NCAs) has been utilized to synthesize versatile polypeptide materials in an efficient manner with minimized side reactions, the preparation of polypeptide-based inorganic/organic hybrid materials with the acceleration strategy remained largely unexplored. Herein, we report the accelerated ring-opening polymerization (ROP) of NCAs mediated by amine-modified inorganic nano-initiators, such as mesoporous silica nanoparticles (MSN-NH2), which is driven by the cooperative effect of the neighboring a-helical polypeptide chains in a dichloromethane (DCM)/water biphasic system. Well-defined nano-hybrids were prepared within 15 min from non-purified NCA monomers, through in situ purification and subsequent ultrafast polymerization process. NCAs can be rapidly initiated by amino groups of MSN uniformly dispersed at the interface of DCM and water, and subsequently formed the well-defined polypeptides within 15 min. The prepared inorganic/organic nano-hybrid with MSN as the core and polypeptide as the shell adopted spherical morphology and uniform size distribution due to the excellent controllability of ROP. Besides, this system is also suitable for a variety of NCAs and inorganic nano-initiators. This research allows efficient and rapid preparation of inorganic/organic nano-hybrids, and further promotes the extensive application of this material in the biomedical fields.