Engineering of hierarchical mesoporous silica nanoparticles via control over surfactant nanoarchitectonics for biological applications

Compared to conventional mesoporous silica nanoparticles (MSNs) with ordered porous structures, hierarchical MSNs (HMSNs) have attracted increasing research interests in biological fields, owing to their highly porous structures with multiple distinct interfaces, which create more possibilities to explore complex biological realms. However, due to the structural complexity, the controllable assembly of HMSNs with desired nanostructures and well-defined particle properties is challenging. Herein, we review the advances of engineering HMSNs via control over surfactant nanoarchitectonics and discuss the synthesis-guiding principles and formation mechanisms. Based on the structural features of HMSNs, the corresponding bio-applications (e.g., macromolecule encapsulation, drug release, biointerface adhesion, immune cell activation and stimuli-responsive target motion) are summarized, highlighting the importance of structure–activity relationship. Challenges and future perspectives are also proposed for characterizations and extended applications of HMSNs.