Intracellular delivery of functional proteins is a promising, but challenging, strategy for many therapeutic applications. Here, we report a new methodology that overcomes drawbacks of traditional mesoporous silica (MSi) particles for protein delivery. We hypothesize that engineering enhancement in interactions between proteins and delivery vehicles can facilitate efficient encapsulation and intracellular delivery. In this strategy, surface lysines in proteins were modified with a self-immolative linker containing a terminal boronic acid for stimulus-induced reversibility in functionalization. The boronic acid moiety serves to efficiently interact with amine-functionalized MSi through dative and electrostatic interactions. We show that proteins of different sizes and isoelectric points can be quantitatively encapsulated into MSi, even at low protein concentrations. We also show that the proteins can be efficiently delivered into cells with retention of activity. Utility of this approach is further demonstrated with gene editing in cells, through the delivery of a CRISPR/Cas9 complex.
Keywords: Protein encapsulation; engineered interactions; gene editing; intracellular protein delivery; mesoporous silica.