Amino/quaternary ammonium groups bifunctionalized large pore mesoporous silica for pH-responsive large drug delivery

Abstract

Mesoporous nanoparticles functionalized with amino groups on the pore surface and quaternary ammonium groups on the particle surface with particle sizes of 500–800 nm in length and 300–500 nm in diameter and a pore size of 7.2–7.4 nm, have been obtained through a post-synthesis and co-condensation method. Bleomycin (BLM) has been chosen as a model anti-cancer drug with a large molecular size, and the iron essential for organisms has been utilized for constructing NH₂–Fe–BLM coordination bond architecture in the pore surface. The BLM was released under mildly acidic pH conditions by cleavage of the Fe–BLM coordination bond triggered by pH reduction. Cell assays show that mesoporous nanoparticles have good dispersity and good cell penetrating properties due to the positively charged quaternary ammonium groups on the outer surface of the nanoparticles. These organic functionalized large pore mesoporous materials can be utilized as carriers in the pH-responsive delivery of an anti-cancer drug with a large molecular size, opening up new opportunities for their further application in controlled release of biomacromolecules.