Nanoassembles constructed from mesoporous silica nanoparticles and surface-coated multilayer polyelectrolytes for controlled drug delivery

Abstract Carboxylated mesoporous silica nanoparticles (MSN-COOH), aminated MSN (MSN-NH 2 ) and hollow MSN (H-MSN), were preloaded with doxorubicin hydrochloride (DOX), and further surface-assembled with polyelectrolytes, such as polycations, 1,4-butanediamine (BDA) and 1,2-ethanediamine (EDA) modified linear or star-shaped polyglycerol methacrylate (PGOHMAs), and polyanion, poly(acrylic acid) (PAA) by layer-by-layer (LbL) self-assembly technique to obtain MSN-polyelectrolytes nanoparticles (MSNPENs). The loading capacity of MSNPENs based on negatively charged MSN-COOH is superior to that based on positively charged MSN-NH 2 owing to its electrostatic interaction with positively charged DOX. Meanwhile, H-MSN with hollow cavity and more free volume inside the nanoparticles also exhibited high loading capacity. Therefore, MSN-COOH and H-MSN were used to deliver DOX in a controlled release fashion. Loading process was characterized by dynamic light scattering (DLS), fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA), and X-ray diffraction spectroscopy (XRD). Nanoassembles constructed from star-shaped polymers exhibited better loading capacity and sustained release. Cytotoxicity assay revealed that MSNPENs were biocompatible and comparatively safe for drug delivery. In vitro release test showed that drug release accelerated at acidic condition but remained within MSNPENs at neutral pH values. These formulations show great potential for safe pH-responsive anti-cancer drug delivery.