Smart Mesoporous Silica Glyconanoparticles for Theranostics

Mesoporous silica nanoparticles provide a versatile drug-delivery platform due to their exceptional properties, such as, high payload uptake, tunable pore width and particle size and protection over the guest molecule. The external surface can be functionalize with bioactive molecules and stimuli responsive polymers, improving the biocompatibility and drug bioavailability, increasing the local dose delivered and decreasing the side effects. The objective of this work was to synthesize fluorescent hybrid MSNs, coated with a co-polymeric shell containing pH-responsive and carbohydrate blocks obtained through RAFT polymerization. Such combination opens the possibility of diagnosis, through carbohydrates recognition ability towards cancer cells, and therapy by a pH mediated controlled release. The fluorescent silica nanoparticles were prepared by the Stöber method, incorporating a high quantum yield perylenediimide (PDI) in the silica structure. The nanoparticles were characterized by transmission electronic microscopy, with diameters of 30 nm and 65 nm with low size dispersity. The homo and co-polymers were synthesized by RAFT polymerization and characterized by UV-Vis and size exclusion chromatography (SEC), with a polydispersity below 1.2. The external surface of the MSNs was functionalized to allow the immobilization of the smart polymer. Surface modifications were assessed and quantified using 1H-NMR, UV-Vis and ζ-Potential. Polymer immobilization on the MSNs external surface were performed using four different methods: “transfer to”, “graft to”, “graft from” and a hybrid method. The particles modified with the homo carbohydrate polymer were obtained with polymer weight percentage between 0.5% and 4.3%. The immobilization of the final pH-responsive/carbohydrate co-polymer was achieved with a 2% polymer weight via “graft to” method. The immobilization by the hybrid method was also achieved, with promising results, indicating that our strategy is correct