Theranostic mesoporous silica nanoparticles made of multi-nuclear gold or carbon quantum dots particles serving as pH responsive drug delivery system

Mesoporous silica nanoparticles are promising candidates to deliver proteins, antibodies, and anticancer drugs and to be served as an adsorbent of various types of substrate. Herein, a theranostic approach, in the preparation of fluorescence-type mesoporous silica for pH-responsive delivery of anticancer drug, doxorubicin, is introduced. By this mean, three types of mesoporous silica were synthesized. The ordinary type of mesoporous silica nanoparticles containing propylamine functional groups was synthesized by a controlled-size technique. Two types of fluorescence mesoporous silica were prepared, doped with gold or quantum dots nanoparticles. The fluorescence imaging has shown that the optical properties of the gold or carbon quantum dots have been transferred to the mesoporous matrix in doping processes. The as-prepared mesoporous materials were conjugated to doxorubicin via Schiff-base linkage. Several characterization techniques were utilized to detect the structure of the particles including FT-IR spectroscopy, XRD, N 2 adsorption/desorption, transition, and scanning electron microscopy. The amount of conjugated doxorubicin was analyzed by UV–Vis spectroscopy. The pH-responsive character was proved assessing the release profile in different pH ranges including physiological pH. The safety of the particles was evaluated by cell cytotoxicity assay on breast cancer cell line, MCF-7. As-prepared particles showed no cytotoxic behavior, but when they were loaded by doxorubicin, the appreciable release of the drug and subsequent cytotoxicity resulted against MCF-7 cells. The hemolytic study was conducted to prove the biocompatibility of these particles in the blood. Altogether, the proposed materials are suitable to be considered as safe and to be used as a theranostic platform for therapeutic and imaging purposes. • Three types of MSN were prepared and applied for drug delivery. • The fluorophore MSNs of GNP@MSN and QCD@MSN were organized for theranostic purpose. • DOX was conjugated to MSNs, and released through pH responsive profile. • The fluorophore MSNs showed biocompatibility and fluorescent contrast in MCF-7 cells. • MSNs@DOX showed toxicity in parallel and even higher than of free DOX in MCF-7 cell.