Stable mesoporous silica nanoparticles incorporated with MoS2 and AIE for targeted fluorescence imaging and photothermal therapy of cancer cells

Theranostics for imaging-guided cancer treatment have obtained great attention in recent years for their outstanding capability of both tumor diagnosis and treatment. Molybdenum disulfide (MoS2) nanosheets revealed excellent photothermal conversion efficiency, which could be used as photothermal agents. However, MoS2 nanosheets would often quench or decrease the emission of fluorescence dyes when they were incorporated with these dyes to construct fluorescence-imaging-guided nanotheranostic systems. In this work, MoS2 nanosheets were embedded into mesoporous silica nanoparticles (MSNs), and Aggregation Induced Emission (AIE) fluorogen PhENH2 was chemically modified on the surface of MSNs, which could demonstrate more stable fluorescence emission compared with other MSNs with physically absorbed luminescent molecules. Moreover, folic acid (FA) was also chemically decorated on the nanoparticles to facilitate their targeted bioimaging and photothermal therapy. As expected, the obtained PhENH2-MoS2-FA MSNs could be efficiently taken up by MDAMB-231 cells than HepG2 cells, owing to the over-expressed FA receptors on MDA-MB-231 cells. Meanwhile, these MDA-MB-231 cells could be efficiently killed under an 808 nm laser irradiation. These results indicated that the achieved multifunctional MSNs chemically decorated with AIE fluorogens would demonstrate more stable fluorescence for bioimaging-targeted photothermal therapy of MDA-MB-231 cells, which made them promising nanotheranostics for further cancer treatment.