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Janus gold nanostar-mesoporous silica nanoparticle (AuNSt-MSNP) nanodevices able to release an entrapped payload upon irradiation with near infrared (NIR) light were prepared and characterized. The AuNSt surface was functionalized with a thiolated photolabile molecule (5), whereas the mesoporous silica face was loaded with a model drug (doxorubicin) and capped with proton-responsive benzimidazole-β-cyclodextrin supramolecular gatekeepers (N 1). Upon irradiation with NIR-light, the photolabile compound 5 photodissociated, resulting in the formation of succinic acid, which induced the opening of the gatekeeper and cargo delivery. In the overall mechanism, the gold surface acts as a photochemical transducer capable of transforming the NIR-light input into a chemical messenger (succinic acid) that opens the supramolecular nanovalve. The prepared hybrid nanoparticles were non-cytotoxic to HeLa cells, until they were irradiated with a NIR laser, which led to intracellular doxorubicin release and hyperthermia. This induced a remarkable reduction in HeLa cells viability., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A new photosensitizer (1) based on the 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) scaffold has been synthesized. 1 is water soluble and showed an intense absorption band at 490 nm (ɛ=77,600 cm(-1)  m(-1)) and an emission at 514 nm. In vitro toxicity of 1 in the presence of light and in darkness has been studied with HeLa, HaCaT, MCF-7, and SCC-13 cell lines. Moreover, internalization studies of 1 in these cell lines were also performed. These results suggested that 1 is more toxic for SCC-13 and HeLa carcinoma cells than for the HaCaT non-cancerous immortal human keratinocytes. Toxicity upon light irradiation was due to the formation of singlet oxygen and reactive oxygen species (ROS). Cellular co-localization experiments revealed preferential localization of the dye in the endoplasmic reticulum., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)