Near-Infrared Light-Triggered Hydrophobic-to-Hydrophilic Switch Nanovalve for On-Demand Cancer Therapy.

An on-demand drug delivery nanoplatform based on mesoporous silica (mSiO) coated upconversion nanoparticles (UCNP@mSiO) with a novel near-infrared (NIR) light-triggered hydrophobic-to-hydrophilic switch nanovalve was fabricated. The surface of UCNP@mSiO was first immobilized with hydrophobic 2-diazo-1,2-naphthoquinones (DNQ) guest molecules. After doxorubicin hydrochloride (DOX, a universal anticancer drug) was loaded into channels of mSiO shell, β-cyclodextrin (β-CD) host molecules with a hydrophobic cavity were added as gatekeepers to cap DNQ stalk molecules via hydrophobic affinity, which may play a role in the OFF state of the nanovalve to prevent the drug from being released.

Negative Capacitance in BaTiO3/BiFeO3 Bilayer Capacitors.

Negative capacitances provide an approach to reduce heat generations in field-effect transistors during the switch processes, which contributes to further miniaturization of the conventional integrated circuits. Although there are many studies about negative capacitances using ferroelectric materials, the direct observation of stable ferroelectric negative capacitances has rarely been reported. Here, we put forward a dc bias assistant model in bilayer capacitors, where one ferroelectric layer with large dielectric constant and the other ferroelectric layer with small dielectric constant are needed.

Design and Synthesis of Core-Shell-Shell Upconversion Nanoparticles for NIR-Induced Drug Release, Photodynamic Therapy, and Cell Imaging.

Novel core-shell-shell structured nanoparticles 75 nm in diameter with all-in-one "smart" functional capabilities for simultaneous photoresponsive drug release, photodynamic therapy, and cell imaging are designed and prepared. These nanoparticles consist of an upconversion (UC) emission core, a photosensitizer-embodied silica sandwich shell, and a β-cyclodextrin (β-CD) gated mesoporous silica outmost shell with drugs (Rhodamine B as a model) loaded inside. We show in this proof-of-concept demonstration that, under 980 nm near-infrared irradiation, UC 540 nm green light emissions were emitted for cell imaging, and 660 nm red light emissions were excited for activating photosensitizers to generate singlet oxygen, which could be exploited directly to kill cancer cells and simultaneously dissociate β-CD gatekeeper to release drugs.