Biomimetic synthesis of Ag2Se quantum dots with enhanced photothermal properties and as "gatekeepers" to MSN nanoplatform for chemo-photothermal therapy.

Ag2Se quantum dots (QDs) with near-infrared (NIR) fluorescence have been widely utilized in NIR fluorescence imaging in vivo because of their narrow bulk band gap and excellent biocompatibility. However, most of synthesis methods for Ag2Se QDs were expensive and the reactants were too toxic. In this paper, a new protein-templated biomimetic synthesis approach was proposed for Ag2Se QDs preparation by employing bovine serum albumin (BSA) as template and dispersant. The BSA-templated Ag2Se QDs (Ag2Se@BSA QDs) showed NIR fluorescence with high fluorescence quantum yield (≈21.2%), excellent biocompatibility and good dispersibility in different media. Moreover, the obtained Ag2Se@BSA QDs exhibited remarkable photothermal conversion (≈27.8%), which could be used in photothermal therapy. As a model application in biomedicine, the Ag2Se@BSA QDs were used as "gatekeepers" to cap mesoporous silica nanoparticles (MSNs) by means of electrostatic interaction. By taking the advantages of NIR fluorescence and photothermal property of Ag2Se@BSA QDs, the obtained MSN-DOX-Ag2Se nanoparticles (MDA NPs) were employed as nanoplatform for combined chemo-photothermal therapy. Compared with free DOX and MDA NPs without NIR Laser, the Laser treated MDA NPs exhibited lower cell viability in vitro, implying that Ag2Se@BSA QDs were highly promising potential photothermal agents and the MDA NPs were potential carriers for chemophotothermal therapy.