High dispersibility ratiometric fluorescence sensor designed by functionalized mesoporous silica nanopraticles for sensing and imaging of hydrogen peroxide

Herein, a mesoporous silica nanoparticle (MSN) based ratiometric fluorescence nanosensor (MSN-BA-SiCD) with improved performance was designed for monitoring hydrogen peroxide (H2O2). Specifically, H2O2 response molecule (BA) with AIE feature was synthesized and encapsulated into MSN channel as the fluoresent recognition site. Afterwards, silane-modified carbon dot (SiCD) was covalently connected to the MSN surface which can effectively prevent the leakage of BA and improve the water dispersibility of the nanosensor. The presence of H2O2 could result in a "turn-on" fluorescence of BA as well as concurrent variation in the fluorescence resonance energy transfer (FRET) signal between SiCD and BA. MSN-BA-SiCD displays a specific blue-to-green resolved emission change in response to H2O2 and the detection limit can be as low as 4.78 x 10(-6) M. In addition, the nanosensor exhibited enhanced photostability due to the protection of the material framework. Moreover, the nanosensing system was successfully applied to detect H2O2 in beer, orange juice and living cells. The excellent water dispersibility and photostability of the nanosensor, together with high specificity and biocompatibility, constituted an advanced set of characteristics among existing MSNs, which was expected to further promote the development of H2O2 sensors in the environmental and biological fields.