Highly luminescent pH-responsive carbon quantum dots for cell imaging

Carbon quantum dots (CDs) have attracted tremendous interest owing to their idiosyncratic functions and wide-ranging applications. However, it remains a great challenge to empolder an integrated CDs combining high luminescence, biocompatibility and luminescence color tunability for bioimaging via simple approach. In this work, pH-responsive carbon quantum dots (Si-CDs) with high luminescence (quantum yield = 74.8%) were fabricated by one-step hydrothermal method using (3-mercaptopropyl) triethoxysilane (KH-580) as modifier for the first time. The optical properties of the as-prepared Si-CDs can be controlled from obvious green-blue-violet transformation by altering the pH. More importantly, the change is reversible and repeatable. In addition, the Si-CDs have good biocompatibility and chemically inert in vitro cell system simulation. Such non-toxic, environmental friendly, low-cost, inert CDs materials are promising candidates for biomedical and pH-sensitive sensors.