Carbon dots as dual-functional nanoprobes: Fluorescent labeling of polycaprolactone porous microspheres and enhancement of osteogenic differentiation in rBMSCs

Fluorescent tracer technology has been widely used in real-time visual tracking of materials or cell dynamic processes in vivo. However, the commonly used fluorescent probes have their own disadvantages when used in biological systems, such as intrinsic photobleaching of organic dyes and the potential biotoxicity of rare-earth nano-particles. To address these problems, we employed fluorescent carbon dots (CDs) with low photobleaching, red emission and good biocompatibility as a dual tool for long-term tracing of polycaprolactone (PCL) porous microspheres and regulating cells osteogenic differentiation. In vitro cell experiments suggested that CDs were nontoxic and could promote osteogenic differentiation of rat bone marrow mesenchymal stem cells (rBMSCs). CDs enhanced biological properties of PCL microspheres and were successfully traced for 3 months by fluorescence-related visual imaging methodology. As a dual-functional tool to trace scaffold behavior for a long time and regulating cells osteogenic differentiation, CDs have important research potential in the field of tissue engineering and regenerative medicine.