Microwave-assisted Diels-Alder reaction for rapid synthesis of luminescent nanodiamond with AIE-active dyes and their biomedical applications

Fluorescent nanodiamond (FND) has received increasing research interests for bioimaging and drug delivery owing its outstanding physicochemical properties and low toxicity. However, synthesis of FND in large scale with desirable optical property is still a big challenge. In this work, we reported for the first time that non-fluorescent ND can be facilely converted into FND through surface modified with aggregation-induced emission fluorophore containing luminescent polymers through the microwave-assisted typical Diels-Alder (D-A) reaction. The final FND (named as ND-poly(Phe-PEGMA-IA)) displayed extensive fluorescence, high water dispersibility and desirable biocompatibility. Cell imaging results demonstrated ND-poly(Phe-PEGMA-IA) exhibited great stain performance. Furthermore, anticancer drug (cisplatin, DDP) can be effectively loaded onto ND-poly(Phe-PEGMA-IA) and controlled release it under acidic environment. All of these favorable properties endow ND-poly(Phe-PEGMA-IA) great potential for biological tracing and controlled drug delivery. Taken together, we have developed a microwave-assisted D-A reaction for preparation of multifunctional FND with great potential for biological imaging and controlled drug delivery applications.