Multifunctional Carbon Nanodots: Enhanced Near‐Infrared Photosensitizing, Photothermal Activity, and Body Clearance

Abstract

The emergence of quasispherical carbon nanodots (CNDs) has broadened the family of carbon‐based materials and their applications in many fields. However, the rational design of near‐infrared (NIR) CNDs and their specific applications in theranostic biomedicine are still challenging. Herein, the design and characterization of multifunctional CNDs (MCNDs) as NIR laser‐triggered nanoagents are reported. These MCNDs are constructed by covalent functionalization of CNDs with folic acid and a hydrophobic photosensitizer, chlorin e6 (Ce6), based on a double amidation approach. The resulting MCNDs show high colloidal stability in different physiological environments. They are endowed with NIR fluorescence emission, an enhanced NIR photosensitizing, and a high photothermal activity. The in vitro test indicates that MCNDs own an efficient targeting capacity to penetrate into cancer cells, leading to cell killing at a low dose under NIR laser irradiation. Finally, MCNDs display a long blood circulation time in mice and effective body clearance through a dual hepatobiliary and renal elimination pathway. These features are encouraging for their use as NIR laser‐triggered nanoagents for personalized medicine. This work not only paves a new way for the multifunctionalization of CNDs, simply by integrating other functional components, but also broadens their versatile applications in targeted cancer theranostic nanomedicine.

Keywords

• carbon dots
• carbon materials
• covalent modifications
• fluorescence imaging
• nanoprobes
• phototherapy