Changchun Institute of Optics,Fine Mechanies and Physics,Chinese Academy of Sciences

Carbon Dots with Highly Efficient Multiple Color Emission may lead to important applications

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Carbon dots, as excellent fluorescent agent, have been developed multiple applications on the photovoltaic, LED, detection and bio-imaging fields due to their excellent photoluminescence, good biocompatible, low cytotoxicity, hydrophilic and multiple function groups on the surface. For the bio-related application, long excited wavelength and visible light emission are highly desired. Although most carbon dots exhibit excitation dependent emission the long wavelength emission are quite weak. High fluorescent carbon dots with green and red emission under visible light emission are expected for potential bio-related applications.

Recently, one of CIOMP’s research group, prof. SUN Zaicheng developed a simple route to synthesize highly fluorescent N doped carbon dots with blue, green and yellow emission with UV, blue and green light excitation on Light: Science & Applications (Light: Sci. Appl. 2015, 4, e364). Their photoluminescent quantum yield can reach 90%, 29%, and 22%, respectively. That can be satisfied the bio-imaging application. Furthermore, prof. SUN’s group extended the emission to the red light by doping with S and N. As prepared carbon dots can emit blue, green and red light with 61%, 45 and 8% of photoluminescent quantum yield. This result was published on the Advanced Optical Materials (Adv. Opt. Mater. 2015, 4, 360).

Beyond the synthesis of carbon dots, this group also working on the construction of theranostic agent with targeting, imaging and therapy function together. “We developed a self-targeting carbon dots with one step route.(ACS Nano.2015,9, 11455-11461.) It means two functions: imaging and targeting was combined onto one single carbon dots without further bio-conjugation reaction to connect the targeting molecules,” prof. SUN said.

The collaborators Prof. XIE Zhigang from Changchun Institute of Applied Chemistry and Prof. GAO Huile from Sichuan University performed the biological distribution of carbon dots in tumor bearing mice by fluorescence in vivo imaging system. From the mice in vivo imaging data, carbon dots can quickly penetrate into brain pass by the blood brain barrier, and selectively enriched in brain glioma after the tail vein injection. At the same time, the distribution of carbon dots in the normal brain tissue is very small, which fully confirmed the carbon dots to the brain glioma target imaging function.

These results are very important for the early diagnosis of brain tumors and further building intelligent nano medicines.