Fluorescent carbon dots capture brain tumor cells
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Different luminescent carbon dots are synthesized using citric acid and amine.
Not long ago, the research team of Sun Zaicheng, a researcher at the Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, and the research group of the Institute of Applied Chemistry of the Chinese Academy of Sciences, Xie Zhigang and Jing Yubin, collaborated with the research group of Associate Professor Gao Huile of Sichuan University to pass the fluorescence in vivo imaging system. The biodistribution of carbon spots in tumor-bearing mice was observed, which laid a solid foundation for the early diagnosis of brain tumors and the further construction of intelligent nano drugs.
Bottleneck of brain tumor diagnosis and treatment
Brain tumors are one of the common neurological diseases. Clinically, most of the symptoms of brain tumor patients have reached the middle and late stages. In recent years, with the development of medicine, there are more and more treatment methods for brain tumors, and chemotherapy is one of the methods for treating brain tumors.
"However, brain tumor chemotherapy drugs are not strong in distinguishing between normal cells and malignant cells, and are also toxic to normal cells, causing obvious adverse reactions. As the dose of chemotherapy drugs increases, adverse reactions also increase." Sun Zaicheng told Journal of the Chinese Academy of Sciences.
Therefore, the chemotherapy efficacy of brain tumors depends on the specific drug, the specific chemotherapy method, whether or not to use the adjuvant drug. At present, in view of brain tumors, in principle, the maximum effect is obtained by chemotherapy, and the adverse reactions of chemotherapy drugs are minimized as much as possible.
Brain tumor diagnosis and treatment is a complex systematic project. The medical profession advocates precision medicine, optimized treatment, translational medicine, and early diagnosis and treatment. The precision medicine here consists of three integrations, namely the integration of gene proteins and metabolomics, the integration of clinical and image information, and the integration and analysis of big data information.
Today, the diagnosis and treatment of tumors has reached the bottleneck stage, from unknown to known to new unknowns. Xie Zhigang and Jing Yubin's research group have been engaged in the research of anticancer drugs for many years. They found in an animal experiment that after the injection of drugs into animals, it is impossible to track and monitor the metabolism of drugs.
Sun Zaicheng's team is mainly engaged in the preparation of nanomaterials. The problems encountered by Xie Zhigang and Jing Yubin are just their research direction, so the cooperation is a success.
Synthetic multicolor fluorescent carbon dots
"The method we give is to coat inorganic fluorescent nanoparticles and drugs together and use fluorescence imaging to trace drug metabolism," Sun Zaicheng said.
The carbon dots synthesized by Sun Zaicheng's research group have excellent luminescent properties, good biocompatibility, low toxicity, strong hydrophilicity and easy surface functionalization. This is precisely the material that Jing Yubin's research group is looking for. So the Sun Zaicheng team brought the materials to Changchun Yinghua Institute, and cooperated with Xie Zhigang and Jing Yubin's research group to carry out bio-imaging and tumor treatment experiments.
According to Sun Zaicheng, the use of carbon dots as a fluorescent agent in combination with other functional groups can give more functions and make it have a wide range of potential applications in biological applications.
The team synthesized N-doped fluorescent carbon dots by simply adjusting the reaction solvent, which can produce blue, green and yellow light close to monochromatic under ultraviolet, blue and green excitation, making it under long-wavelength excitation light. It emits visible fluorescence that aids in bioimaging and further applications.
Sun Zaicheng added: "In order to further move the luminescence of the carbon dots in the long wavelength direction, we have synthesized the sulfur and nitrogen co-doped fluorescent carbon dots by a bottom-up method, and obtained blue, green and red colors. Fluorescent carbon dots."
Developing smart nano drugs
The carbon dots developed by Sun Zaicheng's team have excellent multi-color luminescence properties, which help to achieve cell imaging in vitro and fluorescence imaging of deeper tissues in vivo. In addition, they introduce Amino Acid molecules during the synthesis of carbon dots, which gives these carbon dots high selectivity to brain tumor cells without the need for additional introduction of targeting molecules.
In 2014, the two teams collaborated to combine the diagnostic imaging function of the carbon dots with the therapeutic drug molecule oxaliplatin to further achieve controlled release of the drug and reduce normal tissues and cells. Toxicity.
At the same time, they also cooperated with the Gaohuile research group. From the in vivo imaging data of mice, the carbon spots injected through the tail vein can quickly cross the blood-brain barrier within 5 minutes and selectively enrich in the brain. Within the glioma, there is very little distribution in normal brain tissue, which fully confirms the targeted imaging function of this carbon point on glioma.
“Changchun Yinghua Institute conducts biological experiments, we are responsible for synthetic materials, and Sichuan University observes brain tumor imaging.†Sun Zaicheng said, “Our three units are currently cooperating smoothly in the research stage, and the next step is to carry out integration work.â€
Currently, the team is collaborating on building intelligent nanomedicine with multiple functions of targeting, imaging and treatment. "The market prospects for anti-cancer drugs are huge, but our strength is relatively limited. Therefore, we hope that a pharmaceutical company can participate in research work to integrate our existing work and develop it into a kind of targeted, Imaging and treatment as one of the personalized diagnosis and treatment drugs." Sun Zaicheng said.