Investigation effect of cytotoxicity of carbon quantum dots and targeted carbon quantum dots
Investigation effect of cytotoxicity of carbon quantum dots and targeted carbon quantum dots
zahra Shadman,1,*Mohamad Mahani,2Faeze Khakbaz,3Mehdi Yousefian,4
1. Department of Chemistry, Faculty of Chemistry and Chemical Engineering, Graduate University of Advanced Technology, Kerman, Iran. 2. Department of Chemistry, Faculty of Chemistry and Chemical Engineering, Graduate University of Advanced Technology, Kerman, Iran. 3. Department of Chemistry, Shahid Bahonar University of Kerman, Kerman, Iran 4. Department of Chemistry, Faculty of Chemistry and Chemical Engineering, Graduate University of Advanced Technology, Kerman, Iran.
Introduction: Carbon quantum dots can be prepared from precursors such as: glucose [1, 2], graphite [3, 4], carbon nanotubes [5], citrate [6] and so on. Carbon quantum dots have unique properties such as good conductivity, high chemical stability, low toxicity, good biocompatibility, broadband light absorption, high emission photoluminescence and optical properties, easy synthesis and low cost on a large scale [7]. The dimensions of the carbon quantum dots synthesized by hydrothermal method are 1.5-4.5 nm, which are used in bioimaging due to their low toxicity and ability to due to their photostability light. In 2018, Kong et al. Synthesized carbon dots by hydrothermal method using citric acid and ethylene diamine and examined its effect on MCF_7 and L_929 cancer cells in breast cancer. The synthesized carbon dots had a large capacity to load doxorubicin and also had a better antitumor effect in MCF_7 cancer cells [7].
Methods: In this study, carbon quantum dots were synthesized by hydrothermal method. First, citric acid and urea dissolved in distilled water and transferred to an autoclave, then incubated for 4 hours at 160 ° C in the oven. To prepare the modified carbon quantum dots, folic acid dissolved in phosphate buffer, then 200 μl of EDC solution and 200 μl of NHS solution was added to it, and after stirring for 30 minutes, and was added to it 1 ml of dilute solution of carbon quantum dots; and stirred for 24 h. Finally the carbon quantum dots-folic acid was obtained. Similarly, carbon quantum dots-hyaluronic acid and carbon quantum dots-mannose were synthesized.
Results: The particle size of the synthesized carbon quantum dots was 2 nm. Dilute solutions were prepared from carbon quantum dots, carbon quantum dots-folic acid, carbon quantum dots-hyaluronic acid and carbon quantum dots-mannose, and their absorption spectra were recorded; In the absorption spectra of carbon quantum dots and targeted carbon quantum dots, two peaks related to π - π * transitions and n-π * transitions were observed at 240 and 345 nm, respectively. Excitation spectra of carbon quantum dots at the emission wavelength of 440 nm, which shows that the maximum emission intensity at the excitation wavelength is 345 nm. Binding of doxorubicin to carbon quantum dots and targeted carbon quantum dots was performed with a molar ratio of 4:1, and the highest binding between drug and targeted carbon quantum dots with hyaluronic acid was 50%. Drug release was investigated in a neutral and acidic environment, and most drug release (80%) was performed from targeted carbon quantum dots-hyaluronic acid in acidic environment. Cytotoxicity of carbon quantum dots was investigated by MTT assay. carbon quantum dots and targeted carbon quantum dots are non-toxic at all concentrations and do not cause cell death alone. Doxorubicin-bound carbon quantum dots also resulted in higher cell death at high concentrations, and 38.46% of cancer cells survived at the highest concentrations. At the highest concentrations of target quantum dots with folic acid, target quantum dots with hyaluronic acid and target quantum dots with mannose that bind to doxorubicin, 44.42%, 42.3% and 35.25% of cancer cells survived, respectively.
Conclusion: Targeting carbon quantum dots causes specific binding to receptors on the surface of cancer cells. Carbon quantum dots and targeted carbon quantum dots alone are non-toxic, but if the drug binds to them, they can cause death to cancer cell.