title: Microwave assisted green synthesis of fluorescent N-doped carbon dots: Cytotoxicity and bio-imaging applications.
abstract: A fast and facile microwave approach for the synthesis of fluorescent nitrogen-doped carbon dots (N-CDs) is reported. The N-CDs were hydrothermally synthesized using l-ascorbic acid (AA) and β-alanine (BA) as the carbon precursor and the nitrogen dopant, respectively. The morphology of synthesized N-CDs was characterized by high resolution transmission electron microscopy (HR-TEM) and the elemental composition was analyzed using elemental mapping method. The crystallinity and graphitation of N-CDs were examined by X-ray diffraction (XRD) and Raman spectroscopy. The doping of nitrogen over the carbon dots (CDs) was revealed by attenuated total reflection conjunction with Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photo electron spectroscopy (XPS). The optical properties of synthesized N-CDs were examined by UV-Visible (UV-Vis) and fluorescence spectroscopy. The synthesized N-CDs emit strong blue fluorescence at 401nm under excitation of 325nm. The excitation dependent emission property of synthesized N-CDs was exposed from fluorescence results. The quantum yield of synthesized N-CDs is about 14% against the reference quinine sulfate. The cytotoxicity of synthesized N-CDs on Madin-Darby Canine Kidney (MDCK) and HeLa cells were evaluated through Cell Counting Kit-8 (CCK-8) cytotoxicity assay. The results implied that the fluorescent N-CDs showed less cytotoxicity, further which was successfully applied as a staining probe for the confocal imaging of MDCK and HeLa cells.
authors.affiliation: School of Chemical Engineering, Yeungnam University, Gyeongsan 712-749, Republic of Korea.
authors.forename: Thomas Nesakumar Jebakumar Immanuel
authors.initials: TN
authors.lastname: Edison
authors.affiliation: School of Chemical Engineering, Yeungnam University, Gyeongsan 712-749, Republic of Korea.
authors.forename: Raji
authors.initials: R
authors.lastname: Atchudan
authors.affiliation: Department of Chemistry, Gandhigram Rural Institute Deemed University, Gandhigram 624 302, Dindigul District, Tamil Nadu, India. Electronic address: mgsethu@gmail.com.
authors.forename: Mathur Gopalakrishnan
authors.initials: MG
authors.lastname: Sethuraman
authors.affiliation: School of Chemical Engineering, Yeungnam University, Gyeongsan 712-749, Republic of Korea.
authors.forename: Jae-Jin
authors.initials: JJ
authors.lastname: Shim
authors.affiliation: School of Chemical Engineering, Yeungnam University, Gyeongsan 712-749, Republic of Korea. Electronic address: yrlee@yu.ac.kr.
authors.forename: Yong Rok
authors.initials: YR
authors.lastname: Lee
mesh_terms: D000818:Animals; D002244:Carbon / Q000737:chemistry*; D002470:Cell Survival / Q000187:drug effects; D004285:Dogs; D006367:HeLa Cells; D006801:Humans; D061985:Madin Darby Canine Kidney Cells; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D008872:Microwaves; D009584:Nitrogen / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D045663:Quantum Dots / Q000737:chemistry* / Q000633:toxicity / Q000648:ultrastructure; D013050:Spectrometry, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D014961:X-Ray Diffraction
chemical_list: D002244:Carbon; D009584:Nitrogen
keywords: Carbonization; Cell imaging; Cytotoxicity; Fluorescence; Microwave synthesis; N-doped carbon dots