Enhanced photoluminescence and characterization of multicolor carbon dots using plant soot as a carbon source.
Carbon dots (C-dots) are a class of novel fluorescent nanomaterials, which have drawn great attention for their potential applications in bio-nanotechnology. Multicolor C-dots have been synthesized by chemical nitric acid oxidation using the reproducible plant soot as raw material. TEM analysis reveals that the prepared C-dots have an average size of 3.1 nm. The C-dots are well dispersed in aqueous solution and are strongly fluorescent under the irradiation of ultra-violet light. X-ray photoelectron spectroscopy characterization demonstrates that the O/C atomic ratio for C-dots change to from 0.207 to 0.436 due to the chemical oxidation process. The photo bleaching experiment reveals that the C-dots show excellent photostability as compared with the conventional organic dyes, fluorescein and rhodamine B. The fluorescence intensity of the C-dots did not change significantly in the pH range of 3-10. To further enhance the fluorescence quantum yield, the C-dots were surface modified with four types of passivation ligands, 4,7,10-trioxa-1,13-tridecanediamine (TTDDA), poly-L-lysine (PLL), cysteine and chitosan and the fluorescence quantum yields of the TTDDA, PLL, cysteine and chitosan passivated C-dots were improved 1.53-, 5.94-, 2.00- and 3.68-fold, respectively. Fourier-transform infrared (FTIR) spectra were employed to characterize the surface groups of the C-dots. The bio-application of the C-dots as fluorescent bio-probes was evaluated in cell imaging and ex vivo fish imaging, which suggests that the C-dots may have potential applications in biolabeling and bioimaging.
Laboratory of Biomedical Material Engineering, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, PR China. Electronic address: mqtan@dicp.ac.cn.
Mingqian
M
Tan
Lingxin
L
Zhang
Rong
R
Tang
Xiaojie
X
Song
Yimin
Y
Li
Hao
H
Wu
Yanfang
Y
Wang
Guojun
G
Lv
Wanfa
W
Liu
Xiaojun
X
Ma
D000818:Animals; D002244:Carbon / Q000737:chemistry*; D048271:Chitosan / Q000737:chemistry; D003545:Cysteine / Q000737:chemistry; D003959:Diamines / Q000737:chemistry; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D008163:Luminescent Measurements; D008856:Microscopy, Fluorescence; D057054:Molecular Imaging / Q000379:methods*; D017942:Nitric Acid / Q000737:chemistry; D010084:Oxidation-Reduction; D010316:Particle Size; D017785:Photons; D011036:Poecilia; D011107:Polylysine / Q000737:chemistry; D045663:Quantum Dots; D053260:Soot / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
D003959:Diamines; D005456:Fluorescent Dyes; D053260:Soot; D011107:Polylysine; D017942:Nitric Acid; D002244:Carbon; D048271:Chitosan; D003545:Cysteine
Biolabeling; Carbon dots; Fluorescent probes; Plant soot