物理化学学报 >> 2019, Vol. 35 >> Issue (11): 1267-1275.doi: 10.3866/PKU.WHXB201812053

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由蚕砂制备的碳量子点在不同激发、pH、金属离子、温度及极性环境下的荧光性质研究

黄彦捷1,*(),连超2,周瑾艳1,黄梓宸1,康晓红2,黄振宇1,李小菁1,陈玲1,关妍3,*()   

  1. 1 广东省现代几何与力学计量技术重点实验室,广东省计量科学研究院,广州 510405
    2 北京交通大学理学院化学系,北京 100044
    3 北京大学化学与分子工程学院,北京 100871
  • 收稿日期:2018-12-30 录用日期:2019-02-25 发布日期:2019-03-04
  • 通讯作者: 黄彦捷,关妍 E-mail:yjhuang@scm.com.cn;yanguan@pku.edu.cn
  • 基金资助:
    国家自然科学基金(21204001),广东省科技厅项目(2016A040403072)及广东省质量技术监督局科技项目(2018ZJ02, 2017PJ04)资助

Investigation of Excitation-, pH-, Metal Ion-, Temperature-, and Polarity-Dependent Fluorescence of Carbon Dots Derived from Silkworm Excrement

Yanjie HUANG1,*(),Chao LIAN2,Jinyan ZHOU1,Zichen HUANG1,Xiaohong KANG2,Zhenyu HUANG1,Xiaojing LI1,Lin CHEN1,Yan GUAN3,*()   

  1. 1 Guangdong Provincial Key Laboratory of Modern Geometric and Mechanical Metrology Technology, Guangdong Provincial Institute of Metrology, Guangzhou 510405, P. R. China
    2 Department of Chemistry, School of Science, Beijing Jiaotong University, Beijing 100044, P. R. China
    3 College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
  • Received:2018-12-30 Accepted:2019-02-25 Published:2019-03-04
  • Contact: Yanjie HUANG,Yan GUAN E-mail:yjhuang@scm.com.cn;yanguan@pku.edu.cn
  • Supported by:
    国家自然科学基金(21204001),广东省科技厅项目(2016A040403072)及广东省质量技术监督局科技项目(2018ZJ02, 2017PJ04)资助

摘要:

碳量子点作为一种新兴的荧光纳米材料,具有粒径分布均匀、光稳定性好、激发-发射波长可调控、表面可修饰等优良的性质,兼具低毒性、生物相容性好等优点,在分析检测和生物成像等领域展现出广阔的应用前景。而蚕砂是家蚕的干燥粪便,简单易得。利用蚕砂作为碳量子点制备原料,采用微波合成的方法制备得到了一种平均水合粒径为4.86 nm,含氮、硫修饰的碳量子点材料,可作为针对激发波长、pH、金属离子浓度、温度及溶剂极性的变化有着显著响应特性的碳量子点型荧光探针。该探针的荧光最大发射波长随激发波长或pH的增加而红移;荧光强度随温度或pH的降低而增加;随着金属离子,特别是铜离子的加入而逐渐降低,并随着EDTA络离子的加入而逐渐回复。在多种溶剂中该探针均具有较好的溶解度,当换用不同极性的溶剂时,随着溶剂极性的增加荧光发射波长逐渐红移。荧光性质随多重环境参数变化为该碳量子点在未来的生物检测和成像领域提供了广阔的应用前景。

关键词: 碳量子点, 蚕砂, 纳米材料, 荧光, 传感

Abstract:

As a new fluorescent nanomaterial, carbon dots (CDs) have many advantages, such as uniform particle size distribution, good light stability, adjustable excitation-emission wavelength, and surface modification. Moreover, one of the fascinating characters of CDs is that they are considered to be low-toxic and eco-friendly alternatives in chemical and biological analyses. They have exhibited broad application prospects in the fields of analysis, detection, and bioimaging. Silkworm excrement is dried and easily available. A large number of hydroxyl and carboxyl compounds in silkworm excrement can be used as ideal starting materials for the preparation of CDs. Also, compounds containing nitrogen and sulfur in silkworm excrement can be used as nitrogen and sulfur sources; thus, when used in the preparation of CDs, silkworm excrement can impart many more unique properties to CDs. Nitrogen-containing CDs prepared by microwave synthesis have an average hydration diameter of 4.86 nm. Elemental analysis data show that the prepared CDs contained 59.84% carbon, 5.46% nitrogen, and 2.32% sulfur. XPS spectra reveals sulfur (2p), carbon (1s), nitrogen (1s), and oxygen (1s) in CDs. FTIR data demonstrate that the prepared CDs may contain hydroxyl, amino, carbonyl, sulfonic, ester, and ether functional groups as well as carbon-nitrogen structures. The XRD pattern of the CDs has a broader peak of the amorphous carbon phase at approximately 2θ = 24.6°, and only D bands (at ~1400 cm-1) can be obviously detected in the Raman spectra of CDs. The intensity of fluorescence emission peak of CDs increases first and then decreases with the increase in excitation wavelength. The maximum intensity of fluorescence emission shifts gradually with the red shift of the excitation wavelength, and the relationship between excitation and emission wavelengths is exponential. In the pH ranging from 2.18 to 10.24, the fluorescence emission intensity of CDs decreases gradually with the increase in pH, and the maximum fluorescence emission intensity shifts gradually with the increase in pH. There is a linear relationship between pH and maximum emission wavelength. The fluorescence emission intensity of CDs decreases gradually with the increase in metal ion concentration. Under neutral conditions, CDs can selectively detect Cu2+. Under acidic conditions, CDs can detect Cu2+, Fe3+, Al3+, Ni2+, and Fe2+ separately without interference from other ions. There is a Stern-Volmer linear relationship between metal ion concentration and fluorescence intensity. The intensity of the fluorescence emission peak of CDs decreases with the increase in temperature, which may be due to the non-radiative transition process caused by molecular thermal motion. There is a linear relationship between temperature and fluorescence intensity. The maximum fluorescence emission intensity of CDs gradually shifts with the increase in polarity of the dispersed solvents. There is a linear relationship between fluorescence intensity and empirical constant ET of solvent polarity. Compared with the reported CDs prepared from natural products, silkworm-excrement-based CDs have abundant surface groups although they do not have an obvious crystal structure, which makes them have excellent response to various environmental factors (pH, temperature, ion concentration, temperature, solvent polarity, etc.) in a wide range. Above all, the fluorescence property changes with multiple environmental parameters will facilitate a broad application of silkworm-excrement-based CDs in biodetection and imaging.

Key words: Carbon dots, Silkworm excrement, Nano-materials, Fluorescence, Sensing

MSC2000: 

  • O644.17