title: Interaction between fluorescein isothiocyanate and carbon dots: Inner filter effect and fluorescence resonance energy transfer.
abstract: Carbon dots (CDs) have been widely used for the preparation of multifunctional probes by conjugation with organic fluorescent dyes. However, the effect of organic fluorescent dyes on CDs still remains poorly understood. Herein, the effect of fluorescein isothiocyanate (FITC) on CDs was explored by spectroscopic techniques at pH5.1, 7.0 and 9.0. The fluorescent intensity of CDs was found to be quenched gradually after mixing directly with different concentrations of FITC, but the fluorescent lifetime of CDs remained unchanged. According to the results of UV-vis absorption spectra and fluorescent lifetime measurements, a pH-dependent inner filter effect (IFE) between CDs and FITC was proposed. However, the fluorescent lifetime of CDs deceased after their conjugation with FITC, implying the fluorescence resonance energy transfer (FRET) between CDs and FITC. This study has revealed two different effects of FITC on CDs with varying pH values and provided useful theoretical guidelines for further research on the interaction between other nanoparticles and fluorophores.
authors: College of Science, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, PR China.
authors: Huabing
authors: H
authors: Liu
authors: College of Science, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, PR China.
authors: Chaoyong
authors: C
authors: Xu
authors: College of Science, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, PR China.
authors: Yanli
authors: Y
authors: Bai
authors: College of Science, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, PR China.
authors: Lin
authors: L
authors: Liu
authors: College of Science, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, PR China.
authors: Dongmei
authors: D
authors: Liao
authors: College of Science, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, PR China. Electronic address: liangjg@mail.hzau.edu.cn.
authors: Jiangong
authors: J
authors: Liang
authors: College of Science, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, PR China. Electronic address: liulingzhi_1981@mail.hzau.edu.cn.
authors: Lingzhi
authors: L
authors: Liu
authors: College of Science, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, PR China.
authors: Heyou
authors: H
authors: Han
keywords: Carbon dots; Fluorescein isothiocyanate; Fluorescence resonance energy transfer; Inner filter effect