Research ArticlePolyethyleneimine-functionalized carbon dots as a fluorescent probe for doxorubicin hydrochloride by an inner filter effect
Introduction
Doxorubincin hydrochloride (DOX) is an anthraquinone-based anti-tumor drug, which is widely used in clinical medicine to treat breast cancer, lymphoma, hematological malignancies, lung cancer and other tumor cells [1]. The imbalance of DOX concentration in biological fluids can cause many diseases, including nausea, hair loss, liver damage, vomiting, abdominal pain and heart failure. Therefore, real-time monitoring of DOX concentration is necessary [2]. At present, many efforts are devoted to the development of analytical techniques for the detection of DOX, including high-performance liquid chromatography (HPLC) [3,4], electrochemical methods [5,6], mass spectrometry [7], chemiluminescenc [8] and capillary electrochromatography [9]. Among the diversiform analytical means available, fluorescence spectroscopy has the advantages of facile operation procedures, high sensitivity and fast responses over other methods [10,11]. Nevertheless, it is still a challenging task to design a fluorescent sensor with a perfect combination of low-cost, easy-to-synthesize, high-stability and selectivity to determine DOX [12,13].
As the newest member of nanomaterials, fluorescent carbon quantum dots (CDs) with a size less than 10 nm have attracted widespread attention in recent years due to their unique optical and electrochemical properties [14]. Compared with traditional organic fluorescence dyes, CDs have the advantages of excellent photo/chemical-stability, good biocompatibility, robust chemical inertness and low toxicity, which makes possible many new techniques for bioanalysis and bioimaging fileds [15,16]. More importantly, its surface can be easily incorporated hydrophilic functional groups through various surface modifications such as ethylenediamine, polyethylene glycol (PEG) and polyethyleneimine (PEI) to broaden its application range [17,18]. At present, CDs have been applied in the determination of molecular substances, ions and pH [[19], [20], [21], [22], [23], [24]]. The sensing mechanisms of CDs-based fluorescent sensor incorporate fluorescence resonance energy transfer (FRET), intramolecular charge transfer (ICT), twisted intramolecular charge transfer (TICT), photo induced electron transfer (PET) and inner filter effect (IFE) etc [25]. In 1991, Gabor and Walt reported IFE for the first time, involving the participation of two chemical moieties, in which excitation light and/or emission light are absorbed by an absorber [26]. In the detection system, the linking between the absorbers and the fluorophores is no longer required, making the IFE-based fluorescent probe relatively simple and flexible [27]. Using IFE can convert the absorption value of the nanoprobe into a fluorescent signal, constructing a simple sensing method, which effectively avoids the complicated modification or construction of the nanoprobe and improves the sensitivity and selectivity of sensing. Hence, it has appeared as an effective strategy for the construction of fresh sensor platforms [[28], [29], [30], [31]].
In this study, we successfully demonstrated a simple “synthesis-modification integration” means for the fabrication of PEI-functionalized CDs (PEI-CDs), shunning uncontrollable and intricate surface modification. By exploiting the complementary overlap between the emission band of PEI-CDs and the absorption band of DOX, an IFE-based DOX fluorescence sensor was constructed, which is absolutely different from the previously reported DOX assays. Such sensing technology would greatly decrease the testing cost, simplify testing procedure and exhibit high photostability. To evaluate the reliability of the sensing strategy, we successfully applied it to detect the concentration of DOX in urine samples and satisfactory results were obtained. At present, there are no reports about PEI-CDs as fluorophores to detect DOX based on IFE.
Section snippets
Materials
The relevant chemicals and materials used are listed in the Supplementary Materials, all reagents are used directly without further purification.
Characterization
Fluorescence performances were performed using an F-7000 fluorescence spectrometer Record (Hitachi, Japan) equipped with a quartz cell (1.0 cm × 1.0 cm) and a 150 W Xenon light source. The Zeta potentials were measured using a Nano-ZS analyzer (Brookhaven Instruments Ltd, US). Powder X-ray diffraction (XRD) patterns were characterized by a Rigaku D/MAX
Characterization of the PEI-CDs
In earlier research, CDs are normally defined as small carbons nanoparticles with all kinds of surface passivation forms, among which the surface functionalization or modification with polymeride or organic molecules is believed to be effective for brightening fluorescence emissions [35]. Although the exhaustive mechanism of carbon dots formation is still unclear, it could be deduced that CA is first decomposed to produce soluble molecules in a high temperature environment, then these soluble
Conclusions
In a word, we have systematically studied the detection mechanism for the quenching of PEI-CDs by DOX, and established a new IFE-based system for sensing DOX. The developed detection method was applied to the determination of DOX in urine samples, and satisfactory results were gained. The most remarkable advantage of this assay method is that it can avoid time-consuming and complex chemical modifications. Therefore, we believe that the developed IFE-based fluorescence sensing means will provide
CRediT authorship contribution statement
Min Yang: Data curation, Writing - original draft, Writing - review & editing, Data processing, Manuscript writing. Yujia Yan: Material preparation and characterization. Enzhou Liu: Funding acquisition. Xiaoyun Hu: Funding acquisition. Hong Hao: Manuscript correction. Jun Fan: Funding acquisition.
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
This work was supported by the National Natural Science Foundation of China (Nos. 22078261 and 11974276), the Project funded by China Postdoctoral Science Foundation (No. 2016M600809).
References (51)
- et al.
Simultaneous determination of doxorubicin and its dipeptide prodrug in mice plasma by HPLC with fluorescence detection
J. Pharm. Anal.
(2016) - et al.
Gold nanocluster-based fluorescence turn-off probe for sensing of doxorubicin by photoinduced electron transfer
Sensor. Actuator. B Chem.
(2019) - et al.
Application of bioactive cyclic oligosaccharide on the detection of doxorubicin hydrochloride in unprocessed human plasma sample: a new platform towards efficient chemotherapy
Microchem. J.
(2019) - et al.
Internal standard method for the measurement of doxorubicin and daunorubicin by capillary electrophoresis with in-column double opticalfiber LED-induced fluorescence detection
J. Pharmaceut. Biomed. Anal.
(2016) - et al.
Efficient inner filter effect sensors based on CdTeS quantum dots and Ag nanoparticles for sensitive detection of L-cysteine
J. Alloys Compd.
(2019) - et al.
Nitrogen and chlorine dual-doped carbon nanodots for determination of curcumin in food matrix via inner filter effect
Food Chem.
(2019) - et al.
The carbon dots as colorimetric and fluorescent dual-readout probe for 2-nitrophenol and 4-nitrophenol detection
J. Lumin.
(2019) - et al.
Hydrothermal treatment of red lentils for the synthesis of fluorescent carbon quantum dots and its application for sensing Fe3+
Opt. Mater.
(2019) - et al.
Nitrogen-sulfur co-doped pH-insensitive fluorescent carbon dots for high sensitive and selective hypochlorite detection
Spectrochim. Acta
(2020) - et al.
A strong blue fluorescent nanoprobe for highly sensitive and selective detection of mercury(II) based on sulfur doped carbon quantum dots
Mater. Chem. Phys.
(2019)