Coumarin-Modified Graphene Quantum Dots as a Sensing Platform for Multicomponent Detection and Its Applications in Fruits and Living Cells

Abstract

In this work, coumarin derivatives (C) are used to enhance the fluorescence of graphene quantum dots (GQDs) by covalently linking the carboxyl groups on the edge of the GQD sheet. The as-synthesized coumarin-modified graphene quantum dots (C-GQDs) have a uniform particle size with an average diameter of 3.6 nm. Simultaneously, the C-GQDs have strong fluorescence emission, excellent photostability, and high fluorescence quantum yield. C-GQDs and CN– can form a C-GQDs+CN– system due to deprotonation and/or intermolecular interactions. The introduced hydroquinone (HQ) is oxidized to benzoquinone (BQ), and the interaction between BQ and the C-GQDs+CN– system could lead to fluorescence enhancement of C-GQDs. Meanwhile, the redox reaction between BQ and ascorbic acid (AA) can be used for quantitative detection of AA with CN– and HQ being used as substrates. Based on the above mechanism, C-GQDs are developed as a multicomponent detection and sensing platform, and the detection limits for CN–, HQ, and AA were 4.7, 2.2, and 2.2 nM, respectively. More importantly, satisfactory results were obtained when the platform was used to detect CN–, HQ, and AA in living cells and fresh fruits.

Graphene and its derivatives: understanding the main chemical and medicinal chemistry roles for biomedical applications

“…Its advantages, such as low toxicity, water-solubility, high biocompatibility, and ease of functionalization, are crucial for biomedical applications. They have also attracted growing interests in catalysis, bioimage, and flowering detection [ 82 ].…”

Outstanding Graphene Quantum Dots from Carbon Source for Biomedical and Corrosion Inhibition Applications: A Review

“…The glucose sensor is the general system of detection that uses different GQDs containing polar -COOH and -OH surface recoveries and cationic corrosive bipyridinium (BBV) salt to operate under natural conditions [110,111]. GQDs in this sensor provided as fluorescent components and BBV act as a rapid glucose receptor and good fluorescence quencher [112].…”

Recent progress on graphene quantum dots‐based fluorescence sensors for food safety and quality assessment applications

“…The proposed sensing assay was successfully used in detecting NO 2− in pickled foods, and it exhibited a detection range of 0.3 µmol/L. A multicomponent system based on the coumarin-modified GQDs OFF−ON−OFF fluorescent probe was constructed for the simultaneous detection of CN − , hydroquinone, and ascorbic acid (AA) in living cells and fresh fruits (Yu et al, 2020). The detection mechanism follows a simple OFF−ON−OFF process (Figure 4[i]).…”

“…Interestingly, the sensing probe showed satisfactory results in living cells and fresh fruits for CN − , HQ, and AA. A simple GDQs-based fluorescence sensing probe was reported for the selective detection of AA in the presence of copper ions (Yu et al, 2020).…”

“…Wang, Zheng, et al (2015) demonstrated the fluorescence sensing ability of AuNP-PEP@GQDs toward CN − in cassava by directly soaking the sliced cassava tissue (0.2 mm thick) in the aqueous dispersion of the GQDs. Yu et al utilized coumarin-modified GQDs to detect AA in fruit samples (Yu et al, 2020). The real samples were prepared by homogenizing fresh fruits using a commercial blender.…”