Nitrogen-doped graphene quantum dots-based fluorescent probe for the sensitive turn-on detection of glutathione and its cellular imaging

Abstract

Fluorescence turn-on sensor based on nitrogen-doped graphene quantum dots can be used for glutathione detection in living cells.

Ultrafast ammonia-driven, microwave-assisted synthesis of nitrogen-doped graphene quantum dots and their optical properties

“…For example, NGQDs have been synthesized using glycine [21], glucose [14], or citric acid [22][23][24][25][26][27] as carbon source or using ammonia [14,22,23], dicyandiamide [24,25], tris(hydroxymethyl) aminomethane [26], 3,4-dihydroxy-L-phenylalanine [27], or glycine [21] as nitrogen source through hydrothermal reaction [14,[21][22][23][24][25] or high-temperature treatment [26,27]. Such one-step methods usually require high temperature and/ or high pressure.…”

A novel electrochemiluminescence sensor for the detection of nitroaniline based on the nitrogen-doped graphene quantum dots

“…For example, the N atom, having a Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/bios comparable atomic size and five valence electrons for bonding with carbon atoms, has been widely used for doping of GQDs. After nitrogen-doping, the PL quantum yields of N-GQDs can be improved largely (Tam et al, 2014;Ju et al, 2014). N-GQDs with more active sites are ideal luminescence labels and promising catalytic roles.…”

Recent Advances in Graphene Quantum Dots as Bioimaging Probes

“…Because of their low cost and easy availability, natural resources such as coffee grounds [100], cow milk [101,102] and neem leaf extract [103] are used to fabricate fluorescent GQDs by hydrothermal or microwave irradiation strategies. Low-cost organic compounds, such as citric acid [104][105][106][107][108][109][110][111][112], acetylacetone [113], glucose [114][115][116][117], fructose [118], ethylene diamine tetraacetic acid (EDTA) [119], adenosine 5′-triphosphate disodium salt (ATP) [119,120], glutamic acid [121] and humic acid [122], are also the most commonly used starting materials for the synthesis of GQDs either via pyrolysis or microwave irradiation or hydrothermal/solvothermal treatment. Moreover, due to their similarity in structure, polycyclic aromatic hydrocarbons are generally regarded as nanoscaled fragments of graphene, which gives them great promise for preparing monodispersed GQDs with precisely tailored structure, morphology and size.…”

“…Furthermore, doping and/or surface passivation are effective methods to modulate the electronic density of bulk semiconductor materials and to tune their optical and electrical properties. So, dicyandiamide (DCD) [105,106,112], ammonium hydroxide [77,89,91,93,114,115,[129][130][131][132], diethylenetriamine (DETA) [133], urea [107], ethylenediamine (EDA) [111], dimethylformamide (DMF) [38,134] and hydrazine hydrate [123] are chosen as the nitrogen source for doping or modifying GQDs to synthesize nitrogen-functionalized GQDs, while 1,4-phenylene bis(boronic acid) [65], boron oxide (B 2 O 3 ) [76] and Na 2 B 4 O 7 [135] are employed as boron sources to prepare boron-functionalized GQDs. Also, nitrogen and sulfur co-functionalized GQDs are successfully obtained using nitrogen and sulfur containing compounds of 1-methyl-1-propylpiperidinium bis(trifluoromethylsulfonyl) imide [68], polythiophene [136] and thiourea [110].…”

“…One of the key issues that is a prerequisite for these biomedical applications of GQDs is their cytotoxicity. The cytotoxicity of GQDs is usually evaluated through the 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) cell proliferation test [112,129], and a variety of cells have been utilized for testing and evaluating. Of them, Kumar et al [147] have upscaled synthesized GQDs via a top-down chemical oxidation etching method.…”