Synthesis and spectroscopic studies of functionalized graphene quantum dots with diverse fluorescence characteristics

Chhabra, Varun A.; Kaur, Rajnish; Kumar, Naveen; Deep, Akash; Rajesh, Changanamkandath; Kim, Ki‐Hyun

doi:10.1039/c8ra01148f

Cited by 101 publications

(51 citation statements)

References 62 publications

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“…8(a)) yielded a higher I D /I G ratio compared with that of the GOQDs in the fibre. The results obtained are consistent with the report by Chhabra et al (2018).…”

Section: Raman Spectroscopy Analysissupporting

confidence: 93%

“…The particle sizes obtained from DLS analysis was found to be 4.1 nm, which were not very different from the particle sizes obtained using TEM histogram. The particle sizes determined suggest that the emission properties of the GOQDs are due to quantum size effect or recombination of holes and electrons in the quantumsized nanoparticles (Chhabra et al 2018).…”

Section: Morphology and Particle Size Analysis Of The Goqdsmentioning

confidence: 98%

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Poly (ether) sulfone electrospun nanofibrous membranes embedded with graphene oxide quantum dots with antimicrobial activity

Tshangana

Muleja

Nxumalo

et al. 2020

Environ Sci Pollut Res

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This work describes the development of novel electrospun nanofibrous membranes (ENMs) prepared by embedding graphene oxide quantum dots (GOQDs) into poly (ether) sulfone (PES). FTIR and Raman spectroscopy confirmed the successful incorporation of the GOQDs into the PES membranes. The optimal electrospinning polymer concentration that showed no defects or bead formation was at 26 wt% of the PES polymer. Spectroscopy, microscopy and contact angle were some of the techniques used to characterize the ENMs. SEM images showed smooth and unbranched ENMs. The average diameter upon incorporation of the GOQDs was determined to be 2.45 μm. XRD revealed that the GOQDs were structurally close to graphite with an interlaying space of 0.36 nm. The antimicrobial effect of the GOQDs-PES electrospun nanofibrous membranes was assessed against three bacterial strains (Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Bacillus cereus (B. cereus)) using the disc diffusion method. The electrospun nanofibres containing 10 wt% of GOQDs showed the most active antimicrobial activity against all three bacterial strains tested. The zones of inhibition ranged from 9 to 40 mm. The minimum inhibitory concentration (MIC) was determined to be 0.5 mg/mL, 0.3 mg/mL and 0.2 mg/mL for E. coli, B. cereus and S. aureus, respectively. The results demonstrated that incorporating GOQDs in the PES nanofibre gives rise to new antimicrobial properties, and as a result, the GOQDs-PES nanofibrous membrane can be used in antimicrobial applications such as water treatment.

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“…8(a)) yielded a higher I D /I G ratio compared with that of the GOQDs in the fibre. The results obtained are consistent with the report by Chhabra et al (2018).…”

Section: Raman Spectroscopy Analysissupporting

confidence: 93%

Section: Morphology and Particle Size Analysis Of The Goqdsmentioning

confidence: 98%

Poly (ether) sulfone electrospun nanofibrous membranes embedded with graphene oxide quantum dots with antimicrobial activity

Tshangana

Muleja

Nxumalo

et al. 2020

Environ Sci Pollut Res

View full text Add to dashboard Cite

show abstract

“…The IR spectra of NH 2 -GQDs ( Figure 1 D) showed a band around ~3200 cm −1 that was associated with the N–H stretching vibration of amine groups [ 23 ]. The band at 1656 cm −1 corresponded to amide I (the –C=O stretch) and at 1536 cm −1 was assigned to amide II (the –C–N stretch and –C–N–H deformation) [ 24 ].…”

Section: Resultsmentioning

confidence: 99%

Graphene Quantum Dots’ Surface Chemistry Modulates the Sensitivity of Glioblastoma Cells to Chemotherapeutics

Perini

Palmieri

Ciasca

et al. 2020

IJMS

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Recent evidence has shown that graphene quantum dots (GQDs) are capable of crossing the blood–brain barrier, the barrier that reduces cancer therapy efficacy. Here, we tested three alternative GQDs’ surface chemistries on two neural lineages (glioblastoma cells and mouse cortical neurons). We showed that surface chemistry modulates GQDs’ biocompatibility. When used in combination with the chemotherapeutic drug doxorubicin, GDQs exerted a synergistic effect on tumor cells, but not on neurons. This appears to be mediated by the modification of membrane permeability induced by the surface of GQDs. Our findings highlight that GQDs can be adopted as a suitable delivery and therapeutic strategy for the treatment of glioblastoma, by both directly destabilizing the cell membrane and indirectly increasing the efficacy of chemotherapeutic drugs.

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“…Moreover, Chhabra et al. also reported the preparation of indigo‐emitting GQDs by citric acid pyrolysis . The reports on blue emission of GQDs are more common and have been observed for GQDs obtained from graphene, graphite and carbon fibre sources, or by photo‐Fenton reaction of graphene oxide .…”

Section: Resultsmentioning

confidence: 99%

Additive‐Free Electrophoretic Deposition of Graphene Quantum Dots Thin Films

Nguyen

Geuli

Yeo

et al. 2019

Chemistry A European J

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The electrophoretic deposition (EPD)o fg raphenebased materials on transparent substrates is highly potential for many applications. Several factorsc an determine the yield of the EPD process,s uch as applied voltage, deposition time and particularly the presence of dispersion additives (stabilisers) in the suspension solution. This study presents an additive-free EPD of graphene quantum dot( GQD) thin films on an indium tinoxide (ITO) glass substrate and studies the deposition mechanism with the variation of the applied voltage (10-50 V) and deposition time (5-25 min). It is found that due to the small size ( % 3.9nm) and high content of deprotonatedc arboxylic groups,the GQDs form as table dis-persion (zeta-potential of about À35 mV) without using additives.T he GQD thin films can be deposited onto ITO with optimal surfacem orphologya t3 0Vin 5min (surfacer oughness of approximately (3.1 AE1.3) nm). In addition, as-fabricated GQD thin films also possess some interesting physico-optical properties, such as ad ouble-peak photoluminescence at about l = 417 and 439 nm, with approximately 98 %v isible transmittance. This low-cost and eco-friendly GQD thin film is ap romisingm aterialf or various applications,f or example,t ransparent conductors, supercapacitors and heat conductive films in smart windows.

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Synthesis and spectroscopic studies of functionalized graphene quantum dots with diverse fluorescence characteristics

Abstract: In this research, we report a facile method for synthesizing a series of carboxyl functionalized graphene quantum dots (GQDs) using graphite flakes (300 meshes) as raw material.

Cited by 101 publications

References 62 publications

Poly (ether) sulfone electrospun nanofibrous membranes embedded with graphene oxide quantum dots with antimicrobial activity

Poly (ether) sulfone electrospun nanofibrous membranes embedded with graphene oxide quantum dots with antimicrobial activity

Graphene Quantum Dots’ Surface Chemistry Modulates the Sensitivity of Glioblastoma Cells to Chemotherapeutics

Additive‐Free Electrophoretic Deposition of Graphene Quantum Dots Thin Films

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