Optical properties of few layered graphene quantum dots

Choudhary, Raghvendra Pratap; Shukla, Shobha; Vaibhav, Kumar; Pawar, Pranav Bhagwan; Saxena, Sumit

doi:10.1088/2053-1591/2/9/095024

Cited by 42 publications

(31 citation statements)

References 20 publications

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“…The doublet around 500 cm −1 and a singlet peak at 718 cm −1 can be attributed to the Mn-O bending modes of octahedral MnO 6 structures [30]. While the presence of GQDs in the fiber matrix was confirmed by the C=C and C-O bending vibrations in the graphitic plane at 1580 cm −1 and 1377 cm −1 , respectively [31], thereby confirming the formation of MnO 2 /GQD nanocomposites. Meanwhile, the presence of Mn and C, corresponding to α-MnO2 and GQD, respectively, is confirmed from EDX mapping shown in Figure 2b, which is the first indication of nanocomposite formation.…”

Section: Surface Characterization Of α-Mno 2 /Gqd Nanocompositesmentioning

confidence: 73%

An Enzymatic Multiplexed Impedimetric Sensor Based on α-MnO2/GQD Nano-Composite for the Detection of Diabetes and Diabetic Foot Ulcer Using Micro-Fluidic Platform

et al. 2021

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Diabetes is widely considered as a silent killer which affects the internal organs and ultimately has drastic impacts on our day-to-day activities. One of the fatal outcomes of diabetes is diabetic foot ulcer (DFU); which, when becomes chronic, may lead to amputation. The incorporation of nanotechnology in developing bio-sensors enables the detection of desired biomarkers, which in our study are glucose and L-tyrosine; which gets elevated in patients suffering from diabetes and DFUs, respectively. Herein, we report the development of an enzymatic impedimetric sensor for the multi-detection of these biomarkers using an electrochemical paper-based analytical device (µ-EPADs). The structure consists of two working electrodes and a counter electrode. One working electrode is modified with α-MnO2-GQD/tyrosinase hybrid to aid L-tyrosine detection, while the other electrode is coated with α-MnO2-GQD/glucose oxidase hybrid for glucose monitoring. Electrochemical impedance spectroscopy has been employed for the quantification of glucose and L-tyrosine, within a concentration range of 50–800 mg/dL and 1–500 µmol/L, respectively, using a sample volume of approximately 200 µL. The impedance response exhibited a linear relationship over the analyte concentration range with detection limits of ~58 mg/dL and ~0.3 µmol/L for glucose and tyrosine respectively, with shelf life ~1 month. The sensing strategy was also translated to Arduino-based device applications by interfacing the µ-EPADs with miniaturized electronics.

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Section: Surface Characterization Of α-Mno 2 /Gqd Nanocompositesmentioning

confidence: 73%

An Enzymatic Multiplexed Impedimetric Sensor Based on α-MnO2/GQD Nano-Composite for the Detection of Diabetes and Diabetic Foot Ulcer Using Micro-Fluidic Platform

et al. 2021

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“…The FTIR spectrum of α‐MnO 2 /GQD nanostructures, as shown in Figure 2d , demonstrated a broad envelope between 3400 cm −1 and 3000 cm −1 , corresponding to OH stretching vibrations. The doublet around 500 cm −1 and a singlet peak at 718 cm −1 can be attributed to the Mn‐O bending modes of octahedral MnO 6 structures [ 26 ], while the presence of GQDs in the fibre matrix was confirmed by the C=C, C‐O and C‐O‐C bending vibrations in graphitic plane at 1580 cm −1 , 1377 cm −1 and 1276 cm −1 , respectively [ 27 ], thereby confirming the formation of MnO 2 /GQD nanocomposites.…”

Section: Resultsmentioning

confidence: 99%

Design and development of a portable resistive sensor based on α‐MnO ₂ /GQD nanocomposites for trace quantification of Pb(II) in water

Gupta‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬

Khanna

Roy

et al. 2021

IET Nanobiotechnology

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The occurrence of heavy metal ions in food chain is appearing to be a major problem for mankind. The traces of heavy metals, especially Pb(II) ions present in water bodies remains undetected, untreated, and it remains in the food cycle causing serious health hazards for human and livestock. The consumption of Pb(II) ions may lead to serious medical complications including multiple organ failure which can be fatal. The conventional methods of heavy metal detection are costly, time-consuming and require laboratory space. There is an immediate need to develop a cost-effective and portable sensing system which can easily be used by the common man without any technical knowhow. A portable resistive device with miniaturized electronics is developed with microfluidic well and α-MnO 2 /GQD nanocomposites as a sensing material for the sensitive detection of Pb(II). α-MnO 2 /GQD nanocomposites which can be easily integrated with the miniaturized electronics for realtime on-field applications. The proposed sensor exhibited a tremendous potential to be integrated with conventional water purification appliances (household and commercial) to give an indication of safety index for the drinking water. The developed portable sensor required low sample volume (200 µL) and was assessed within the Pb(II) concentration range of 0.001 nM to 1 uM. The Limit of Detection (LoD) and sensitivity was calculated to be 0.81 nM and 1.05 kΩ/nM/mm 2 , and was validated with the commercial impedance analyser. The shelf-life of the portable sensor was found to be ∼45 days.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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“…9 Many generalized reviews have appeared showing remarkable optical properties of graphene and its derivatives over other nanomaterials. [111][112][113][114][115][116] Pristine graphene has a zero intrinsic band gap thereby limiting its use in many optical applications that are based on photo-excited PL. However, band-gap in graphene can be introduced or tuned (as we have discussed in the previous sections) by converting 2D graphene sheets to GO, rGO, GQDs, etc.…”

Section: Graphene Based Optical Biosensing Systemmentioning

confidence: 99%

Graphene based biosensors—Accelerating medical diagnostics to new-dimensions

2017

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Graphene has emerged as a champion material for a variety of applications cutting across multiple disciplines in science and engineering. Graphene and its derivatives have displayed huge potential as a biosensing material due to their unique physicochemical properties, good electrical conductivity, optical properties, biocompatibility, ease of functionalization, and flexibility. Their widespread use in making biosensors has opened up new possibilities for early diagnosis of life-threatening diseases and real-time health monitoring. Following an introduction and discussion on the significance of fabrication protocols and assembly, this review is intended to assess why graphene is suitable to build better biosensors, the working of existing biosensing schemes and their current status toward commercialization for wearable diagnostic and prognostic devices. We believe this review will provide a critical insight for harnessing graphene as a suitable biosensor for the clinical diagnostics, its future prospects and challenges ahead.

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Optical properties of few layered graphene quantum dots

Cited by 42 publications

References 20 publications

An Enzymatic Multiplexed Impedimetric Sensor Based on α-MnO2/GQD Nano-Composite for the Detection of Diabetes and Diabetic Foot Ulcer Using Micro-Fluidic Platform

An Enzymatic Multiplexed Impedimetric Sensor Based on α-MnO2/GQD Nano-Composite for the Detection of Diabetes and Diabetic Foot Ulcer Using Micro-Fluidic Platform

Design and development of a portable resistive sensor based on α‐MnO ₂ /GQD nanocomposites for trace quantification of Pb(II) in water

Graphene based biosensors—Accelerating medical diagnostics to new-dimensions

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Optical properties of few layered graphene quantum dots

Cited by 42 publications

References 20 publications

An Enzymatic Multiplexed Impedimetric Sensor Based on α-MnO2/GQD Nano-Composite for the Detection of Diabetes and Diabetic Foot Ulcer Using Micro-Fluidic Platform

An Enzymatic Multiplexed Impedimetric Sensor Based on α-MnO2/GQD Nano-Composite for the Detection of Diabetes and Diabetic Foot Ulcer Using Micro-Fluidic Platform

Design and development of a portable resistive sensor based on α‐MnO 2 /GQD nanocomposites for trace quantification of Pb(II) in water

Graphene based biosensors—Accelerating medical diagnostics to new-dimensions

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Design and development of a portable resistive sensor based on α‐MnO ₂ /GQD nanocomposites for trace quantification of Pb(II) in water