Colorimetric and Fluorescent Dual-Modality Sensing Platform Based on Fluorescent Nanozyme

Compared with natural enzymes, nanozymes based on carbonaceous nanomaterials are advantages due to high stability, good biocompatibility, and the possibility of multifunctionalities through materials engineering at an atomic level. Herein, we present a sensing platform using a nitrogen-doped graphene quantum dot (NGQD) as a highly efficient fluorescent peroxidase mimic, which enables a colorimetric/fluorescent dual-modality platform for detection of hydrogen peroxide (H2O2) and biomolecules (ascorbic acid-AA, acid phosphatase-ACP) with high sensitivity. NGQD is synthesized using a simple hydrothermal process, which has advantages of high production yield and potential for large-scale preparation. NGQD with uniform size (3.0 ± 0.6 nm) and a single-layer graphene structure exhibits bright and stable fluorescence. N-doping and ultrasmall size endow NGQD with high peroxidase-mimicking activity with an obviously reduced Michaelis–Menten constant (Km) in comparison with natural horseradish peroxidase. Taking advantages of both high nanozyme activity and unique fluorescence property of NGQD, a colorimetric and fluorescent dual-modality platform capable of detecting H2O2 and biomolecules (AA, ACP) with high sensitivity is developed as the proof-of-concept demonstration. Furthermore, the mechanisms underlying the nanozyme activity and biosensing are investigated.

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Colorimetric Nanoplasmonics to Spot Hyperglycemia From Saliva

Frontiers in Bioengineering and Biotechnology ◽

10.3389/fbioe.2020.601216 ◽

2020 ◽

Vol 8 ◽

Author(s):

Paolo Donati ◽

Tania Pomili ◽

Luca Boselli ◽

Pier P. Pompa

Keyword(s):

Large Scale ◽

Point Of Care ◽

High Sensitivity ◽

Diabetic Patients ◽

Visual Response ◽

Colorimetric Sensing ◽

Chronic Patients ◽

Self Monitoring ◽

Sensing Platform ◽

Signal Color

Early diagnostics and point-of-care (POC) devices can save people’s lives or drastically improve their quality. In particular, millions of diabetic patients worldwide benefit from POC devices for frequent self-monitoring of blood glucose. Yet, this still involves invasive sampling processes, which are quite discomforting for frequent measurements, or implantable devices dedicated to selected chronic patients, thus precluding large-scale monitoring of the globally increasing diabetic disorders. Here, we report a non-invasive colorimetric sensing platform to identify hyperglycemia from saliva. We designed plasmonic multibranched gold nanostructures, able to rapidly change their shape and color (naked-eye detection) in the presence of hyperglycemic conditions. This “reshaping approach” provides a fast visual response and high sensitivity, overcoming common detection issues related to signal (color intensity) losses and bio-matrix interferences. Notably, optimal performances of the assay were achieved in real biological samples, where the biomolecular environment was found to play a key role. Finally, we developed a dipstick prototype as a rapid home-testing kit.

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Fabrication and Superhydrophobic Property of ZnO Micro/Nanocrystals via a Hydrothermal Route

Journal of Nanomaterials ◽

10.1155/2014/680592 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6 ◽

Cited By ~ 2

Author(s):

Chunmei Xiao ◽

Jing Yan ◽

Taohai Li

Keyword(s):

Large Scale ◽

Hydrothermal Process ◽

Hydrothermal Route ◽

One Pot ◽

Uniform Size ◽

Water Contact ◽

X Ray ◽

Superhydrophobic Property ◽

Surface Modified ◽

Scanning Electron

Superhydrophobic ZnO micro/nanocrystals were fabricated on a large scale using a facile one-pot hydrothermal process successfully. The morphologies and chemical composition of as-synthesized ZnO were investigated by the scanning electron microscope (SEM) and X-ray powder diffraction (XRD). The morphology of ZnO products changed from uniform size microrods to flower-like micronanostructures, when the temperature changed from 120°C to 180°C. The morphology of ZnO was strongly affected by the pH. The wettability of the as-synthesized ZnO micro/nanocrystals was studied by measuring water contact angle (CA). The largest static CA for water is 167°, which is closely related to both the ZnO micro/nanostructure and chemical modification. Furthermore, the as-prepared ZnO surface showed superhydrophobicity for some corrosive liquids such as basic and acidic aqueous solutions. The CAs of the surface modified with ZnO prepared at 160°C were over 155° in the range of pH = 1–13.

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Highly Sensitive Picric Acid Chemical Sensor Based on Samarium (Sm) Doped ZnO Nanorods

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2019.16105 ◽

2019 ◽

Vol 19 (6) ◽

pp. 3637-3642 ◽

Cited By ~ 3

Author(s):

Yas Al-Hadeethi ◽

Ahmad Umar ◽

Kulvinder Singh ◽

Ahmed A Ibrahim ◽

Saleh. H Al-Heniti ◽

...

Keyword(s):

Large Scale ◽

Chemical Sensor ◽

Limit Of Detection ◽

Picric Acid ◽

Zno Nanorods ◽

Hydrothermal Process ◽

High Sensitivity ◽

Highly Sensitive ◽

Doped Zno ◽

Facile Hydrothermal Process

Herein, we report the synthesis, characterization and picric acid chemical sensing application of samarium (Sm) doped ZnO nanorods. The Sm-doped ZnO nanorods were synthesized by facile hydrothermal process and characterized using various analytical methods which confirmed the large-scale synthesis and wurtzite hexagonal crystal structure for the synthesized nanorods. The doping of Sm ions in the lattices of the synthesized nanorods was evaluated by the energy dispersive X-ray spectroscopy (EDS). The synthesized Sm-doped ZnO nanorods were used as potential scaffold to fabricate high sensitive and reproducible picric acid chemical sensor based on I–V technique. The fabricated picric acid chemical sensor based on Sm-doped ZnO nanorods exhibited a high sensitivity of 213.9 mA mM−1 cm−2 with the limit of detection of ∼0.228 mM and correlation coefficient of R═0.9889. The obtained results revealed that the facile grown Sm-doped ZnO nanorods can efficiently be used to fabricate high sensitive and reproducible chemical sensors.

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Optical response of large scale single layer graphene

Applied Physics Letters ◽

10.1063/1.3555425 ◽

2011 ◽

Vol 98 (7) ◽

pp. 071905 ◽

Cited By ~ 74

Author(s):

Chul Lee ◽

Joo Youn Kim ◽

Sukang Bae ◽

Keun Soo Kim ◽

Byung Hee Hong ◽

...

Keyword(s):

Large Scale ◽

Single Layer ◽

Optical Response ◽

Single Layer Graphene ◽

Layer Graphene

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Dynamic Modification of Fermi Energy in Single-Layer Graphene by Photoinduced Electron Transfer from Carbon Dots

Nanomaterials ◽

10.3390/nano10030528 ◽

2020 ◽

Vol 10 (3) ◽

pp. 528 ◽

Cited By ~ 1

Author(s):

Angelo Armano ◽

Gianpiero Buscarino ◽

Fabrizio Messina ◽

Alice Sciortino ◽

Marco Cannas ◽

...

Keyword(s):

Electron Transfer ◽

Fermi Energy ◽

Carbon Dots ◽

Mutual Influence ◽

Solid Phase ◽

Surface States ◽

Single Layer ◽

Single Layer Graphene ◽

N Doping ◽

Carbon Based Nanomaterials

Graphene (Gr)—a single layer of two-dimensional sp2 carbon atoms—and Carbon Dots (CDs)—a novel class of carbon nanoparticles—are two outstanding nanomaterials, renowned for their peculiar properties: Gr for its excellent charge-transport, and CDs for their impressive emission properties. Such features, coupled with a strong sensitivity to the environment, originate the interest in bringing together these two nanomaterials in order to combine their complementary properties. In this work, the investigation of a solid-phase composite of CDs deposited on Gr is reported. The CD emission efficiency is reduced by the contact of Gr. At the same time, the Raman analysis of Gr demonstrates the increase of Fermi energy when it is in contact with CDs under certain conditions. The interaction between CDs and Gr is modeled in terms of an electron-transfer from photoexcited CDs to Gr, wherein an electron is first transferred from the carbon core to the surface states of CDs, and from there to Gr. There, the accumulated electrons determine a dynamical n-doping effect modulated by photoexcitation. The CD–graphene interaction unveiled herein is a step forward in the understanding of the mutual influence between carbon-based nanomaterials, with potential prospects in light conversion applications.

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Low-cost and high sensitivity glucose sandwich detection using a plasmonic nanodisk metasurface

Nanoscale ◽

10.1039/d0nr00288g ◽

2020 ◽

Vol 12 (19) ◽

pp. 10809-10815 ◽

Cited By ~ 1

Author(s):

Zhongwen Long ◽

Yuzhang Liang ◽

Lei Feng ◽

Hui Zhang ◽

Mingze Liu ◽

...

Keyword(s):

Large Scale ◽

Low Cost ◽

High Sensitivity ◽

Glucose Detection ◽

Sensing Platform ◽

Highly Sensitive

A low-cost, large scale plasmonic metasurface sensing platform shows enormous potential for highly sensitive and selective SERS-based glucose detection.

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Graphene Production With Stirred Media Mills

MRS Proceedings ◽

10.1557/proc-1259-s12-01 ◽

2010 ◽

Vol 1259 ◽

Cited By ~ 2

Author(s):

Catharina Knieke ◽

Angela Berger ◽

Wolfgang Peukert

Keyword(s):

Large Scale ◽

Chemical Properties ◽

Single Layer ◽

Single Layer Graphene ◽

High Yield ◽

Graphene Sheets ◽

Multilayer Graphene ◽

Scale Production ◽

Graphite Particles ◽

Media Milling

AbstractSince the discovery of stable graphene sheets by Novoselov und Geim in 2004 the one atom thick carbon material has been attracted great interest because of its outstanding physical, mechanical and chemical properties. Although there had been intensive research to find new ways in the preparation of single-layer graphene sheets in the last few years, especially the large-scale production of graphene still remains challenging. In this paper we present a new approach, which allows the high-yield production of graphene sheets in a simple stirred media milling process. Under mild milling conditions single- and multilayer graphene sheets have been successfully produced from commercial graphite powder in a liquid medium. During the delamination procedure, the graphite particles were stressed between the milling beads. Shear and compressive normal forces can lead under mild milling conditions, i.e. low stress energies, to a continuous mechanical peeling of graphene sheets from the graphite surface. By means of Atomic Force Microscopy a high yield of single- and multilayer graphene sheets was detected. A concentration of exfoliated sheets of 2 wt% starting from a 5 wt% suspension of coarse graphite particles could be determined after a milling time of only 3 h. This concentration is much higher than those, which were reached by most of the known chemical methods. Since stirred media milling can be realized as large-scale process, a high-yield and low-cost production of graphene flakes becomes possible at ambient temperature.

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A Platform for Large-Scale Graphene Electronics - CVD Growth of Single-Layer Graphene on CVD-Grown Hexagonal Boron Nitride

Advanced Materials ◽

10.1002/adma.201204904 ◽

2013 ◽

Vol 25 (19) ◽

pp. 2746-2752 ◽

Cited By ~ 174

Author(s):

Min Wang ◽

Sung Kyu Jang ◽

Won-Jun Jang ◽

Minwoo Kim ◽

Seong-Yong Park ◽

...

Keyword(s):

Boron Nitride ◽

Large Scale ◽

Hexagonal Boron Nitride ◽

Single Layer ◽

Single Layer Graphene ◽

Layer Graphene ◽

Cvd Growth

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Direct electrosynthesis of 52% concentrated CO on silver’s twin boundary

Nature Communications ◽

10.1038/s41467-021-22428-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Can Tang ◽

Peng Gong ◽

Taishi Xiao ◽

Zhengzong Sun

Keyword(s):

Twin Boundary ◽

Large Scale ◽

Graphene Film ◽

Single Layer ◽

Gaseous Product ◽

Single Layer Graphene ◽

Volume Percentage ◽

Faradaic Efficiency ◽

Boundary Density ◽

Exchange Membrane

AbstractThe gaseous product concentration in direct electrochemical CO2 reduction is usually hurdled by the electrode’s Faradaic efficiency, current density, and inevitable mixing with the unreacted CO2. A concentrated gaseous product with high purity will greatly lower the barrier for large-scale CO2 fixation and follow-up industrial usage. Here, we developed a pneumatic trough setup to collect the CO2 reduction product from a precisely engineered nanotwinned electrocatalyst, without using ion-exchange membrane. The silver catalyst’s twin boundary density can be tuned from 0.3 to 1.5 × 104 cm−1. With the lengthy and winding twin boundaries, this catalyst exhibits a Faradaic efficiency up to 92% at −1.0 V and a turnover frequency of 127 s−1 in converting CO2 to CO. Through a tandem electrochemical-CVD system, we successfully produced CO with a volume percentage of up to 52%, and further transformed it into single layer graphene film.

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