Influence of Chitosan-Based Carbon Dots on Astaxanthin Production of Green Alga Tetraselmis sp.

2021 ◽  
Vol 21 (7) ◽  
pp. 3689-3696
Author(s):  
Minh Kim Nguyen ◽  
Duckshin Park ◽  
Young-Chul Lee
Keyword(s):  
Light Emission ◽  
Amino Groups ◽  
Absolute Quantum Yield ◽  
Astaxanthin Production ◽  
One Step ◽  
Low Cytotoxicity ◽  
Fluorescent Nanomaterials ◽  
Nano Size ◽  
Absolute Quantum ◽  
Formation Step

CDs are carbon fluorescent nanomaterials that have gained significant attention in recent years owing to their unique properties. In this work, we utilized a simple solution to produce CDs with func-tionalized amino groups via a one-step carbonization from a chitosan precursor. This simultaneous approach does not use special reagent for either the formation step or the amino-functionalization step of CDs. The as-prepared amino-functionalized CDs that possesses expected characteristics, such as nano-size distribution, monodispersible, high blue light emission, high absolute quantum yield of 5.52%, and functionalized amino groups on the surface. Furthermore, this work demonstrated the low cytotoxicity and high biocompatibility of the CDs, through the improvements in the astaxanthin production of alga Tetraselmis sp. (more than doubled (up to 0.044 mg/L), relative to the control). Thus, as-prepared CDs have promising properties not only for applications in bioimaging, drug delivery or sensors, but also as promoter in algal biorefinery

Fluorescent Nanotechnology: An Evolution in Optical Sensors

2020 ◽  
Vol 17 ◽  
Author(s):  
Dilawar Hassan ◽  
Hadi Bakhsh ◽  
Asif M. Khurram ◽  
Shakeel A. Bhutto ◽  
Nida S. Jalbani ◽  
...  
Keyword(s):  
Optical Properties ◽  
Optical Sensors ◽  
Light Emission ◽  
Environmental Contaminants ◽  
Fluorescent Nanoparticles ◽  
Sensing Applications ◽  
Properties Of Materials ◽  
Optical Properties Of Materials ◽  
Fluorescent Nanomaterials

Background: The optical properties of nanomaterials have evolved enormously with the introduction of nanotechnology. The property of materials to absorb and/or emit specific wavelength has turned them into one of the most favourite candidates to be effectively utilized in different sensing applications e.g organic light emission diodes (OLEDs) sensors, gas sensors, biosensors and fluorescent sensors. These materials have been reported as a sensor in the field of tissue and cell imaging, cancer detection and detection of environmental contaminants etc. Fluorescent nanomaterials are heling in rapid and timely detection of various contaminants that greatly impact the quality of life and food, that is exposed to these contaminants. Later, all the contaminants have been investigated to be most perilous entities that momentously affect the life span of the animals and humans who use those foods which have been contaminated. Objective: In this review, we will discuss about various methods and approaches to synthesize the fluorescent nanoparticles and quantum dots (QDs) and their applications in various fields. The application will include the detection of various environmental contaminants and bio-medical applications. We will discuss the possible mode of action of the nanoparticles when used as sensor for the environmental contaminants as well as the surface modification of some fluorescent nanomaterials with anti-body and enzyme for specific detection in animal kingdom. We will also describe some RAMAN based sensors as well as some optical sensing-based nanosensors. Conclusion: Nanotechnology has enabled to play with the size, shape and morphology of materials in the nanoscale. The physical, chemical and optical properties of materials change dramatically when they are reduced to nanoscale. The optical properties can become choosy in terms of emission or absorption of wavelength in the size range and can result in production of very sensitive optical sensor. The results show that the use of fluorescent nanomaterials for the sensing purposes are helping a great deal in the sensing field.

scholarly journals Hydrothermal synthesis of nanocrystalline hydroxyapatite–graphene nanosheet on Ti-6Al-7Nb: mechanical and in vitro corrosion performance

2021 ◽  
Vol 32 (4) ◽  
Author(s):  
Oktay Yigit ◽  
Burak Dikici ◽  
Niyazi Ozdemir
Keyword(s):  
Hydrothermal Reaction ◽  
Hybrid Coatings ◽  
Stoichiometric Ratio ◽  
Corrosion Performance ◽  
Graphene Nanosheet ◽  
Graphene Layers ◽  
Nanocrystalline Hydroxyapatite ◽  
One Step ◽  
Nano Size

AbstractThe hybrid coatings containing the graphene nano-sheet (GNS) and nano-hydroxyapatite (nHA) phases have been successfully synthesized on Ti6Al7Nb alloys by a one-step hydrothermal method. The hydrothermal reaction was carried out for 24 h at 200 °C. The GNS ratio has been altered as 1, 3, 5 and 7 wt.% in the coatings and, the results have compared with non- GNS containing coatings. The effect of the GNS ratio on the microstructure, hardness, and in vitro corrosion responses has been investigated in detail. The characterizations of the coatings were carried out by SEM, EDS, AFM, XRD and, FTIR. The corrosion behavior of the hybrid coatings was compared in Kokubo’s solution at 37 °C by using potentiodynamic polarization tests. The results showed that the hydroxyapatite phases were deposed on the graphene layers with nano-size nucleation with its Ca/P stoichiometric ratio. The best hydrophilicity (~52°) property has been obtained in nHA/3GNS coatings. In addition, the corrosion rates of coatings increased in the following order: nHA/3GNS < nHA/1GNS < nHA/7GNS < nHA/5GNS < only nHA.

Optical properties of hemicyanines with terminal amino groups and their applications in near-infrared fluorescent imaging of nucleoli

2014 ◽  
Vol 2 (40) ◽  
pp. 7065-7072 ◽  
Author(s):  
Jia-Tao Miao ◽  
Chen Fan ◽  
Ru Sun ◽  
Yu-Jie Xu ◽  
Jian-Feng Ge
Keyword(s):  
Optical Properties ◽  
Near Infrared ◽  
Water Solubility ◽  
Stokes Shift ◽  
Fluorescent Imaging ◽  
Amino Groups ◽  
Long Wave ◽  
Terminal Amino ◽  
Wave Emission ◽  
Low Cytotoxicity

A cellular dye with properties of long-wave emission, large Stokes shift, water solubility, low cytotoxicity, and good photostability is reported.

scholarly journals One-Step Synthesis of Diamine-Functionalized Graphene Quantum Dots from Graphene Oxide and Their Chelating and Antioxidant Activities

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 104 ◽  
Author(s):  
Rabeb El-Hnayn ◽  
Laetitia Canabady-Rochelle ◽  
Christophe Desmarets ◽  
Lavinia Balan ◽  
Hervé Rinnert ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Oxide ◽  
Colloidal Stability ◽  
Antioxidant Activities ◽  
Graphene Quantum Dots ◽  
Average Diameter ◽  
Functionalized Graphene ◽  
One Step ◽  
Low Cytotoxicity ◽  
Health Applications

2,2’-(Ethylenedioxy)bis(ethylamine)-functionalized graphene quantum dots (GQDs) were prepared under mild conditions from graphene oxide (GO) via oxidative fragmentation. The as-prepared GQDs have an average diameter of ca. 4 nm, possess good colloidal stability, and emit strong green-yellow light with a photoluminescence (PL) quantum yield of 22% upon excitation at 375 nm. We also demonstrated that the GQDs exhibit high photostability and the PL intensity is poorly affected while tuning the pH from 1 to 8. Finally, GQDs can be used to chelate Fe(II) and Cu(II) cations, scavenge radicals, and reduce Fe(III) into Fe(II). These chelating and reducing properties that associate to the low cytotoxicity of GQDs show that these nanoparticles are of high interest as antioxidants for health applications.

Manifestation of Сoncentration Quenching of Fluoroaluminate Glasses Doped with Erbium

2019 ◽  
Vol 822 ◽  
pp. 871-877
Author(s):  
Victor Klinkov ◽  
Aleksander Semencha ◽  
Evgenia Tsimerman ◽  
Artem Osipov ◽  
Margarita G. Dronova
Keyword(s):  
Quantum Yield ◽  
Decay Curve ◽  
Emission Spectra ◽  
Luminescence Spectra ◽  
Ion Energy ◽  
Maximum Value ◽  
Absolute Quantum Yield ◽  
Concentration Dependences ◽  
Yield Values ◽  
Absolute Quantum

Fluoroaluminate glasses of the composition 2Ва (РО3)2–98MgCaSrBaYAl2F14-xErF3, where x=0, 0.1, 0.5, 1.0 mol. % have been prepared by melt quenching technique and characterized by optical absorption, emission spectra and decay curve analysis. Measured transmission spectra indicate the high practical relevance of the composition of glasses under investigation for photonics and optoelectronics products. In the region of 500–700 nm, luminescence spectra with peaks at about 522, 550, and 665 nm were obtained. The positions of the luminescence bands have been described using an erbium ion energy scheme. The concentration dependences of the absolute quantum yield values for the series of Er3+-doped fluoroaluminate glasses were also established. The maximum value of absolute quantum yield was found for a sample with Er3+ concentration 0.21∙1020 сm-3. The main reason for reducing the values of absolute quantum yield is concentration quenching.

One-Step Synthesis of Nano-Size Iron Oxide /Three-Dimensional Wormlike Hierarchical Mesoporous SiO2 Catalysts and its Catalytic Performance on Phenol Hydroxylation

2013 ◽  
Vol 662 ◽  
pp. 202-206
Author(s):  
Jia Feng Wu ◽  
Yu Mei Zhao ◽  
Peng Liang
Keyword(s):  
Iron Oxide ◽  
High Surface ◽  
High Surface Area ◽  
Three Dimensional ◽  
Catalytic Performance ◽  
Phenol Hydroxylation ◽  
Weight Percentage ◽  
One Step ◽  
Hierarchical Pore ◽  
Nano Size

A series of nano-sized iron oxide supported on 3D wormlike hierarchical mesoporous SiO2 catalysts were synthesized by one-step hydrothermal synthesis. The samples were characterized by XRD, N2 sorption, FT-IR, UV–Vis, TEM and ICP-AES. The catalysts were probed for the oxidation of phenol employing hydrogen peroxide. The results indicate that the materials exhibit high surface area and 3D wormlike hierarchical pore, iron ions exist as isolated framework species when the weight percentage content of iron is below 0.24 and nano-size iron oxide is dispersed in the surface (iron content above 0.24 wt%). Catalytic performance indicates that nano-size iron oxide supported on SiO2 is useful to enhance both the catalytic activity and the selectivity of target products compared with isolated iron species.

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