scholarly journals Synthesis of Exosome-Based Fluorescent Gold Nanoclusters for Cellular Imaging Applications

2021 ◽  
Vol 22 (9) ◽  
pp. 4433
Author(s):  
Eun Sung Lee ◽  
Byung Seok Cha ◽  
Seokjoon Kim ◽  
Ki Soo Park
Keyword(s):  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
Stokes Shift ◽  
Gold Nanoclusters ◽  
Human Colon ◽  
Cellular Imaging ◽  
Metal Nanoclusters ◽  
Human Colon Cancer ◽  
X Ray ◽  
High Concentrations

In recent years, fluorescent metal nanoclusters have been used to develop bioimaging and sensing technology. Notably, protein-templated fluorescent gold nanoclusters (AuNCs) are attracting interest due to their excellent fluorescence properties and biocompatibility. Herein, we used an exosome template to synthesize AuNCs in an eco-friendly manner that required neither harsh conditions nor toxic chemicals. Specifically, we used a neutral (pH 7) and alkaline (pH 11.5) pH to synthesize two different exosome-based AuNCs (exo-AuNCs) with independent blue and red emission. Using field-emission scanning electron microscopy, energy dispersive X-ray microanalysis, nanoparticle tracking analysis, and X-ray photoelectron spectroscopy, we demonstrated that AuNCs were successfully formed in the exosomes. Red-emitting exo-AuNCs were found to have a larger Stokes shift and a stronger fluorescence intensity than the blue-emitting exo-AuNCs. Both exo-AuNCs were compatible with MCF-7 (human breast cancer), HeLa (human cervical cancer), and HT29 (human colon cancer) cells, although blue-emitting exo-AuNCs were cytotoxic at high concentrations (≥5 mg/mL). Red-emitting exo-AuNCs successfully stained the nucleus and were compatible with membrane-staining dyes. This is the first study to use exosomes to synthesize fluorescent nanomaterials for cellular imaging applications. As exosomes are naturally produced via secretion from almost all types of cell, the proposed method could serve as a strategy for low-cost production of versatile nanomaterials.

scholarly journals Reversal of Multidrug Resistance in Human Colon Cancer and Human Leukemia Cells by Three Plant Extracts and Their Major Secondary Metabolites

Medicines ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 123 ◽  
Author(s):  
Jun-Xian Zhou ◽  
Michael Wink
Keyword(s):  
Colon Cancer ◽  
Cell Line ◽  
Abc Transporters ◽  
Human Colon ◽  
Rhodamine 123 ◽  
Human Leukemia ◽  
Dependent Manner ◽  
Human Colon Cancer ◽  
High Concentrations ◽  
Resistant Cells

Background: We studied the effect of three plant extracts (Glycyrrhiza glabra, Paeonia lactiflora, Eriobotrya japonica) and six of their major secondary metabolites (glycyrrhizic acid, 18β glycyrrhetinic acid, liquiritigenin, isoliquiritigenin, paeoniflorin, ursolic acid) on the multidrug resistant human colon cancer cell line Caco-2 and human leukemia cell line CEM/ADR 5000 as compared to the corresponding sensitive cell line CCRF-CEM, and human colon cancer cells HCT-116, which do not over-express ATP-binding cassette (ABC) transporters. Methods: The cytotoxicity of single substances in sensitive and resistant cells was investigated by MTT assay. We also applied combinations of extracts or single compounds with the chemotherapeutic agent doxorubicin or doxorubicin plus the saponin digitonin. The intracellular retention of the ABC transporter substrates rhodamine 123 and calcein was examined by flow cytometry to explore the effect of the substances on the activity of ABC transporters P-glycoprotein and MRP1. Real-time PCR was applied to analyse the gene expression changes of ABCB1, ABCC1, caspase 3, caspase 8, AhR, CYP1A1, and GSTP1 in resistant cells under the treatment of the substances. Results: All the substances moderately inhibited cell growth in sensitive and resistant cells to some degree. Whereas ursolic acid showed IC50 of 14 and 22 µM in CEM/ADR 5000 and Caco-2 cells, respectively, glycyrrhizic acid and paeoniflorin were inactive with IC50 values above 400 μM. Except for liquiritigenin and isoliquiritigenin, all the other substances reversed MDR in CEM/ADR 5000 and Caco-2 cells to doxorubicin. Ue, ga, 18ga, and urs were powerful reversal agents. In CEM/ADR 5000 cells, high concentrations of all the substances, except Paeonia lactiflora extract, increased calcein or rhodamine 123 retention in a dose-dependent manner. In Caco-2 cells, all the substances, except liquiritigenin, retained rhodamine 123 in a dose-dependent manner. We also examined the effect of the plant secondary metabolite (PSM) panel on the expression of ABCB1, ABCC1, caspase 3, caspase 8, AhR, CYP1A1, and GSTP1 genes in MDR cells. Conclusions: The extracts and individual PSM could reverse MDR in CEM/ADR 5000 and Caco-2 cells, which overexpress ABC transporters, in two- and three-drug combinations. Most of the PSM also inhibited the activity of ABC transporters to some degree, albeit at high concentrations. Ue, ga, 18ga, and urs were identified as potential multidrug resistance (MDR) modulator candidates, which need to be characterized and validated in further studies.

scholarly journals Yttrium Doped TiO2 Thin Film for Gas Sensing Application Prepared by Spin Coating Method

2020 ◽  
Author(s):  
M Abdul Kaiyum ◽  
Naim Ahmed ◽  
Arif Alam ◽  
M Shamimur Rahman
Keyword(s):  
Thin Film ◽  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
Low Cost ◽  
Pure Titanium ◽  
X Ray ◽  
Sensing Applications ◽  
Coating Method ◽  
Set Up ◽  
Spin Coater

Abstract Yttrium (Y) doped and pure Titanium Di-oxide (TiO2) thin films were prepared by using spin coater. The coater was set up in laboratory with low cost investment. The films were calcined at 450 °C for 1 hour. For characterization, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Atomic Force Microscopy (AFM) were carried out. LCR Bridge - GW Instek LCR-821 was used for gas sensing applications. XPS showed that the change of electronic structure due to Y doping. SEM and AFM analysis were carried out to determine the surface morphology of the films. Yttrium (Y) decreased the crystallite size of the films and increased the surface roughness and porosity value, which was very good for many sensing applications. Gas sensing property of the deposited films were improved by the incorporation of yttrium impurities and the sensing property improved almost two times than pure TiO2 thin film. Different researches have been done their research related to this topic but no one researchers provide a precise explanation of their results, authors of this research have tried to do that. Moreover the films were prepared by a simple spin coater to reduce the production cost also.

Gold nanoclusters reductively deposited on porous silicon: morphology and electronic structures

1998 ◽  
Vol 76 (11) ◽  
pp. 1707-1716 ◽  
Author(s):  
I Coulthard ◽  
S Degen ◽  
Y -J Zhu ◽  
T K Sham
Keyword(s):  
Gold Nanoparticles ◽  
Porous Silicon ◽  
Photoelectron Spectroscopy ◽  
Gold Nanoclusters ◽  
Gold Complex ◽  
X Ray Diffraction ◽  
Complex Ions ◽  
X Ray ◽  
Preparation Conditions ◽  
P Type

Utilizing porous silicon as a reducing agent and a substrate, gold complex ions [AuCl4]- were reduced from aqueous solution to produce nanoparticles of gold upon the surface of porous silicon. Scanning electron microscopy (SEM) was utilized to study the morphology of the porous silicon layers and the deposits of gold nanoparticles. It is found that preparation conditions have a profound effect on the morphology of the deposits, especially on porous silicon prepared from a p-type wafer. The gold nanoparticles, varying from micrometric aggregates of clusters of the order of 10 nm, to a distribution of nearly spherical clusters of the order of 10 nm, to strings of ~10 nm were observed and compared to bulk gold metal using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS). These techniques confirm and complement the SEM findings. The potential for this reductive deposition technique is noted.Key words: gold nanostructures, reductive deposition, porous silicon, morphology, X-ray spectroscopy.

scholarly journals Nanosheets of CuCo2O4 As a High-Performance Electrocatalyst in Urea Oxidation

2019 ◽  
Vol 9 (4) ◽  
pp. 793 ◽  
Author(s):  
Camila Zequine ◽  
Fangzhou Wang ◽  
Xianglin Li ◽  
Deepa Guragain ◽  
S.R. Mishra ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Nickel Foam ◽  
Low Cost ◽  
Agricultural Waste ◽  
Bifunctional Catalyst ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electroactive Material

The urea oxidation reaction (UOR) is a possible solution to solve the world’s energy crisis. Fuel cells have been used in the UOR to generate hydrogen with a lower potential compared to water splitting, decreasing the costs of energy production. Urea is abundantly present in agricultural waste and in industrial and human wastewater. Besides generating hydrogen, this reaction provides a pathway to eliminate urea, which is a hazard in the environment and to people’s health. In this study, nanosheets of CuCo2O4 grown on nickel foam were synthesized as an electrocatalyst for urea oxidation to generate hydrogen as a green fuel. The synthesized electrocatalyst was characterized using X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The electroactivity of CuCo2O4 towards the oxidation of urea in alkaline solution was evaluated using electrochemical measurements. Nanosheets of CuCo2O4 grown on nickel foam required the potential of 1.36 V in 1 M KOH with 0.33 M urea to deliver a current density of 10 mA/cm2. The CuCo2O4 electrode was electrochemically stable for over 15 h of continuous measurements. The high catalytic activities for the hydrogen evolution reaction make the CuCo2O4 electrode a bifunctional catalyst and a promising electroactive material for hydrogen production. The two-electrode electrolyzer demanded a potential of 1.45 V, which was 260 mV less than that for the urea-free counterpart. Our study suggests that the CuCo2O4 electrode can be a promising material as an efficient UOR catalyst for fuel cells to generate hydrogen at a low cost.

An Efficient Simple Hydrothermal Method to Synthesis FeS2 Microspheres and their Optical Property

2016 ◽  
Vol 847 ◽  
pp. 72-77
Author(s):  
Yu Xuan Liang ◽  
Peng Peng Bai ◽  
Shu Qi Zheng
Keyword(s):  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
Wave Length ◽  
Functional Materials ◽  
Optical And Electrical Properties ◽  
X Ray Diffraction ◽  
Synthetic Sample ◽  
X Ray ◽  
New Type ◽  
Good Uniformity

Pyrite (FeS2) is an important semiconductor material which shows various excellent optical and electrical properties and extensive applied prospect as a new-type, photoelectrical functional materials. In this study, a low cost and efficient simple hydrothermal two-step synthetic method was given to obtain FeS2 microspheres with 2-3 μm in diameter. The obtained products were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and ultraviolet and visible spectrophotometer (UV-Vis). XRD showed that the synthetic sample consisted of two crystal structures of FeS2, pyrite and marcasite. SEM observation indicated that FeS2 microspheres were well crystallized and had good uniformity. UV-Vis spectrum had a strong optical absorption in the region of 200-400 nm wave length. The reaction temperature had an impact on the size of FeS2 microspheres. A possible mechanism for the size of the FeS2 microspheres generated at high temperature is smaller than that at low temperature is discussed.

scholarly journals Structural and optical study of alternating layers of In and GaAs prepared by magnetron sputtering

2019 ◽  
Vol 24 (3) ◽  
pp. 523-542 ◽  
Author(s):  
Santiago Torres-Jaramillo ◽  
Camilo Pulzara-Mora ◽  
Roberto Bernal-Correa ◽  
Miguel Venegas de la Cerda ◽  
Salvador Gallardo-Hernández ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Low Cost ◽  
Longitudinal Mode ◽  
Longitudinal Optical ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mode Behavior ◽  
Optical Modes ◽  
High Concentrations ◽  
Secondary Ion

Currently, the obtention of nano-structures based on III-V materials is expensive. This calls for novel and inexpensive nanostructure manufacturing approaches. In this work we report on the manufacture of a nanostructures consisting of alternating layers of In and GaAs on a silicon substrate by magnetron sputtering. Furthermore, we characterized the produced nanostructures using secondary ion mass spectroscopy (SIMS), X-ray diffraction analysis, and Raman spectroscopy. SIMS revealed variation in the concentration of In atoms across In/GaAs/In interphases, and X-ray diffraction revealed planes corresponding to phases associated with GaAs and InAs due to In interfacial diffusion across GaAs layers. Finally, in order to study the composition and crystalquality of the manufactured nanostaructures, Raman spectra were taken using laser excitation lines of 452 nm, 532 nm, and 562 nm at different points across the nanostructures.This allowed to determine the transverse and longitudinal optical modes of GaAs and InAs,characteristic of a two-mode behavior. An acoustic longitudinal vibrational mode LA(Γ) of GaAs and an acoustic longitudinal mode activated by disorder (DALA) were observed. These resulted from the substitution of Ga atoms for In atoms in high concentrations due to the generation of Ga(VGa) and/or Arsenic(VAs) vacancies.This set of analyses show that magnetron sputtering can be aviable and relatively low-cost technique to obtain this type of semiconductors.

scholarly journals Removal Efficiency and Mechanism of Cr(VI) from Aqueous Solution by Maize Straw Biochars Derived at Different Pyrolysis Temperatures

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 781 ◽  
Author(s):  
Wang ◽  
Zhang ◽  
Lv
Keyword(s):  
Aqueous Solution ◽  
Removal Efficiency ◽  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
X Ray ◽  
Removal Capacity ◽  
Maize Straw ◽  
Efficient Adsorbent ◽  
Positively Charged ◽  
Maximum Removal

The removal efficiency and mechanism of Cr(VI) removal from aqueous solution on semi-decomposed maize straw biochars pyrolyzed at 300 to 600 °C were investigated. The removal of Cr(VI) by the biochars decreased with pyrolysis temperature increasing from 300 to 600 °C, and the maximum removal capacity of Cr(VI) for maize straw biochar pyrolyzed at 300 °C was 91 mg/g at pH 2.0. The percentage removal of Cr(VI) rapidly decreased with pH increasing from 2.0 to 8.0, with the maximum (>99.9%) at pH 2.0. The variation of Cr(VI) and Cr(III) concentrations in the solution after reaction showed that Cr(VI) concentration decreased while Cr(III) increased and the equilibrium was reached after 48 h, while the redox potential after reaction decreased due to Cr(VI) reduction. X-ray photoelectron spectroscopy (XPS) semi-quantitative analysis showed that Cr(III) accounted for 75.7% of the total Cr bound to maize straw biochar, which indicated reductive adsorption was responsible for Cr(VI) removal by the biochars. Cr(VI) was firstly adsorbed onto the positively charged biochar surface and reduced to Cr(III) by electrons provided by oxygen-containing functional groups (e.g., C=O), and subsequently part of the converted Cr(III) remained on the biochar surface and the rest released into solution. Fourier transform infrared (FTIR) data indicated the participation of C=O, Si–O, –CH2 and –CH3 groups in Cr(VI) removal by the biochars. This study showed that maize straw biochar pyrolyzed at 300 °C for 2 h was one low-cost and efficient adsorbent for Cr(VI) removal from aqueous solution.

Low Cost Integrated Sensors Utilizing Patterned Nano-Structured Titania Arrays Fabricated Using a Simple Process

2004 ◽  
Vol 828 ◽  
Author(s):  
Zuruzi Abu Samah ◽  
Andrei Kolmakov ◽  
Martin Moskovits ◽  
Noel C. MacDonald
Keyword(s):  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Aqueous Hydrogen Peroxide ◽  
X Ray ◽  
Sensing Systems ◽  
Potential Applications ◽  
Nano Wires ◽  
Low Temperature Process

ABSTRACTUsing a novel low-temperature process, we demonstrate the facile integration of crack-free nanostructured titania (NST) as sensing elements in microsystems. Unlike conventional sol-gel methods, NST layers of interconnected nano-walls and nano-wires were formed by reacting Ti surfaces with aqueous hydrogen peroxide solution. Cracks were observed in NST layers formed on blanket Ti films but absent on arrays of patterned Ti pads below a threshold dimension. Analyses using TEM, high resolution SEM, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) reveal that NST consists of anatase TiO2 nano-crystals. NST pads were found able to detect oxygen gas of a few ppm. NST pad arrays were integrated on rigid and flexible substrates with potential applications in low cost and wearable sensing systems.

scholarly journals Effect of Nobel Metal Ions on the Synthesis of Metal Nanoclusters for Selective Detection of Various Heavy Metals

2020 ◽  
Author(s):  
AMIT NAIN
Keyword(s):  
Metal Ions ◽  
Photoelectron Spectroscopy ◽  
Sea Water ◽  
Metal Nanoclusters ◽  
Average Life ◽  
Metal Core ◽  
X Ray ◽  
Metal Metal ◽  
Pl Quenching

In this study, effect of noble metal ions (Au, Ag and Cu) on the synthesis of metal nanoclusters (MNCs) have been investigated. Through heating at 70ºC, TSA/BSA–Au, –Ag and –Cu NCs were separately prepared from Au3+, Ag+ and Cu2+ respectively in the presence of bovine serum albumin (BSA) and thiosalicylic acid (TSA). They exhibit photoluminescence (PL) at 700, 624 and 430 nm, with an average life times of 1500, 100 and 11.71 ns, respectively, when excited at 350 nm. X–ray photoelectron spectroscopy (XPS) data support the presence of metal core (M0) and metal–thiolate shell (Mn–SRm) in each of the TSA/BSA–Metal nanoclusters (MNCs). Spectroscopic measurements reveal the formation of Au32–SR, Ag9–SR and (Cu4–Cu13)–SR species in the TSA/BSA–Au, –Ag and –Cu NCs respectively. Through PL quenching of the TSA/BSA–Au, –Ag and –Cu NCs, they have been used separately for quantitation of Hg2+, As3+ and Cr6+ , with linear ranges of 1400, 418, and 40400 nM and limits of detection (LODs) of 0.25, 2.34 and 3.54 nM, respectively. The PL quenching is mainly due to aggregation of the MNCs via metal–metal or metal–thiol interaction. The stable TSA/BSA–Au, –Ag and –Cu NCs have been employed separately for the determination of the concentrations of Hg2+, As3+ and Cr6+ ions in the spiked sea water samples, showing advantages of simplicity, rapidity, high selectivity, and sensitivity.

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