Biosensing Surfaces Based on Quantum Dots Array

2014 ◽  
Vol 490-491 ◽  
pp. 1602-1606 ◽  
Author(s):  
Jana Drbohlavová ◽  
Jana Chomoucka ◽  
Radim Hrdý ◽  
Vojtech Svatos ◽  
Jaromir Hubalek
Keyword(s):  
Quantum Dots ◽  
Chemical Composition ◽  
Fluorescence Spectroscopy ◽  
Surface Topography ◽  
Electrochemical Detection ◽  
Physical Adsorption ◽  
Homogeneous Distribution ◽  
Alumina Template ◽  
Detection Of Biomolecules

The fabrication of self-ordered semiconductor (TiO2) and noble metal (Au) QDs arrays was successfully achieved by advanced nonlithographic template based method, namely using nanoporous alumina template. The emphasis was placed on the successful preparation of QDs arrays with the desired size, homogeneous distribution and optical (especially fluorescence) properties. Titania and gold QDs characterization by SEM, EDX and fluorescence spectroscopy was performed in order to verify their surface topography, chemical composition and emission properties in UV/VIS range of spectra, respectively. The surface biofunctionalization of QDs was realized via simple physical adsorption of glutathione tripeptide, which makes these arrays suitable for potential biosensing application, mainly in optical and electrochemical detection of biomoleculesin vitro.

Nontoxic Silicon Nanocrystals and Nanodiamonds as Substitution for Harmful Quantum Dots

2009 ◽  
Vol 1241 ◽  
Author(s):  
Anna Fucikova ◽  
Jan Valenta ◽  
Ivan Pelant ◽  
Vitezslav Brezina
Keyword(s):  
Quantum Dots ◽  
Chemical Composition ◽  
Silicon Nanocrystals ◽  
Nanocrystalline Silicon ◽  
Semiconductor Quantum Dots ◽  
In Vivo Studies ◽  
Long Term Stability

AbstractThe commercially available semiconductor quantum dots have been proven to be slightly to significantly toxic by recent publications depending on the chemical composition. We are developing new non-toxic fluorescent labels based on (i) nanocrystalline silicon, suitable for in vivo studies due to their biodegrability, and on (ii) nanodiamonds, intended mainly for in vitro use due to their long-term stability and nondegradilibity.

Collagen fibrillogenesis in vitro: interaction of types I and V collagen

1986 ◽  
Vol 44 ◽  
pp. 210-211
Author(s):  
Arthur J. Wasserman ◽  
Kathy C. Kloos ◽  
David E. Birk
Keyword(s):  
Type I Collagen ◽  
Corneal Stroma ◽  
Minor Component ◽  
Homogeneous Distribution ◽  
Type I ◽  
Type V Collagen ◽  
Fibril Morphology ◽  
Type V ◽  
In Vitro Interaction

Type I collagen is the predominant collagen in the cornea with type V collagen being a quantitatively minor component. However, the content of type V collagen (10-20%) in the cornea is high when compared to other tissues containing predominantly type I collagen. The corneal stroma has a homogeneous distribution of these two collagens, however, immunochemical localization of type V collagen requires the disruption of type I collagen structure. This indicates that these collagens may be arranged as heterpolymeric fibrils. This arrangement may be responsible for the control of fibril diameter necessary for corneal transparency. The purpose of this work is to study the in vitro assembly of collagen type V and to determine whether the interactions of these collagens influence fibril morphology.

Protective Effect of Boswellic Resin Against Memory Loss and Alzheimer’s Induced by Aluminum Tetrachloride and D-Galactose (Experimental study in Mice)

2020 ◽  
Author(s):  
K. Zerrouki ◽  
N. Djebli ◽  
L. Gadouche ◽  
I. Erdogan Orhan ◽  
F. SezerSenol Deniz ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Protective Effect ◽  
Cell Damage ◽  
Memory Loss ◽  
Control Group ◽  
Total Extract ◽  
Swiss Mice ◽  
Octyl Acetate

Nowadays, because of the industrialization, a lot of contaminant were available ; the consequences of this availability are apparition of diseases including neurodegeneration. Neurodegenerative diseases of the human brain comprise a variety of disorders that affect an increasing percentage of the population. This study is based on the effect of the Boswellic resin, which is from a medicinal plant and known for its antioxidant effects on nerve cell damage. The objective of this work was to evaluate the in vitro and in vivo effects of the Boswellic resin on anticholinesterase activity and Alzheimer’s disease (AD) induced by D-galactose and aluminum tetrachloride in Swiss mice. Chemical composition of the resin essential oil was identified by the CG-MS analysis. The antioxidant activity was also assessed by the DMPD and metal chelation methods. In order to understand the mechanism of memory improvement, the acetylcholinesterase, AChE, and butyrylcholinesterase, BChE, inhibitory assays were performed. In vivo part of the study was achieved on Swiss mice divided into four groups: control, AD model, treated AD, and treated control group. The identification of chemical composition by CG-MS reach the 89.67% of the total extract compounds presented some very important molecules (p-Cymene, n-Octyl acetate, α-Pinene…). The present study proves that Boswellic resin improves memory and learning in treated Alzheimer’s group, modulates the oxidative stress and be involved in the protective effect against amyloid deposition and neurodegeneration, and stimulates the immune system in mice’s brain.

Comparative Analysis of In-Vitro Biological Activities of Methyl Eugenol Rich Cymbopogon khasianus Hack., Leaf Essential Oil with Pure Methyl Eugenol Compound

2020 ◽  
Vol 21 (10) ◽  
pp. 927-938 ◽  
Author(s):  
Roktim Gogoi ◽  
Rikraj Loying ◽  
Neelav Sarma ◽  
Twahira Begum ◽  
Sudin K. Pandey ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Essential Oil ◽  
Biological Activities ◽  
Methyl Eugenol ◽  
Dpph Assay ◽  
Pure Compound ◽  
Allium Cepa Assay ◽  
Anti Inflammatory ◽  
Lemongrass Essential Oil

Background: The essential oil of methyl eugenol rich Cymbopogon khasianus Hack. was evaluated and its bioactivities were compared with pure methyl eugenol. So far, methyl eugenol rich essential oil of lemongrass was not studied for any biological activities; hence, the present study was conducted. Objective: This study examined the chemical composition of essential oil of methyl eugenol rich Cymbopogon khasianus Hack., and evaluated its antioxidant, anti-inflammatory, antimicrobial, and herbicidal properties and genotoxicity, which were compared with pure compound, methyl eugenol. Material and Methods: Methyl eugenol rich variety of Cymbopogon khasianus Hack., with registration no. INGR18037 (c.v. Jor Lab L-9) was collected from experimental farm CSIR-NEIST, Jorhat, Assam (26.7378°N, 94.1570°E). The essential oil wasobtained by hydro-distillation using a Clevenger apparatus. The chemical composition of the essential oil was evaluated using GC/MS analysis and its antioxidant (DPPH assay, reducing power assay), anti-inflammatory (Egg albumin denaturation assay), and antimicrobial (Disc diffusion assay, MIC) properties, seed germination effect and genotoxicity (Allium cepa assay) were studied and compared with pure Methyl Eugenol compound (ME). Results: Major components detected in the Essential Oil (EO) through Gas chromatography/mass spectroscopy analysis were methyl eugenol (73.17%) and β-myrcene (8.58%). A total of 35components were detected with a total identified area percentage of 98.34%. DPPH assay revealed considerable antioxidant activity of methyl eugenol rich lemongrass essential oil (IC50= 2.263 μg/mL), which is lower than standard ascorbic acid (IC50 2.58 μg/mL), and higher than standard Methyl Eugenol (ME) (IC50 2.253 μg/mL). Methyl eugenol rich lemongrass EO showed IC50 38.00 μg/mL, ME 36.44 μg/mL, and sodium diclofenac 22.76 μg/mL, in in-vitro anti-inflammatory test. Moderate antimicrobial activity towards the 8 tested microbes was shown by methyl eugenol rich lemongrass essential oil whose effectiveness against the microbes was less as compared to pure ME standard. Seed germination assay further revealed the herbicidal properties of methyl eugenol rich essential oil. Moreover, Allium cepa assay revealed moderate genotoxicity of the essential oil. Conclusion: This paper compared the antioxidant, anti-inflammatory, antimicrobial, genotoxicity and herbicidal activities of methyl eugenol rich lemongrass with pure methyl eugenol. This methyl eugenol rich lemongrass variety can be used as an alternative of methyl eugenol pure compound. Hence, the essential oil of this variety has the potential of developing cost-effective, easily available antioxidative/ antimicrobial drugs but its use should be under the safety range of methyl eugenol and needs further clinical trials.

scholarly journals Chemical Composition, In Vitro and In Silico Antioxidant Potential of Melissa officinalis subsp. officinalis Essential Oil

Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1081
Author(s):  
Matilda Rădulescu ◽  
Călin Jianu ◽  
Alexandra Teodora Lukinich-Gruia ◽  
Marius Mioc ◽  
Alexandra Mioc ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Chemical Composition ◽  
Essential Oil ◽  
In Silico ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Inhibitory Effect ◽  
Melissa Officinalis ◽  
Β Carotene

The investigation aimed to study the in vitro and in silico antioxidant properties of Melissa officinalis subsp. officinalis essential oil (MOEO). The chemical composition of MOEO was determined using GC–MS analysis. Among 36 compounds identified in MOEO, the main were beta-cubebene (27.66%), beta-caryophyllene (27.41%), alpha-cadinene (4.72%), caryophyllene oxide (4.09%), and alpha-cadinol (4.07%), respectively. In vitro antioxidant properties of MOEO have been studied in 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging, and inhibition of β-carotene bleaching assays. The half-maximal inhibitory concentration (IC50) for the radical scavenging abilities of ABTS and DPPH were 1.225 ± 0.011 μg/mL and 14.015 ± 0.027 μg/mL, respectively, demonstrating good antioxidant activity. Moreover, MOEO exhibited a strong inhibitory effect (94.031 ± 0.082%) in the β-carotene bleaching assay by neutralizing hydroperoxides, responsible for the oxidation of highly unsaturated β-carotene. Furthermore, molecular docking showed that the MOEO components could exert an in vitro antioxidant activity through xanthine oxidoreductase inhibition. The most active structures are minor MOEO components (approximately 6%), among which the highest affinity for the target protein belongs to carvacrol.

scholarly journals Antimicrobial Activity and Chemical Characterization of a Non-Polar Extract of Saffron Stamens in Food Matrix

Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 703
Author(s):  
Severino Zara ◽  
Giacomo L. Petretto ◽  
Alberto Mannu ◽  
Giacomo Zara ◽  
Marilena Budroni ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Fatty Acid Content ◽  
Chemical Characterization ◽  
Antimicrobial Activities ◽  
Added Value ◽  
Gas Chromatography Mass Spectrometry ◽  
Food Matrix ◽  
Bacterial Strains ◽  
By Products

The production of saffron spice generates large quantities of plant by-products: over 90% of the plant material collected is discarded, and a consideration fraction of this waste is plant stamens. This work investigated the chemical composition and the antimicrobial activities of the non-polar fraction extracted from four different saffron flower stamens. The chemical composition of ethereal extracts of the saffron stamens was qualitatively assessed by means of gas–chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) analyses. These analyses revealed ethereal extracts to possess a high polyunsaturated fatty acid content. In vitro antibacterial activity of stamen extracts showed no large differences between Gram-positive and Gram-negative bacteria in terms of minimal inhibitory concentration (MIC). In food matrix microbial analysis of the bacterial strains belonging to the main foodborne pathogen species, including Staphylococcus aureus DSM 20231, Escherichia coli DSM 30083, and Listeria monocytogenes DSM 20600, using low-fat UHT milk, revealed a statistically significant reduction in the number of cells (particularly for E. coli and S. aureus with a complete elimination of the population of the two target bacteria following incubation in diethyl ether extracts of saffron stamen (DES) at high concentrations tested, both at 37 °C and 6 °C (for 48 h and 7 days, respectively). A synergic effect was observed when the pathogens were incubated at 6 °C with DES. This work shows these by-products to be excellent sources of bioactive compounds, which could be exploited in high-added-value products, such as food, cosmetics, and drugs.

scholarly journals The Physical Adsorption of Gelatinized Starch with Tannic Acid Decreases the Inhibitory Activity of the Polyphenol against α-Amylase

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1233
Author(s):  
Yueyi Wang ◽  
Shuangshuang Li ◽  
Fangting Bai ◽  
Junwei Cao ◽  
Lijun Sun
Keyword(s):  
Enzyme Inhibition ◽  
Tannic Acid ◽  
Inhibitory Activity ◽  
Adsorption Property ◽  
Physical Adsorption ◽  
Enzyme Active Site ◽  
Opposite Trend ◽  
Gelatinized Starch ◽  
The Difference

The effects of mixing orders of tannic acid (TA), starch, and α-amylase on the enzyme inhibition of TA were studied, including mixing TA with α-amylase before starch addition (order 1), mixing TA with pre-gelatinized starch before α-amylase addition (order 2) and co-gelatinizing TA with starch before α-amylase addition (order 3). It was found that the enzyme inhibition was always highest for order 1 because TA could bind with the enzyme active site thoroughly before digestion occurred. Both order 2 and 3 reduced α-amylase inhibition through decreasing binding of TA with the enzyme, which resulted from the non-covalent physical adsorption of TA with gelatinized starch. Interestingly, at low TA concentration, α-amylase inhibition for order 2 was higher than order 3, while at high TA concentration, the inhibition was shown with the opposite trend, which arose from the difference in the adsorption property between the pre-gelatinized and co-gelatinized starch at the corresponding TA concentrations. Moreover, both the crystalline structures and apparent morphology of starch were not significantly altered by TA addition for order 2 and 3. Conclusively, although a polyphenol has an acceptable inhibitory activity in vitro, the actual effect may not reach the expected one when taking processing procedures into account.

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