scholarly journals NANOPARTICLE BASED BIOSENSOR FOR PENICILLIN QUANTIFICATION IN PHARMACEUTICALS

2019 ◽  
pp. 102-107
Author(s):  
EMINE KARAKUS ◽  
CISEM TURAN
Keyword(s):  
Response Time ◽  
Zno Nanoparticles ◽  
Pharmaceutical Preparation ◽  
Zno Nanorods ◽  
Zno Nanorod ◽  
Buffer Concentration ◽  
Optimum Temperature ◽  
Short Response Time ◽  
Biosensor System ◽  
Optimum Ph

Objective: The objective of this study was to develop a new biosensor system based on nanoparticle to determine penicillin in pharmaceuticals. Methods: The characterization and optimization of the potentiometric penicillin biosensor (PB) were prepared by using synthesized surface-dependent and surface-independent ZnO nanoparticles named ZnO nanorods and chitosan were carried out. It was preferred ZnO nanorod because of its electrical, optical, physical and photocatalyst properties, biocompatibility and non-toxicity in the construction of the penicillin biosensor. Results: The operating range was obtained as 10-1-10-3M, the optimum buffer concentration was 10 mmol, optimum pH was 7.4 and the optimum temperature was 25 °C for the PB. The PB has advantages in terms of short response time, long enough shelf life, cheap, and easy elaborate. Conclusion: Whether the biosensor can be used to determine penicillin and accurately measure penicillin, the amount of penicillin in a commercial pharmaceutical preparation named Alfoxil was successfully made by using our prepared penicillin biosensor.

Tampon Derişiminin Biyosensör Cevabına Etkisi

2019 ◽  
pp. 8-11
Keyword(s):  
Ph Value ◽  
Electrochemical Studies ◽  
Buffer Concentration ◽  
Buffer Solutions ◽  
Biosensor System ◽  
Optimum Ph ◽  
Enzymatic Systems ◽  
Working Cell ◽  
Standard Solution ◽  
Biosensor Response

Objectives: All enzymes have a specific optimum pH value. Buffer solutions are used for optimal pH value in enzyme studies. Buffer concentrations play a key role in enzymatic systems. Material and Methods: In order to examine the effects of working cell buffer concentration used in enzyme-based biosensors on biosensor response, changes in the system's response to the same standard solution were studied using buffers in different concentrations in the biosensor system that determined ferric iron. Results: In electrochemical studies, it has been observed that changing the buffer concentration can change the results of other applications. Conclusions: In electrochemical studies, optimum buffer concentration is essential to obtain healthy results. Keywords: Buffer concentration, Biosensor, Iron

Facile Synthesis of a Porous ZnO Nanorod Array with Enhanced Photocatalysis for Photoelectrochemical Water Splitting Application

2020 ◽  
Vol 20 (6) ◽  
pp. 3512-3518
Author(s):  
Saleh Khan ◽  
Xiao-He Liu ◽  
Xi Jiang ◽  
Qing-Yun Chen
Keyword(s):  
Annealing Temperature ◽  
Zno Nanorods ◽  
Nanorod Array ◽  
Photocurrent Density ◽  
Zno Nanorod ◽  
Nanorod Arrays ◽  
Zno Nanorod Arrays ◽  
Irradiation Intensity ◽  
Heat Treated ◽  
Positive Effect

Highly efficient and effective porous ZnO nanorod arrays were fabricated by annealing ZnO nanorod arrays grown on a substrate using a simple hydrothermal method. The annealing had a positive effect on the nanorod morphology, structure and optical properties. The porosity was closely related to the annealing temperature. After heating at 450 °C, pores appeared on the nanorods. It was demonstrated that the porosity could be exploited to improve the visible light absorption of ZnO and reduce the bandgap from 3.11 eV to 2.99 eV. A combination of improved charge separation and transport of the heat-treated ZnO thus led to an increase in the photoelectrochemical properties. At an irradiation intensity of 100 mW/cm−2, the photocurrent density of the porous nanorod array was approximately 1.3 mA cm−2 at 1.2 V versus Ag/AgCl, which was five times higher than that of the ZnO nanorods. These results revealed the synthesis of promising porous ZnO nanorods for photoelectrochemical applications.

Monodispersed hierarchical ZnGa2O4 microflowers for self-powered solar-blind detection

2016 ◽  
Vol 4 (15) ◽  
pp. 3113-3118 ◽  
Author(s):  
Yue Teng ◽  
Le Xin Song ◽  
Wei Liu ◽  
Zhe Yuan Xu ◽  
Qing Shan Wang ◽  
...  
Keyword(s):  
Response Time ◽  
Bias Voltage ◽  
Dark Current ◽  
Blind Detection ◽  
Current Ratio ◽  
Zero Bias ◽  
Single Crystalline ◽  
Short Response Time ◽  
Solar Blind ◽  
Self Powered

We successfully synthesized ZnGa2O4 microflowers self-assembled by hexagonal single-crystalline nanopetals. The ZnGa2O4 crystal exhibits improved solar-blind detection performance such as short response time, large light to dark current ratio and high photocurrent stability under zero bias voltage.

Immobilization and Characterization of Tannase and its Haze-removing

2009 ◽  
Vol 15 (6) ◽  
pp. 545-552 ◽  
Author(s):  
Erzheng Su ◽  
Tao Xia ◽  
Liping Gao ◽  
Qianying Dai ◽  
Zhengzhu Zhang
Keyword(s):  
Kinetic Parameter ◽  
High Activity ◽  
Green Tea ◽  
Storage Stability ◽  
Residual Activity ◽  
Black Tea ◽  
Optimum Temperature ◽  
Oolong Tea ◽  
Optimum Ph

Tannase was effectively immobilized on alginate by the method of crosslinking-entrapment-crosslinking with a high activity recovery of 76.6%. The properties of immobilized tannase were investigated. Its optimum temperature was determined to be 35 ° C, decreasing 10 °C compared with that of free enzyme, whereas the optimum pH of 5.0 did not change. The thermal and pH stabilities of immobilized tannase increased to some degree. The kinetic parameter, Km, for immobilized tannase was estimated to be 11.6 × 10-4 mol/L. Fe2+ and Mn2+ could activate the activity of immobilized tannase. The immobilized tannase was also applied to treat the tea beverage to investigate its haze-removing effect. The content of non-estern catechins in green tea, black tea and oolong tea increased by 52.17%, 12.94% and 8.83%, respectively. The content of estern catechins in green tea, oolong tea and black tea decreased by 20.0%, 16.68% and 5.04%, respectively. The anti-sediment effect of green tea infusion treated with immobilized tannase was significantly increased. The storage stability and reusability of the immobilized tannase were improved greatly, with 72.5% activity retention after stored for 42 days and 86.9% residual activity after repeatedly used for 30 times.

Fabrication of an Electrochemical Sensor for Glucose Detection using ZnO Nanorods

MRS Advances ◽  
2016 ◽  
Vol 1 (13) ◽  
pp. 861-867 ◽  
Author(s):  
Sanghamitra Mandal ◽  
Mohammed Marie ◽  
Omar Manasreh
Keyword(s):  
Response Time ◽  
Glass Substrate ◽  
Glucose Sensor ◽  
Limit Of Detection ◽  
Sol Gel ◽  
Zno Nanorods ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Coated Glass Substrate ◽  
Coated Glass

ABSTRACTAn electrochemical glucose sensor based on zinc oxide (ZnO) nanorods is fabricated, characterized and tested. The ZnO nanorods are synthesized on indium titanium oxide (ITO) coated glass substrate, using the hydrothermal sol-gel technique. The working principle of the sensor under investigation is based on the electrochemical reaction taking place between cathode and anode, in the presence of an electrolyte. A platinum plate, used as the cathode and Nafion/Glucose Oxidase/ZnO nanorods/ITO-coated glass substrate used as anode, is immersed in pH 7.0 phosphate buffer solution electrolyte to test for the presence of glucose. Several amperometric tests are performed on the fabricated sensor to determine the response time, sensitivity and limit of detection of the sensor. A fast response time less than 3 s with a high sensitivity of 1.151 mA cm-2mM-1 and low limit of detection of 0.089 mM is reported. The glucose sensor is characterized using the cyclic voltammetry method in the range from -0.8 – 0.8 V with a voltage scan rate of 100 mV/s.

ZnO nanorod arrays grown on an AlN buffer layer and their enhanced ultraviolet emission

CrystEngComm ◽  
2017 ◽  
Vol 19 (41) ◽  
pp. 6085-6088 ◽  
Author(s):  
Amany Ali ◽  
DongBo Wang ◽  
JinZhong Wang ◽  
ShuJie Jiao ◽  
FengYun Guo ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Zno Nanorods ◽  
Zno Nanorod ◽  
Nanorod Arrays ◽  
Zno Nanorod Arrays ◽  
Ultraviolet Emission ◽  
Aln Buffer

The ultraviolet luminescence of ZnO nanorods was greatly enhanced through introducing an AlN buffer layer.

Role of Pristine and Acid-Functionalized Fullerene on Breaking Dye Aggregates and its Impact on the Efficiency of Solar Cells

2014 ◽  
Vol 67 (5) ◽  
pp. 819
Author(s):  
Syed Mujtaba Shah ◽  
Zafar Iqbal ◽  
Muzaffar Iqbal ◽  
Naila Shahzad ◽  
Amina Hana ◽  
...  
Keyword(s):  
Solar Cells ◽  
Zno Nanoparticles ◽  
Self Assembly ◽  
Zno Nanorods ◽  
Active Material ◽  
Dye Sensitized Solar Cells ◽  
Dye Sensitized ◽  
Transmission Electron ◽  
Sensitized Solar Cells

Porphyrin dyes have an inherent tendency to aggregate. This leads to a self-quenching phenomenon that hinders electron transfer to the conduction band of semiconductors in dye-sensitized solar cells. Self-quenching adversely affects the efficiency of solar cells. Here, we report the interaction of porphyrin with pristine and acid-functionalized fullerene molecules on the surface of ZnO nanoparticles under chemisorbed conditions. Chemisorption of porphyrin only on ZnO nanoparticles instigates aggregation of the porphyrin molecules. These aggregates can be effectively broken by chemisorbing fullerene molecules on the surface of the ZnO nanoparticles. This is due to self-assembly formation processes because of porphyrin–fullerene interactions. The nanohybrid material, consisting of ZnO nanorods, acid-functionalized porphyrin, and fullerene derivatives, was characterized by UV–visible spectroscopy, fourier transform infrared spectroscopy, fluorescence spectroscopy, and transmission electron microscopy. The material generates better performing dye-sensitized solar cells when compared with those fabricated from porphyrin-based photo-active material.

Butane/Propane Gas Sensing Using Zinc Oxide Film Grown by Successive Ionic Layer Adhesion and Reaction

2016 ◽  
Vol 705 ◽  
pp. 273-277 ◽  
Author(s):  
Emmanuel A. Florido ◽  
Sarah Allyssa Solidum
Keyword(s):  
Zinc Oxide ◽  
Oxide Film ◽  
Response Time ◽  
Recovery Time ◽  
Zno Nanorods ◽  
Hot Water ◽  
Zinc Oxide Film ◽  
Zno Film ◽  
Voltage Output ◽  
Ionic Layer

This study was aimed to test the ability of zinc oxide (ZnO) film fabricated by successive ionic layer adsorption and reaction (SILAR) to detect liquid petroleum gas consisting of a mixture of butane/propane gas. The film was fabricated by alternate dipping of pre-cleaned glass substrates in a sodium zincate bath and in a 95°C hot water bath using an automated dipping machine to control the sequence and dipping time. Scanning electron microscopy (SEM) revealed a uniform film consisting of wurtzite ZnO nanorods for the sample grown using 0.1M concentration of sodium zincate and 200 dippings. Current-voltage characterization of the samples showed an average resistivity of 1.343 Ω-m. EDS analysis of the film confirmed the existence of zinc oxide with 65.9% zinc and 34.1% oxygen. The ZnO film exhibited an ability to detect the gas with an average gas response of 0.44, average response time of 14 seconds and average recovery time of 25 seconds using a gas concentration in air of 1.5 % by volume. Response time is the time for the sensor to reach the peak voltage output from the start of gas exposure while recovery time is the time for the voltage output to return to the initial value without gas when the gas is removed from the chamber. The zinc oxide film also showed a voltage output of 100, 109.31, 118.92, 123.61, 133.5, and 149.52 mV when exposed to percent volume gas concentrations of 0, 0.5, 0.75, 1.0, 1.25, and 1.5, respectively with a correlation coefficient of 0.97. The sensor sensitivity is 32 Δ(mV)/Δ(%conc).

scholarly journals Properties of a new fungal b-galactosidase with potential application in the dairy industry

1999 ◽  
Vol 30 (3) ◽  
pp. 265-271 ◽  
Author(s):  
Rubens Cruz ◽  
Vinícius D'Arcádia Cruz ◽  
Juliana Gisele Belote ◽  
Marcelo de Oliveira Khenayfes ◽  
Claudia Dorta ◽  
...  
Keyword(s):  
Hydrolytic Activity ◽  
Industrial Applications ◽  
Transferase Activity ◽  
Optimum Temperature ◽  
Milk Whey ◽  
Beneficial Effects ◽  
Optimum Ph ◽  
Semi Solid ◽  
Good Productivity ◽  
Hydrolysis Of

<FONT FACE="Symbol">b</font>-Galactosidase or <FONT FACE="Symbol">b</font>-D-galactoside-galactohydrolase (EC. 3.2.1.23) is an important enzyme industrially used for the hydrolysis of lactose from milk and milk whey for several applications. Lately, the importance of this enzyme was enhanced by its galactosyltransferase activity, which is responsible for the synthesis of transgalactosylated oligosaccharides (TOS) that act as functional foods, with several beneficial effects on consumers. Penicillium simplicissimum, a strain isolated from soil, when grown in semi-solid medium showed good productivity of <FONT FACE="Symbol">b</font>-galactosidase with galactosyltransferase activity. The optimum pH for hydrolysis was in the 4.04.6 range and the optimum pH for galactosyltransferase activity was in the 6.07.0 range. The optimum temperature for hydrolysis and transferase activity was 55-60°C and 50°C, respectively, and the enzyme showed high thermostability for the hydrolytic activity. The enzyme showed a potential for several industrial applications such as removal of 67% of the lactose from milk and 84% of the lactose from milk whey when incubated at their original pH (4.5 and 6.34, respectively) under optimum temperature conditions. When incubated with a 40% lactose solution in 150 mM McIlvaine buffer, pH 4.5, at 55°C the enzyme converted 86.5% of the lactose to its component monosaccharides. When incubated with a 60% lactose solution in the same buffer but at pH 6.5 and 50°C, the enzyme can synthetize up to 30.5% TOS, with 39.5% lactose and 30% monosaccharides remaining in the preparation.

scholarly journals Characterization of Biosynthetic Enzymes for Ectoine as a Compatible Solute in a Moderately Halophilic Eubacterium, Halomonas elongata

1999 ◽  
Vol 181 (1) ◽  
pp. 91-99 ◽  
Author(s):  
Hisayo Ono ◽  
Kazuhisa Sawada ◽  
Nonpanga Khunajakr ◽  
Tao Tao ◽  
Mihoko Yamamoto ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Apparent Molecular Mass ◽  
Optimum Temperature ◽  
Sds Page ◽  
Halomonas Elongata ◽  
Optimum Ph

ABSTRACT 1,4,5,6-Tetrahydro-2-methyl-4-pyrimidinecarboxylic acid (ectoine) is an excellent osmoprotectant. The biosynthetic pathway of ectoine from aspartic β-semialdehyde (ASA), in Halomonas elongata, was elucidated by purification and characterization of each enzyme involved. 2,4-Diaminobutyrate (DABA) aminotransferase catalyzed reversively the first step of the pathway, conversion of ASA to DABA by transamination with l-glutamate. This enzyme required pyridoxal 5′-phosphate and potassium ions for its activity and stability. The gel filtration estimated an apparent molecular mass of 260 kDa, whereas molecular mass measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was 44 kDa. This enzyme exhibited an optimum pH of 8.6 and an optimum temperature of 25°C and had Km s of 9.1 mM forl-glutamate and 4.5 mM for dl-ASA. DABA acetyltransferase catalyzed acetylation of DABA to γ-N-acetyl-α,γ-diaminobutyric acid (ADABA) with acetyl coenzyme A and exhibited an optimum pH of 8.2 and an optimum temperature of 20°C in the presence of 0.4 M NaCl. The molecular mass was 45 kDa by gel filtration. Ectoine synthase catalyzed circularization of ADABA to ectoine and exhibited an optimum pH of 8.5 to 9.0 and an optimum temperature of 15°C in the presence of 0.5 M NaCl. This enzyme had an apparent molecular mass of 19 kDa by SDS-PAGE and a Km of 8.4 mM in the presence of 0.77 M NaCl. DABA acetyltransferase and ectoine synthase were stabilized in the presence of NaCl (>2 M) and DABA (100 mM) at temperatures below 30°C.

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