Immobilization of urease in poly(1-vinyl imidazole)/poly(acrylic acid) network

2010 ◽  
Vol 64 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Mehmet Şenel ◽  
Agah Coşkun ◽  
M. Fatih Abasıyanık ◽  
Ayhan Bozkurt
Keyword(s):  
Acrylic Acid ◽  
Enzyme Immobilization ◽  
Storage Stability ◽  
Polymer Network ◽  
Ft Ir ◽  
Basic Characteristics ◽  
And Storage ◽  
Menten Constant ◽  
Ft Ir Spectroscopy ◽  
Poly Acrylic Acid

AbstractIn this study, urease was immobilized in a polymer network obtained by complexation of poly(1-vinyl imidazole) (PVI) with poly(acrylic acid) (PAA). Preparation of the polymer network was monitored by FT-IR spectroscopy. Scanning electron microscopy (SEM) revealed that enzyme immobilization had a strong effect on film morphology. Proton conductivity of the PVI/PAA network was measured via impedance spectroscopy under humidified conditions. Values of the Michaelis-Menten constant (K M) for immobilized urease were higher than for the free enzyme, indicating a decreased affinity of the enzyme to its substrate. The basic characteristics (pHopt, pHstability, T opt, T stability, reusability, and storage stability) of immobilized urease were determined. The results show that the PAA/PVI polymer network is suitable for enzyme immobilization.

Synthesis and Characteristics of Interpenetrating Polymer Network Hydrogels Based on Konjac Glucomannan with Different Molecular Weights and Poly(acrylic acid)

2011 ◽  
Vol 393-395 ◽  
pp. 1004-1007
Author(s):  
Xue Yao ◽  
Xue Gang Luo ◽  
Ben Chao Han
Keyword(s):  
Acrylic Acid ◽  
Enzymatic Degradation ◽  
Drug Carrier ◽  
Polymer Network ◽  
Konjac Glucomannan ◽  
Interpenetrating Polymer Network ◽  
Swelling Ratio ◽  
Molecular Weights ◽  
Ft Ir ◽  
Poly Acrylic Acid

Konjac glucomannan with different molecular weights/poly(acrylic acid) hydrogels were prepared in this paper. The structure of the IPN hydrogels was characterized by FT-IR and SEM. The swelling ratio of these hydrogels showed they had pH-sensitive properties and the enzymatic degradation tests showed the hydrogels retain the enzymatic degradation character of KGM. Furthermore, hydrogel composed of native KGM degraded sharply in enzymatic degradation test and it had bigger swelling ratio and weight loss ratio than those hydrogels which composed of lower molecular weights KGM. Therefore, hydrogels composed of lower molecular weight might release drug more stable when they were used as drug carrier.

scholarly journals Polyethylene Migration from Food Packaging on Cheese Detected by Raman and Infrared (ATR/FT-IR) Spectroscopy

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3872
Author(s):  
Klytaimnistra Katsara ◽  
George Kenanakis ◽  
Zacharias Viskadourakis ◽  
Vassilis M. Papadakis
Keyword(s):  
Vibrational Spectroscopy ◽  
Food Packaging ◽  
Time Frame ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Ft Ir ◽  
Comparative Results ◽  
Short Time ◽  
And Storage ◽  
Ft Ir Spectroscopy

For multiple years, food packaging migration has been a major concern in food and health sciences. Plastics, such as polyethylene, are continuously utilized in food packaging for preservation and easy handling purposes during transportation and storage. In this work, three types of cheese, Edam, Kefalotyri and Parmesan, of different hardness were studied under two complementary vibrational spectroscopy methods, ATR-FTIR and Raman spectroscopy, to determine the migration of low-density polyethylene from plastic packaging to the surface of cheese samples. The experimental duration of this study was set to 28 days due to the degradation time of the selected cheese samples, which is clearly visible after 1 month in refrigerated conditions at 4 °C. Raman and ATR-FTIR measurements were performed at a 4–3–4–3 day pattern to obtain comparative results. Initially, consistency/repeatability measurement tests were performed on Day0 for each sample of all cheese specimens to understand if there is any overlap between the characteristic Raman and ATR-FTIR peaks of the cheese with the ones from the low-density polyethylene package. We provide evidence that on Day14, peaks of low-density polyethylene appeared due to polymeric migration in all three cheese types we tested. In all cheese samples, microbial outgrowth started to develop after Day21, as observed visually and under the bright-field microscope, causing peak reverse. Food packaging migration was validated using two different approaches of vibrational spectroscopy (Raman and FT-IR), revealing that cheese needs to be consumed within a short time frame in refrigerated conditions at 4 °C.

scholarly journals Bentonite-supported catalase

2005 ◽  
Vol 70 (5) ◽  
pp. 721-726 ◽  
Author(s):  
S. Alkan ◽  
H. Ceylan ◽  
O. Arslan
Keyword(s):  
Ionic Strength ◽  
Kinetic Parameters ◽  
Enzyme Immobilization ◽  
Storage Stability ◽  
High Ionic Strength ◽  
Enzyme Inactivation ◽  
Valuable Method ◽  
And Storage

The properties of the clay bentonite as a support for enzyme immobilization were studied using the enzyme catalase. Such an immobilization does not result in enzyme inactivation and constitutes a valuable method for immobilizing catalase at high ionic strength. The bentonite-supported catalase was characterized in terms of pH and ionic strength dependencies, thermal and storage stability and kinetic parameters. These studies indicate that bentonite is a valuable support for the simple adsorption of enzymes. .

scholarly journals Formation and Stability of Smooth Thin Films with Soft Microgels Made of Poly(N-Isopropylacrylamide) and Poly(Acrylic Acid)

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2638
Author(s):  
Elena Buratti ◽  
Ilaria Sanzari ◽  
Franco Dinelli ◽  
Themistoklis Prodromakis ◽  
Monica Bertoldo
Keyword(s):  
Acrylic Acid ◽  
Colloidal Particles ◽  
Polymer Network ◽  
Spin Speed ◽  
Glass Substrates ◽  
Smooth Film ◽  
The Difference ◽  
The Stability ◽  
Individual Particles ◽  
Poly Acrylic Acid

In this work, soft microgels of Poly(N-Isopropylacrylamide) (PNIPAm) at two different sizes and of interpenetrated polymer network (IPN) composed of PNIPAm and Poly(Acrylic Acid) (PAAc) were synthesized. Then, solutions of these different types of microgels have been spin-coated on glass substrates with different degrees of hydrophobicity. PNIPAm particles with a larger diameter form either patches or a continuous layer, where individual particles are still distinct, depending on the dispersion concentration and spin speed. On the other, PNIPAm particles with a smaller diameter and IPN particles form a continuous and smooth film, with a thickness depending on the dispersion concentration and spin-speed. The difference in morphology observed can be explained if one considers that the microgels may behave as colloidal particles or macromolecules, depending on their size and composition. Additionally, the microgel size and composition can also affect the stability of the depositions when rinsed in water. In particular, we find that the smooth and continuous films show a stimuli-dependent stability on parameters such as temperature and pH, while large particle layers are stable under any condition except on hydrophilic glass by washing at 50 °C.

Dual-Charge Nanofiber Mats Made of Chitosan(CS)/Poly(Vinyl Alcohol) (PVA) and Poly-(Acrylic Acid-Co-Maleic Acid) (PAMA)/PVA

2019 ◽  
Vol 819 ◽  
pp. 145-150
Author(s):  
Thapakorn Chareonying ◽  
Junnasir M. Sakilan ◽  
Theerasak Rojanarata ◽  
Prasopchai Patrojanasophon ◽  
Prasert Akkaramongkolporn ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Maleic Acid ◽  
Vinyl Alcohol ◽  
Electrospinning Process ◽  
Poly Vinyl Alcohol ◽  
Water Capacity ◽  
Ft Ir ◽  
Nanofiber Mats ◽  
Positively Charged ◽  
Poly Acrylic Acid

Nanofibers have been widely used for tissue engineering. Using charged polymers for the preparation of nanofibers can be useful for the loading of substances or macromolecules. Dual charge nanofiber mats are expected to be able to immobilize both positively charged and negatively charged substances in one versatile nanofiber mat. The purpose of this study was to prepare and characterize dual-charge nanofibers generated from poly (vinyl alcohol) (PVA)/poly-(acrylic acid-co-maleic acid) (PAMA) and chitosan (CS)/PVA. The polymer solutions of PAMA/PVA (1:1.63 w/w) and CS/PVA (1:2.33 w/w) were electrospun to form the nanofibers using dual-jet electrospinning process. The obtained dual-charge nanofibers were thermally crosslinked by leaving the nanofibers in the oven at 110-130 °C for 0.5, 1, 3, 5 h. The appearance of the nanofiber mat was characterized by a scanning electron microscope (SEM), and the diameter of nanofibers were determined by an image analysis software (J-micro vision®). The percentage water insolubilization and FT-IR spectra were also determined. The dual-size nanofiber mats with smooth and bead-free fibers were obtained. The diameter of the PAMA/PVA and CS/PVA fibers was 574.54 ± 142.98 nm and 225.69 ± 41.92 nm, respectively. The desirable temperature and time for the crosslink of the dual-charge nanofiber mats was 130 °C for 1 h which could provide a high insolubilization with water capacity of 93.22 ± 2.23%.

scholarly journals Structural analysis of microbial poly(ɛ-L-lysine)/poly(acrylic acid) complex by FT-IR, DSC, and solid-state 13C and 15N NMR

2011 ◽  
Vol 44 (2) ◽  
pp. 200-203 ◽  
Author(s):  
Shiro Maeda ◽  
Yasuhiro Fujiwara ◽  
Chizuru Sasaki ◽  
Ko-Ki Kunimoto
Keyword(s):  
Solid State ◽  
Structural Analysis ◽  
Acrylic Acid ◽  
15N Nmr ◽  
Acid Complex ◽  
Ft Ir ◽  
Poly Acrylic Acid

scholarly journals Characterization of the Spindle Morphology Nanomicelles Assembled from Sericin and Gelatin

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Xiaozhou Su ◽  
Lei Li ◽  
Weihan Huang
Keyword(s):  
Electron Microscopy ◽  
Protein Concentration ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Ft Ir ◽  
And Storage ◽  
Ft Ir Spectroscopy

Complex nanomicelles were prepared by sericin and type A gelatin with molecular weight of 5789 Da and 128664 Da separately. The assembling conditions were as follows: mass ratio (sericin/gelatin) was 1 : 1, protein concentration was 0.5%, temperature was 35°C, and assembling time was 18 hours. Scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), and dynamic light scattering (DLS) were conducted to observe and characterize the complex nanomicelles. Results showed that the complex sericin/gelatin micelles was a kind of nanospindle micelles. The micelles had high electrochemical stability, thermal stability, antidilution stability, and storage stability.

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