scholarly journals Cross-Linked Enzyme Aggregates of Naringinase: Novel Biocatalysts for Naringin Hydrolysis

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Maria H. L. Ribeiro ◽  
Marco Rabaça
Keyword(s):  
Polyethylene Glycol ◽  
Ammonium Sulphate ◽  
Mechanical Stability ◽  
Butyl Alcohol ◽  
Cross Linking ◽  
Enzyme Complex ◽  
Food Industries ◽  
Highly Active ◽  
New Generation ◽  
Polyethylene Glycol 6000

Cross-linked enzyme aggregates (CLEAs) have emerged as interesting biocatalyst design for immobilization. These new generation enzyme biocatalysts, CLEAs, in addition to exhibiting good mechanical stability, can be highly active, since they do not include large amounts of foreign particulate nonenzymatic material and may have increased stability. Naringinase (NGase) is an enzyme complex with high potential in pharmaceutical and food industries. In fact, NGase can be used in the biotransformation of steroids, of antibiotics and mainly on glycosides hydrolysis. In this paper, the formation of CLEAs was tried using ammonium sulphate, polyethylene glycol 6000 and tert-butyl alcohol as precipitant agents and glutaraldehyde as cross-linking agent, at different pH, time, and temperature conditions. However, among the precipitant agents tested, only tert-butyl alcohol cross-linked with glutaraldehyde allowed the formation of CLEAs, at pH 4.0 and at temperature between 7 and 10∘C. Different enzyme loadings were tested. The NGase-CLEAs were highly effective in naringin hydrolysis. The operational stability of the NGase-CLEAs aggregates was studied through six successive reutilizations.

Injectable, Tough and Cytocompatible Dual Cross-Linking Hydrogels with Enhanced Mechanical Stability

2020 ◽  
Author(s):  
Zezhao Qin ◽  
Xiaofeng Yu ◽  
Haiyang Wu ◽  
Lei Yang ◽  
Hongying Lv ◽  
...  
Keyword(s):  
Mechanical Stability ◽  
Cross Linking

Hepatitis a Virus Concentration from Experimentally Contaminated Distilled, Tap, Waste and Seawater

1989 ◽  
Vol 21 (3) ◽  
pp. 255-258 ◽  
Author(s):  
Evangélos Biziagos ◽  
Jacques Passagot ◽  
Jean-Marc Crance ◽  
Robert Deloince
Keyword(s):  
Cell Culture ◽  
Polyethylene Glycol ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Tap Water ◽  
Virus Concentration ◽  
Beef Extract ◽  
Polyethylene Glycol 6000

The concentration of cell-culture-adapted hepatitis A virus (HAV) from experimentally contaminated distilled, drinking, waste and seawater was performed by using a filter adsorption-elu-tion method in the following conditions: HAV seeded in water was adsorbed at pH 4.0 to two nitrocellulose membranes (1.2 and 0.45 µm porosity for distilled and tap water or 8.0 and 3.0 µm porosity for waste and seawater), then eluted by 3% beef-extract at pH 8.5 and further concentrated by polyethylene glycol 6000 precipitation. Thus, HAV in 5 to 50 liters of seeded waters was concentrated approximately 1,700 to 17,000 fold with greater than 70% recovery of the initial virus added to the samples.

scholarly journals Toward Physicochemical and Rheological Characterization of Different Injectable Hyaluronic Acid Dermal Fillers Cross-Linked with Polyethylene Glycol Diglycidyl Ether

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 948
Author(s):  
Nicola Zerbinati ◽  
Sabrina Sommatis ◽  
Cristina Maccario ◽  
Maria Chiara Capillo ◽  
Giulia Grimaldi ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Polyethylene Glycol ◽  
Biological Activities ◽  
Diglycidyl Ether ◽  
Dermal Filler ◽  
Cross Linking ◽  
Matrix Structure ◽  
Dermal Fillers ◽  
Rheological Characterization

(1) Background: Injectable hyaluronic acid (HA) dermal fillers are used to restore volume, hydration and skin tone in aesthetic medicine. HA fillers differ from each other due to their cross-linking technologies, with the aim to increase mechanical and biological activities. One of the most recent and promising cross-linkers is polyethylene glycol diglycidyl ether (PEGDE), used by the company Matex Lab S.p.A., (Brindisi, Italy) to create the HA dermal filler PEGDE family. Over the last few years, several studies have been performed to investigate the biocompatibility and biodegradability of these formulations, but little information is available regarding their matrix structure, rheological and physicochemical properties related to their cross-linking technologies, the HA content or the degree of cross-linking. (2) Methods: Seven different injectable HA hydrogels were subjected to optical microscopic examination, cohesivity evaluation and rheological characterization in order to investigate their behavior. (3) Results: The analyzed cross-linked dermal fillers showed a fibrous “spiderweb-like” matrix structure, with each medical device presenting different and peculiar rheological features. Except for HA non cross-linked hydrogel 18 mg/mL, all showed an elastic and cohesive profile. (4) Conclusions: The comparative analysis with other literature works makes a preliminary characterization of these injectable medical devices possible.

scholarly journals Molecularly imprinted membrane for transport of urea, creatinine, and vitamin B12 as a hemodialysis candidate membrane

2021 ◽  
Vol 19 (1) ◽  
pp. 806-817
Author(s):  
Muhammad Cholid Djunaidi ◽  
Nabilah Anindita Febriola ◽  
Abdul Haris
Keyword(s):  
Polyethylene Glycol ◽  
Vitamin B12 ◽  
Kidney Function ◽  
Cross Linking ◽  
Vitamin B ◽  
Molecularly Imprinted ◽  
Selective Transport ◽  
Molecularly Imprinted Membrane ◽  
Better Than ◽  
Imprinted Membrane

Abstract High levels of urea and creatinine in the blood are a sign of decreased kidney function. To remove these substances from the blood, hemodialysis which utilizes membranes could be used. In this study, a molecularly imprinted membrane (MIM) was synthesized for the selective transport of urea. The synthesis is initiated with the polymerization of eugenol into polyeugenol and then into polyeugenoxy acetate (PA). The PA is then contacted with urea and then used as the functional polymer in the synthesis of MIM with polysulfone as the membrane base, and polyethylene glycol as the cross-linking agent. The result was later analyzed with FTIR and SEM-EDX. The membrane is then used in the transport of urea, creatinine, and vitamin B12 and then compared with the non-imprinted membrane (NIM) performance. By using UV-Vis spectrophotometry, the results showed that the membrane with 10 h heating variation is able to transport more urea and is more selective than NIM; this proves that the urea template on the MIM enables it to recognize urea molecules better than creatinine and vitamin B12. The order of transport from the best results is urea > creatinine > vitamin B12.

Ionic cross-linking of cellulose nanofibers: an approach to enhance mechanical stability for dynamic adsorption

2019 ◽  
Vol 26 (28) ◽  
pp. 28842-28851 ◽  
Author(s):  
Muhammad Muqeet ◽  
Umair Ahmed Qureshi ◽  
Rasool Bux Mahar ◽  
Zeeshan Khatri ◽  
Farooq Ahmed ◽  
...  
Keyword(s):  
Mechanical Stability ◽  
Cellulose Nanofibers ◽  
Cross Linking ◽  
Dynamic Adsorption

Polyacryloyl hydrazide based injectable & stimuli responsive hydrogels with tunable properties

2014 ◽  
Vol 2 (42) ◽  
pp. 7429-7439 ◽  
Author(s):  
Anuj Kumar ◽  
Sabindra K. Samal ◽  
Rupesh Dash ◽  
Umaprasana Ojha
Keyword(s):  
Polyethylene Glycol ◽  
Acrylic Acid ◽  
Diethyl Malonate ◽  
Synthesis And Characterization ◽  
Cross Linking ◽  
Stimuli Responsive ◽  
Polyethylene Glycol Diacrylate ◽  
Glycol Diacrylate ◽  
Responsive Hydrogels

The synthesis and characterization of a series of injectable and stimuli responsive hydrogels based on polyacryloyl hydrazide have been accomplished using dimethyl 2,2′-thiodiacetate, acrylic acid, diethyl malonate and polyethylene glycol diacrylate as cross-linkers through a chemical or dual cross-linking pathway.

scholarly journals Metallic Nanowire Percolating Network: From Main Properties to Applications

2020 ◽  
Author(s):  
Daniel Bellet ◽  
Dorina T. Papanastasiou ◽  
Joao Resende ◽  
Viet Huong Nguyen ◽  
Carmen Jiménez ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Mechanical Stability ◽  
Low Cost ◽  
Transparent Electrodes ◽  
Energy Devices ◽  
Energy Technologies ◽  
New Generation ◽  
Industrial Demand ◽  
High Mechanical Stability ◽  
Percolating Network

There has been lately a growing interest into flexible, efficient and low-cost transparent electrodes which can be integrated for many applications. This includes several applications related to energy technologies (photovoltaics, lighting, supercapacitor, electrochromism, etc.) or displays (touch screens, transparent heaters, etc.) as well as Internet of Things (IoT) linked with renewable energy and autonomous devices. This associated industrial demand for low-cost and flexible industrial devices is rapidly increasing, creating a need for a new generation of transparent electrodes (TEs). Indium tin oxide has so far dominated the field of TE, but indium’s scarcity and brittleness have prompted a search into alternatives. Metallic nanowire (MNW) networks appear to be one of the most promising emerging TEs. Randomly deposited MNW networks, for instance, can present sheet resistance values below 10 Ω/sq., optical transparency of 90% and high mechanical stability under bending tests. AgNW or CuNW networks are destined to address a large variety of emerging applications. The main properties of MNW networks, their stability and their integration in energy devices are discussed in this contribution.

A new automated turbidimetric immunoassay for quantifying alpha 1-antitrypsin in serum.

1986 ◽  
Vol 32 (6) ◽  
pp. 1020-1022 ◽  
Author(s):  
J A Viedma ◽  
A de la Iglesia ◽  
M Parera ◽  
M T López
Keyword(s):  
Polyethylene Glycol ◽  
Parametric Estimation ◽  
Tween 20 ◽  
Upper Limit ◽  
Analytical Recovery ◽  
The Mean ◽  
Alpha 1 Antitrypsin ◽  
Polyethylene Glycol 6000 ◽  
Immunoprecipitation Reaction ◽  
Turbidimetric Immunoassay

Abstract This rapid, sensitive equilibrium turbidimetric immunoassay for quantification of alpha 1-antitrypsin involves a monospecific antibody, polyethylene glycol 6000 to accelerate and enhance the immunoprecipitation reaction, and Tween 20 surfactant to decrease and stabilize the sample-blank values. Turbidity at 334 nm is measured by an automated discrete analyzer. Grossly lipemic, icteric, or hemolyzed samples can be assayed. Correlation with results by radial immunodiffusion (RID) was excellent (r = 0.97, n = 84). Analytical recovery averaged 97.7 (SD 2.9)%. Within-run CVs ranged from 1.6 to 1.9%, between-day CVs from 2.0 to 3.5%. Reference values for healthy adults (n = 147) were determined by parametric estimation (for an assumed normal distribution of untransformed data). The lower limit (g/L) with its 0.90 confidence interval is 1.23 (range 1.18-1.28), the upper limit is 2.15 (2.10-2.20), and the mean is 1.69 g/L.

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