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How to correctly preserve organic matter with ethylene and polyethylene glycol?

How to correctly preserve organic matter with ethylene and polyethylene glycol?


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I am trying to preserve and dye flowers, especially roses. Let me walk you through the process I am trying to optimize:

1) Soaking flowers in 96%-ethanol for a day to dehydrate them. This step removes a lot of the color from the petals - red roses for example become faint pink. The flower itself becomes brittle to the touch, since almost all water is removed.

2) Putting the dehydrated flower into a mix of 96%-ethanol, polyethylene glycol 400 and reactive dye which is used in textile industry. I am still experimenting with the ration of ethanol:PEG. Soaking duration is a couple of days. In theory, the PEG gets into the cells of the petals - this preserves the petals and gives them most of their flexibility back.

3) Removing the flower from the mix and rinsing it for a minute in 96%-ethanol. This should remove the excessive PEG on the surface of the petals. Otherwise it looks glossy and stays sticky.

My problem begins at step 1): If I remove a flower from the dehydrating ethanol-bath, the petals turn opaque in a weird way. Some connected areas of a petal start to change their appearance abruptly (some sort of bursting, cracking, rupturing)! This starts some seconds after removing the petal from the ethanol and after a couple of minutes, almost all of the petal has turned opaque. Usually the outer edges of the petals don't turn opaque. I am not sure about this, but could it be, that the ethanol somehow destroys the cells of the petals? Is this a behaviour that is to be expected or am I doing something wrong? I think I would benefit a lot if I could understand where this abrupt change of quality comes from.

it doesn't matter, if I remove the flower after step 1, 2 or 3, the result is always this abruptly turning opaque behaviour.

Since my goal is to dye them to look nice and pretty, I need to find the mistake I am making. I was hoping you experts could help me.

You find two pics of already dyed petals attached.

(I wouldn't mind if they stay all transparent. In that case the petals should not turn opaque. But I also wouldn't mind if they become opaque - but on 100% of their surface. Also at the outer edges. This actually may be better - I think it looks nice this way.)


I find that using mixture of PEG 400 and Ethanol 2:1 reduce the transparency. You also need to bake the pental in microwave 360w for 15 seconds. Still some small transparency but acceptable.


What is Polyethylene Glycol (PEG)?

Polyethylene glycol (PEG) is a biocompatible, synthetic, hydrophilic polyether compound that has many applications, mostly in the medical industry, but also in the chemical and industrial sectors. The structure of the compound is known as H&minus(O&minusCH2&minusCH2)n&minusOH.

Image Credit: StudioMolekuul/Shutterstock.com

The synthesis of PEG is done by polymerizing ethylene oxide, the main ingredient in antifreeze, using a ring-opening technique, which allows for PEGs of a range of molecular weights and molecular weight distributions to be constructed. This range in weights is what makes it suitable for several uses.


How to correctly preserve organic matter with ethylene and polyethylene glycol? - Biology

All articles published by MDPI are made immediately available worldwide under an open access license. No special permission is required to reuse all or part of the article published by MDPI, including figures and tables. For articles published under an open access Creative Common CC BY license, any part of the article may be reused without permission provided that the original article is clearly cited.

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How to correctly preserve organic matter with ethylene and polyethylene glycol? - Biology

Henan Forever Medical Co.,Ltd
Add: Room 806, Wanda Center, Jinshui District, Zhengzhou, China
Tel: +86-371-61315851
Contact Person:Ms Cassie Yang
Whatsapp: +86-18236758227

Since ethylene oxide is flammable, explosive, and toxic to humans, it must be carried out in a closed ethylene oxide sterilizer.

(1) Ethylene oxide sterilizer and its application:

1) There are many types of ethylene oxide sterilizers currently in use. Large containers have tens of cubic meters, medium ones have 1-10 cubic meters, and small ones have a few tenths to 1 cubic meter. They each have different purposes.

Large-scale ethylene oxide sterilizer: generally used for the sterilization of a large number of processed items, with a dosage of 0.8kg/m³~1.2kg/m³, and an action of 6h at 55℃~60℃.

3) Medium-sized ethylene oxide sterilizer: generally used for sterilization of disposable medical supplies. This kind of sterilization equipment is complete and highly automated, and can be used with pure ethylene oxide or a mixed gas of ethylene oxide and carbon dioxide. Generally required sterilization conditions are: concentration, 800 mg/L~1000mg/L, temperature, 55℃~60℃, relative humidity 60%~80%, action time 6 hours. Vacuum is required to complete the sterilization. Sterilized items are usually sealed and packaged with plastic film permeable to ethylene oxide. If there is a filter membrane that can filter air on the small package, the sterilization effect will be better.

4) Small ethylene oxide sterilizers are mostly used in the medical and health departments to process a small amount of medical equipment and supplies. Currently, there are 100% pure ethylene oxide or a mixture of ethylene oxide and carbon dioxide. This kind of sterilizer has a relatively high degree of automation, can automatically vacuum, automatically add medicine, automatically adjust the temperature and relative humidity, and automatically control the sterilization time.

5) The requirements for medium and small ethylene oxide sterilizers are: good pressure resistance and airtight performance, should be able to withstand a hydraulic test of 1.25 times the working pressure, without degeneration and leakage, and can be vacuumed To above 53.3 kPa accurate dosage, good heat preservation performance, can adjust the temperature and relative humidity in the sterilizer when flushing with external ambient air after sterilization, the input air passes through a high-efficiency filter, which can filter out particles ≥0.3&microm 99.6% or more the discharged residual ethylene oxide is harmlessly treated, the residual ethylene oxide in the sterilized articles should be less than 15.2mg/m the concentration of ethylene oxide in the sterilization environment should be less than 2mg/ m.

(2) Preparation and packaging of items before sterilization: Items that need to be sterilized must be thoroughly cleaned. Note that they cannot be cleaned with saline. There should be no water droplets or too much water on the sterilized items to avoid dilution and hydrolysis of ethylene oxide. . Ethylene oxide can be used for the sterilization of almost all medical supplies, but it is not suitable for the sterilization of food, liquids, oils, talcum powder and animal feed. Packaging materials suitable for ethylene oxide sterilization include paper, composite dialysis paper, cloth, non-woven fabrics, ventilated rigid containers, polyethylene, etc. packaging materials that cannot be used for ethylene oxide sterilization include metal foil, Polyvinyl chloride, cellophane, nylon, polyester, polyvinylidene chloride, impermeable polypropylene. Changes to packaging materials should be verified to ensure the reliability of the sterilization of the sterilized items.

(3) Sterilized items loading: The items loaded in the sterilizer should have gaps up, down, left, and right (the sterilized items cannot touch the cabinet wall), and the items should be placed in a metal mesh basket or on a metal net rack the amount of items loaded is not Should exceed 80% of the total volume in the cabinet.

(4) Sterilization: It should be implemented in accordance with the operating instructions of the manufacturer of the ethylene oxide sterilizer select the appropriate sterilization parameters according to the type, packaging, loading and method of the sterilized items.

1) The relationship between concentration, temperature and sterilization time: Within a certain range, the increase in temperature and concentration can shorten the sterilization time. When using ethylene oxide for sterilization, the temperature, concentration and time parameters must be selected reasonably.

2) Control the relative humidity of the sterilization environment and the water content of the items: The water content of the bacteria itself and the water content of the sterilized items have a significant impact on the sterilization effect of ethylene oxide. Under normal circumstances, the relative humidity is 60% to 80%. Too little water content will affect the penetration of ethylene oxide and the alkylation of ethylene oxide, reducing its sterilization ability too much water content will dilute and hydrolyze ethylene oxide, which will also affect the sterilization effect. In order to achieve the ideal humidity level, the first step is to pre-wet the sterilized material. Generally, the sterilized material must be placed under 50% relative humidity for at least 2 hours in the second step, a humidification device can be used to ensure the ideal humidity in the cabinet. Level.

3) Pay attention to the influence of the bacteria in vitro protection on the sterilization effect: The more organic matter on the surface of the bacteria, the more difficult it is to kill the organic matter can not only affect the penetration of ethylene oxide, but also consume part of the ethylene oxide. Microorganisms in inorganic salts or organic crystals are difficult to kill with ethylene oxide. Therefore, before ethylene oxide sterilization, organic and inorganic contaminants on the items must be fully cleaned to ensure successful sterilization.

①Ethylene oxide sterilization procedures need to include preheating, pre-wetting, vacuuming, introducing vaporized ethylene oxide to reach a predetermined concentration, maintaining the sterilization time, clearing the ethylene oxide gas in the sterilizer, and analyzing to remove Residues of ethylene oxide in sterilized items.

②100% pure ethylene oxide or mixed gas of ethylene oxide and carbon dioxide can be used for ethylene oxide sterilization. The use of Freon is prohibited.

③Analysis can be continued in an ethylene oxide sterilizer, or it can be placed in a special fume hood, and natural ventilation should not be used. The repeatedly input air should be filtered with high efficiency, which can filter out more than 99.6% of particles ≥0.3um.

④Ethylene oxide residue mainly refers to the ethylene oxide remaining in articles and packaging materials after ethylene oxide sterilization and its two by-products, chloroethanol ethane and ethylene glycol ethane exposure to excessive ethylene oxide Alkane residues can cause burns and irritation to patients. The amount of ethylene oxide residue is related to the materials of the sterilized articles, the parameters of the sterilization, the packaging materials and the size of the packaging, the loading capacity, and the analysis parameters. When the polyvinyl chloride catheter is at 60℃, it is analyzed for 8h when it is 50℃, it is analyzed for 12h. Some materials can shorten the resolution time, such as metal and glass can be used immediately, and some materials need to extend the resolution time, such as a built-in pacemaker. 5) Ethylene oxide emission: The first choice for ethylene oxide emission in hospitals, the installation requirements: There must be a special exhaust piping system, and the exhaust pipe material must be ethylene oxide and not permeable such as copper pipes. There should be no flammable materials and building air inlets such as doors or windows within 7.6m from the exhaust if the length of the vertical part of the exhaust pipe exceeds 3m, a water collector must be installed, and the exhaust pipe should not be dented Or the loop will cause water vapor to accumulate or freeze in winter, blocking the pipe the exhaust pipe should be led to the outdoors and reversed at the exit to prevent water vapor from staying on the pipe wall or causing the pipe wall to be blocked a professional must be requested Installation engineer, and combined with the requirements of the ethylene oxide sterilizer manufacturer to install. If ethylene oxide is discharged into the water, the entire discharge system (pipes, sinks, etc.) must be sealed, otherwise a large amount of hot ethylene oxide will overflow from the water and pollute the surrounding working environment.


Abstract

Amphiphilic block copolymers based on hydrophobic polysulfides (poly(propylene sulfide), PPS) and hydrophilic polyethers (poly(ethylene glycol), PEG) have been used to solubilize and disperse single-walled carbon nanotubes (SWNTs). The obtained highly concentrated aqueous dispersions are stable for months. The factors that affect the dispersant activity of the studied block copolymers have been characterized, and comparisons with the much more investigated oxygen analogues (Pluronics) are reported. The biocompatibility and the stability after dilution of the most representative suspensions have been investigated as prospective drug carriers.


Abstract

The MARTINI coarse-grained beads are parameterized to match the partition coefficients of several organic molecules in different solvents. Here, we test the method when modeling the partitioning properties of poly(ethylene oxide) between solvents of different polarities. We show that, among the existing models, the latest model developed by Lee and co-workers [ Lee, H. Pastor, R. W. J. Phys. Chem. B 2011 , 115, 7830−7837] is the one that most successfully reproduces the hydration free energy of short oligomers, although it predicts highly negative solvation free energies in octanol and hexane. We develop a new CG model matching the solvation free energy of the monomer in different solvents and propose a simple method to select the Lennard-Jones parameters that reproduce the desired partition coefficients. The model correctly reproduces water/hexane partition properties for oligomers up to 10 monomers but still suffers from a transferability problem for larger molecular weight.


How to correctly preserve organic matter with ethylene and polyethylene glycol? - Biology

All articles published by MDPI are made immediately available worldwide under an open access license. No special permission is required to reuse all or part of the article published by MDPI, including figures and tables. For articles published under an open access Creative Common CC BY license, any part of the article may be reused without permission provided that the original article is clearly cited.

Feature Papers represent the most advanced research with significant potential for high impact in the field. Feature Papers are submitted upon individual invitation or recommendation by the scientific editors and undergo peer review prior to publication.

The Feature Paper can be either an original research article, a substantial novel research study that often involves several techniques or approaches, or a comprehensive review paper with concise and precise updates on the latest progress in the field that systematically reviews the most exciting advances in scientific literature. This type of paper provides an outlook on future directions of research or possible applications.

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to authors, or important in this field. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.


Methods

All the reagents employed in this study were of analytical grade and were used without any further purification. The synthesis of magnetic nanoparticles has been performed with the following products: iron(III) chloride hexahydrate (FeCl3 6H2O) (Roth, ≥98 %), polyethylene glycol 200 (PEG200) (Roth, ≥99 %), and sodium acetate trihydrate (NaAc) (Roth, ≥99.5 %).

The general synthetic procedure for the preparation of iron oxide magnetic nanoparticles was as follows: FeCl3 6H2O (0.675 g) and sodium acetate (NaAc) (1.8 g) were mixed and dissolved in either 60 or 90 ml of PEG200. The solutions were stirred thoroughly at room temperature for 30 min, transferred in sealed glass bottles, and heated at 240 °C for 6, 8, 10, and 12 h. The final temperature was reached at heating rates of 43 and 5 °C/min. The glass bottles were let to cool at room temperature, the excess liquid was discharged, and the obtained black precipitates were washed with ethanol, several times, in order to remove the excess of ligands and unreacted precursors. Finally, the black precipitates were dispersed and kept in double distilled water for further analysis.

TEM images were taken on a Jeol JEM 1010 transmission electron microscope (Jeol Ltd., Tokyo, Japan), equipped with a Mega VIEW III camera (Olympus, Soft Imaging System, Münster, Germany), operating at 80 kV. For TEM examination, 5-μl drops of each solution were deposited on carbon-coated copper grids. After 1 min, the excess water was removed by filter paper and the samples were left to dry under ambient air.

X-ray diffraction (XRD) measurements were carried out on powder samples at room temperature on a Bruker D8 Advance diffractometer using Cu Kα radiation. The lattice parameters and phase percentages were calculated using the FullProf software.

XPS measurements were performed with a SPECS PHOIBOS 150 MCD instrument, equipped with monochromatized Al Kα radiation (1486.69 eV) at 14 kV and 20 mA and a pressure lower than 10 −9 mbar. The binding energy scale was charge referenced to the C1s photoelectron peak at 285 eV. A low energy electron flood gun was used for all measurements to minimize sample charging. The elemental composition on the outermost layer of samples (about 5 nm deep from surface) was estimated from the areas of the characteristic photoelectron lines in the survey spectra assuming a Shirley type background. High-resolution spectra were recorded in steps of 0.05 eV using analyzer pass energy of 30 eV. The spectra deconvolution was accomplished with Casa XPS (Casa Software Ltd., UK).

The mid-infrared spectrum of powder IOMNPs, sodium acetate, and PEG200 was recorded on a Jasco 4000 FTIR spectrometer in attenuated total reflectance (ATR) mode using a one reflection ATR accessory with ZnSe crystal. The detection system consisted in a DTGS detector, the spectral resolution of the recorded FT-IR spectrum being 4 cm −1 .

Raman measurements were recorded using a multilaser confocal Renishaw InVia Reflex Raman spectrometer. The wavelength calibration was performed by using a silicon waver buffer. The 633-nm laser line of a He–Ne laser was employed as the excitation source. The Raman spectra were recorded on powder deposited on aluminum-covered glass, with a 50× objective and an acquisition time of 10–20 s, while the emitting laser power was varied between 15 mW and maximum value of 150 mW. The spectral resolution of the spectrometer was 0.5 cm −1 .

Dynamic light scattering (DLS) measurements were taken using a Zetasizer Nano ZS90 (Malvern Instruments, Worcestershire, UK) in a 90° configuration. One cycle of 30 measurements was performed for each sample.

Magnetic measurements were performed on powder samples in the 4–300 K temperature range in external applied fields up to 2 T, using a vibrating sample magnetometer (VSM) produced by Cryogenic Limited.

Hyperthermia measurements were recorded with a magnetic heating system Easy Heat 0224 provided by Ambrell (Scottsville, NY, USA). The samples, usually 0.5 ml of IOMNP suspensions at different concentrations were placed in a thermally insulated vial, at the center of an 8-turn coil, connected to the remote heat station of the device. With this setup, alternating magnetic fields with strengths up to 65 kA/m and frequencies between 100 and 400 kHz were generated in the center of the coil. The temperature was measured using a fiber-optic probe, placed in the center of the vial, connected to a computer, providing the temperature values each second. The calibration of the setup, the recording protocol of temperature change versus time, and the SAR calculation are briefly described in the “Additional File”.


Abstract

We explore the effects of preparation protocol on the morphology and stability of aggregates from a poly(ethylene glycol-b-propylene sulfide-b-ethylene glycol) triblock copolymer, PEG44−PPS76−PEG44. Fluorescence spectra and excimer formation of the probe molecule pyrene elucidated the various stages of aggregate formation, and cryo-TEM yielded insight into aggregate morphology. When prepared by direct hydration of polymer films, an extraordinary variety of morphologies was formed, ranging from spherical micelles to wormlike micelles, Y-junctions, blackberry micelles, and vesicles. Aging produced more uniform structural ensembles, including wormlike micelles with undulations and eventually spherical micelles, indicating the nonequilibrium nature of the system as initially formed. On the contrary, preparation by dilution from organic solvent yielded only structures that were closer to equilibrium distributions.

Ecole Polytechnique Fédérale de Lausanne.

To whom correspondence should be addressed. Address: Integrative Biosciences Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), LMRP Station 15, CH-1015 Lausanne, Switzerland. Tel: +41 21 693 9681. Fax: +41 21 693 9665. E-mail: [email protected]


Recent trends in the development of nano-bioactive compounds and delivery systems

4.5 Nanoniosomes

Niosomes are the type of liposome but these vesicles mainly composed of the hydrated non-ionic surfactants with cholesterol (CHOL) or its derivatives, in many cases. The specialized structures of niosomes allow the encapsulation of both hydrophilic as well as lipophilic compounds. The encapsulation is generally achieved by adsorbing the desired compound on the bilayer surfaces or by entrapment of hydrophilic compounds in vesicular aqueous core whereas the lipophilic substances are encapsulated by their partitioning into the lipophilic area of the bilayers. The niosomes having size in the range of 10–1000 nm commonly referred to as “nanoniosomes” ( Mukherjee et al., 2007 Bragagni et al., 2012 ).