- Jagruti Meshram asked a question:NewWhat are the advantages of ester for wound dressings?
Biopolymers having COOH and OH undergo esterification reaction observed in most of the biopolymers used for wound dressing. If ester is not formed and only mixture is formed between the 2 polymers. whether it will affect the property of wound dressing.Following
- Peter Rehbein asked a question:OpenCould anyone point me to literature discussing the mechanical properties of silica coated micro-beads?
I am trying to gather information on the mechanical properties (force measurements, stability until breakage etc.) of silica coated biopolymer beads - I did a literature search, but there is very little information on this topic, it seems.
Thanks for any hints!Following
- Guillermina Burillo added an answer:4Has anyone experience on grafting a monomer on the surface of another polymer by Electron Beam technology?
I want to graft a monomer on the surface of another polymer by using electron beam technology. The problem is, there are variety of papers on this topic but I cannot find any article that explains the whole process in detail and the most important parameters that should be considered.
For instance, some of researchers covered the surface of polymer by a solution of the monomer, then irradiated by electron beam system, while others irradiated the surface of the polymer and then drenched the polymer into a monomer solution to graft it on the surface.
What is the phenomena behind these two different procedures?
Is there any difference between the outcomes of the two methods?
Additionally, I cannot find the irradiation time period required to do grafting? I thought it should be a crucial parameter when using Electron beam device.
An interesting book about radiation grafting condition and mechanisms is that of Chapiro A. , Radiation Chemistry of Polymeric systems of Interscience publishers, a división of John Wiley and Sons. of 1962.
I have the book and if it is important to you, I can send you the chapter of Radiation grafting.Following
- Titus Sobisch added an answer:3Is there a relation between "be partially wetted by both water and oil phase" and "be surface active"?
A polysaccharide aggregate can be partially wetted by both water and oil phase, even if this polysaccharide did not alter the interfacial tension between oil-water? It means is there a relation between these two properties: be partially wetted by both water and oil phase and be surface active?
usually polysaccharides are not surface active at oil-water interface (not interphase) because they are well soluble in water but not in oil or at least water swellable.
I doubt it is your experiment after which you state "partially wetted by both water and oil phase". Maybe entrapped air makes you believe it is oil wetted.Following
- Artem V Badasyan added an answer:3Is the pharma' industry interested in modelling water-biopolymer-drug systems?
I am just curious, if any pharma industry is interested in modelling water-protein-drug interactions. These interactions are strongly sequence and temperature dependent, so, in practice, when potential drug is suggested, how do you decide, which is a better candidate?
Thanks for your response! The problem is that what you said is the general problem statement, exactly what I think. IN practice, however, when I contacted R&D sections of several pharma companies, they didn't get interested at all. And I was not asking for money, but to take part in joint grant proposal. To my surprise, they are just not interested. I know that current models work very poorly. I know they use these models. What I do not understand, is how do they still develop drags with that software? Improving prediction by 10-20% will cut production expenses by same percentage, and is pure income. Then why don't they get interested? They don't trust me? OK. But what they loose if they state a couple of particular problems they have? Time? Money? Hidden methodology? No, no, no. Time as much as couple of days to state the problem, which is certainly not relevant (a week of a full-time researcher). And I suggest them to finance research that they may use in their production. And its actually me suggesting new ideas.
Really, I cannot understand the logics behind several pharma companies I contacted.Following
- Shakeel Ahmed added an answer:15How do I incorporate plant extract into a polymer film?
I have synthesized bio-polymer film. In order to improve its properties, i want to incorporate the plant extract into the films. Is there any proper method to incorporate extract into films?
Will the concentration of extract effect the physical properties of films/membranes?
Keywords: Chitosan, Gelatin, Plant extract, physical properties, thermal properties
Thanks.. Harfiz Salehudin for your valuable suggestion.Following
- Kaoru Aou added an answer:3How can I inexpensively extract polyols from castor beans for the production of biobased polyurethane?
How can I inexpensively extract polyols from castor beans for the production of biobased polyurethane?
Castor oil has ricinoleic acid units as part of the fatty acid triglyceride. So if you extract castor oil, you have your polyol without further chemistry. For examples of how to extract castor oil - this is a commercially relevant question, so the patent literature is usually a good first stop. The link below is one example (found via Google Patents and keywords "castor oil extraction"). It appears that solvent extraction has been the practice, although who knows what the best practice is now.... Also, castor beans have ricin (a toxin) in it, so be warned, this is not a recommendation from me re: how to do the oil extraction.Following
- Vehid Salih added an answer:5What is the proper collagen gel preparation method?
What is the best method to prepare collagen gel?
as far as I know it involves COL-1 drived from rat tail and when we add the NaOH with a spesific amount it should cause a polymrization to the matrix within 15 - 30 minutes and the gels will contract afterwords because of the isometric tension caused by the PDL fibroblasts within the gel . However the amounts in which to mix varies from experiment to experiment and sometimes involves adding acetic acid or other matrials . So how do we know the exact mixing amounts , matrials , and polymarization time ? Is there a clear protocol that we can follow?
Further to the valuable answers already given, it is imperative to have an appropriate protein concentration. I use rat-tail collagen from First Link, UK, at a concentration of 1.6-2.0 mg/L. Good luckFollowing
- Josef Chmelar added an answer:7Any advice on the swelling method to investigate cross linking?
I have some basic questions about the swelling method used to investigate cross linking, any advise is appreciated!
1) You can not use a solvent, in which the polymer dissolves. You would lose a part of your material and this would render your swelling data incorrect. So the NaOH/urea is not suitable for you.
2) The Flory-Rehner equation enables you to estimate the extent of cross-linking based on the measured swelling behavior and some additional parameters. It is not a way of evaluating the degree of swelling. Weighing the sample is ok, but you have to be careful about the procedure. If the sample will be fragile, you can have problems with manipulation. You must also dry the sample prior to weighing so that you do not measure liquid on the surface. It is therefore highly preferable to have the polymer in a compact form (e.g., film). This method is sometimes used for studying the sorption of liquids in polymer membranes, so you can try to find a paper on this topic as inspiration for your experiment. My former colleagues tested the same method for PE films, but it is sadly not yet published.
- Shilpa Gupte added an answer:7What are the suitable mediums for thermophilic biopolymer producing anaerobic bacteria?
I just want to know what are the media are using for themophilic biopolymer producing anaerobic bacteria during the isolation.
Thermophilic bacteria are sensitive for temperature so kindly maintain the desire optimum temperature requirement of the organisms. For the production of biopolymer provide high concentration of simple carbon source and nitrogen source in the minimum amount, this kind of medium will enhance the production of biopolymer.Following
- Ömer Alkan added an answer:3Does anyone know a solvent for dissolving of Polylactides and at same time compatible with Polystyrol for cell culture experiments?
I'm currently preparing an experiment for a Cell Culture practical course in our University and am having some problems.
The students first synthesize Biopolymers in the first part of the practical course: particularly Polylactides, Polyglycolides in D, L, D/L-forms or copolymerized with NPC or Caprolactone. To solve the solids, we use Chloroform.
In the second part of the practical course, these Biopolymers are made into thin biofilms and are covered with HaCaT-cells to test the different growth rates on the different Biofilms, but it only works on glass plates, since Chloroform corrodes Polystyrol materials...
So my question, is there a chemical with both functions: to dissolve the Biopolymers and at the same time is compatible with Polystyrol ? Any experience ? Or should I just use glass ?
thanks for the answers. I talked with my Prof and the problem was that they need these special wellplates for the computer-assisted microscope that takes pictures every hour....so glass is no viable option.
- Ajit Patil added an answer:5What are the different techniques to measure molecular weight of Biopolymers & Modified Biopolymers?
Techniques other than GPC, Molecular weight > 100000,
Thank you all of you for valuable information. I have modified one Biopolymer which is having swelling behavior. After modification it is not soluble in water, DMSO, THF, DCM, Alcohols, Ether, Xylene etc solvents. Even I have tried to low acidic and basic pH it is insoluble in pH range n Buffered solvents too. Thas why it is now very difficult to me to find out technique or method to know exact molecular weight of it. GPC, HPLC techniques were not useful due to solvent problem.Following
- Milad Raiszadeh added an answer:4How do I design a procedure to extract chitosan from shrimp in a mass scale?
I mean, we extract it in beaker, but we want a procedure to do it a big scale, I am very grateful if you can help me with some papers, theses or proposals about this topic.
Thanks sir , so helpfullFollowing
- Adel Badria added an answer:3How do I extract bacterial capsular polysaccharides?
Hi, i am going to research about bacterial capsular polysaccharide of Streptococcus pneumoniae and i am looking for the best protocol to extract the capsular polysachharide. is there a best method or Kit for extraction and purification of capsular polysaccharide especially from Streptococcus pneumoniae ? thank you very much for your help.
Sorry I have a question similar to this question. I functionalized heparin (polysaccharide) with thiol group (using EDC/HOBT then DTT). In the paper -that I'm using- they were doing column purification. My Question is can I do ethanol purification and What is the effect of ethanol on thiol groups ?? Thanks in advanceFollowing
- Cédric Delattre added an answer:3How much should we deacetylate chitosan for manufacturing bandage?
I want some information specially some papers about deacetylation of chitosan for manufacturing bandage
- Sivananth Murugesan added an answer:2What is the best way of forming soy bean lecithin based micelles?
From journals , it was clear that soy bean lecithin is good in forming micelles that can be used to deliver hydrophobic drugs when administered as oral drug delivery. what would be the best soy bean lecithin system to form micelle to separate hydrophobic biopolymer from the solution, when I did create soy bean lecithin dissolved in chloroform that can be used to form micelles by cloud point extraction, the added chloroform readily forms a two phase, while those of alcohol and acetone interact with the water, making the system more hydrophilic that the cloud point is already above 80 degree Celsius.
Can some one suggest me what would be the best concentration and system to study soy bean lecithin micelle by cloud point extraction
Dear Gregory Barshtein , Thanks for the article though it doesnt speak much about the micelle partFollowing
- Mustafa Çiçekler added an answer:2Do you know the molecular weight of the cellulose [14C(U)] from Nicotiana tobacum?
I will work with different organic amendments to be added to soil and cellulose will be one of those. I will also work with 14C and need to know the molecular weight of 14C cellulose from Nicotiana tobacum in order to calculate the exact amount of 14C to be spiked into a 12C cellulose solution from a different source, and, therefore with a different amount of C per gram of soil. On top of that, the manufacturer of the 14C cellulose said that they don't know the molecular weight of their product! Any suggestion?
If you know degree of polimerization (DP) of cellulose, you can calculate molecular weigth. You must know viscosity of cellulose in order to determine DP. For any help, contact me.Following
- Dr Murugesan Muthu added an answer:3How can I calculate the molecular mass and degree of substitution of biopolymer after modification?
I have modified the biopolymer, now I want to calculate the molecular mass and degree of substitution of the modified one kindly send me the easy and feasible methods.
Solubility: product is soluble in water but insoluble in organic solvents
please find attached the ref, as you requested.
Quantify the amino group before and after functionalisationFollowing
- Cédric Delattre added an answer:2Does anyone have succinoglycan exopolysaccharide ?
I think my exopolysaccharide is similar properties like succinoglycan so compare with it I want to buy standard succinoglycan. Can anyone provide me any information regarding this matter?
you could send to me 100mg of your EPS in order to investigate FTIR and GC analyses.
- Gerhard Behrendt added an answer:4Can anyone provide me with information about Polyurea resistant paints?
I want to know about the chemistry of polyurea or polyurethane resistant paint.
If it is possible please guide me
Please, provide information to what resistance you are aiming. There are so many ways to produce polyurethane coatings, e. g. solvent containing, high solids, one component, two component systems, solvenfree systems, aqueous dispersions etc. If you want detailed information you have to define at least the type of application and the type of resistance.
Polyurea systems are usually two component systems based on isocyanate prepolymers (their design determines properties) and di- or polyamines. By the choice of the composition of the prepolymer and the type of amine you determine the reaction and tack free times and properties. Another way is to you carbamates and perform a trans-amidation with amines in substance or solution. Again, the type of application and desired resistance determine the type of raw material.
If you want further information on commercial products go to www.nitroil-polyurea.comFollowing
- Edward Michelini added an answer:4Did anyone experience degradation of disulfide bonds in protein-polymer conjugates upon purification or storage in aqueous medium?
Stability of disulfide bonds in protein-polymer conjugates?
Since we live at the bottom of an ocean of O2 reduction of S-S is usually not a problem! Whats the purification step/buffer where they degrade?Following
- Prakrthi A N added an answer:2How can I electrospin pure starch?
for prepare starch fiber by electrospiningFollowing
- Nick J Walters added an answer:4Any tips for prolonging gelation time of polysaccharide hydrogel?
I am currently working with hydrogels formed from gellan gum, a plant-derived polysaccharide which can be gelated using divalent cations such as Ca2+. An alternative method of gelation, which I am investigating, involves the use of polyamines, such as spermine, as the crosslinker. In both cases, the crosslinkers induce gelation instantaneously upon mixing with the GG. This rapid gelation time makes it very difficult to mix the gel homogeneously and also to measure gelation time via rheometry.
A disaccharide is included in both the GG and crosslinker solutions in order to reduce osmotic pressure. Increasing disaccharide concentration to up to 60 wt% reportedly strengthens the gel; however, the substantial increase in viscosity of the GG solution makes it almost impossible to mix the gel. At 10 wt% disaccharide, the gel can be mixed but it is difficult to make homogeneous and impossible to measure by rheometry.
I mix the GG with crosslinker at 37ºC. Bringing the temperature down to 4ºC may slow the speed at which the polyamine crosslinks the gel, but conversely, this low temperature makes the GG extremely viscous and difficult to mix.
I would appreciate any advice that could help me overcome this catch-22 situation!
Hi Merlin, thanks very much for the suggestion. This particular project is focused on the use of polyamines for crosslinking the gels, as opposed to divalent cations such as Ca2+. The reason for focusing on this is that certain polyamines have have been shown to have anti-inflammatory effects, protection against oxidative stress and to play a positive role in several regenerative processes. By incorporating them as part of the physical structure of the gel, it is possible to control the physical properties of the gel and to control the release of these and other incorporated molecules.
I am not looking to incorporate Ca2+, since it would compete with the polyamine, making gelation even more rapid and also potentially preventing some of the polyamine from binding and causing it to be released more rapidly.
GDL appears to act as a chelating agent. Do you or your colleague think it is possible that this would act on the polyamine in a similar way to how it acts on the CaCO3, delaying gelation via the polyamine crosslinker?Following
- Muhammad Radifar added an answer:11What is different between chitosan and alginate?
Can anyone tell me why lysozyme could enzymatically degrade chitosan while alginate is stable under same conditions?
Yes, that's true, but unless lysozyme is a non-specific enzyme like lipase or CYP450, then in my opinion lysozyme won't be able hydrolyze other substrate than chitosan/chitin. Carboxyl versus amine aside, there are 5 chiral atom in every monomer, which means every hydroxide/ether group must be in the correct position to be bound by the corresponding amino acid residue inside the binding cavity of lysozyme.Following
- Dorra Ghorbel added an answer:2How can I choose the column and the standards for an HPSEC apparatus?
We must measure the molecular mass distribution of biopolymers: polysaccharides (amylose, fibers.) and proteins.
Thank you very much, I'll read them.Following
- Milad Raiszadeh added an answer:4How can we get Chitosan from shrimp shell?
I want some information specially some papers about chitosan biopolymer and the industerial methods to get it from shrimp shell
thanks sir , i get useful hints from itFollowing
Polymers synthesized by living organisms. They play a role in the formation of macromolecular structures and are synthesized via the covalent linkage of biological molecules, especially AMINO ACIDS; NUCLEOTIDES; and CARBOHYDRATES.