Biopolymers

Biopolymers

  • Peter Mathew added an answer:
    5
    What are the possible solvents for the dissolution of microcrystalline cellulose?

    I am trying to make thin films of microcrystalline cellulose. Could you suggest possible solvents for the dissolution of of cellulose for the same

    Peter Mathew

    @Jagadevappa S Patil: MCC is insoluble in water, ethanol, ether and dilute mineral acids

  • Saeideh Hosseini added an answer:
    2
    What is exact tg value of chitosan biopolymer?

    as i am doing dsc measurement of ionically crosslinked chitosan  blend..i want to know what is its exact tg value?

    Saeideh Hosseini

    you can see the attached links

    + 3 more attachments

  • Rattaphon Jaichakan asked a question:
    New
    What is the best protocol to extract arabinoxylan from defatted rice bran?

    I tried many protocol to extract AX from defatted rice bran (gift from oil industry). it is seem not work with xylanase. 

  • Haroon Rashid added an answer:
    1
    Alginate physical detials?

    I want to work with alginate. so can anyone know about one alginate particle size, Chain length of the alginate and surface area of the alginate? if any paper is available please inform me..

    Haroon Rashid

    Hello. Well as far as dentistry is concerned, Alginate has been most widely used for recording of the impressions for dentate and edentulous patients. Due to its reasonable cost and reasonable properties, it is sometimes the material of choice for many clinicians in dentistry. I personally prefer it for patients requiring cast partial dentures and also I prefer using high viscosity type for initial impressions of the edentulous patients. It is very cheap and does the job really well. There are many types available for dental use from low to high viscous, quick and delayed setting types.

    Dimensional stability is one of the problems but can be overcome with ease. I am attaching some paper links for you here. This may help if you want to look at it from dental point of view.

    + 2 more attachments

  • Nizar Matar added an answer:
    16
    Is Polymethyl methacrylate (PMMA) degradable in the body?

    Biopolymers, Biodegradable polymers

    Nizar Matar

    Just a simple note: PMMA is not degradable in the body unless it was treated before its use physically or chemically. The main uses of PMMA for healthcare are at the dentist clinic for teeth fillings/false teeth and at the optician's clinic as hard contact lenses. These contact lenses were problematic so researchers moved into using HEMA "2-hydroxyethylmethacrylate" homopolymer which was better but was not a very good one. Comfortable soft contact lenses were,eventually, made from copolymers of HEMA with other monomers including MMA, silicone...etc. taking into account two main criteria: water & air smooth passage and optical transperancy.

  • Guy Havet added an answer:
    3
    What happens exactly if a biopolymer has increasing melting temperatue and decrease in tensile strength?

    as i am preparing ionically crosslinking chitosan blends.the tm is increasing as croslinker is increasing and tensile strength is decreasing with increase in E%.i am not getting the reason through litrature...what it means plz suggest me 

    Guy Havet

    Firdos,

    "What happens exactly if a biopolymer has increasing melting temperatue and decrease in tensile strength? "

    To answer exactly to your question you'll have to provide us with more details about your system and its exact experimental conditions both for the preparation of the mixture and the measurements of the thermo-mechanical properties.

    Then we would need to have a look at the curves you obtained before and after "crosslinking".

    Without these informations everything would be pure blind speculation.  

  • Asit Baran Samui added an answer:
    1
    Any tips on removing cleanly the PEDGA from the PDMS features without a crumbly mess using crosslinked PEGDA hydrogel as a PDMS microcasting mold?

    I have a photo-crosslinked PEGDA as a sacrificial mold for PDMS microcasting, and post-casting, I wish to remove the PEGDA so that I can then use the resulting PDMS. Problem is, the PEGDA becomes a brittle, crumbly mess, and I can't extract it from the PDMS cleanly. 

    Does anyone have any tips on how to cleanly extract it, or maybe dissolve the PEGDA?

    Asit Baran Samui

    Use UV crosslinkable polymer which form reversible crosslink. Bisbenzylidene based polymers and other polymers making cyclobutane ring during crosslinking can be used which is crosslinked at 365 nm and uncrosslink at 254 nm. I believe your sacrificial mold will not have any problem.

  • Ulf Nobbmann added an answer:
    12
    How can you measure the molecular weight of a synthetic polymer?
    In our laboratory we synthesized a new polymer by adding some molecules as branches on the base polymer chain. The molecular weight of the base polymer chain and molecules which were added are known.
    Ulf Nobbmann

    GPC is probably the best tool for your project. Advanced GPC detection (light scattering for molecular weight and intrinsic viscosity for structural insights) can be done if your sample is well-dissolved in the mobile phase.

    To gain a quick understanding of the size of your polymer and whether it is aggregated or not, dynamic light scattering may also be quite useful.

  • Leonid V Vladimirov added an answer:
    4
    Does potassium nitrate partially dissolve in ethanol?

    i want potassium nitrate to be get crosslinked to biopolymer..so weather pot.nitrate will be partially dissolve in ethanol or not?if yes den weather crosslinking will be done in partially dissolve solvent?

    Leonid V Vladimirov

    Dear Jahan:

    In my 1st response I gave you: 0.6g/100ml - from the Handbook. Basing on this data - I successfully dissolved 0.5g in 100ml of ETHANOL -at RT. It took 5 or 6 hours, but I was in no rush. Thus - I am surprised - why you could not reproduce this experiment.

    Oh, now I saw that you used METHANOL as the solvent !!!!!!, which ability to dissolve KNO3 is already much higher than that of Ethanol (?!).

    If I were you - I would continue my attempts - by increasing the amounts of BOTH i.e. of salt and of alcohol; then filtering out the insoluble portion; and checking - for examle - by evaporation - how much of KNO3 - you were able to really dissolve.

    Best Regards,  Leonid

  • Amr M. Bakry added an answer:
    2
    Could 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!

    Amr M. Bakry

    Good luck my brother.

    + 8 more attachments

  • Carina Heigl added an answer:
    5
    Can anyone suggest a spectrophotometry based method for the estimation of biopolymer PHB (Poly hydroxy butyrate)?

    PHB is generally estimated using GC

    Carina Heigl

    Sorry, but I wasn't able to reproduce this protocol. I don't know why, but even my blank stays changing between 4 and 0,7. I don't know where I am missing. 

  • Dobrila Andonovska added an answer:
    4
    What 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.    

    Dobrila Andonovska

    Alginates

  • Guillermina Burillo added an answer:
    4
    Has 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.

    Guillermina Burillo

    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.

  • Titus Sobisch added an answer:
    3
    Is 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?

    Titus Sobisch

    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.

  • Artem V Badasyan added an answer:
    3
    Is 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? 

    Artem V Badasyan

    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. 

  • Shakeel Ahmed added an answer:
    15
    How 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

    Shakeel Ahmed

    Thanks.. Harfiz Salehudin for your valuable suggestion.

  • Kaoru Aou added an answer:
    3
    How 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?

    Kaoru Aou

    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.

  • Vehid Salih added an answer:
    5
    What is the proper collagen gel preparation method?

    Hello.

    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?

    Vehid Salih

    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 luck

  • Josef Chmelar added an answer:
    7
    Any 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!

    Q1) 

    Josef Chmelar

    Hello

    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.

    Regards, Josef

  • Shilpa Gupte added an answer:
    7
    What 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.

    Shilpa Gupte

    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. 

  • Ömer Alkan added an answer:
    3
    Does anyone know a solvent for dissolving of Polylactides and at same time compatible with Polystyrol for cell culture experiments?

    Hey,

    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 ?

    Ömer Alkan

    Hey,

    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.

    Thanks, anyways

  • Ajit Patil added an answer:
    5
    What are the different techniques to measure molecular weight of Biopolymers & Modified Biopolymers?

    Techniques other than GPC, Molecular weight > 100000,

    Ajit Patil

    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. 

  • Milad Raiszadeh added an answer:
    4
    How 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.

    Milad Raiszadeh

    Thanks sir , so helpfull

  • Adel Badria added an answer:
    3
    How 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.

    Adel Badria

    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 advance

  • Cédric Delattre added an answer:
    3
    How much should we deacetylate chitosan for manufacturing bandage?

    I want some information specially some papers about deacetylation of chitosan for manufacturing bandage

    Cédric Delattre

    you're welcome!

    Cédric

  • Sivananth Murugesan added an answer:
    2
    What 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

    Sivananth Murugesan

    Dear Gregory Barshtein , Thanks for the article though it doesnt speak much about the micelle part 

  • Mustafa Çiçekler added an answer:
    2
    Do 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?

    Mustafa Çiçekler

    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. 

About Biopolymers

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.

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