Questions related to Polymeric Biomaterials
Tried low MW PEG for example, PEG 200. Had very good results but its viscosity is still much higher than the acceptable range.
In the leaching process,Why does NaCl settle despite sieving?
How can we understand how much solvent the system needs?
And, how can enhance the mechanical strength in this process and find the optimum solvent?
Hi. I was able to synthesize hydrogel by crosslinking polyvinyl alcohol with borax and by reinforcing with a filler (silica from rice husks and cellulose). One week after my synthesis, however, the gels became dehyrdated and turned into a thin film. How can I avoid this?
I'm trying to make PCL aligned fibers.
I've tried to adjust voltage, flow rate and needle-collector distance.
- 15% PCL in acetone (weight/volume)
- Needle-collector distance: 5 to 20 cm
- Voltage: 5 to 20 kV
- Flow rate : 1 to 10 mL/h
- Rotating speed: 500 to 2400 rpm
I manage to get fibers (at the lowest rotation speed) but they are not aligned.
I've tried to reduce flow rate, but still the rotation speed is too low and thus fibers are not aligned enough.
Above 500 rpm I can't manage to get a Taylor cone, and the droplet/jet constantly moves and solidifies.
I've read publications using similar parameters to mine and getting aligned fibers, what am I missing ?
Hi everyone, I'm currently working on bone-targeting polymeric nanoparticles for treatment of osteoporosis. Just wondering what kind of human osteoblast (or other bone cells) are best suitable for the cytotoxicity test. I've bought primary human osteoblast from sigma but found it growing extremely slowly. I've also tried MG-63 cells but it was criticised as a cancer cell (not suitable for examination of nanoparticles cytotoxicity). Is there a human osteoblast cell line that is not cancer cells and growing fast? Could anyone give me a clue? Thank you very much!
I haven't found much literature on wound assays performed on an electrospun scaffold, was wondering if anyone is currently trying to optimise or successfully have done?
Is it possible, a rigid or flexible foam be OK during the producing procedure but after long time, during the using or utilizing, it shows undesirable properties?
I have accessibility to a cheap source of plexiglass scraps. I am thinking to a recycling projects and producing new products based on PMMA recycling. What is your suggestion for PMMA recycling? What can we make from recycled plexiglass which has both economic value and innovation??
I work with polymeric nanoparticles,
they have about 0,1 polidispertion index,
but the distribution is from 60 to 456 nm.
In this case, can I use Z-average result or just diameter average?
In reference to the fish collagen what is technical difference between the fish collagen, hydrolysates of fish skin collagen and Fish Collagen Peptides in terms of physical and chemical properties.
What is the best solvent for Polyactivetm polymer (77 wt % of PEO (1500 g/mol) and 23 wt % of PBT)?
I should make at least 3 wt.% solution to cover PSF support. So the solvents shouldn't affect polysulfone. Any suggestions?
free radical polymerization using PEG-ABCPA as macroinitiator
We're just trying to fabricate PVA/Chitosan & PEO/Chitosan electrospun fibers. The used solutions were:
Chitosan Solution:1wt% chitosan in 5% v/v glacial acetic acid
PVA Solution:5wt% PVA in distilled water
PEO Solution: 1wt% PEO in 5% v/v glacial acetic
Subsequently, the solutions were blended in order to obtain different proportions of PVA/Chitosan & PEO/Chitosan solutions.
The problem is that we couldn't obtain any fibers and we have just observed some particles on the collector.
We think that the viscosity of our solutions are so low and this problem is because of low concentration of chitosan in the initial solution. But firstly, as a lot of references have reported, we made a 3wt% chitosan in 5% v/v glacial acetic acid. The prepared solution was so viscose that we couldn't even stir it and it was like a solid gel.
We are using medium molecular weight chitosan with the molecular weight of 190,000-310,000.
What is the solution?
Thank you very much in advance
I have created oil in water emulsions and have performed a particle size analysis using a Zetasizer Nano series. I'm getting the units d[4:3] "volume moment mean" and I don't understand the physical meaning of this unit. I realise that this is "weighted" towards the volume distribution, but in that case why not use d[3:0]? Hope you can help :)
why is polyacrylamide hydrogel cant be considered as superabsorbent polymer while copolymer polyacrylamide can be considered superabsorbent polymer?
Is there any non toxic electroactive biodegradable polymer or oligomer beside aniline oligomers? specifically for tissue engineering
My solution is Polycapralactone blended in some single and binary solvents. I would like to measure the surface tension with a volume of 1-5ml.
Wilhelmy plate method requires 20-40ml and I cannot use the pendant drop method since my solvents are volatile. Therefore, time is also a factor. But the more important criteria is the volume of solution required.
Thank you in advance!
Most of the naturally available biodegradable materials such as agarose, chitin, chitosan, collagen, hyaluronan, gelatin etc. have already been explored. What else can I try? How about pectin?
I will be trying to assess the biocompatibility of cellulose acetate - polylactic acid nanofibers in wound healing applications by subjecting it to hemolysis, cytotoxicity and proliferation assays. Is there a commercial wound dressing that actually interacts with the wound or degrades as the wound heals? I plan on using such, if it exists, as a control.
Hi polymer experts,
in our certain case, we analyzed poly(ethylene glycol) (PEG) with high performance size exclusion chromatography (HPSEC). Solvent was 10x PBS (aqueous solution).
For instance, we analyzed PEG with molecular weight (MW) of 40000 and 4 different architectures: linear, Y-shaped ("3-arm"), star-shaped ("4-arm") and 8-arm. These polymers elute at different elution times (not such a huge difference, but still there is a difference). The architecture has an effect on the size of the polymers in solution, e.g. the linear one will be more bulky while the 8-arm will be more compact and therefore elute at a later time point, although they have the same MW.
So is there any formula around to predict that behaviour? Since PEG is widely used, there my be something for PEG only in different solvent systems. We do not want to get the MW from the elugrams (we get it with MALDI), just want to explain the differences with a scientifically approved model, if there is one.
Thanks a lot for your help!
First off, eventually what I want to get is a close-packed, monolayer of polystyrene(PS) spheres at the air/water interface (Langmuir-Blodgett method). But unlike those mentioned in many references, my polystyrene spheres are not dispersed in ethanol or butanol, but rather they are dispersed in water. This complicates the method since the spheres in water cannot float upon the water sub-phase for the LB method.
Other than synthesis of polystyrene spheres from scratch, is there a way to replace the water media with ethanol?
While i dry microbeads after formation, they stick with paper, filter paper or petri dish and lose its round shape. What i must do? any suggestion?
I often work with hydrogels and in many cases I have small pieces of plastic tubing embedded in the hydrogel. I am not very well versed in the terminology around this subject, but I would like to know how I can improve the "adhesive" force between the plastic and the hydrogel. I flow liquid through the tubing and I would like the space around the tubing to be as liquid-tight as possible, with the goal during flow conditions being unidirectional flow, and no backflow back out around the tubing. Since the hydrogel is mostly water, is what I'm asking an accurate description of what is possible? I am currently using perfluoroalkoxy (PFA) tubing in fibrin, transglutaminase-crosslinked fibrin-gelatin, and collagen hydrogel. We treat the PFA tubing with a concentrated solution of poly-L-lysine for several hours but I am not even sure if this is accomplishing anything since we have not thought of a way to test it.The PFA tubing is what we had on hand, but we would consider tubing of a different material or other chemical treatments. I would appreciate any comments or suggestion, as well as any references. Thank you!
Dear all, I would be very interested in the possibility to simulated a polymer micelle in water containing hydrophobic molecules. I would be interested in the hydrophobe-polymer segregation, mobility and interactions.
Anybody can help?
Thanks in advance
I am looking for preparation biodegradable polymers from plant extract and I need to know any plant extract which can be used for the preparing such polymers.
Hey guys I've started using a gel spinner this week, I'm just wondering if there is a way to automate the process? or if someone has an automated gel spinner and can recommend where to get one?
I basically have a rotating mandrel, and am manually extruding the solution through the syringe, but its hard to get constant flow rate ( have no gaps and no bubbles)
I was thinking of getting an automated syringe pump I could couple to it, or else finding/ asking someone to build me one that could be programable thoughts?
Basically, I have tried to attach umbelliferone to the alginate back bone through EDC/DMAP mechanism (Ester formation). I should mention that I have used potassium carbonate (dilute solution) to increase the solubility of umbelliferone in water. What happened was that after 1 hr into the reaction the color of media turned to red and tended to stay that way through out the reaction. Interestingly, no precipitation was observed through the whole course of reaction. Does anyone have a clue what caused the sudden change in color of the solution?
hello everybody. I need some suggestion regarding preparation of bioadhesive. I am using albumin and gluteraldehyde for the preparation but as I followed protocal of different papers. it is impossible to get its adhesive property. Is anyone working for this project? can you please give me suggestion for the adhesive properties?
I performed surface area analysis by DR, Longmuier, BET and V-t and obtained following data !
Based on this how to decide which model is best fit for my adsorption studies,?
Hi! I am currently working in the development of a synthetic material formulation to form tube-like structures by seeding HUVECs on top of the material. The goal is to have the tube formation always take place at the same time, instead of at different time points as I saw previously with Matrigel. I already have some organization of the cells, which indeed happens always at the same time; now I would like evaluate/rate the quality of the network formed, anyone has a suggestion of tests or markers to perform this characterization? Thank you very much.
All i found in the paper is the DP of amylose and amylopectin , or their molecular weight distribution, I want to know their actual length in the real space. That is , single amylose chain are arranged at atomic level or ? of course, we need to consider the linear or twisted amylose, However, I just want the length region
As chitosan is a hydrophillic in nature, i want to decrease its hydrophilicity without affecting its other properties. I am in search of a suitable polymer and crosslinker which will decrease its hydrophilicity. Can anyone suggest me...
Hello to everyone,
Can anyone recommend me some paper or some source where i can learn about the commercial scaffolds that are used in Tissue Engineering. I find a article in which they differentiate the scaffolds on the base of material such as synthetic polymer or natural polymer. However, i am looking some commercial scaffolds that designs are available too.
Can anyone suggest me a protocol to effectively reduce molecular weight of carboxymethyl cellulose for performing NMR as the intact polymer is very viscous to be loaded in NMR tubes?
I cant use acid hydrolysis as it may hydrolyze the chemical modifications I have performed. While enzymatic degradation seems like a good option but I dont know how to separate the enzyme from the hydrolyzed product!
I want to prepare starch based hydrogel, which can be used as green absorbent.
Does 1,1,1,3,3,3-Hexafluoro-2-propanol(hfip) react with polypropylene that is being used in making MCTs? i have been getting unknown particulate contaminations in my sample after treating with HFIP. Since HFIP is corrosive in nature I am considering it to be the culprit but I am not sure.
I am working in the area of tissue engineering at Texas Tech University with concentration on poly(caprolactone) (PCL) based biodegradable articular cartilage scaffolds. Currently, my research is at a point where in I am planning to perform in vitro cell culture studies on the scaffolds using mammalian chondrocytes.
I am writing to sincerely request if anyone has mammalian chondrocyte cell lines that they could donate to us to perform in vitro cell culture studies. Else, I would appreciate if you could please direct me to someone that I could ask or any other resources that might be helpful. I appreciate your help towards this.
I have synthesized PVA-borax hydrogel. It dissolved, after two hours immersion in water. How can i measure swelling ratio?
Is it usual for PVA-borax hydrogel to dissolve in water in a short time?
if we want to compare this polymer versus polyvinylpyrrolidone, which one is better to use as a thermosensitive polymer capable to transport a hydrophobic drug to a cell?
If we cannot cross-link two pre-cross-linked layers, how can I prepare a multilayer of alginate and chitosan?
i am trying to freeze dry Sodium alginate solution to make porous sponge. but during freezing it is forming long ice crystals (defects) which is causing the porous film to have defects. how can i get rid of ice crystal formation?
while developing bio-polymer based adsorbent material , we aim in hybridizing chitosan over carbon nitride nano sheets?
I'm working with blocks of bovine gelatin and crosslinking these samples with Formaldehyde for 24 hours. Before I crosslink these samples, I weigh them on a 4 decimal balance. After 24 hours, I'm noticing that these samples have lost weight due to the crosslinking process.
Gelatin blocks left for 24 hours in a pentri dish exhibit no weight loss at all, so I'm sure this is down to the action of the formaldehyde crosslink.
I've been trying to find the reason for this, but would appreciate input from anybody who may be able to shed some insight on this.
Looking for a hydrogel with properties like...
- very fast crosslinking procedure, in the range of seconds,
- cytocompatible before and after crosslinking (cell won't be encapsulated within the gel but they would be in contact with it for long term),
- non-degradable under physiological conditions/ in-vivo,
- low viscosity prior to crosslinking, like PEG-DA solutions for example,
- high strength and elasticity after crosslinking
Until now, I was curing PEG-DA solutions under visible light with Eosin Y and TEA. I did not use any catalyst like 1-vinyl-2-pyrrolidone since it is assumed to be cancerogenic. Furthermore, I don't want to use UV light for the same reason. Without catalyst the polymerization lasts 2 min which is still too long.
Thank you in advance for you help!
Composite hydrogels produce air bubbles when they are subjected to gamma radiation during production.
Other properties are close, for example viscosity, pH, degree of hydrolysis (86-89%), Tg, etc. Thanks for your answers!
I am working on a blend of functionalized graphene nanoplatelets with cellulose acetate and polyalactic acid, when used DSC for testing there were no change and no Tg reported.
Is it dispersed in the porogen used or precipitated as a powder? When I prepare it, the prepared polymer precipitate in the bottom of the flask with a light rubbery consistency? when it dries out after washing it is powder. Is that correct?
I did GAG estimation for native tissues and decellularized samples by DMMB method. Decellularized samples are showing high content of GAG protein than in the native tissue. Is the DMMB reagents reacts with the detergents or the cellular lysate? Give your suggestions please
I am working on a photopolymerized hydrogel thin film project using the electrospray method. Does anybody ever use this method? I plan to use PEGMA and EGDMA as a crosslinker. And derivatives of acetophenone as the initiator.
I would like to know whether it is possible to have a very high density open-cell rigid PU foam, let's said at minimum 1100 kg/m^3. If not possible, on what reason and what is the possible max density and possible max open-cell content (%)? Any answer would be greatly appreciated
I'm trying to develop a hydrogel which can release proteins at a controlled rate.
I'm currently using 4 arm PEG maleimide (10 & 20 kDa) and 2 kDa PEG dithiol has the crosslinker via micheal type addition reaction.
According to Zustiak and Leach (2010) Biomacromolecules, 11, 1348-1357 - the Mw of a crosslinker is related to the degredation of the hydrogel. they have results showing hydrogels crosslinked with 8 kDa crosslinker degraded faster then 2 kDa crosslinker.
So am i right to assume if i use 1kDa PEG dithiol the PEG Malemidie will be more stable?
Has anyone used other crosslinkers apart from PEG Dithiol?
In hip replacement surgery orthopedic surgeon inner surface of the acetabular cavity in the pelvic area that has been corrupted to make a full hemisphere. A hemisphere-shaped metal bowl placed inside the cavity. Inside the metal bowl placed a polyethylene plastic bowl. Sometimes plastic bowl without metal bowl attached into the acetabulum cavity by bone cement .
In some cases it has been observed that after a few months or a few years, polyethylene is causing loosening of the artificial joint and bone fractures.
We want to know how the bone fracture affects polyethylene.
please see the pictures.
I want to know about overlap and fusion of fibers in the C part in attached picture. it can cause changes in the mechanical strength of electrospun scaffolds? how?
increase or decrease?
can you introduce an article to me? thanks
While using the combination of synthetic polymers like Carbopol with naturally derived polysaccharides, I came across to the fact that the viscosity has been going down despite it should have the increment in the viscosity. I just want to know, the reason behind this unusual trend in terms of viscosity seen. Your input would be appreciated....Thank you..
I wanted to extract the water-soluble polysaccharides from a sample of wood chips I treated with white-rot fungi. After culturing the fungi on the woodchips, I added D.H2O and autoclaved the sample for 60 minutes at 136C. I then precipitated the filtrate with 5x ethanol, and recovered a lot of precipitate. I am wondering if this is mostly plant/fungal DNA or hemicellulose? Will the DNA precipitate in the ethanol even without a high salt concentration?
Actually, I am planning to prepare transparent cellulose hydrogels. For cellulose dissolving I am using this solvent medium DMAc/LiCl. Is it possible to prepare transparent hydrogels by using the above solution via free radical
Actually, I am planning to prepare Cellulose/ PVA transparent hydrogels. For preparation of Cellulose/ PVA transparent hydrogels I am using this solvent medium DMAc/LiCl. Is it possible to prepare Cellulose/ PVA transparent hydrogels by using the above (DMAc/LiCl) medium via freeze thaw technique by combination of PVA. Which % of PVA is suitable for the preparation of cellulose/ PVA transparent hydrogels?