Science topic

Hydrogel - Science topic

Hydrogels play a crucial role in controlled molecule release, biosensors, cell scaffolds, and development of biomaterials such as organs and tissues. Synthetic hydrogels include protein-based networks, hybrid gels containing protein domains, DNA based gels and hydrogels for tissue engineering.
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Hi, I have seen functionalization of glass slides with APTES/CTMS and tried to search what exactly it does to the surface (in context of gels). Can anyone please explain the need of it in simple terms. All the available information has confused me a little. Your responses are highly appreciated.
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APTES (aminopropyltriethoxysilane) generally increases binding to protic species such as proteins and nucleotides. CTMS (chlorotrimethylsilane aka trimethylchlorosilane) generally produces hydrophobic surfaces. APTES is often referred to as a silane coupling agent while CTMS is a hydrophobic surface treatments. Attached are two short review articles.
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Hi, I wanted to make PAM gels which contains a hydrophobic crosslinker. I was thinking of using DMSO as a solvent and I have read that we can use AIBN as a thermal initiator in such organic condition. However, I was wondering if we can use TEMED/APS and get the same result?
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Dear Aafreen Ansari, as far as you are looking for a hydrogel, the choice of solvent or a combination of solvents, there must be some care in doing that because of their direct influence on the final properties, mainly swelling and porosity. DMSO is usually used in combination with water, but it is not recommanded for some reasons. If you want to use a redox couple for initiation, then precaution is to be taken regarding its reactivity and possible side reactions, especially with reactive solvents such as DMSO. Please have a look at the following documents. My Regards
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i am trying to make hydrogel from decellularized extracellular matrix of cardiac tissue.
the decllularization of tissue was done by the protocol reported in the following paper;
Liguori, G. R., Liguori, T. T. A., de Moraes, S. R., Sinkunas, V., Terlizzi, V., van Dongen, J. A., . . . Harmsen, M. C. (2020). Molecular and biomechanical clues from cardiac tissue decellularized extracellular matrix drive stromal cell plasticity. Frontiers in bioengineering and biotechnology, 8, 520.
unfortunately the process of hydrogel formation isn't succeeding at all (i have tried almost everything), so now i am intended to use EDC cross-linker. The optimum concentration of EDC decided is about 1mM. 20mg of decellularized tissue will be used for digestion in 2mg/ml of pepsin. can anyone help me what volume of 1mM EDC should i use for 20mg of decellularized tissue?
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Dear Nukhba Akbar, Everything depends on the degree of cross-linking that is in direct correlation with the mechanical and rheological properties. I would suggest to use ox dextran
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Because in my experiments even by adding adhesive molecules such as collagen, gelatin, fibronectin I always get cell aggregates and not adhesion as in the plate. Could the stiffness of the gel have something to do with it? Or is it difficult to see stretched cells on the gel?
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Antony Ieva When you add your cells to a hydrogel, the 3D internal structure will provide multiple points of contact for the cell to adhere unlike a 2D monolayer where the cell is stretched out and has contact with the one side of the TC plate.
If your cell density is low, initially the cells will appear as spheres similar to cells when they are trypsinised and in suspension. To visualize cells stretching out into their original shape, you will have to culture them for long time for example, 2-3 weeks. The cells will form clusters (high cell density) or remain in spherical form (low to medium cell density) in the first week.
Another consideration in the stiffness of your gel. Since A549 are lung epithelial cells, you may find references to native lung tissue ECM stiffness (compression modulus) and make your gels in a similar stiffness range.
As long as your cells do not die and not crawl out of your gel, they are fine and have adhered to the gel. if your gels are translucent enough, you can stain your cells with Rhodamin-phalloidin/DAPI and perform confocal /multiphoton imaging (after 2 weeks) to check the actual cytoskeleton to give you better understanding.
Hope this helps
All the best.
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I have a problem with my dissertation research in forming or producing PVA hydrogel with freeze-thaw method. After freeze-thaw treatment, PVA is drained in the incubator but still can not produce cubic-shaped hydrogel with semi-solid texture. The hydrogel that I produced can be seen in the attached picture. How could I form a cubic-shaped semi solid hydrogel?
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I don't think these are the right conditions, usually freezing at -20°C, thawing at+20°C. I will provide you sooner with some documents, meanwhile, find the original paper of Peppas (1991).
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Hello everyone, I wish to prepare a normal hydrogel for practice purpose. I have PEG Mn=4000, 35000, 20000 in my lab for now.
This is the first time I am preparing the same so I am confused with some things-
1. For cross-linking, we prefer MBA right?
2. In solvent method of hydrogel preparation, we use solvent and add the reqd chemicals and go for the preparation, right?
Any normal basic protocol for hydrogel formation would help me a lot. Please if possible someone provide me the with the link regarding the same.
Thanks and Regards
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Dear Rahul Deka, if you want to use MBA, then you have to have acrylate (C=C) PEG endgroups and not OH ended PEGs. PEGs may be crosslinked via both polyaddition and step-growth reactions routes. Please have a look at the following documents. My Regards
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I worked on a hydrogel which formed by combining Xanthan gum, Acrylic acid, styrene sulphonic acid Na salt. The hydrogel solution was irradiated with Co-60 gamma rays. When I measure it's swelling ratio and gel fraction, I found out that both decrease with increasing radiation. Is there any explanation on it?
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Gamma radiation has a high energy. It breaks the covalent bonds of macromolecular compounds and their gelation and swelling coefficient becomes less.
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I am looking for a plain/empty gel system, which we can directly buy and load the drug for the purpose of transdermal delivery. Your kind help will be appreciated.
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generally, based on the nature of the drug we have to select the polymers to prepare any formulation .
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I have been preparing a hydrogel from acrylic acid and lignin. I am using n,n’-bis(acryloyl) cystamine as a crosslinker and ammonium persulfate as an initiator and crosslinking in an oven at 80 degrees Celsius.
This has been working fine to make stretchy and adhesive hydrogels until I added PEDOT nanoparticles in a DI water solution and now the gels are just evaporating and not crosslinking. I will try adding the nanoparticles in dry to see if this helps.
Just wondering if anyone has any tips on the incorporation of nanoparticles into hydrogels?
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Dear Caitriona Winters, please have a look at the following paper, hope it will answer your question. My Regards
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Please suggest the way of cutting the upper part of the hydrogels.
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It is dependent on the strength of your hydrogel. You should probably freeze it to allow for a clean cut with the microtome.
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Ca-alginate beads are effective drying beads, but I was wondering if they can change anything in the gel structure?
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Ethanol groups induce the intermolecular interactions, So its lead to rigid hydrogels
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I need to create a hydrogel (preferably chitosan based) that can form its gel structure within 30 minutes, but I can't seem to find any methods that take less than 30 minutes.
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Khondoker Kabbyo Shariar pleasure to help, Sir
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I have looked on many different publication websites but I cannot seem to find any papers relating to the idea of having a two-stage release profile for a loaded hydrogel. Would it be feasible to create a gel loaded with an attractant protein towards the edges of the gel with a chemotherapeutic drug in the center to treat cancer post-resection? Thank you in advance.
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Dear Stephen Szpak, one way to do that is via "dual stimuli hydrogel". Also Gels having two LCSTs present dual thermoresponses. My Regards
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I am working on hydrogels but am unable to find a suitable microscopic model
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Dear Sateesh kumar Gupta, the question as it is asked is very broad and general, some screening criteria are to be outlined. Manning two phase condensation theory is good to start with. Please have a look at the following documents, hope they will be usefull. My Regards
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I have prepared a nanocomposite hydrogel by freeze-thaw method and then dried it at 60 degrees Celsius in vacuum oven. What would be the appropriate nomenclature for this gel now? Would it be xerogel or aerogel? Also I have added nanocomposites into it. Can I say it nanogel or nanocomposite gel or porous aerogel?
Your kind suggestions are much appreciated.
Thank you!
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So, it will be either a xerogel nanocomposite or an aerogel nanocomposite, depending on the morphology you will find. The first reference in my last answer deals with this type of composite gels. Best of Luck
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as for hydrogel, high mechanical property and good injectability is important index to determine its functional application for example, wound healing. in many outstanding papers, hydrogel with higher than 1000kPa storage modulus(G') still has good injectability(even througn 23 gauge). in my approach, i obtained hydrogel immediately after pH adjusted to alkali, but its really hard to inject using 23 gauge needle even when its G' is less than 400Pa.(a 40.0  mm parallel
plate with plate gap of 1.0  mm adopted like most papers). it is really awkward! hydrogel is not so tough before injection, then turns into very tough status after released from needle? for reaching that high strength do i need to increase the consistency of polymer components solution? this question makes me so confused.
Second, consistency of polymers in hydrogel is different according to reports, some papers realized the high strength at more than 10% consistency (dry mass of hydrogel), other papers make it at less than 5%.Here, questions raises. if polymer component is very viscous at high consistency(CMC, chitosan), and the mixing of polymers immediately form a hydrogel (many examples are from papers), then how they can ensure the homogenous dispersion in hydrogel(especially in those hydrogel entrapping small biomolecules or drug nanoparticles) in the high consistency solution? please let me free from misunderstanding , thanks
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For the first point, check for the shear thinning properties of the materials, that may strongly affect the injectability. Hydrogels are non-newtonian formulations with viscosity that may change over the applied stress.
For the second point, materials differ not only in their concentration but also in their intrinsic features (e.g., length of the molecular chains, strength of the bonds). There is not a general rule on the concentration to be used.
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Articles have only mentioned that cell-laden hydrogel scaffolds were lyophilized before SEM analyses for cell adhesion. However, no details were mentioned.
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Samples were fixed by adding 5% glutaraldehyde solution overnight which was replaced with a fresh sterilised solution of PBS and changed three times before soaking in fresh sterilised deionised water for one hour twice. Then, the CCC samples were frozen at −80 °C for three hours before placing them into a Christ ALPHA 2–4 freeze-dryer for 24 hours.
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I'm searching for different ways to create hydrogel or chitosan films on hard surface
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Wisnu Sudjarwo thank you for your answer,can you please also describe the cleaning method of the quartz discs?
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Hello, everyone!
I have a problem when I add alginate in chitosan solution to my hydrogel It becomes agglomerated, and I don't know what I should do to prevent this.
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Dear Mohammad Amin Fathollah Maghsoudi, both ionic and covalent crosslinked hydrogels are prepared and studied from these two biopolymers. Please have a look at the following links. My Regards
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I m going to check the zeta potential for alginate beads (hydrogels with a size of 1 mm diameter)by surpass 3 (with cylindrical cell) but in high pressure (600 or 500 on rinse process), my samples are gone from the measuring cell and disperse in the solution. However, I use a filter and fix the shaft tightly. I,m adjusting the permeability index at 100 by tightening the adjustment screw.
does anybody has some experience with this device?
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For general sample mounting instruction with the cylindrical cell of the SurPASS 3, you can also check this tutorial video: https://www.youtube.com/watch?v=7qO8TBnxJzw&list=PLVPW8NM5rINLjgJOovr9u9-6g_1NRzYZp&index=18
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i have been trying to make hydrogel from cardiac tissue. the decellularization protocol i have used consists 0.05% Trypsin in PBS, 1% SDS, 1% Triton-X100, 1% Sodium Deoxycholate and 6M NaCl. after lyophilization i have used the common protocol of digestion by using 2mg/ml pepsin in 0.01 M HCl at room temperature and then after the digestion is completed, i have kept my digested dECM solution at 37℃ but no hydrogel is formed.
PS. the detailed procedures i have followed is attached .
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Yes in 6 hours dECM was not fully digested so i have extended the time untill i got clear solution that was upto 48 hours.
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Hello everyone,
I'm synthesizing a conductive hydrogel made of a PVA, CMC BORAX, and active carbon. I'm trying to measure its conductivity by impedance: What I'm doing is putting the hydrogel on a coin cell and measuring its impedance. Is it the right method? Because I'm assuming that the hydrogel is the electrolyte and both sides of the coin cells are the electrodes? is it possible even if the hydrogel is conductive?
Thank you for your help.
Myriam.
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Can anyone please suggest a cheap hydrogel brand available to buy for 3D cell culture?
Or if someone can share a recipe to prepare homemade hydrogel (for 3D cell culture), that would be fantastic.
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I am using the Tissue Labs hydrogel. It is not as expensive as others on the market and there is availability to buy the hydrogel according to the tissue that will be studied.
Take a look and see if it works for you.
Good luck!
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I want to prepare a self-healing hydrogel with PVA and TA. Can you say me the protocol of synthesis?
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Dear Erfan Behjat, please check this simple google search results, you will see the diverse possibilities on the preparation routes. My Regards
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can we make a thermally stable alginate/gelatin at 37 C?
I have tried to seed cells on cross linked alginate/gelatin hydrogels with different ratios but they are not stable at 37 C.
Can anyone help me with that?
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Thank you all for your respond.
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Hello,
I am making acrylamide-based hydrogels and want to ensure removal of any unreacted acrylamide. I know of the water dialysis method, but am wondering if anyone has ever used probiotics for the removal? Also, if there are any other (faster) ways to remove it, please share.
Thanks
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Dear Molly Acord, please have a look at the following free patent and the attached file. My Regards
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Need to know the concentration of MBA in PEG hydrogel synthesis.
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Dear Enosh Phillips, providing you have the adequate PEG, the ratio depends on the crosslinking density needed. Please have a look at the following free RG document and the references therein. My Regards
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I want to study the wound healing on an animal model using nanocomposite hydrogel. For a wound of 10 mm diameter, how much moisture is created that causes the wound dressing to swell and release the therapeutic agent? Usually in literature moisture content around 60-80% is reported for wound dressing.
I would be grateful for your help.
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That depends upon so many factors! In addition to the dressing type, things like the location of the wound, the wound etiology, the stage of healing, the activity level of the patient, and the biobirden all influence exudate levels.
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I want to check the antibacterial activity through kinetic growth assay of hydrogel containing metal nanoparticles. What should be the mass of hydrogel added to how much LB media?
Thank you for your response
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I purchased PEDOT:PSS (1.3% suspension in water) from Sigma-Aldrich. Currently, I am preparing a conductive hydrogel using PEDOT:PSS. In the paper the volume of PEDOT:PSS is mentioned as 0.01%, 0.03% and 0.05%. I need to mix these amounts in 40 ml DI water. What should be these amounts in ml? Do you have any idea?
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A first-year university student should be able to do this. Even a high school student (if he remembers the proportions) is able to calculate this. It is important to do it yourself, without shifting the responsibility to others. Then a small victory (like a mistake) will be yours and only yours. The teacher's role is not to do the work for the student, but to stimulate independent decision by intervening in time to correct the mistake.
Once on a hiking trip with me, a little boy (about 4 years old) offered his hand to his mother, trying to help her get over a pile of stones. She (very annoyed) told him: "Don't interfere, you will drop me and fall yourself!"
- Mom, if I were you, I would do everything so that the child could help you. And so you missed the chance to take a step forward in its development (This is what I wanted to tell her)...
So try it yourself, you will succeed!
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Hi community,
we isolate decellularized ECM from various organs and produce hydrogels of these. I am looking for protocols to label ECM or ECM hydrogels with fluorophores, biotin, digoxigenin or otherwise in order to monitor e.g. degradation / turnover in time. What would be advisable?
Many thanks,
Martin Harmsen
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During degradation, the covalent bonds of the ECM protein are broken. However, the properties of a hydrogel are very dependent on the state of the water in it. You can change the state of water by adding inorganic salt, temperature. Even adding a fluorophore will change her condition. The state of the hydrogel is controlled by the energies of thermal kT and quantum fluctuations ħω.
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As it is well established that hydrogels have great moisture absorbing capacity, they will be able to protect the food product from environmental moisture. But what if the food product also contains moisture and that is absorbed by hydrogels???
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Dear Ramandeep Kaur, most biopolymers used in packaging are not used in their native or virgin version, rather modified to improve their barrier properties such as the stability to moisture/water. Please have a look at the following reviews. My Regards
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What is the effect of hydrogel on humus and NPK in the soil?
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Hydrogel reduces the mineralization of humus in the soil and the denitrification process of nitrogen.
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It has been reported in the literature that Tween80 is a porogen. It increases the number of pores in the polymer hydrogel. I have read that 100:1 v/v Polymer: Tween 80 quantity of tween can be added in to the polymer solution. Can anyone help me in this regard?
Thank you so much for your time.
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Dear Noor Ul Ain, please have a look at the following document. My Regards
10.1016/j.cplett.2020.137175
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I dissolved methacrylated hyaluronic acid as 1, 3 and 5% in water (in dark and covered bottle) and added Irgacure-2959 to the solution. My problem is when I make the 3 and 5%, they become like gel and not be like solution. I have the same problem when I store the 1% refrigerator and so can't use them for molding, although in articles they are used.
How I can make them like a solution?
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The viscosity of HAMA solutions depends on the molecular weight of HAMA. My suggestion is to use HAMA with a low molecular weight that could become a solution at concentrations of 1 - 3. In general, 5% of HAMA is very viscous, regardless of its molecular weight.
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Microwave prepared Hydrogel
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Dear Itishree JOGAMAYA Das, both are possible depending on the requirements to be fullfield by the scaffold in a given task. Crosslinking is usually a choice when the mechanical properties, and in some applications such as drug delivery (to controle diffusion) are of concern. Please have a look at the attached file. My Regards
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Ferric ions undergo a gelation reaction with acrylic acid to form a polymeric hydrogel. Several articles stated that iron (III) undergoes either a complexation reaction or an electrostatic reaction. Furthermore, calcium, zinc, and copper can also form hydrogels with polyacrylic acid. In all these cases, scientists reported that metal-containing hydrogel showed self-healing properties. By using electrostatic interaction theory, it is possible to discuss the mechanism of self-healing. But if their complexation is present, what would be the possible mechanism?
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I am working with hydraulic permeability of hydrogels. I am not sure at what extend the Darcy law is applicable and at what values of pressure, volume flow rate, the Darcy law becomes invalid. Any related papers or ideas would be helpful.
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As the flow rate approaches zero or when high rates of flow occur in high hydraulic conductivity material like fractures or karst features, the flow may not be linear and thus, Darcy's law does not appropriately present at these conditions.
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I prepare macrophages from mouse bone marrow and grow them in a sponge-like porous hydrogel that we make.
I am accumulating data that indicates different tightly controlled pore sizes affects resting phenotype and inflammatory response to toll-like receptor stimulation (LPS in my case).
I want to look at cellular metabolism in the materials with different pore sizes with and without stimulation.
I specifically want to compare the balance of glycolysis to oxidative phosphorylation.
As a rough start on the glycolysis side I can collect conditioned media from the cultures over time and measure lactate production before and after LPS.
What has me stumped is the oxidative phosphorylation. Oxygen consumption rate seems hard to get at here. The implant material is opaque. Most of the assays I see need a clear light path through a well in a 96 well plate.
I frequently grind up our cell colonized porous hydrogel to obtain cell lysates for protein and/or RNA studies.
Is there anything that can be done with conditioned media samples as far as oxidative phosphorylation? Is there any substrate that could be fed in to these cultures generate a stable soluble end-point product?
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To get your pO2 in your hydrogels over time, you may want to see the couple papers below that use fast responding bare-fibre oxygen sensors. The papers below measure pO2 in Hydrogels using the OxyLite over time.
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Hi all,
due to the shortage of Matrigel, we would like to find suitable alternatives for the culture of iPSCs.
We have tried Geltrex without success. Next, we will try Vitronectin. Some colleagues have tried Synthemax but did not like it.
By browsing other topics on Research Gate, I read about Jellagen and plant cellulose -based hydrogels (GrowDex-T) and I'd like to know if anyone tried these with iPSC specifically.
I also read about Cell Basement Membrane from ATCC, any opinion on this one?
I will be grateful for any help and tips!
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I have used Geltrex for iPSC culture (both 2D and 3D culture) and they work similar to Matrigel.
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I am working on NaCMC based hydrogels.
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Dear Sateesh kumar Gupta, different models are available, it is to find the one in which you experimental resiluts fit. There are many variables and conditions. Here are some references. My Regards
doi: 10.1016/j.biomaterials.2004.02.062
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i am working on NaCMC based hydrogels
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Dear Sateesh kumar Gupta, please have a look at the following documents. My Regards
DOI: 10.5772/24553
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The alginate hydrogel was fixed in 4% PFA for 2h, dehydrated in 30% surcose overnight, and embed in OCT. After snap frozen, the alginate hydrogel was cryo-sectioned onto a charged glass slide. However, during HE staining, the samples will detached from the slides. Is there a way to prevent the sections from detachment?
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You can try increasing the concentration of PLL used or by coating with gelatin as mentioned before by the researcher. The slides need to be socked in PBS or water to remove OCT and sucrose carefully before proceeding for staining otherwise chances of detachment are more.
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I am working on hydrogel coated mesh that can be used to separate vegetable oil from oil/water mixture. I can see that it is working well for the separation. However, there is a small amount of oil in filtrated water after the separation . Could you please suggest what is the best method to detect oil concentration in water? 
From the literature I know that I need to use a solvent but I do not have a concentrate reference for that or the actual procedure how is it need to be done. 
I have used a refractometer but it did not work, as oil is not soluble in water, so the results keep changing. 
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You can measure by using infrared oil content analyzer
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How will it affect the conformation of peptides?
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Dear Kalpana Kumari in addition to the expert answers provided by John Carter please also have a look at the following potentially useful article which might help you in your analysis:
1,1,1,3,3,3-Hexafluoro-2-propanol and 2,2,2-trifluoroethanol solvents induce self-assembly with different surface morphology in an aromatic dipeptide
This article is freely available as public full text right here on RG. Good luck with your work!
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While determining the oxidation% of my PDA solution in my hydrogel project, I am suddenly curious why we do this, this way.
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Dear Biswarup Goswami, because it becomes inert instead of hydrophilic. This transformation allow it to be applied in many application as support in biocatalysis. Other benit is that cytotoxicity is reduced. Please have a look at the following documents. My Regards
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Currently I am working on a microfluidic chip. An integral part of it should be a semi-permeable membrane which allows the flow of H2O and smaller ions (nothing bigger than a dinucleotide) but effectively blocks all DNA bigger than 12 nt.
For in situ polymerisation I use PEGDA (~MW = 700, others are in the shelf), a photostarter (Darocur 1153) and some water. Polymerisation starts with UV exposure and so far everything goes fine, the structure is where I need it to be and the mechanical stability also according to the requirement.
Is there a way to calculate the pore size upfront or a table where I can look up which composition leads to which result?
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You might find some answer about mesh size of PEGDA hydrogel (but with longer chains) in the following article:
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Hello scientists! To what extent can the effect of hydrogel polymer on soil moisture levels change?
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Dear Shokhrukh Abdullaev, in soil hydrogels are essentially used for water retention, of course other types are used for other purposes such nutriants and pesticides releases. More advencements are combining this feature with other properties such as self-healing and fire resistance. Please have a look at the following documents. My Regards
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There are different theories reported in the literature regarding swelling and porosity of polymer upon addition of clay into the polymer. Its confusing.
I will be thankful for your help.
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Dear Noor Ul Ain, the general behavior is the opposite, i.e., swelling and porosity both increase. Please have a look at the following free access document. My Regards
DOI: 10.5772/intechopen.74478
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Do you know someone if the photoinitiator Irgacure 2959 in the Hydrogel Kit can be stored at -20°C in methanol?
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Many thanks Suman
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We are trying to grow cells in a hydrogel containing NaOH but the cells didn't survive, while the survival rate was good enough in the hydrogel without NaOH.
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Dear Shahid Hussain, cancer cells do not live or grow under basic pH, shift the medium to acidic and you can monitor cells growth. My Regards
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Hey guys,
for an application I will need to a semipermeable membrane into a microfluidic chip. It should catch the DNA after an electrophoretic run.
The constraints are:
- MWCO at 2 kDa
- storable / not easily biodegradable
- low electrical resistance when trenched in a conductive solution
Do you have any suggestions? Are there hydrogels which are better suited than others?
Thanks
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The way that I have planned for my own work was to use a box like shoes' box by using lithography and inside box create two slites. The solid membrane would be prepared and then shift inside the site. Something like the old camera. The negative film would be replaced by the membrane. I have not tried it yet. I worry about the leakage but it seems there might be a way for it as well. I am not sure it works for soft membranes.
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I am preparing a 5% GelMA hydrogel in PBS using APS and TEMED at 20mM concentration. Even after long exposure to UV, there doesn't seem to be any change in the precursor solution. Not even any viscosity changes. Any idea why this might be so? What might I be doing wrong?
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APS and TEMED are thermal initiators, so you have to introduce heat in your system to start the polymerization reaction. Usually, it is done by heating up at 37°C for a small period of time, or overnight at room temperature, to assure that the curing is complete. Today, there are some photoinitiators that could assist your intent, especially if oxygen is depleted from your system. LAP is one of the best ones. It is water-soluble, of relatively low toxicity and can be started even with blue light (405 nm)
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I have prepared and hydrogel via freeze thaw method and then I performed its physical characterization like swelling, water content, moisture retention, gel content etc. Before conducting these experiments first I dried my hydrogels. I want to know it is the right way to perform the analysis? I have read the literature and it is mentioned that for these experiments hydrogels are dried but in few studies they have not mentioned whether they have processed the samples before these experiments.
I would appreciate the response
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Dear Noor,
Typically, the as-prepared hydrogels are dried before characterization (as you did). After the freeze-thaw process, it is also important to purify the hydrogel to remove non-crosslinked chains or other chemicals. The presence of liquid within the swollen hydrogel can lead you to the wrong interpretation of results collected from the experiments mentioned by you (swelling, water retention, etc.). Taking in mind that the drying process used by you (oven, vacuum, lyophilization, etc.) can also affect your results.
Regards, André
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Hi Everyone,
We need to attach metal beads to contact lenses for a project, and I could not find any adhesive that works with contact lenses (preferably biocompatible) . I know that they are made of hydrogels , any suggestions on what to search/look for would be helpful.
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Dear Varun Perumal, many adhesives have been studied for this purpose, such those based on cyanoacrylates, proteins and others. Please have a look at the following documents. My Regards
doi:10.1371/journal.pone.0105512
doi: 10.1002/jbm.820280304
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Hi, I am interested in Conferences, workshops, webinars, forums, and any related space regarding plant-based hydrogels, and agricultural applications. Could you suggest any? Thank you in advance.
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Interesting question.
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Hello everyone
I am going to fabricate a hydrogel using PEG-SH via a thiol-en reaction. It is well known that PEG-Thiol is prone to oxidation, and it has been suggested in the literature that it would be better if one could use a glove box or deoxygenated water.
unfortunately, I don,t have access to the equipment to do so,
I wanted to know if there are any alternative ways to make this hydrogel efficiently.
Is using a reducing agent applicable for this? Does,t it interfere with the formation of hydrogel?
I would appreciate any recommendations.
Thanks
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Dear Maryam Alizadeh, you can use a Shlank setup. For further details, please google search the following book, you may find a free to download copy. My Regards
The Manipulation of Air–Sensitive Compounds
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A pH-responsive hydrogel was synthesized and dried. It swells at higher pH and shrinks at lower pH. How can this behavour be utilized in making a biosensing device?
Moreover, if superparamagnetic iron oxide nanoparticles are embedded in the pH-sensitive hydrogel, how can this material be used in making a biosensor?
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Dear Anurag Priyadarshi, please have a look at the following attached free review papers. My Regards
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What is a good bio-adhesive with low cytotoxicity that could be used to subcutaneously implant an electronic device in mice, without having to suture the device to the tissue?
Any commercially available options? Dermabond and vetbond are not recommended for internal use.
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Check with these Fibrin Glue. These are the commercial names Tisseel, Vistaseal, Evicel, Reliseal Kit.
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I will stain the osteoblast cells we planted on our hydrogels with Alizarin on the 14th and 21st days.
In the protocols I found, 2 grams of Alizarin Red S is dissolved in 100 ml of distilled water to prepare the dye. Unfortunately, I have just Alizarin (Mordant Red 11, 97% Sigma: 122777) on hand. Is it possible for me to implement the same protocol with this?
I have tried dissolving it in both water and DPBS but the dye sinks to the bottom and I get a feculent orangeish liquid. As far as I know, Alizarin Red S is not this color. Please help if you have any tips or experience on this.
I also noticed that when I used Alizarin Red S before, there was a lot of dye residue and it was difficult to see specific stains. No matter how many times I wash, I cannot remove the dye from the gels. I would be glad if you help.
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Hi Gulsah,
To get rid of precipitates, you need to filter Alizarin red once you make the solution.
Also, before staining, cells need to be fixed in 10% neutral buffered formalin (NBF) for an hour (or overnight at 4 degree) and then washed with PBS and stain for alizarin red for 30 min-1 hour. You can also buy a readymade solution of alizarin red (TMS-008). We use it all the time. You can dilute it 1:1 in distilled water and stain your cells, no need to even filter. If you want to use your own stain, dissolve it in water, I think you also need to put it at 37 degree for some time to dissolve properly and then filter to get rid of insoluble alizarin red particles.
Note: Fixation with NBF is very important, without it, your cells will not stain.
Disclaimer: I am not intended to promote any company product here, it is based on my personal experience.
Hope it helps!
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Hello,
i recently printed a hydrogel-bioink made from alginate (2% w/v) and methylcellulose (3%, 5% & 7% w/v) containing NIH-3T3 cells in 24 well plates and cultivated those in DMEM high glucose medium.
After staining with Calcein-AM and Propidium Iodide i noticed deposits on the bottom the wells which fluoresce under the microscope for both staining wavelength as shown in the attached pictures.
  • They are also visible under the microscope using "normal" light
  • They are in every well i have looked at regardless of the concentrations
  • The medium does not show any contamination
  • The deposits are visible as a rough layer on the bottom of each well when changing medium
  • They can't be washed of when changing medium but can be scratched of without much force
  • They almost always present in this dimer like structure
My theory at the moment is that these are methylcellulose deposits which formed either during printing or during cross-linking of the hydrogel with CaCl2, has anyone had any experience with these kinds of deposits and can share their experience with me or point me in the right direction?
Kind Regards and thank you for every answer!
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You see several different things here.
For example, in the EGFP.png image on the left, with a darker background, you can see crystallisations (or flower-like crystalls) that have taken up green fluorescent dye more than the background surface. In the right, heavily over-coloured area, you can see numerous point-like objects that contain the green fluorescent dye. Presumably, these are cells that have remained relatively round as when seeded, i.e. not spread, and have settled at the bottom of the well following gravity, even if formulated in a hydrogel. According to the size, if I can trust the scaling bar, they cannot be bacteria such as cocci, etc. NIH3T3 is a mouse cell line composed of several embryonic cell types of fibroblastic phenotype of the mouse. The cells of this cell line show relatively pronounced spreading, not only on tissue culture polystyrene (TCPS or TCP abbreviated), i.e. on a 2D surface, but also in 3D gels (e.g. hydrogels), provided that their macromolecules have suitable attachment points, ligands for the cell membrane-bound e.g. integrin receptors in a suitable spatial distribution. This is not the case with the hydrogel or hydrogel blend you use.
Best regards,
Jochen
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After formation of PVA hydrogel through freeze thaw-method. It was dried in vacuum oven. To determine the porosity of the PVA film, ethanol displacement method is used. Does the PVA film dissolve in ethanol?
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Dear Noor Ul Ain, it is not specified whether it is a chemical or physical gel. PVA is slightly soluble in ethanol. Please have a look at the following attached files. My Regards
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A pH sensitive hydrogel is embedded with superparamagnetic nanoparticles. This, in response to pH change, swells or shrinks. Also, the hydrogel has now magnetic sensitivity as well as for pH. How can the hydrogel's swelling/shrinking behaviour be characterised by an electrochemical analyzer?
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Dear Anurag Priyadarshi, please go through the following review paper. My Regards
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Dear Experts, In order to apply carbon dots (CDs) for the removal of analytes, why do we need to encapsulate these nanodots with other materials? Is it possible to use CDs as a lone adsorbent? Thanks in advance for your valuable comments.
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Considering the fluorescence origin, CDs were encapsulated in silica matrices by reacting a silane precursor with surface hydroxy groups that do not contribute to the emission process. It enables CDs in the uniform dispersion in silica to preserve their narrow emission in the solid state by avoiding aggregation.
To enhance the optical properties, stability and to preserve emissions
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I want to find out the porosity of the hydrogel for wound dressing application. I have read different articles, most of them reported the ethanol displacement method. But some mentioned water for determining the porosity. My query is whether water or absolute ethanol or mixture of water and ethanol in certain percentage would be used for porosity.
Thanks in advance for your answers
#hydrogel #wounddressing #scaffold #porosity #liquiddisplacementmethod #physicalproperties
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When the gel was dried, an airgel was obtained, then the porosity was already determined. In your question, instead of hydrogel, you should have written airgel. In this case, why prepare anhydrous alcohol. Its preparation and storage is worth the time, care. Use regular alcohol to determine pores.
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How do I get sodium alginate beads from CaCl2 solution after coagulation? What is the best way to store such hydrogel beads for further experiments like swelling ration and adsorption capacity?
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It depends why you want to store them and how long you want to store them. you can store them simply in water. you can add CaCl2 in very concentration with some antimicrobial agent NaN3 (Toxic !). you can do vacuum drying, if you do freeze drying it will be crispy or floppy. you can also store them in sugar solution after sterilization. All depends on your objective.
You can consider reading this paper. It might help your.
  • DOI:10.1016/j.carbpol.2021.119047
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I'm working on development of drug loaded lipid based topical carbopol based hydrogel for future treatment on diabetic wounds. It includes the characterization study regarding the former things and looking for a journal within impact 1-2. Kindly help me suggesting suitable journals.
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Below are some suggestions within the scope and JCR you need:
Carbohydrate Research (JCR: 2.1)
Journal of Food Processing and Preservation (JCR: 2.2)
Protein & Peptide Letters (JCR: 1.9)
Current Nanoscience (JCR: 1.8)
Medicinal Chemistry Research (JCR: 1.9)
Applied Biological Chemistry (JCR: 1.8)
International Journal of Peptide Research and Therapeutics (JCR: 1.9)
However, I suggest you access the following pages below. They are specific tools of the best publishers, which enable authors to find appropriate Journals for their submission. It's easy to use, briefly, you add the title and abstract of the paper and some Journals that publish works within the scope of your work will be suggested.
I hope this helped you.
Journals Elsevier Finder
Wiley Online
Taylor & Francis
Springer
Regards,
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The gel mass fraction is an important indicator for the preparation of the hydrogel
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Let's say you are crosslinking an epoxy with polyamine. The more you add polyamine , the more there will be cross-linking points and the higher the viscosity, and then the curing of the composite, will be. I remind you once again that a gel is a polymer + water dispersed system. The more polymer in the gel, the more it will be bound to the crosslinking agent, the lower its concentration in the composition will be.
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Hello,
Can you please tell me if I need to break the 3D bioprint structures containing the cells first before adding the CellTiterGlo kit so that the reagent can penetrate and lyse the cells inside the hydrogels or not?
Thanks in advance for your feedback
Good evening.
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It likely depends on the bioprinting matrix if the reagents are able to penetrate to cells inside the matrix without disintegrating it. CellTiterGlo works well with e.g. nanofibrillar cellulose based culture matrices such as GrowDex
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stable gel with sodium alginate and calcium chloride
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Dear Hajar Mohamadzade, please refer to the following documents. My Regards
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stable gel with sodium alginate and calcium chloride
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many thanks
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I need a book recommendation to understand how hydrogel adsorb dyes
the mechanism and kinetics
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you are welcome
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Whether increasing or decreasing the thickness of hydrogel effect the antimicrobial properties?
#hydrogel #nanocomposite #wound #wounddressing #woundhealing #nanoparticles #metalnanoparticles
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Dear Noor Ul Ain thanks for sharing this interesting technical question with other RG members. I'm not an expert in this area of research but I assume that the thickness just affects the effective period of a hydrogel, but not its antibacterial properties. For more general information about this topic please have a look at the following relevant literature references which might help you in your analysis:
Antimicrobial hydrogels: promising materials for medical application
Antibacterial Properties and pH Sensitive Swelling of Insitu Formed Silver-Curcumin Nanocomposite Based Chitosan Hydrogel
and
A review on nanocomposite hydrogels and their biomedical applications
Fortunately all three articles have been posted by the authors as public full texts on RG, so that you can freely download all three of them as pdf fiiles.
Good luck with your research and please stay safe and healthy! With best wishes, Frank Edelmann
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Anyone tell the current trend in edible films and coatings? Hydrogel can be used for making films
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Dear Arjun Arulvel, the following chapter deals with the latest progress in this area. My Regards