This research was partially supported by the Ministry of Science and Technology, Taiwan under grant numbers 106-2119-M-008 -003, 105-2119-M-008-006, and 104-2221-E-008-107-MY3. This research was also supported by the Taiwan Landseed Hospital Project (NCU-LSH-105-A-001). A Grant-in-Aid for Scientific Research (number 15K06591) from the Ministry of Education, Culture, Sports, Science and Technology of Japan is also acknowledged. A. Higuchi would like to acknowledge for the International Scientific Partnership Program (ISPP-0062) Vice Rectorate for Graduate Studies and Research, King Saud University, Riyadh 11451, Kingdom of Saudi Arabia.

The experiments in this study were approved by the ethics committees of the Taiwan Landseed Hospital (IRB-13-05) and the National Central University. All experiments were conducted in accordance with all relevant and applicable governmental and institutional guidelines and regulations during this study.
1. Solution and Media Preparation
<ol>
	<li>Polymer purification
	<ol>
		<li>Purify P-IA with carboxylic acid group with a degree of hydrolysis of &#62;96.5% by washing P-IA ...

<ol>
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The authors have nothing to disclose.

P-IA-oligoECM and P-IA-ECM hydrogels with varying stiffness were developed for the long-term expansion of human ES and iPS cells maintaining their pluripotency for over ten passages in xeno-free conditions, as well as for the culture of human AFS cells, ADS cells, and hematopoietic stem cells25,28,32. P-IA hydrogels immobilized with oligoECM are an excellent candidate for cell cultivation materials to investigate the effect of c...

The fate of stem cell differentiation into a specific lineage of cells and the long-term proliferation of stem cells, especially human induced pluripotent (iPS) cells and human embryonic stem (ES) cells, is known to be regulated by inhibitors, growth factors, and/or small bioactive molecules in culture media. Recently, the physical cues of the biomaterials, particularly the stiffness of cell culture biomaterials, have been recognized to be an important factor guiding the fate of stem cell proliferation and differentiation1,2,3,4,5,6. Therefore, several researchers have started to investigate the fate of stem cells, which are cultured on hydrogels, on differentiation, mainly using polyacrylamide hydrogels with varying stiffness.
The stiffness of biomaterials can control focal adhesions, cell morphology, cell phenotype, and stem cell adhesion, especially in two-dimensional (2-D) cultivation1,2,3,5. Mechano-sensing of biomaterials by stem cells is generally controlled by focal adhesion signaling via integrin receptors. NMMIIA, nonmuscle myosin IIA-dependent contractility of the cytoskeleton of actin plays a critical role in the mechanosensing process of stem cells in 2-D cell cultivation systems3,4,5,7,8,9,10,11.
Engler and his colleagues developed an interesting notion that adult stem cells, such as bone marrow stem (BMS) cells cultivated on cell culture biomaterials with a similar stiffness to that of specific tissues, tend to differentiate into cells originated from specific tissues5. BMS cells incubated on 2-D soft polyacrylamide hydrogels coated with collagen type I (with a stiffness comparable to that of brain tissues) in expansion media were spontaneously induced to differentiate into early neuron lineages, whereas BMS cells cultured on hydrogels with a stiffness similar to that of muscle or collagenous bone tissues were found to induce differentiation into early lineages of myocytes and osteoblasts, respectively, on 2-D polyacrylamide hydrogels3,5. Many researchers have investigated the stem cell fate of differentiation cultured on polyacrylamide hydrogels immobilized with collagen type I12,13,14,15,16,17,18,19,20,21. However, it should be mentioned that some contradictory reports1,18,22,23,24 exist for the well-known idea suggested by Engler et al.5 This is because Engler&#39;s idea5 was developed solely on polyacrylamide hydrogels and their results have originated from specific characteristics of the biomaterial (polyacrylamide), and not solely from the physical cue (stiffness) of the biomaterial. Therefore, it is important to develop another type of hydrogel, of which the stiffness can be controlled by crosslinking of the hydrogels. For this purpose, bioinert hydrogels were developed, which were prepared from polyvinyl alcohol-co-itaconic acid (P-IA) with a different stiffness, which was controlled by the crosslinking degree with a changing crosslinking time25,26,27,28,29,30,31,32. The stem cells can be cultivated on nonmodified P-IA hydrogels, as well as P-IA hydrogels grafted with extracellular matrices (ECMs) and oligopeptides. In a previous study25, human hematopoietic stem cells (hHSCs) from umbilical cord blood were cultivated on P-IA hydrogels with different stiffness values ranging from a 3 kPa to 30 kPa storage modulus where fibronectin or an oligopeptide derived from fibronectin (CS1, EILDVPST) was grafted onto the P-IA hydrogels. High ex vivo fold expansion of hHSCs was observed in the P-IA hydrogels grafted with CS1 or fibronectin, which displayed an intermediate stiffness ranging from 12 kPa to 30 kPa25.
Human iPS and ES cells cannot be cultivated on conventional tissue culture polystyrene (TCP) dishes33,34 because human ES and iPS cells require specific binding to ECMs, such as vitronectin or laminin to maintain their pluripotency during long-term culture. Therefore, several structures of oligopeptide-grafted P-IA hydrogels with optimal stiffness characteristics were designed and prepared in formations of a single chain, a single chain with a joint segment, a dual chain with a joint segment, and a branched-type chain32. Oligopeptide sequences were selected from integrin- and glycosaminoglycan-binding domains of ECMs. The P-IA hydrogels grafted with vitronectin-derived oligopeptides with a dual chain or joint segment, which have a storage modulus at approximately 25 kPa, supported the long-term culture of human ES and iPS cells for over 12 passages under xeno-free and chemical defined conditions32. The joint segment and dual chain with cell adhesion molecules on the hydrogels facilitated the proliferation and pluripotency of human ES and iPS cells32. Here, a protocol for preparing P-IA hydrogels (with a storage modulus from 10 kPa to 30 kPa, which was measured under wet conditions in the air) grafted with and without oligopeptides or ECMs is described. How to culture and passage several stem cells (including amniotic fluid stem cells, adipose-derived stem cells, human ES cells, and human iPS cells) is shown.

<table>
	<tbody>
		<tr>
			<td>GTPGPQGIAGQRGVV</td>
			<td>PH Japan</td>
			<td>none</td>
			<td>Specification: Oligopeptide 
			Abbreviation: Cyclic RGD, cRGD</td>
		</tr>
		<tr>
			<td>GACRGDCLGA</td>
			<td>PH Japan</td>
			<td>none</td>
			<td>Specification: Oligopeptide 
			Abbreviation: FN1</td>
		</tr>
		<tr>
			<td>KGGAVTGRGDSPASS</td>
			<td>PH Japan</td>
			<td>none</td>
			<td>Specification: Oligopeptide 
			Abbreviation: CS1</td>
		</tr>
		<tr>
			<td>EILDVPST</td>
			<td>PH Japan</td>
			<td>none</td>
			<td>Specification: Oligopeptide 
			Abbreviation: VN1</td>
		</tr>
		<tr>
			<td>KGGPQVTRGDVFTMP</td>
			<td>PH Japan</td>
			<td>none</td>
			<td>Specification: Oligopeptide 
			Abbreviation: HBP1</td>
		</tr>
		<tr>
			<td>GKKQRFRHRNRKG</td>
			<td>PH Japan</td>
			<td>none</td>
			<td>Specification: Oligopeptide 
			Abbreviation: HBP2C</td>
		</tr>
		<tr>
			<td>CGGGKKQRFRHRNRKG</td>
			<td>PH Japan</td>
			<td>none</td>
			<td>Specification: Oligopeptide 
			Abbreviation: VN1G</td>
		</tr>
		<tr>
			<td>GGGGKGGPQVTRGDVFTMP</td>
			<td>PH Japan</td>
			<td>none</td>
			<td>Specification: Oligopeptide 
			Abbreviation: VN2C</td>
		</tr>
		<tr>
			<td>GCGGKGGPQVTRGDVFTMP</td>
			<td>PH Japan</td>
			<td>none</td>
			<td>Specification: Extracellular matrix 
			Abbreviation: rVN</td>
		</tr>
		<tr>
			<td>Vitronectin</td>
			<td>Thermo Fisher scientific</td>
			<td>A14700</td>
			<td>Specification: Extracellular matrix 
			Abbreviation: FN</td>
		</tr>
		<tr>
			<td>Fibronectin</td>
			<td>Sigma-Aldrich</td>
			<td>F2006</td>
			<td>Specification: Commercially available coating material 
			Abbreviation: Synthemax II</td>
		</tr>
		<tr>
			<td>Synthemax II</td>
			<td>Corning</td>
			<td>3535</td>
			<td>Specification: Polymer</td>
		</tr>
		<tr>
			<td>Polyvinylalcohol-co-itaconic acid</td>
			<td>Japan VAM &#38; Poval</td>
			<td>AF-17</td>
			<td>Specification: Chemical</td>
		</tr>
		<tr>
			<td>Glutaraldehyde</td>
			<td>Sigma-Aldrich</td>
			<td>G5882</td>
			<td>Specification: Chemical</td>
		</tr>
		<tr>
			<td>Na2SO4</td>
			<td>Sigma-Aldrich</td>
			<td>239313</td>
			<td>Specification: Chemical</td>
		</tr>
		<tr>
			<td>H2SO4</td>
			<td>Sigma-Aldrich</td>
			<td>339741</td>
			<td>Specification: Chemical 
			Abbreviation: EDC</td>
		</tr>
		<tr>
			<td>N-(3-Dimethylaminopropyl)-N&#39;-ethylcarbodiimide hydrochloride</td>
			<td>Sigma-Aldrich</td>
			<td>E7750</td>
			<td>Specification: Chemical 
			Abbreviation: NHS</td>
		</tr>
		<tr>
			<td>N-hydroxysuccinimide</td>
			<td>Sigma-Aldrich</td>
			<td>56480</td>
			<td>Specification: Chemical</td>
		</tr>
		<tr>
			<td>Paraformaldehyde</td>
			<td>Sigma-Aldrich</td>
			<td>P6148</td>
			<td>Specification: Chemical</td>
		</tr>
		<tr>
			<td>Triton-X100</td>
			<td>Sigma-Aldrich</td>
			<td>T8787</td>
			<td>Specification: Cell culture consumable</td>
		</tr>
		<tr>
			<td>Cell scraper</td>
			<td>Corning</td>
			<td>3008</td>
			<td>Specification: Cell culture consumable</td>
		</tr>
		<tr>
			<td>Dispase II</td>
			<td>Sigma-Aldrich</td>
			<td>SI-D4693</td>
			<td>Specification: Cell culture medium</td>
		</tr>
		<tr>
			<td>Essential 6</td>
			<td>Thermo Fisher scientific</td>
			<td>A1516401</td>
			<td>Specification: Cell culture medium</td>
		</tr>
		<tr>
			<td>Essential 8</td>
			<td>Thermo Fisher scientific</td>
			<td>A1517001</td>
			<td>Specification: Cell culture medium</td>
		</tr>
		<tr>
			<td>DMEM/F12</td>
			<td>Thermo Fisher scientific</td>
			<td>11330-032</td>
			<td>Specification: Cell culture medium</td>
		</tr>
		<tr>
			<td>DMEM</td>
			<td>Thermo Fisher scientific</td>
			<td>12800-017</td>
			<td>Specification: Cell culture medium</td>
		</tr>
		<tr>
			<td>MCDB 201</td>
			<td>Sigma-Aldrich</td>
			<td>M6770</td>
			<td>Specification: ES cell</td>
		</tr>
		<tr>
			<td>Human ES cell</td>
			<td>WiCell Research Institute, Inc..</td>
			<td>WA09</td>
			<td>Specification: iPS cell</td>
		</tr>
		<tr>
			<td>Human iPS cell</td>
			<td>Riken Cell Bank</td>
			<td>HS0077</td>
			<td>Specification: 35 mm 
			Abbreviation: TCP</td>
		</tr>
		<tr>
			<td>TCP dish</td>
			<td>Corning</td>
			<td>353001</td>
			<td>Specification: 60 mm 
			Abbreviation: TCP</td>
		</tr>
		<tr>
			<td>TCP dish</td>
			<td>Corning</td>
			<td>353002</td>
			<td>Specification: 24 well dish</td>
		</tr>
		<tr>
			<td>24 well dish</td>
			<td>Corning</td>
			<td>353047</td>
			<td>Specification: Blocking agent</td>
		</tr>
		<tr>
			<td>Bovine serum albumin</td>
			<td>Sigma-Aldrich</td>
			<td>A8806</td>
			<td>Specification: Detection reagent</td>
		</tr>
		<tr>
			<td>Alkaline phosphatase live stain</td>
			<td>Thermo Fisher scientific</td>
			<td>A14353</td>
			<td>Specification: Detection reagent</td>
		</tr>
		<tr>
			<td>Hematoxylin &#38; eosin</td>
			<td>Sigma-Aldrich</td>
			<td>1.05175</td>
			<td>Specification: EB formation dish</td>
		</tr>
		<tr>
			<td>6-well ultralow attachment dish</td>
			<td>Corning</td>
			<td>3471</td>
			<td>Specification: Coating material</td>
		</tr>
		<tr>
			<td>gelatin</td>
			<td>Sigma-Aldrich</td>
			<td>G9391</td>
			<td>Specification: Coating material</td>
		</tr>
		<tr>
			<td>Matrigel</td>
			<td>Corning</td>
			<td>354230</td>
			<td>Specification: Mice</td>
		</tr>
		<tr>
			<td>NOD-SCID mice</td>
			<td>National Applied Research Laboratories</td>
			<td>None</td>
			<td>Specification: Serum</td>
		</tr>
		<tr>
			<td>Fetal bovine serum</td>
			<td>Biological Industries</td>
			<td>04-001-1A</td>
			<td>Specification: Antibiotic</td>
		</tr>
		<tr>
			<td>antimycotic antibiotic</td>
			<td>Thermo Fisher scientific</td>
			<td>15240-062</td>
			<td>Specification: Antibody</td>
		</tr>
		<tr>
			<td>Antibody for Nanog</td>
			<td>Invitrogen</td>
			<td>MA1-017</td>
			<td>Specification: Antibody</td>
		</tr>
		<tr>
			<td>Antibody for SSEA4</td>
			<td>Abcam</td>
			<td>ab16287</td>
			<td>Specification: Antibody</td>
		</tr>
		<tr>
			<td>Antibody for OCT3/4</td>
			<td>Invitrogen</td>
			<td>PA5-27438</td>
			<td>Specification: Antibody</td>
		</tr>
		<tr>
			<td>Antibody for Sox2</td>
			<td>Invitrogen</td>
			<td>48-1400</td>
			<td>Specification: Antibody</td>
		</tr>
		<tr>
			<td>Antibody for Smooth Muscle Actin</td>
			<td>Invitrogen</td>
			<td>PA5-19465</td>
			<td>Specification: Antibody</td>
		</tr>
		<tr>
			<td>Antibody for AFP</td>
			<td>Invitrogen</td>
			<td>PA5-21004</td>
			<td>Specification: Antibody</td>
		</tr>
		<tr>
			<td>Antibody GFAP</td>
			<td>Invitrogen</td>
			<td>MA5-15086</td>
			<td>Specification: Antibody</td>
		</tr>
		<tr>
			<td>Alexa Fluor 555 &#8211; conjugated Goat anti-Mouse antibody</td>
			<td>Invitrogen</td>
			<td>A-21422</td>
			<td>Specification: Antibody</td>
		</tr>
		<tr>
			<td>Alexa Fluor 488 &#8211; conjugated Goat anti-Rabbit antibody</td>
			<td>Invitrogen</td>
			<td>A-11008</td>
			<td>Specification: Antibody</td>
		</tr>
	</tbody>
</table>

human pluripotent stem cell culture on polyvinyl alcohol-co-itaconic acid hydrogels with varying stiffness under xeno-free conditions

The effect of physical cues, such as the stiffness of biomaterials on the proliferation and differentiation of stem cells, has been investigated by several researchers. However, most of these investigators have used polyacrylamide hydrogels for stem cell culture in their studies. Therefore, their results are controversial because those results might originate from the specific characteristics of the polyacrylamide and not from the physical cue (stiffness) of the biomaterials. Here, we describe a protocol for preparing hydrogels, which are not based on polyacrylamide, where various stem, cells including human embryonic stem (ES) cells and human induced pluripotent stem (iPS) cells, can be cultured. Hydrogels with varying stiffness were prepared from bioinert polyvinyl alcohol-co-itaconic acid (P-IA), with stiffness controlled by crosslinking degree by changing crosslinking time. The P-IA hydrogels grafted with and without oligopeptides derived from extracellular matrix were investigated as a future platform for stem cell culture and differentiation. The culture and passage of amniotic fluid stem cells, adipose-derived stem cells, human ES cells, and human iPS cells is described in detail here. The oligopeptide P-IA hydrogels showed superior performances, which were induced by their stiffness properties. This protocol reports the synthesis of the biomaterial, their surface manipulation, along with controlling the stiffness properties and finally, their impact on stem cell fate using xeno-free culture conditions. Based on recent studies, such modified substrates can act as future platforms to support and direct the fate of various stem cells line to different linkages; and further, regenerate and restore the functions of the lost organ or tissue.

P-IA hydrogels grafted with ECM-derived oligopeptide (oligoECM) or ECM with different elasticities were prepared by following the reaction scheme, as seen in Figure 1A, using different types of oligoECM (Figure 1B). The elasticities of the hydrogels were regulated by the applied crosslinking intensity (time) (Figure 1C). P-IA hydrogels grafted with vitronectin-derived oligopeptides, which has a stora...

Watch this Scientific Journal Video about Human Pluripotent Stem Cell Culture on Polyvinyl Alcohol-Co-Itaconic Acid Hydrogels with Varying Stiffness Under Xeno-Free Conditions at JoVE.com

Human Pluripotent Stem Cell Culture on Polyvinyl Alcohol-Co-Itaconic Acid Hydrogels with Varying Stiffness Under Xeno-Free Conditions

A protocol is presented to prepare polyvinyl alcohol-co-itaconic acid hydrogels with varying stiffness, which were grafted with and without oligopeptides, to investigate the effect of the stiffness of biomaterials on the differentiation and proliferation of stem cells. The stiffness of the hydrogels was controlled by the crosslinking time.

The effect of physical cues, such as the stiffness of biomaterials on the proliferation and differentiation of stem cells, has been investigated by ...

The overall goal of this experiment is to prepare either unmodified or oligopeptide or extra-cellular matrix-grafted polyvinyl alcohol-co-itaconic acid hydrogels with the optimal elasticity for culturing and passaging stem cells. This method can help answer key questions in the stem cell research field about long term content of stem cells under xeno-free conditions. The main advantage of this technique is that it provides a platform to investigate a different hydrogel elasticity on stem cell differentiation into specific lineages.Demonstrating the procedure will be me, Jia-Sin Yang and Yeh-Chia Tseng, graduate students from Professor Higuchi's laboratory. To begin the procedure, place 20 grams of P-IA and 200 milliliters of ethanol in a 500 milliliter conical flask. Stir the mixture for 24 to 30 hours, replacing the ethanol every eight to ten hours.Collect the purified P-IA on Buchner funnel. Dry the P-IA under vacuum at room temperature for 24 hours. Next, over the course of 15 minutes, slowly dissolve 15 milligrams of purified P-IA in 100 milliliters of ultra-pure water.Heat the solution to above 60 degrees Celsius and stir for one hour. Confirm that the solution has become clear before proceeding. Then, turn off the heat.Allow the P-IA solution to cool to room temperature on the cooling hot plate while stirring. Continue stirring the solution at room temperature for 48 hours. Then, leave the P-IA solution undisturbed at room temperature for 20 to 24 hours to ensure that visible air bubbles are not present in the solution.Next, dispense one milliliter of the P-IA solution into each of eight 35 milliliter tissue culture-treated dishes. Dry the dishes in an oven at 45 degrees Celsius for two days to produce P-IA films in the dishes. Next, add to 10 milliliters of ultra-pure water 100 microliters of a high-purity aqueous 25%glutaraldehyde solution, two grams of sodium sulfate and 100 microliters of sulfuric acid.Stir the mixture well to obtain the crosslinking solution. Gently add one milliliter of the crosslinking solution to each dish, being careful not to damage the fragile P-IA films. Leave each film immersed in the crosslinking solution for half, one, two, four, six, twelve, twenty four or forty eight hours to obtain the hydrogels.Rinse each hydrogel with one milliliter of ultra-pure water after its crosslinking period. Sterilize each hydrogel by immersion in an aqueous 75%ethanol solution for one minute. Rinse each sterilized hydrogel with ultrapure water six times.Cover the hydrogels in fresh ultra-pure water, place the lids on the dishes and store the hydrogel dishes in a clean area until ready for activation and grafting. Next, activate each sterilized hydrogel by immersion in one milliliter of an aqueous solution containing 10 milligrams per milliliter each of EDC and NHS, either for one hour at 37 degrees Celsius or four hours at four degrees Celsius. Then, rinse each activated hydrogel with one milliliter of Ph 7.2 phosphate-buffered saline three times.Immerse each hydrogel in one milliliter of a solution of either oligopeptides or ECMs in PBS for 24 hours at four degrees Celsius. Finally, wash each hydrogel with one milliliter of ultra-pure water three times after grafting is complete. Use standard method to culture human ES or IPS cells on a membrane matrix in six centimeter culture dishes until near confluent.Then, incubate the cells in DMMF-12 supplemented with two milligrams per milliliter of dispase-2 at 37 degrees Celsius for eight to ten minutes. Rinse the cells twice with DMMF-12. Add two milliliters of DMMF-12 to each culture dish and attach weekly adherent colonies with the pipette or cell scraper.Collect the cells in 15 milliliter centrifuge tubes and centrifuge the cells at 160 times G for five minutes at 37 degrees Celsius. Discard the supernatant and re-suspend the cells in one milliliter of xeno-free eight component medium. Count the cell density in the suspension.Then, obtain culture dishes or multi-well plates containing sterilized P-IA hydrogels grafted with either oligopeptides or ECMs. Load the appropriate volumes of the cell suspension onto the hydrogels. Passage the cells on grafted P-IA hydrogels until 80%confluent the desired number of times.To begin the immuno-staining process for a 24 well plate of passaged human ES or IPS cells on grafted hydrogels, add 0.5 milliliters of four per cent paraformaldahyde by volume to each well. Incubate the cells at four degrees Celsius for 15 minutes to fix the cells. Aspirate the paraformeldehyde solution from the wells.Add one milliliter of PBS to each well and aspirate the PBS. Perform this PBS rinse three times in total. Then, add 0.5 milliliters of 0.3%octoxynol 9 by volume in PBS to each well.Incubate for 30 minutes at room temperature. Aspirate the octoxynol 9 solution. Add 300 microliters of two per cent BSA and PBS to each well and incubate for another 30 minutes at room temperature.Aspirate the two per cent BSA solution from the cells and add the primary antibodies. Incubate the cells for one day at four degrees Celsius. Then, aspirate the primary antibody solutions and wash the cells with 300 microliters of 05 per cent polysorbate 20 in PBS three times.Add 300 microliters of secondary antibodies specific to the primary IDG subtype in two per cent BSA to each well. Incubate the cells for one hour at room temperature in the absence of light. Finally, wash the cells with 300 microliters of 05 per cent polysorbate 20 and PBS three times in the dark.Image the stained cells with fluorescence microscopy. P-IA hydrogels crosslinked for 24 hours and grafted with vitronectin-derived oligopeptides, supported cultures of human ES and IPS cells for at least 10 to 20 passages. Human ESLs cultured on commercially available coated dishes were found to be more easily differentiated at the edges of the colonies.Differentiated cells were not observed on the hydrogels, indicating that human ESLs maintained their pluripotency. Pluripotency proteins were satisfactorily expressed on human ES cells cultured on hydrogels grafted with three different Vitronectin-derived oliogopeptide designs for ten passages. Satisfactory expression was also observed on recomibinent Vitronectin-coated dishes.Similar results were observed for human IPS cells. Both human ES and IPS cells differentiated into cells derived from all three germ layers after cultivation on P-IA hydrogels and on recombinant Vitronectin-coated dishes for at least ten passages. Human ES cells cultivated on hydrogels grafted with Vitronectin-derived oligopeptides were injected into NOD mice.The harvested teratomas exhibited cells originating from all three germ layers indicating that pluripotency is maintained in vivo. Following this procedure, methods like media screening can be performed to answer additional questions like the effect of calcium arterial and stem cell differentiation and proliferation. After this development, this technique paved the way for researchers in the field of stem cell co-division to explore tissue or organ regeneration in neurodegenerative medicine.Once mastered, this technique can be done in four days if it's performed properly. After watching this video, you should have a good understanding of how to prepare P-IA hydrogel dishes, both with and without ECM. While attempting this procedure, remember to set up a clean environment for preparing P-IA hydrogel dishes.Don't forget that working with ethanol, hot water and the sulfuric acid can be extremely hazardous. The appropriate lab coat, gloves and the protective glasses should always be worn while performing this procedure.

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JoVE Journal

Bioengineering

9.2K Görüntüleme.  National Central University. The overall goal of this experiment is to prepare either unmodified or oligopeptide or extra-cellular matrix-grafted polyvinyl alcohol-co-itaconic acid hydrogels with the optimal elasticity for culturing and passaging stem cells. This method can help answer key questions in the stem cell research field about long term content of stem cells under xeno-free conditions. The main advantage of this technique is that it provides a platform to investigate a different hydrogel elasticity on stem cell...