Name: comparable decellularization of fetal and adult cardiac tissue explants as 3d-like platforms for in vitro studies
Uploaded: 2019-03-21T12:30:00
Description: Watch this Scientific Journal Video about Comparable Decellularization of Fetal and Adult Cardiac Tissue Explants as 3D-like Platforms for In Vitro Studies at JoVE.com

The authors are indebted to all members of Pinto-do-&#211; laboratory for relevant critical discussion. This work was supported by Programa MIT-Funda&#231;&#227;o para Ci&#234;ncia e Tecnologia (FCT) under the project &#34;CARDIOSTEM-Engineered cardiac tissues and stem cell-based therapies for cardiovascular applications&#34; (MITP-TB/ECE/0013/2013). A.C.S. is a recipient of a FCT fellowship [SFRH/BD/88780/2012] and M.J.O. is a FCT Fellow (FCT-Investigator 2012).

All the methodologies described were approved by the i3S Animal Ethics Committee and Dire&#231;&#227;o Geral de Veterin&#225;ria (DGAV) and are in accordance with the European Parliament Directive 2010/63/EU.
1. Preparation of the decellularization solutions
NOTE: All decellularization solutions should be filtered through a 0.22 &#956;m membrane filter and stored for a maximum of 3 months, except specified otherwise.
<ol>
	<li>For 1x PBS: Mix 8 g of NaCl, 1.01 g o...

<ol>
	<li>Frantz, C., Stewart, K. M., Weaver, V. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+extracellular+matrix+at+a+glance.">The extracellular matrix at a glance.</a> Journal of Cell Science. 123 (24), 4195-4200 (2010).</li><li>Rozario, T., DeSimone, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+extracellular+matrix+in+development+and+morphogenesis:+a+dynamic+view.">The extracellular matrix in development and morphogenesis: a dynamic view.</a> Dev Biol. 341 (1), 126-140 (2010).</li><li>Badylak, S. F., Taylor, D., Uygun, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Whole-Organ+Tissue+Engineering:+Decellularization+and+Recellularization+of+Three-Dimensional+Matrix+Scaffolds.">Whole-Organ Tissue Engineering: Decellularization and Recellularization of Three-Dimensional Matrix Scaffolds.</a> Annu Rev Biomed Eng. 13 (1), 27-53 (2011).</li><li>Ott, H. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Perfusion-decellularized+matrix:+using+nature's+platform+to+engineer+a+bioartificial+heart.">Perfusion-decellularized matrix: using nature's platform to engineer a bioartificial heart.</a> Nat Med. 14 (2), 213-221 (2008).</li><li>Silva, A. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional+scaffolds+of+fetal+decellularized+hearts+exhibit+enhanced+potential+to+support+cardiac+cells+in+comparison+to+the+adult.">Three-dimensional scaffolds of fetal decellularized hearts exhibit enhanced potential to support cardiac cells in comparison to the adult.</a> Biomaterials. 104, 52-64 (2016).</li><li>Nakayama, K. H., Batchelder, C. A., Lee, C. I., Tarantal, A. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Decellularized+rhesus+monkey+kidney+as+a+three-dimensional+scaffold+for+renal+tissue+engineering.">Decellularized rhesus monkey kidney as a three-dimensional scaffold for renal tissue engineering.</a> Tissue Eng Part A. 16 (7), 2207-2216 (2010).</li><li>Williams, C., Quinn, K. P., Georgakoudi, I., Black, L. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Young+developmental+age+cardiac+extracellular+matrix+promotes+the+expansion+of+neonatal+cardiomyocytes+in+vitro.">Young developmental age cardiac extracellular matrix promotes the expansion of neonatal cardiomyocytes in vitro.</a> Acta Biomater. 10 (1), 194-204 (2014).</li><li>Fong, A. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-Dimensional+Adult+Cardiac+Extracellular+Matrix+Promotes+Maturation+of+Human+Induced+Pluripotent+Stem+Cell-Derived+Cardiomyocytes.">Three-Dimensional Adult Cardiac Extracellular Matrix Promotes Maturation of Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes.</a> Tissue Eng Part A. 22 (15-16), 1016-1025 (2016).</li><li>Tapias, L. F., Ott, H. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Decellularized+scaffolds+as+a+platform+for+bioengineered+organs.">Decellularized scaffolds as a platform for bioengineered organs.</a> Curr Opin Organ Transplant. 19 (2), 145-152 (2014).</li><li>Crapo, P. M., Gilbert, T. W., Badylak, S. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+overview+of+tissue+and+whole+organ+decellularization+processes.">An overview of tissue and whole organ decellularization processes.</a> Biomaterials. 32 (12), 3233-3243 (2011).</li><li>Gilbert, T. W., Sellaro, T. L., Badylak, S. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Decellularization+of+tissues+and+organs.">Decellularization of tissues and organs.</a> Biomaterials. 27 (19), 3675-3683 (2006).</li><li>Pinto, M. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Decellularized+human+colorectal+cancer+matrices+polarize+macrophages+towards+an+anti-inflammatory+phenotype+promoting+cancer+cell+invasion+via+CCL18.">Decellularized human colorectal cancer matrices polarize macrophages towards an anti-inflammatory phenotype promoting cancer cell invasion via CCL18.</a> Biomaterials. 124, 211-224 (2017).</li><li>Garlikova, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+a+close-to-native+in+vitro+system+to+study+lung+cells-ECM+crosstalk.">Generation of a close-to-native in vitro system to study lung cells-ECM crosstalk.</a> Tissue Eng Part C: Methods. , (2017).</li><li>Wong, M. L., Griffiths, L. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immunogenicity+in+xenogeneic+scaffold+generation:+Antigen+removal+vs.+decellularization.">Immunogenicity in xenogeneic scaffold generation: Antigen removal vs. decellularization.</a> Acta Biomaterialia. 10 (5), 1806-1816 (2014).</li><li>Motsavage, V. A., Kostenbauder, H. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+influence+of+the+state+of+aggregation+on+the+specific+acid-catalyzed+hydrolysis+of+sodium+dodecyl+sulfate.">The influence of the state of aggregation on the specific acid-catalyzed hydrolysis of sodium dodecyl sulfate.</a> J Colloid Sci. 18 (7), 603-615 (1963).</li><li>Rahman, A., Brown, C. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+pH+on+the+critical+micelle+concentration+of+sodium+dodecyl+sulphate.">Effect of pH on the critical micelle concentration of sodium dodecyl sulphate.</a> J Appl Polymer Sci. 28 (4), 1331-1334 (1983).</li><li>Brown, B. N., Badylak, S. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extracellular+matrix+as+an+inductive+scaffold+for+functional+tissue+reconstruction.">Extracellular matrix as an inductive scaffold for functional tissue reconstruction.</a> Transl Res. 163 (4), 268-285 (2014).</li><li>Ieda, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+fibroblasts+regulate+myocardial+proliferation+through+beta1+integrin+signaling.">Cardiac fibroblasts regulate myocardial proliferation through beta1 integrin signaling.</a> Dev Cell. 16 (2), 233-244 (2009).</li><li>Whitby, D. J., Ferguson, M. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+extracellular+matrix+of+lip+wounds+in+fetal,+neonatal+and+adult+mice.">The extracellular matrix of lip wounds in fetal, neonatal and adult mice.</a> Development. 112 (2), 651-668 (1991).</li><li>Brennan, E. P., Tang, X. H., Stewart-Akers, A. M., Gudas, L. J., Badylak, S. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemoattractant+activity+of+degradation+products+of+fetal+and+adult+skin+extracellular+matrix+for+keratinocyte+progenitor+cells.">Chemoattractant activity of degradation products of fetal and adult skin extracellular matrix for keratinocyte progenitor cells.</a> J Tissue Eng Regen Med. 2 (8), 491-498 (2008).</li><li>Coolen, N. A., Schouten, K. C., Middelkoop, E., Ulrich, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+between+human+fetal+and+adult+skin.">Comparison between human fetal and adult skin.</a> Arch Dermatol Res. 302 (1), 47-55 (2010).</li></ol>

The extracellular matrix (ECM) is a highly dynamic and complex meshwork of fibrous and adhesive glycoproteins, consisting of a reservoir of numerous bioactive peptides and entrapped growth factors. As the major modulator of cell adhesion, cytoskeleton dynamics, motility/migration, proliferation, differentiation and apoptosis, ECM actively regulates cellular function and behavior. Knowing that cellular behavior differs in 2D and 3D cultures, there have been efforts to develop novel organotypic models that can accurately r...

An erratum was issued for:&#160;<a href="https://www.jove.com/video/56924/comparable-decellularization-fetal-adult-cardiac-tissue-explants-as">Comparable Decellularization of Fetal and Adult Cardiac Tissue Explants as 3D-like Platforms for In Vitro Studies</a>.&#160; The&#160;affiliations were&#160;updated.
The fourth&#160;affiliation&#160;was corrected from:
Gladstone Institutes, University of California San Francisco
to:
Gladstone Institute&#160;of Cardiovascular Disease
An additional affiliation was added for Todd C. McDevitt:
University of California San Francisco

An erratum was issued for:&#160;<a href="https://www.jove.com/video/56924/comparable-decellularization-fetal-adult-cardiac-tissue-explants-as">Comparable Decellularization of Fetal and Adult Cardiac Tissue Explants as 3D-like Platforms for In Vitro Studies</a>.&#160; An affiliation&#160;was updated.

Erratum: Comparable Decellularization of Fetal and Adult Cardiac Tissue Explants as 3D-like Platforms for In Vitro Studies

The extracellular matrix (ECM) is a dynamic network of molecules that regulate important cellular processes, namely fate-decision, proliferation and differentiation1,2. The investigation of cell-ECM interactions has been performed mainly in two-dimensional (2D) in vitro cultures coated with ECM components, which constitute a simplification of native ECM properties found in vivo. Decellularization generates acellular 3D-like ECM bioscaffolds that largely preserve the extracellular architecture and composition of native tissues and organs3,4. In addition to serving as bioactive scaffolds for tissue engineering, decellularized 3D ECM biomaterials are emerging as novel platforms to assess cell-ECM biology that parallel the in vivo environment.
Assessment of the differential role of the ECM components of distinct tissues, organs and age will benefit with the use of similar protocols of generating native bioscaffolds. In the heart, we have developed a versatile protocol for decellularization of fetal and adult-derived samples, as an alternative approach to perform comparative studies of the organ microenvironment. Using this methodology, we captured the native cardiac microenvironment and showed that fetal ECM promotes higher repopulation yields of cardiac cells5. Decellularization further provided identification of resident structural differences between fetal and adult ECM at the level of basement lamina and pericellular matrix mesh arrangement and fiber composition5. Prior to this work, head-to-head comparison of tissues at different ontogenic stages using the same decellularization approach has only been reported for rhesus monkey kidneys and rodent hearts. In addition, a limited number of studies report fetal tissue/organ decellularization per se5,6,7. This has been achieved using SDS as a unique decellularization agent; however, distinct SDS concentrations were used for the decellularization of fetal and adult cardiac tissue7,8. SDS is one of the most effective ionic detergents for clearance of cytoplasmic and nuclear material, and widely used in the decellularization of different tissues and specimens9,10. Solutions containing high SDS concentrations and extended periods of exposure have been correlated with protein denaturation, glycosaminoglycan (GAGs) loss and disruption of collagen fibrils10,11, and therefore a balance between ECM preservation and cell removal is necessary. To apply the same procedure to fetal and adult heart tissue, the protocol described herein is divided in three sequential steps: cell lysis by osmotic shock (hypotonic buffer); solubilization of lipid-protein, DNA-protein and protein-protein interactions (0.2% SDS); and nuclear material removal (DNase treatment).
Our protocol shows several advantages: i) the possibility of equivalent decellularization of age-specific cardiac tissues by the application of the same decellularization strategy; ii) no requirements for specialized methods or equipment; iii) ready adaptation to other tissues and species as it has been successfully applied with minor alterations in human intestine biopsies12 and mouse lung13; and, importantly, iv) can address ECM biomechanical properties while enabling the assembly of 3D-like organotypic cultures that more closely mimic the molecular features of the native tissue microenvironment.

<table>
	<tbody>
		<tr>
			<td colspan="4">Equipment</td>
		</tr>
		<tr>
			<td>Incubated Benchtop Shaker</td>
			<td>Orbital Shakers</td>
			<td>IKA:3510001</td>
			<td>Recommended</td>
		</tr>
		<tr>
			<td>Fluorimeter</td>
			<td>-</td>
			<td>-</td>
			<td>Equipment available</td>
		</tr>
		<tr>
			<td>Digital weight scale</td>
			<td>-</td>
			<td>-</td>
			<td>Equipment available</td>
		</tr>
		<tr>
			<td>Inverted Microscope</td>
			<td>-</td>
			<td>-</td>
			<td>Equipment available</td>
		</tr>
		<tr>
			<td>Cell culture incubator</td>
			<td>-</td>
			<td>-</td>
			<td>Equipment available</td>
		</tr>
		<tr>
			<td>Fridge (4&#186;C)</td>
			<td>-</td>
			<td>-</td>
			<td>Equipment available</td>
		</tr>
		<tr>
			<td>Deep freezer (-80&#186;C)</td>
			<td>-</td>
			<td>-</td>
			<td>Equipment available</td>
		</tr>
		<tr>
			<td>Microtome</td>
			<td>-</td>
			<td>-</td>
			<td>Equipment available</td>
		</tr>
		<tr>
			<td colspan="4">Cirurgical Instruments</td>
		</tr>
		<tr>
			<td>Vannas Spring Scissors - 2.5mm Cutting Edge</td>
			<td>Fine Science Tools</td>
			<td>5000-08</td>
			<td>Recommended</td>
		</tr>
		<tr>
			<td>Dumont 5 Fine Forceps - Biologie/Inox</td>
			<td>Fine Science Tools</td>
			<td>11254-20</td>
			<td>Recommended</td>
		</tr>
		<tr>
			<td>Dumont 7 forceps</td>
			<td>Fine Science Tools</td>
			<td>11272-30</td>
			<td>Recommended</td>
		</tr>
		<tr>
			<td>Dissecting Scissors, straight</td>
			<td>-</td>
			<td>-</td>
			<td>Tool available</td>
		</tr>
		<tr>
			<td>Forceps, serrated, curved</td>
			<td>-</td>
			<td>-</td>
			<td>Tool available</td>
		</tr>
		<tr>
			<td colspan="4">Materials</td>
		</tr>
		<tr>
			<td>24 well plates, individually wrapped</td>
			<td>VWR</td>
			<td>29442-044</td>
			<td>-</td>
		</tr>
		<tr>
			<td>96 well plates, individually wrapped</td>
			<td>VWR</td>
			<td>71000-078</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Steriflip-GV, 0.22&#181;m, PVDF, Radio-Sterilized</td>
			<td>Millipore</td>
			<td>SE1M179M6</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Eppendorff</td>
			<td>-</td>
			<td>-</td>
			<td>Material available</td>
		</tr>
		<tr>
			<td>15 mL Falcon tubes</td>
			<td>Fisher Scientific</td>
			<td>430791</td>
			<td>-</td>
		</tr>
		<tr>
			<td>50 mL Falcon tubes</td>
			<td>Fisher Scientific</td>
			<td>430829</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Four-Compartment Biopsy Processing/Embedding Cassettes with Lid</td>
			<td>Electron Microscopy Science</td>
			<td>70075-B</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Fisherbrand Superfrost Plus Microscope Slides</td>
			<td>Thermo Fisher Scientific</td>
			<td>22-037-246</td>
			<td>-</td>
		</tr>
		<tr>
			<td colspan="4">Tissue cryopreservation</td>
		</tr>
		<tr>
			<td>Shandon Cryomatrix embedding resin</td>
			<td>Thermo Scientific</td>
			<td>6769006</td>
			<td>-</td>
		</tr>
		<tr>
			<td>2-METHYLBUTANE ANHYDROUS 99+% (isopentane)</td>
			<td>Sigma-Aldrich</td>
			<td>277258-1L</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Dry ice</td>
			<td>-</td>
			<td>-</td>
			<td>-</td>
		</tr>
		<tr>
			<td colspan="4">Decellularization</td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>BDH Prolabo</td>
			<td>27810.364</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Na2HPO4</td>
			<td>Sigma-Aldrich</td>
			<td>S-31264</td>
			<td>-</td>
		</tr>
		<tr>
			<td>KH2PO4</td>
			<td>Sigma-Aldrich</td>
			<td>P5379-100g</td>
			<td>-</td>
		</tr>
		<tr>
			<td>KCl</td>
			<td>Sigma-Aldrich</td>
			<td>P8041-1KG</td>
			<td>-</td>
		</tr>
		<tr>
			<td>TrisBASE</td>
			<td>Sigma-Aldrich</td>
			<td>T6066-500G</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Sodium dodecyl sulfate</td>
			<td>Sigma-Aldrich</td>
			<td>L-4390</td>
			<td>-</td>
		</tr>
		<tr>
			<td>MgCl2</td>
			<td>MERCK</td>
			<td>1.05833.1000</td>
			<td>-</td>
		</tr>
		<tr>
			<td>DNAse I</td>
			<td>AplliChem</td>
			<td>A3778,0050</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Gentamicin</td>
			<td>Gibco</td>
			<td>15710-049</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Fungizone</td>
			<td>Gibco BRL</td>
			<td>15290-026</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Deionized water (DI water)</td>
			<td>-</td>
			<td>-</td>
			<td>-</td>
		</tr>
		<tr>
			<td colspan="4">Histology</td>
		</tr>
		<tr>
			<td>10 % formalin neutral buffer</td>
			<td>Prolabo</td>
			<td>361387P</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Eosin Y AQUEOUS</td>
			<td>Surgipath</td>
			<td>01592E</td>
			<td>Can be replaced by alcoholic eosin</td>
		</tr>
		<tr>
			<td>Richard-Allan Scientific HistoGel Specimen Processing Gel</td>
			<td>Thermo Fisher Scientific</td>
			<td>HG-4000-012</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Ethanol ethilic alcohol 99,5% anydrous</td>
			<td>Aga</td>
			<td>4,006,02,02,00</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Deionized water (DI water)</td>
			<td>-</td>
			<td>-</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Clear Rite 3</td>
			<td>Richard-Allan Scientific</td>
			<td>6915</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Shandon Histoplast</td>
			<td>Thermo Fisher Scientific</td>
			<td>RAS.6774006</td>
			<td>-</td>
		</tr>
		<tr>
			<td colspan="4">Kits</td>
		</tr>
		<tr>
			<td>PureLink Genomic DNA Mini Kit</td>
			<td>Thermo Fisher Scientific</td>
			<td>K182001</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Quant-iT PicoGreen&#160;dsDNA kit</td>
			<td>Invitrogen</td>
			<td>P11496</td>
			<td>-</td>
		</tr>
		<tr>
			<td colspan="4">Cell culture</td>
		</tr>
		<tr>
			<td>DPBS</td>
			<td>VWR</td>
			<td>45000-434</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Penicillin-Streptomycin Solution 100X</td>
			<td>Labclinics</td>
			<td>L0022-100</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Fungizone</td>
			<td>Gibco BRL</td>
			<td>15290-026</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Cell culture media of the cell of interest</td>
			<td>-</td>
			<td>-</td>
			<td>-</td>
		</tr>
	</tbody>
</table>

comparable decellularization of fetal and adult cardiac tissue explants as 3d-like platforms for in vitro studies

Current knowledge of extracellular matrix (ECM)-cell communication translates to large two-dimensional (2D) in vitro culture studies where ECM components are presented as a surface coating. These culture systems constitute a simplification of the complex nature of the tissue ECM that encompasses biochemical composition, structure, and mechanical properties. To better emulate the ECM-cell communication shaping the cardiac microenvironment, we developed a protocol that allows for the decellularization of the whole fetal heart and adult left ventricle tissue explants simultaneously for comparative studies. The protocol combines the use of a hypotonic buffer, a detergent of anionic surfactant properties, and DNase treatment without any requirement for specialized skills or equipment. The application of the same decellularization strategy across tissue samples from subjects of various age is an alternative approach to perform comparative studies. The present protocol allows the identification of unique structural differences across fetal and adult cardiac ECM mesh and biological cellular responses. Furthermore, the herein methodology demonstrates a broader application being successfully applied in other tissues and species with minor adjustments, such as in human intestine biopsies and mouse lung.

The decellularization efficiency should be assessed through three main techniques: macroscopic observation, histology and DNA quantification. The macroscopic appearance of samples post-SDS treatment indirectly affects the efficacy of cell removal. After SDS incubation, samples should appear as translucent to whitish (Figure 1C). Fetal (E18) decellularized tissues are characterized by a highly translucent structure while adult explants have a translucent to wh...

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Comparable Decellularization of Fetal and Adult Cardiac Tissue Explants as 3D-like Platforms for In Vitro Studies

The cardiac extracellular matrix (ECM) is a complex network of molecules that orchestrate key processes in tissues and organs while enduring physiological remodeling throughout life. Standardized decellularization of fetal and adult hearts permits comparative experimental studies of both tissues in a 3D context by capturing native architecture and biomechanical properties.

Current knowledge of extracellular matrix (ECM)-cell communication translates to large two-dimensional (2D) in vitro culture studies where ECM components ...

This method can help address important questions in the cardiovascular field about the impact the extracellular matrix has during different physiological and developmental stages of the heart. The main advantage of this technique is that it allows a comparative analysis between fetal and adult extracellular matrices by applying a similar decellularization method to both types of tissue. So this method have been successful applied to other organs such as surgical resections from cancer patients facilitating the study of the extracellular matrix in different contexts.Begin by briefly rinsing the fetal and adult mouse hearts with ice-cold PBS. Then place the tissues under a dissecting microscope and use straight small scissors to remove the atria, right ventricle, and the septa from the adult mouse hearts. Transfer the left ventricle to a new Petri dish and divide the left ventricle free wall into two millimeter thick longitudinal strips.The use of adult mouse left ventricle explants of a homogeneous size is essential for a consistent decellularization efficiency. Use the scalpel and serrated tweezers with curved tip to remove the papillary muscle before using a two by two millimeter grid to further mince the strips into smaller tissue fragments. When all of the tissue has been minced, briefly rinse the pieces with enough PBS to cover the explants.And transfer the fetal hearts and pieces of adult heart tissue into individual 1.5 milliliter microcentrifuge tubes containing 250 microliters of optimal cutting temperature or OCT compound per tube. Then, freeze the cardiac tissue samples in dry ice cooled isopentane for storage at negative 80 degrees Celsius. To decellularize the cryo-preserved tissues place the frozen samples in a Petri dish containing enough PBS to completely cover the explants.After the OCT has melted, submerge the samples in a new Petri dish of PBS and wash the samples three times on a shaker for 10 to 15 minutes at 60 RPM per wash. After the last wash, add one milliliter of working hypotonic buffer to each well of a sterile 24-well tissue culture plate and use fine forceps to transfer one fragment to each well. Incubate the plate at 25 degrees Celsius for 18 hours, at 165 RPM followed by three one-hour washes in one milliliter of PBS per well, per wash.After the last wash, add one milliliter of freshly prepared sodium dodecyl sulfate or SDS solution to each well for a 24-hour incubation at 25 degrees Celsius. The next day, rinse the samples with three 20 minute washes in one milliliter of hypotonic wash buffer per wash followed by the addition of one milliliter of DNase treatment solution to each well for a three-hour incubation, at 37 degrees Celsius. At the end of the incubation, the decellularized samples should lose their gelatin-like consistency.Then wash the tissue fragments three times with one milliliter of PBS for 20 minutes per wash followed by an overnight wash in one milliliter of fresh PBS per well at room temperature and 60 RPM. To assess the removal of cellular remnants from the decellularized tissue, the next morning fix the samples in one milliliter of freshly prepared 10%formula neutral buffer supplemented with 0.03%of aqueous eosin per well for 2.5 to three hours at room temperature. At the end of the incubation, wash the samples in one milliliter of PBS per well.And use a disposable vinyl specimen mold to encapsulate the decellularized fragments in histology processing gel according to the manufacturer's specifications. Next, transfer the encapsulated fragments to a biopsy processing embedding cassette. And process the samples for paraffin embedding through successive 30-minute incubations in ascending concentrations of ethanol, isoparaffinic aliphatic hydrocarbon solution and two 56 degrees Celsius paraffin emergens.After the second paraffin emergent, mount samples in a paraffin block and use a microtome to obtain three-micrometer thick sections. Then verify the decellularization efficiency by staining the sections with haematoxylin and eosin and Masson's trichrome stains according to standard protocols. After the overnight PBS wash with shaking, add 500 microliters of freshly prepared DPBS, supplementd with 2.5 micrograms per milliliter of amphotericin B 1%antibiotic solution to each scaffold.And store the samples for one to seven days at four degrees Celsius. Before seating the cells, replace the DPBS solution with 500 microliters of cell basal medium supplemented with antibiotics. And incubate the scaffolds for one hour at 37 degrees Celsius.At the end of the incubation, use a microscope to add a four microliter drop of DPBS to the center of one well of a 96-well plate per scaffold. And use thin straight tweezers to transfer one decellularized scaffold to the top of each drop. Remove any extra DPBS by aspiration and confirm that the scaffold is not folded or wrinkled.When the scaffolds have dried at the edges, slowly seat a single cell suspension of the cells of interest on the top of each scaffold. Embryonic day 18 decellularized tissues are characterized by a highly translucent structure while adult explants exhibit a translucent to white appearance. Hematoxylin and eosin and Masson's trichome stains confirm an efficient cell removal by the presence porous mesh.The nuclear material is reduced by approximately 99.8%after decellularization, compared to non-manipulated tissues which is essential for avoiding triggering an undesired inflammatory response upon implantation. The cell viability within seated scaffolds can be monitored during in-vitro culture by calcein staining. Terminal analysis of the cell repopulation and distribution across scaffolds, can also be performed after paraffin processing as observed in these representative images of a central bioscaffold section.So this technique paved the way for researchers in the exploration of the bioactive properties of the extracellular matrix from fetal and adult mouse hearts but also of other tissues.

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Research

JoVE Journal

Bioengineering

Microfabricated Platforms for Mechanically Dynamic Cell Culture

The ability to systematically probe in vitro cellular response to combinations of mechanobiological stimuli for tissue engineering, drug discovery or fundamental cell biology studies is limited by current bioreactor technologies, which cannot simultaneously apply a variety of mechanical stimuli to cultured cells. In order to address this issue, we have developed a series of microfabricated platforms designed to screen for the effects of mechanical stimuli in a high-throughput format. In this protocol, we demonstrate the fabrication of a microactuator array of vertically displaced posts on which the technology is based, and further demonstrate how this base technology can be modified to conduct high-throughput mechanically dynamic cell culture in both two-dimensional and three-dimensional culture paradigms.

In this protocol, we demonstrate the fabrication of a microactuator array of vertically displaced posts on which the technology is based, and how this base technology can be modified to conduct high-throughput mechanically dynamic cell culture in both two-dimensional and three-dimensional culture paradigms.

The ability to systematically probe in vitro cellular response to combinations of mechanobiological stimuli for tissue engineering, drug discovery or ...

Decellularization and Recellularization of Whole Livers

The liver is a complex organ which requires constant perfusion for delivery of nutrients and oxygen and removal of waste in order to survive1. Efforts to recreate or mimic the liver microstructure with grounds up approach using tissue engineering and microfabrication techniques have not been successful so far due to this design challenge. In addition, synthetic biomaterials used to create scaffolds for liver tissue engineering applications have been limited in inducing tissue regeneration and repair in large part due to the lack of specific cell binding motifs that would induce the proper cell functions2. Decellularized native tissues such blood vessels3and skin4on the other hand have found many applications in tissue engineering, and have provided a practical solution to some of the challenges. The advantage of decellularized native matrix is that it retains, to an extent, the original composition, and the microstructure, hence enhancing cell attachment and reorganization5.
In this work we describe the methods to perform perfusion-decellularization of the liver, such that an intact liver bioscaffold that retains the structure of major blood vessels is obtained. Further, we describe methods to recellularize these bioscaffolds with adult primary hepatocytes, creating a liver graft that is functional in vitro, and has the vessel access necessary for transplantation in vivo.

Perfusion decellularization is a novel technique to produce whole liver scaffolds that retains the organ's extracellular matrix composition and microarchitecture. Herein, the method of preparing whole organ scaffolds using perfusion decellularization and subsequent repopulation with hepatocytes is described. Functional and transplantable liver grafts can be generated using this technique.

The liver is a complex organ which requires constant perfusion for delivery of nutrients and oxygen and removal of waste in order to survive1. Efforts to ...

Encapsulation of Cardiomyocytes in a Fibrin Hydrogel for Cardiac Tissue Engineering

Culturing cells in a three dimensional hydrogel environment is an important technique for developing constructs for tissue engineering as well as studying cellular responses under various culture conditions in vitro. The three dimensional environment more closely mimics what the cells observe in vivo due to the application of mechanical and chemical stimuli in all dimensions 1. Three-dimensional hydrogels can either be made from synthetic polymers such as PEG-DA 2 and PLGA 3 or a number of naturally occurring proteins such as collagen 4, hyaluronic acid 5 or fibrin 6,7. Hydrogels created from fibrin, a naturally occurring blood clotting protein, can polymerize to form a mesh that is part of the body's natural wound healing processes 8. Fibrin is cell-degradable and potentially autologous 9, making it an ideal temporary scaffold for tissue engineering.
Here we describe in detail the isolation of neonatal cardiomyocytes from three day old rat pups and the preparation of the cells for encapsulation in fibrin hydrogel constructs for tissue engineering. Neonatal myocytes are a common cell source used for in vitro studies in cardiac tissue formation and engineering 4. Fibrin gel is created by mixing fibrinogen with the enzyme thrombin. Thrombin cleaves fibrinopeptides FpA and FpB from fibrinogen, revealing binding sites that interact with other monomers 10. These interactions cause the monomers to self-assemble into fibers that form the hydrogel mesh. Because the timing of this enzymatic reaction can be adjusted by altering the ratio of thrombin to fibrinogen, or the ratio of calcium to thrombin, one can injection mold constructs with a number of different geometries 11,12. Further we can generate alignment of the resulting tissue by how we constrain the gel during culture 13.
After culturing the engineered cardiac tissue constructs for two weeks under static conditions, the cardiac cells have begun to remodel the construct and can generate a contraction force under electrical pacing conditions 6. As part of this protocol, we also describe methods for analyzing the tissue engineered myocardium after the culture period including functional analysis of the active force generated by the cardiac muscle construct upon electrical stimulation, as well as methods for determining final cell viability (Live-Dead assay) and immunohistological staining to examine the expression and morphology of typical proteins important for contraction (Myosin Heavy Chain or MHC) and cellular coupling (Connexin 43 or Cx43) between myocytes.

We describe the isolation of neonatal cardiomyocytes and the preparation of the cells for encapsulation in fibrin hydrogel constructs for tissue engineering. We describe methods for analyzing the tissue engineered myocardium after the culture period including active force generated upon electrical stimulation and cell viability and immunohistological staining.

Culturing cells in a three dimensional hydrogel environment is an important technique for developing constructs for tissue engineering as well as studying ...

Capillary Force Lithography for Cardiac Tissue Engineering

Cardiovascular disease remains the leading cause of death worldwide1. Cardiac tissue engineering holds much promise to deliver groundbreaking medical discoveries with the aims of developing functional tissues for cardiac regeneration as well as in vitro screening assays. However, the ability to create high-fidelity models of heart tissue has proven difficult. The heart&#8217;s extracellular matrix (ECM) is a complex structure consisting of both biochemical and biomechanical signals ranging from the micro- to the nanometer scale2. Local mechanical loading conditions and cell-ECM interactions have recently been recognized as vital components in cardiac tissue engineering3-5.
A large portion of the cardiac ECM is composed of aligned collagen fibers with nano-scale diameters that significantly influences tissue architecture and electromechanical coupling2. Unfortunately, few methods have been able to mimic the organization of ECM fibers down to the nanometer scale. Recent advancements in nanofabrication techniques, however, have enabled the design and fabrication of scalable scaffolds that mimic the in vivo structural and substrate stiffness cues of the ECM in the heart6-9.
Here we present the development of two reproducible, cost-effective, and scalable nanopatterning processes for the functional alignment of cardiac cells using the biocompatible polymer poly(lactide-co-glycolide) (PLGA)8 and a polyurethane (PU) based polymer. These anisotropically nanofabricated substrata (ANFS) mimic the underlying ECM of well-organized, aligned tissues and can be used to investigate the role of nanotopography on cell morphology and function10-14.
Using a nanopatterned (NP) silicon master as a template, a polyurethane acrylate (PUA) mold is fabricated. This PUA mold is then used to pattern the PU or PLGA hydrogel via UV-assisted or solvent-mediated capillary force lithography (CFL), respectively15,16. Briefly, PU or PLGA pre-polymer is drop dispensed onto a glass coverslip and the PUA mold is placed on top. For UV-assisted CFL, the PU is then exposed to UV radiation (&#955; = 250-400 nm) for curing. For solvent-mediated CFL, the PLGA is embossed using heat (120 &#176;C) and pressure (100 kPa). After curing, the PUA mold is peeled off, leaving behind an ANFS for cell culture. Primary cells, such as neonatal rat ventricular myocytes, as well as human pluripotent stem cell-derived cardiomyocytes, can be maintained on the ANFS2.

In this protocol, we demonstrate the fabrication of biomimetic cardiac cell culture substrata made from two distinct polymeric materials using capillary force lithography. The described methods provide a scalable, cost-effective technique to engineer the structure and function of macroscopic cardiac tissues for in vitro and in vivo applications.

Cardiovascular disease remains the leading cause of death worldwide1. Cardiac tissue engineering holds much promise to deliver groundbreaking medical ...

Tissue Engineering of a Human 3D in vitro Tumor Test System

Cancer is one of the leading causes of death worldwide. Current therapeutic strategies are predominantly developed in 2D culture systems, which inadequately reflect physiological conditions in vivo. Biological 3D matrices provide cells an environment in which cells can self-organize, allowing the study of tissue organization and cell differentiation. Such scaffolds can be seeded with a mixture of different cell types to study direct 3D cell-cell-interactions. To mimic the 3D complexity of cancer tumors, our group has developed a 3D in vitro tumor test system.	
	Our 3D tissue test system models the in vivo situation of malignant peripheral nerve sheath tumors (MPNSTs), which we established with our decellularized porcine jejunal segment derived biological vascularized scaffold (BioVaSc). In our model, we reseeded a modified BioVaSc matrix with primary fibroblasts, microvascular endothelial cells (mvECs) and the S462 tumor cell line. For static culture, the vascular structure of the BioVaSc is removed and the remaining scaffold is cut open on one side (Small Intestinal Submucosa SIS-Muc). The resulting matrix is then fixed between two metal rings (cell crowns).	
	Another option is to culture the cell-seeded SIS-Muc in a flow bioreactor system that exposes the cells to shear stress. Here, the bioreactor is connected to a peristaltic pump in a self-constructed incubator. A computer regulates the arterial oxygen and nutrient supply via parameters such as blood pressure, temperature, and flow rate. This setup allows for a dynamic culture with either pressure-regulated pulsatile or constant flow.	
	In this study, we could successfully establish both a static and dynamic 3D culture system for MPNSTs. The ability to model cancer tumors in a more natural 3D environment will enable the discovery, testing, and validation of future pharmaceuticals in a human-like model.

Tissue Engineering of a Human 3D in vitro Tumor Test System

Methods to create human 3D tumor tissues as test systems are described. These technologies are based on a decellularized Biological Vascularized Scaffold (BioVaSc), primary human cells and a tumor cell line, which can be cultured under static as well as under dynamic conditions in a flow bioreactor.

Cancer is one of the leading causes of death worldwide.  Current therapeutic strategies are predominantly developed in 2D culture  systems, which ...

Eye Irritation Test (EIT) for Hazard Identification of Eye Irritating Chemicals using Reconstructed Human Cornea-like Epithelial (RhCE) Tissue Model

To comply with the Seventh Amendment to the EU Cosmetics Directive and EU REACH legislation, validated non-animal alternative methods for reliable and accurate assessment of ocular toxicity in man are needed. To address this need, we have developed an eye irritation test (EIT) which utilizes a three dimensional reconstructed human cornea-like epithelial (RhCE) tissue model that is based on normal human cells. The EIT is able to separate ocular&#160;irritants and corrosives (GHS Categories 1 and 2 combined) and those that do not require labeling (GHS No Category). The test utilizes two separate protocols, one designed for liquid chemicals and a second, similar protocol for solid test articles. The EIT prediction model uses a single exposure period (30 min for liquids, 6 hr for solids) and a single tissue viability cut-off (60.0% as determined by the MTT assay). Based on the results for 83 chemicals (44 liquids and 39 solids) EIT achieved 95.5/68.2/ and 81.8% sensitivity/specificity and accuracy (SS&#38;A) for liquids, 100.0/68.4/ and 84.6% SS&#38;A for solids, and 97.6/68.3/ and 83.1% for overall SS&#38;A. The EIT will contribute significantly to classifying the ocular irritation potential of a wide range of liquid and solid chemicals without the use of animals to meet regulatory testing requirements. The EpiOcular EIT method was implemented in 2015 into the OECD Test Guidelines as TG 492.

Eye Irritation Test EIT for Hazard Identification of Eye Irritating Chemicals using Reconstructed Human Cornea-like Epithelial RhCE Tissue Model

We have developed an eye irritation test which utilizes a three dimensional reconstructed human cornea-like epithelial (RhCE) tissue model. The test is able to discriminate between ocular irritant and corrosive materials (GHS Categories 1 and 2 combined) and those that do not require labeling (GHS No Category).

To comply with the Seventh Amendment to the EU Cosmetics Directive and EU REACH legislation, validated non-animal alternative methods for reliable and ...

Neonatal Cardiac Scaffolds: Novel Matrices for Regenerative Studies

The only definitive therapy for end stage heart failure is orthotopic heart transplantation. Each year, it is estimated that more than 100,000 donor hearts are needed for cardiac transplantation procedures in the United States1-2. Due to the limited numbers of donors, only approximately 2,400 transplants are performed each year in the U.S.2. Numerous approaches, from cell therapy studies to implantation of mechanical assist devices, have been undertaken, either alone or in combination, in an attempt to coax the heart to repair itself or to rest the failing heart3. In spite of these efforts, ventricular assist devices are still largely used for the purpose of bridging to transplantation and the utility of cell therapies, while they hold some curative promise, is still limited to clinical trials. Additionally, direct xenotransplantation has been attempted but success has been limited due to immune rejection. Clearly, another strategy is required to produce additional organs for transplantation and, ideally, these organs would be autologous so as to avoid the complications associated with rejection and lifetime immunosuppression. Decellularization is a process of removing resident cells from tissues to expose the native extracellular matrix (ECM) or scaffold. Perfusion decellularization offers complete preservation of the three dimensional structure of the tissue, while leaving the bulk of the mechanical properties of the tissue intact4. These scaffolds can be utilized for repopulation with healthy cells to generate research models and, possibly, much needed organs for transplantation. We have exposed the scaffolds from neonatal mice (P3), known to retain remarkable cardiac regenerative capabilities,5-8 to detergent mediated decellularization and we repopulated these scaffolds with murine cardiac cells. These studies support the feasibility of engineering a neonatal heart construct. They further allow for the investigation as to whether the ECM of early postnatal hearts may harbor cues that will result in improved recellularization strategies.

In these studies, we provide methodology for novel, neonatal, murine cardiac scaffolds for use in regenerative studies.

The only definitive therapy for end stage heart failure is orthotopic heart transplantation.  Each year, it is estimated that more than 100,000 donor ...

Fabrication of Extracellular Matrix-derived Foams and Microcarriers as Tissue-specific Cell Culture and Delivery Platforms

Cell function is mediated by interactions with the extracellular matrix (ECM), which has complex tissue-specific composition and architecture. The focus of this article is on the methods for fabricating ECM-derived porous foams and microcarriers for use as biologically-relevant substrates in advanced 3D in vitro cell culture models or as pro-regenerative scaffolds and cell delivery systems for tissue engineering and regenerative medicine. Using decellularized tissues or purified insoluble collagen as a starting material, the techniques can be applied to synthesize a broad array of tissue-specific bioscaffolds with customizable geometries. The approach involves mechanical processing and mild enzymatic digestion to yield an ECM suspension that is used to fabricate the three-dimensional foams or microcarriers through controlled freezing and lyophilization procedures. These pure ECM-derived scaffolds are highly porous, yet stable without the need for chemical crosslinking agents or other additives that may negatively impact cell function. The scaffold properties can be tuned to some extent by varying factors such as the ECM suspension concentration, mechanical processing methods, or synthesis conditions. In general, the scaffolds are robust and easy to handle, and can be processed as tissues for most standard biological assays, providing a versatile and user-friendly 3D cell culture platform that mimics the native ECM composition. Overall, these straightforward methods for fabricating customized ECM-derived foams and microcarriers may be of interest to both biologists and biomedical engineers as tissue-specific cell-instructive platforms for in vitro and in vivo applications.

The tissue-specific extracellular matrix (ECM) is a key mediator of cell function. This article describes methods for synthesizing pure ECM-derived foams and microcarriers that are stable in culture without the need for chemical crosslinking for applications in advanced 3D in vitro cell culture models or as pro-regenerative bioscaffolds.

Cell function is mediated by interactions with the extracellular matrix (ECM), which has complex tissue-specific composition and architecture. The focus ...

Protocol for MicroRNA Transfer into Adult Bone Marrow-derived Hematopoietic Stem Cells to Enable Cell Engineering Combined with Magnetic Targeting

While CD133+ hematopoietic stem cells (SCs) have been proven to provide high potential in the field of regenerative medicine, their low retention rates after injection into injured tissues as well as the observed massive cell death rates lead to very restricted therapeutic effects. To overcome these limitations, we sought to establish a non-viral based protocol for suitable cell engineering prior to their administration. The modification of human CD133+ expressing SCs using microRNA (miR) loaded magnetic polyplexes was addressed with respect to uptake efficiency and safety as well as the targeting potential of the cells. Relying on our protocol, we can achieve high miR uptake rates of 80&#8211;90% while the CD133+ stem cell properties remain unaffected. Moreover, these modified cells offer the option of magnetic targeting. We describe here a safe and highly efficient procedure for the modification of CD133+ SCs. We expect this approach to provide a standard technology for optimization of therapeutic stem cell effects and for monitoring of the administered cell product via magnetic resonance imaging (MRI).

This protocol illustrates a safe and efficient procedure to modify CD133+ hematopoietic stem cells. The presented non-viral, magnetic polyplex-based approach may provide a basis for the optimization of therapeutic stem cell effects as well as for monitoring the administered cell product via magnetic resonance imaging.

While CD133+ hematopoietic stem cells (SCs) have been proven to provide high potential in the field of regenerative medicine, their low retention rates ...

Two Methods for Decellularization of Plant Tissues for Tissue Engineering Applications

The autologous, synthetic, and animal-derived grafts currently used as scaffolds for tissue replacement have limitations due to low availability, poor biocompatibility, and cost. Plant tissues have favorable characteristics that make them uniquely suited for use as scaffolds, such as high surface area, excellent water transport and retention, interconnected porosity, preexisting vascular networks, and a wide range of mechanical properties. Two successful methods of plant decellularization for tissue engineering applications are described here. The first method is based on detergent baths to remove cellular matter, which is similar to previously established methods used to clear mammalian tissues. The second is a detergent-free method adapted from a protocol that isolates leaf vasculature and involves the use of a heated bleach and salt bath to clear the leaves and stems. Both methods yield scaffolds with comparable mechanical properties and low cellular metabolic impact, thus allowing the user to select the protocol which better suits their intended application.

Here we present, and contrast two protocols used to decellularize plant tissues: a detergent-based approach and a detergent-free approach. Both methods leave behind the extracellular matrix of the plant tissues used, which can then be utilized as scaffolds for tissue engineering applications.

The autologous, synthetic, and animal-derived grafts currently used as scaffolds for tissue replacement have limitations due to low availability, poor ...