O autor gostaria de agradecer ao Dr. Dongxuan Jia para assistência técnica. Algumas das imagens que aparecem neste artigo foram em colaboração com o Dr. Malcolm S. Steinberg, Departamento de Biologia Molecular, Universidade de Princeton. O autor também gostaria de agradecer ao Departamento de Defesa Programa de Pesquisa em Câncer de Próstata (subvenções PC-030482-991552 e PC) e os de NCI / NIH (concessão R01CA118755) seu apoio generoso.

1. Preparação de uma suspensão de células Único <ol><li> Culturas de células aderentes devem ser cultivadas a confluência de 90%, quando então monocamadas devem ser lavados duas vezes com PBS. Depois de drenar bem, adicionar 2 ml (para 100 placas mm) de 0,05% de tripsina-EDTA 1 mM, e incubar a 37 ° C até que as células detach. Parar tripsinização adicionando 2 ml de meio completo e gentilmente usar uma pipeta de 5 ml para triturar a mistura até que as células estão em suspensão. Transferência de células para um tubo de 15 ml. </li><li> Adicionar 40 mL de uma 10 mg / ml DNAse estoque e incubar por 5 minutos em temperatura ambiente. Brevemente Vortex e centrifugar a 200 xg por 5 minutos. </li><li> Elimine o sobrenadante e lavar pellet com 1 ml completa meio de cultura de tecidos. Repita, então as células ressuspender em 2 ml de meio completo de cultura de tecidos. </li><li> Contar as células usando um hemocitômetro, ou contador de células automatizado e ajustar a concentração para 2,5 x 10 6 células / ml. Para esta demonstração BioRad um contador de células automatizado TC10 foi usado. </li></ol> 2. Formação de gotas de suspensão. <ol><li> Remova a tampa de um prato de 60 milímetros de cultura de tecidos e coloque 5 ml de PBS no fundo do prato. Este funcionará como uma câmara de hidratação. </li><li> Inverter a tampa e use uma pipeta 20 l para depositar 10 gotas mL para o fundo da tampa. Certifique-se que gotas são colocadas suficientemente distante para não tocar. É possível colocar pelo menos 20 gotas por prato. </li><li> Inverter a tampa do PBS-cheia câmara inferior e incubar a 37 ° CO C / 5% 2 / 95% de umidade, monitorar as gotas diárias e incubar até folhas ou células ou agregados formaram. Um microscópio estéreo pode ser usado para avaliar a formação de agregados. </li><li> Uma vez que formam folhas, podem ser transferidos para fundo redondo de vidro shaker frascos contendo 3 ml de meio completo e incubados em um agitador banho maria a 37 ° C e 5% CO 2 até formar esferóides. </li></ol> 3. Notas <ol><li> Dependendo do tamanho da célula, a concentração pode precisar de ser ajustado para cima ou para baixo. </li><li> As células podem ser marcadas com corantes fluorescentes membrana intercalando antes da formação gota suspensa. </li><li> Dois tipos de células diferentes podem ser diferencialmente manchada e misturado na proporção de 1:1 (ou outro) antes da formação de gotas de suspensão. Estes podem ser câncer e estroma células, tecidos embrionárias, ou células geneticamente modificados para ter as assinaturas adesivo específico. </li><li> As células podem ser separados de pratos de cultura de tecidos utilizando tripsina 0,05% / 2 mM de cálcio para preservar a função caderina. </li><li> Dependendo do experimento, tamanhos de folha pode ser medido, ou agregados pode ser usado para ensaios mecânicos ou por análise bioquímica ou molecular. </li></ol> 4. Resultados representativos: Folha ou formação esferóide normalmente ocorre no prazo de 24 horas, mas pode demorar mais dependendo do tipo de célula. A Figura 1 representa as imagens capturadas após 18 horas de incubação de câncer de próstata não tratado MAT-LyLu (MLL) células em suspensão cultura gota (Figura 1A) ou células tratadas com 25 mm inibidor MEK PD98059. Note-se que os resultados do tratamento Meki em uma compactação marcadas da camada de células. Compactação pode ser quantificado através da medição do tamanho de 10-20 (ou mais) pendurado cai e comparando tamanho médio entre os grupos de tratamento. Normalmente, analisar imagens utilizando o software ImageJ por thresholding cada imagem, em seguida, converter imagens para o modo binário, após o que aplicar a análise de partículas para revelar a área total da imagem em pixels. Isto pode ser facilmente convertida em microns quadrados. A Figura 2 apresenta uma comparação de tamanho para as células não tratadas e Meki MLL-tratada. Como se observa, o tratamento reduz significativamente Meki tamanho da folha em comparação de Student t-test (P &lt;0,0001). Para esta comparação, 10 agregados para cada uma das células tratadas e não tratadas foram medidos. A Figura 3 representa um pintinho esferóide fígado embrionário formado após 24 horas pendurado em cultura queda e dois dias em um banho de shaker. O ensaio de gota em suspensão também pode ser modificado para incluir mais de um tipo de célula para revelar o posicionamento espacial adotada. Por exemplo, células do fígado pinto embrionárias podem ser isoladas, marcadas com um corante fluorescente intercalando membrana e misturado com células embrionárias do coração de galinha que foram marcadas com um marcador fluorescente diferentes. Mostra a figura 4A, que ao invés de permanecer misturados, as células do fígado e do coração tendem a &quot;resolver&quot; a partir de um outro e adotar uma esfera-dentro-de uma esfera de configuração em que as células cardíacas são envolvidas por células do fígado. Esta configuração pode ser explicada por diferenças na adesão intercelular entre células do fígado e coração. Este conceito é codificada na Hipótese de Adesão diferencial que tem sido usada para explicar o comportamento de células de classificação entre o tecido embrionário germe camada de anfíbios 3 e 4 teleost embriões, células pancreáticas para a organização das ilhotas 5 e para a célula de classificação entre duas populações de células idênticas in todos os outros aspectos do que para os níveis de expressão do mesmo tipo de caderina (6 e Figura 4B). Este resultado é particularmente importante para demonstrar como a engenharia uma simples diferença na adesão entre populações de células pode resultar na geração de estrutura do órgão, por exemplo, uma das ilhotas pancreáticas 5. <img src="/files/ftp_upload/2720/2720fig1.jpg" alt="Figura 1" /> Figura 1. Imagens de células incubadas em cultura queda pendurado por 18 horas ou, na ausência (A) ou presença (B) de 25 mm do inibidor de MEK PD98059. As imagens foram captadas com uma Nikon Eclipse TE 300 e um microscópio de epifluorescência fotométricos CoolSnap ES câmera digital. <img src="/files/ftp_upload/2720/2720fig2.jpg" alt="Figura 2" /> Figura 2. Quantificação de Meki induzida compactação de ratos células cancerígenas da próstata MLL. Culturas gotas de suspensão de células não tratadas e Meki MLL-tratados foram incubados por 18 horas whereupon tamanho agregado foi determinado como descrito acima. Análise estatística do tamanho de agregados foi por teste t de Student. O asterisco representa uma diferença estatisticamente significativa no tamanho do agregado (P &lt;0,0001) entre as células não tratadas e tratadas com Meki e sugere que os resultados Meki-tratamento em agregados significativamente menores e mais compactos. <img src="/files/ftp_upload/2720/2720fig3.jpg" alt="Figura 3" /> Figura 3. Um esferóide formada pela incubação de células embrionárias de fígado em pinto pendurado cultura queda para 18 horas, em seguida, em uma incubadora / agitação do banho por 48 horas. Esta imagem foi capturada com um microscópio estéreo Nikon SMZ800 e um Sony Preto câmera CCD. <img src="/files/ftp_upload/2720/2720fig4.jpg" alt="Figura 4" /> Figura 4. Hanging cultura queda revela-out de classificação de comportamento entre diferentes tipos celulares. No painel A, as células do fígado pinto embrionárias foram coradas com PKH-2 da membrana corante intercalando e misturados em proporções iguais com PKH-26 manchado pinto células cardíacas embrionárias. No painel B, dois N-caderina-transfectadas clones L celular (LN4 e LN2a), expressando N-cad em suas superfícies na proporção de 2,4:1, também foram coradas com os corantes fluorescentes membrana intercalando PKH-2 e PKH-26 , (Sigma-Aldrich), misturados em proporções iguais e culta como a suspensão de gotas 7. Após 18 horas de cultura, folhas de células foram transferidas para frascos de agitação e incubadas por mais 48 horas. Agregados foram fixadas em paraformaldeído 2% em tampão fosfato e visto com um sistema de digitalização a laser BioRad MRC600 microscópio confocal acoplada a um microscópio Nikon Optiphot-2. Secções ópticas de ambos os canais verde e vermelho foram coletados e uma estação de trabalho Silicon Graphix Carmesim VGX equipado com Imagens Vital Voxel Ver Ultra software de imagem foi usado para atribuir falsa cor para ambos os canais e fundir as imagens, revelando as configurações anatômicas geradas. (A) secção óptica confocal através de um envolvimento total das células do coração demonstrando (aqui em uma cor amarelo-pseudo) pelas células do fígado em pseudo-azul (de 8). (B) seção Confocal óptica através de um envolvimento total demonstrando alta de N-caderina células que expressam (verde) por aqueles que expressam os níveis mais baixos de N-caderina (vermelho) (de 6).

<ol>
	<li>Cukierman, E., Pankov, R., Yamada, K. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+interactions+with+three-dimensional+matrices.">Cell interactions with three-dimensional matrices.</a> Curr Opin Cell Biol. 14, 633-639 (2002).</li><li>Nelson, C. M., Bissell, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Of+extracellular+matrix,+scaffolds,+and+signaling:+tissue+architecture+regulates+development,+homeostasis,+and+cancer.">Of extracellular matrix, scaffolds, and signaling: tissue architecture regulates development, homeostasis, and cancer.</a> Annu Rev Cell Dev Biol. 22, 287-309 (2006).</li><li>Davis, G. S., Phillips, H. M., Steinberg, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Germ-layer+surface+tensions+and+&amp;quot;tissue+affinities&amp;quot;+in+Rana+pipiens+gastrulae:+quantitative+measurements.">Germ-layer surface tensions and &amp;quot;tissue affinities&amp;quot; in Rana pipiens gastrulae: quantitative measurements.</a> Dev Biol. 192, 630-644 (1997).</li><li>Schotz, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+differences+in+tissue+surface+tension+influence+zebrafish+germ+layer+positioning.">Quantitative differences in tissue surface tension influence zebrafish germ layer positioning.</a> HFSP J. 2, 42-56 (2008).</li><li>Jia, D., Dajusta, D., Foty, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue+surface+tensions+guide+in+vitro+self-assembly+of+rodent+pancreatic+islet+cells.">Tissue surface tensions guide in vitro self-assembly of rodent pancreatic islet cells.</a> Dev Dyn. 236, 2039-2049 (2007).</li><li>Foty, R. A., Steinberg, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+differential+adhesion+hypothesis:+a+direct+evaluation.">The differential adhesion hypothesis: a direct evaluation.</a> Dev Biol. 278, 255-263 (2005).</li><li>Li, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+of+the+casein+kinase+2+subunits+in+Chinese+hamster+ovary+and+3T3+L1+cells+provides+information+on+the+role+of+the+enzyme+in+cell+proliferation+and+the+cell+cycle.">Expression of the casein kinase 2 subunits in Chinese hamster ovary and 3T3 L1 cells provides information on the role of the enzyme in cell proliferation and the cell cycle.</a> J Biol Chem. 274, 32988-32996 (1999).</li><li>Foty, R. A., Pfleger, C. M., Forgacs, G., Steinberg, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+tensions+of+embryonic+tissues+predict+their+mutual+envelopment+behavior.">Surface tensions of embryonic tissues predict their mutual envelopment behavior.</a> Development. 122, 1611-1620 (1996).</li><li>Wendt, D., Riboldi, S. A., Cioffi, M., Martin, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Potential+and+bottlenecks+of+bioreactors+in+3D+cell+culture+and+tissue+manufacturing.">Potential and bottlenecks of bioreactors in 3D cell culture and tissue manufacturing.</a> Adv Mater. 21, 3352-3367 (2009).</li><li>Berry, D. P., Harding, K. G., Stanton, M. R., Jasani, B., Ehrlich, H. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+wound+contraction:+collagen+organization,+fibroblasts,+and+myofibroblasts.">Human wound contraction: collagen organization, fibroblasts, and myofibroblasts.</a> Plast Reconstr Surg. 102, 124-131 (1998).</li><li>Grinnell, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fibroblast+biology+in+three-dimensional+collagen+matrices.">Fibroblast biology in three-dimensional collagen matrices.</a> Trends Cell Biol. 13, 264-269 (2003).</li><li>Wang, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reciprocal+interactions+between+beta1-integrin+and+epidermal+growth+factor+receptor+in+three-dimensional+basement+membrane+breast+cultures:+a+different+perspective+in+epithelial+biology.">Reciprocal interactions between beta1-integrin and epidermal growth factor receptor in three-dimensional basement membrane breast cultures: a different perspective in epithelial biology.</a> Proc Natl Acad Sci U S A. 95, 14821-14826 (1998).</li><li>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=Reversion+of+the+malignant+phenotype+of+human+breast+cells+in+three-dimensional+culture+and+in+vivo+by+integrin+blocking+antibodies.">Reversion of the malignant phenotype of human breast cells in three-dimensional culture and in vivo by integrin blocking antibodies.</a> J Cell Biol. 137, 231-245 (1997).</li><li>Boudreau, N., Werb, Z., Bissell, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Suppression+of+apoptosis+by+basement+membrane+requires+three-+dimensional+tissue+organization+and+withdrawal+from+the+cell+cycle.">Suppression of apoptosis by basement membrane requires three- dimensional tissue organization and withdrawal from the cell cycle.</a> Proc Natl Acad Sci U S A. 93, 3509-3513 (1996).</li><li>Croix, B., Rak, J. W., Kapitain, S., Sheehan, C., Graham, C. H., Kerbel, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reversal+by+hyaluronidase+of+adhesion-dependent+multicellular+drug+resistance+in+mammary+carcinoma+cells.">Reversal by hyaluronidase of adhesion-dependent multicellular drug resistance in mammary carcinoma cells.</a> J. Nat. Cancer Inst. 88, 1285-1296 (1996).</li><li>Bissell, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue+structure,+nuclear+organization,+and+gene+expression+in+normal+and+malignant+breast.">Tissue structure, nuclear organization, and gene expression in normal and malignant breast.</a> Cancer Res. 59, 1757-1763 (1999).</li><li>Marrero, B., Messina, J. L., Heller, R. <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+tumor+spheroid+in+a+microgravity+environment+as+a+3D+model+of+melanoma.">Generation of a tumor spheroid in a microgravity environment as a 3D model of melanoma.</a> In Vitro Cell Dev Biol Anim. 45, 523-534 (2009).</li><li>Napolitano, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Scaffold-free+three-dimensional+cell+culture+utilizing+micromolded+nonadhesive+hydrogels.">Scaffold-free three-dimensional cell culture utilizing micromolded nonadhesive hydrogels.</a> Biotechniques. 43, 494-496 (2007).</li><li>Tibbitt, M. W., Anseth, K. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrogels+as+extracellular+matrix+mimics+for+3D+cell+culture.">Hydrogels as extracellular matrix mimics for 3D cell culture.</a> Biotechnol Bioeng. 103, 655-663 (2009).</li></ol>

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Estudos têm demonstrado que a cultura de células em um contexto tridimensional (3D) produz morfologia celular e sinalização distintas quando comparado a um rígido sistema de cultura de duas dimensões (2D) 9. Por exemplo, géis de fibroblastos de colágeno povoadas demonstram que a morfologia de fibroblastos em 3D é bastante distinta da observada em 2D 10,11. Da mesma forma, a cultura 3D pode induzir a diferenciação de tecidos específicos de células epiteliais mamárias. Sistemas de cultu...

<ul><li> contador automático de células (BioRad TC10) </li><li> tremendo banho de água com CO 2 Modelo cobrir gable 3540 (Lab-line) </li></ul>

a simple hanging drop cell culture protocol for generation of 3d spheroids

Estudos de célula-célula e célula substrato coesão-adesão têm sido historicamente realizados em culturas de monocamada aderente sobre substratos rígidos. Células dentro de um tecido, no entanto, normalmente são encerrados dentro de uma massa de tecido de forma compacta em que as células estabelecer conexões íntimas com muitas quase-vizinhos e com componentes da matriz extracelular. Assim, o meio químico e forças físicas experimentadas por células dentro de um tecido 3D são fundamentalmente diferentes do que aqueles experimentados por células cultivadas em cultura em monocamada. Isto tem sido demonstrado que marcadamente impacto morfologia celular e sinalização. Vários métodos têm sido desenvolvidos para gerar culturas de células em 3D, incluindo encapsulamento de células em géis de colágeno ou em um biomaterial andaimes 2. Tais métodos, embora úteis, não recapitular a arquitetura de adesão íntima direto célula-célula encontrada em tecidos normais. Ao contrário, eles mais de perto os sistemas aproximados de cultura em que as células individuais são frouxamente dispersas dentro de uma malha 3D de produtos ECM. Aqui, descrevemos um método simples em que as células são colocadas em cultura pendurado queda e incubados em condições fisiológicas, até que a verdadeira forma esferóides 3D em que as células estão em contato direto uns com os outros e com componentes da matriz extracelular. O método não requer equipamento especializado e pode ser adaptado para incluir a adição de qualquer agente biológico em quantidades muito pequenas que podem ser do seu interesse na elucidação efeitos sobre célula-célula ou célula-ECM interação. O método também pode ser usado para co-cultura dois (ou mais) diferentes populações de células, de modo a elucidar o papel das interações célula-célula ou célula-ECM na especificação de relações espaciais entre as células. Célula-célula e célula coesão ECM-adesão são os pilares dos estudos de desenvolvimento embrionário interação celular, tumor de estroma na invasão maligna, cicatrização de feridas, e para aplicações de engenharia de tecidos. Este método simples irá fornecer um meio de gerar tecido celular-como agregados para a medição de propriedades biomecânicas ou para análise molecular e bioquímica em um modelo fisiologicamente relevantes.

Watch this Scientific Journal Video about A Simple Hanging Drop Cell Culture Protocol for Generation of 3D Spheroids at JoVE.com

A Simple Hanging Drop Cell Culture Protocol for Generation of 3D Spheroids

Nós descrevemos um método simples e rápida de gerar tecido 3D-como esferóides e sua potencial aplicação para quantificar as diferenças de interações célula-célula.

Uma simples gota de suspensão Protocolo Cultura de Células para a geração de esferóides 3D

Studies of cell-cell cohesion and cell-substratum adhesion have historically been performed on monolayer cultures adherent to rigid substrates. Cells ...

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Bioengineering

57.1K visualizações.  UMDNJ-Robert Wood Johnson Medical School. Nós descrevemos um método simples e rápida de gerar tecido 3D-como esferóides e sua potencial aplicação para quantificar as diferenças de interações célula-célula.

Vídeo: A Simple Hanging Drop Cell Culture Protocol for Generation of 3D Spheroids

Preparation of 3D Fibrin Scaffolds for Stem Cell Culture Applications

Stem cells are found in naturally occurring 3D microenvironments in vivo, which are often referred to as the stem cell niche 1. Culturing stem cells inside of 3D biomaterial scaffolds provides a way to accurately mimic these microenvironments, providing an advantage over traditional 2D culture methods using polystyrene as well as a method for engineering replacement tissues 2. While 2D tissue culture polystrene has been used for the majority of cell culture experiments, 3D biomaterial scaffolds can more closely replicate the microenvironments found in vivo by enabling more accurate establishment of cell polarity in the environment and possessing biochemical and mechanical properties similar to soft tissue.3 A variety of naturally derived and synthetic biomaterial scaffolds have been investigated as 3D environments for supporting stem cell growth. While synthetic scaffolds can be synthesized to have a greater range of mechanical and chemical properties and often have greater reproducibility, natural biomaterials are often composed of proteins and polysaccharides found in the extracelluar matrix and as a result contain binding sites for cell adhesion and readily support cell culture. Fibrin scaffolds, produced by polymerizing the protein fibrinogen obtained from plasma, have been widely investigated for a variety of tissue engineering applications both in vitro and in vivo 4. Such scaffolds can be modified using a variety of methods to incorporate controlled release systems for delivering therapeutic factors 5. Previous work has shown that such scaffolds can be used to successfully culture embryonic stem cells and this scaffold-based culture system can be used to screen the effects of various growth factors on the differentiation of the stem cells seeded inside 6,7.
 This protocol details the process of polymerizing fibrin scaffolds from fibrinogen solutions using the enzymatic activity of thrombin. The process takes 2 days to complete, including an overnight dialysis step for the fibrinogen solution to remove citrates that inhibit polymerization. These detailed methods rely on fibrinogen concentrations determined to be optimal for embryonic and induced pluripotent stem cell culture. Other groups have further investigated fibrin scaffolds for a wide range of cell types and applications - demonstrating the versatility of this approach 8-12.

This work details the preparation of 3D fibrin scaffolds for culturing and differentiating plutipotent stem cells. Such scaffolds can be used to screen the effects of various biological compounds on stem cell behavior as well as modified to contain drug delivery systems.

Preparação de fibrina Andaimes 3D para aplicações de cultura de células-tronco

Stem cells are found in naturally occurring 3D microenvironments in vivo, which are often referred to as the stem cell niche 1. Culturing stem cells ...

Bioengenharia

Generation and Recovery of &beta;-cell Spheroids From Step-growth PEG-peptide Hydrogels

Hydrogels are hydrophilic crosslinked polymers that provide a three-dimensional microenvironment with tissue-like elasticity and high permeability for culturing therapeutically relevant cells or tissues. Hydrogels prepared from poly(ethylene glycol) (PEG) derivatives are increasingly used for a variety of tissue engineering applications, in part due to their tunable and cytocompatible properties. In this protocol, we utilized thiol-ene step-growth photopolymerizations to fabricate PEG-peptide hydrogels for encapsulating pancreatic MIN6 b-cells. The gels were formed by 4-arm PEG-norbornene (PEG4NB) macromer and a chymotrypsin-sensitive peptide crosslinker (CGGYC). The hydrophilic and non-fouling nature of PEG offers a cytocompatible microenvironment for cell survival and proliferation in 3D, while the use of chymotrypsin-sensitive peptide sequence (CGGY&darr;C, arrow indicates enzyme cleavage site, while terminal cysteine residues were added for thiol-ene crosslinking) permits rapid recovery of cell constructs forming within the hydrogel. The following protocol elaborates techniques for: (1) Encapsulation of MIN6 &beta;-cells in thiol-ene hydrogels; (2) Qualitative and quantitative cell viability assays to determine cell survival and proliferation; (3) Recovery of cell spheroids using chymotrypsin-mediated gel erosion; and (4) Structural and functional analysis of the recovered spheroids.

Generation and Recovery of &#946;-cell Spheroids From Step-growth PEG-peptide Hydrogels

The following protocol provides techniques for encapsulating pancreatic &#x03B2;-cells in step-growth PEG-peptide hydrogels formed by thiol-ene photo-click reactions. This material platform not only offers a cytocompatible microenvironment for cell encapsulation, but also permits user-controlled rapid recovery of cell structures formed within the hydrogels.

Geração e recuperação de β-esferóides de células a partir do passo de crescimento-PEG-péptido Hidrogéis

Hydrogels are hydrophilic crosslinked polymers that provide a three-dimensional  microenvironment with tissue-like elasticity and high permeability for  ...

3D Hydrogel Scaffolds for Articular Chondrocyte Culture and Cartilage Generation

Human articular cartilage is highly susceptible to damage and has limited self-repair and regeneration potential. Cell-based strategies to engineer cartilage tissue offer a promising solution to repair articular cartilage. To select the optimal cell source for tissue repair, it is important to develop an appropriate culture platform to systematically examine the biological and biomechanical differences in the tissue-engineered cartilage by different cell sources. Here we applied a three-dimensional (3D) biomimetic hydrogel culture platform to systematically examine cartilage regeneration potential of juvenile, adult, and osteoarthritic (OA) chondrocytes. The 3D biomimetic hydrogel consisted of synthetic component poly(ethylene glycol) and bioactive component chondroitin sulfate, which provides a physiologically relevant microenvironment for in vitro culture of chondrocytes. In addition, the scaffold may be potentially used for cell delivery for cartilage repair in vivo. Cartilage tissue engineered in the scaffold can be evaluated using quantitative gene expression, immunofluorescence staining, biochemical assays, and mechanical testing. Utilizing these outcomes, we were able to characterize the differential regenerative potential of chondrocytes of varying age, both at the gene expression level and in the biochemical and biomechanical properties of the engineered cartilage tissue. The 3D culture model could be applied to investigate the molecular and functional differences among chondrocytes and progenitor cells from different stages of normal or aberrant development.

Cartilage repair represents an unmet medical challenge and cell-based approaches to engineer human articular cartilage are a promising solution. Here, we describe three-dimensional (3D) biomimetic hydrogels as an ideal tool for the expansion and maturation of human articular chondrocytes.

3D Hidrogel Andaimes para articular de condrócitos Cultura e Geração de cartilagem

Human articular cartilage is highly susceptible to damage and has limited self-repair and regeneration potential. Cell-based strategies to engineer ...

Micropatterning and Assembly of 3D Microvessels

In vitro platforms to study endothelial cells and vascular biology are largely limited to 2D endothelial cell culture, flow chambers with polymer or glass based substrates, and hydrogel-based tube formation assays. These assays, while informative, do not recapitulate lumen geometry, proper extracellular matrix, and multi-cellular proximity, which play key roles in modulating vascular function. This manuscript describes an injection molding method to generate engineered vessels with diameters on the order of 100 &#181;m. Microvessels are fabricated by seeding endothelial cells in a microfluidic channel embedded within a native type I collagen hydrogel. By incorporating parenchymal cells within the collagen matrix prior to channel formation, specific tissue microenvironments can be modeled and studied. Additional modulations of hydrodynamic properties and media composition allow for control of complex vascular function within the desired microenvironment. This platform allows for the study of perivascular cell recruitment, blood-endothelium interactions, flow response, and tissue-microvascular interactions. Engineered microvessels offer the ability to isolate the influence from individual components of a vascular niche and precisely control its chemical, mechanical, and biological properties to study vascular biology in both health and disease.

This manuscript presents an injection molding method to engineer microvessels that recapitulate physiological properties of endothelium. The microfluidic-based process creates patent 3D vascular networks with tailorable conditions, such as flow, cellular composition, geometry, and biochemical gradients. The fabrication process and examples of potential applications are described.

Micropatterning e Montagem de microvasos 3D

In vitro platforms to study endothelial cells and vascular biology are largely limited to 2D endothelial cell culture, flow chambers with polymer or glass ...

Tunable Hydrogels from Pulmonary Extracellular Matrix for 3D Cell Culture

Here we present a method for establishing multiple component cell culture hydrogels for in vitro lung cell culture. Beginning with healthy en bloc lung tissue from porcine, rat, or mouse, the tissue is perfused and submerged in subsequent chemical detergents to remove the cellular debris. Histological comparison of the tissue before and after processing confirms removal of over 95% of double stranded DNA and alpha galactosidase staining suggests the majority of cellular debris is removed. After decellularization, the tissue is lyophilized and then cryomilled into a powder. The matrix powder is digested for 48 hr in an acidic pepsin digestion solution and then neutralized to form the pregel solution. Gelation of the pregel solution can be induced by incubation at 37 &#176;C and can be used immediately following neutralization or stored at 4 &#176;C for up to two weeks. Coatings can be formed using the pregel solution on a non-treated plate for cell attachment. Cells can be suspended in the pregel prior to self-assembly to achieve a 3D culture, plated on the surface of a formed gel from which the cells can migrate through the scaffold, or plated on the coatings. Alterations to the strategy presented can impact gelation temperature, strength, or protein fragment sizes. Beyond hydrogel formation, the hydrogel stiffness may be increased using genipin.

This is a method to create a 3-dimensional cell culture scaffold from pulmonary extracellular matrix. Intact lung is processed into hydrogels that can support the growth of cells in three-dimensions.

Sintonizável hidrogéis a partir de Pulmonar Matriz Extracelular para Cultura Celular 3D

Here we present a method for establishing multiple component cell culture hydrogels for in vitro lung cell culture. Beginning with healthy en bloc lung ...

A Protocol for Real-time 3D Single Particle Tracking

Real-time three-dimensional single particle tracking (RT-3D-SPT) has the potential to shed light on fast, 3D processes in cellular systems. Although various RT-3D-SPT methods have been put forward in recent years, tracking high speed 3D diffusing particles at low photon count rates remains a challenge. Moreover, RT-3D-SPT setups are generally complex and difficult to implement, limiting their widespread application to biological problems. This protocol presents a RT-3D-SPT system named 3D Dynamic Photon Localization Tracking (3D-DyPLoT), which can track particles with high diffusive speed (up to 20 &#181;m2/s) at low photon count rates (down to 10 kHz). 3D-DyPLoT employs a 2D electro-optic deflector (2D-EOD) and a tunable acoustic gradient (TAG) lens to drive a single focused laser spot dynamically in 3D. Combined with an optimized position estimation algorithm, 3D-DyPLoT can lock onto single particles with high tracking speed and high localization precision. Owing to the single excitation and single detection path layout, 3D-DyPLoT is robust and easy to set up. This protocol discusses how to build 3D-DyPLoT step by step. First, the optical layout is described. Next, the system is calibrated and optimized by raster scanning a 190 nm fluorescent bead with the piezoelectric nanopositioner. Finally, to demonstrate real-time 3D tracking ability, 110 nm fluorescent beads are tracked in water.

This protocol details the construction and operation of a real-time 3D single particle tracking microscope capable of tracking nanoscale fluorescent probes at high diffusive speeds and low photon count rates.

Um protocolo para rastreamento em tempo real 3D única partícula

Real-time three-dimensional single particle tracking (RT-3D-SPT) has the potential to shed light on fast, 3D processes in cellular systems. Although ...

Construction of a Multilayered Mesenchymal Stem Cell Sheet with a 3D Dynamic Culture System

Stem cell therapy shows a promising future in regenerating injured organ and tissues, and the cell sheet technique has been developed to improve the low cell retention and poor survival within the target zone. However, during the in vitro construction process, a solution for maintaining stem cell bioactivity and increasing the cell amount within the cell sheet is urgently needed. Here, this protocol presents a method for constructing a multilayered cell sheet with favorable stem cell bioactivity and optimal operability. Decellularized porcine pericardium (DPP) is prepared by phospholipase A2 (PLA2) decellularization method as the cell sheet scaffold, and rat bone marrow mesenchymal stem cells (BMSCs) are isolated and expanded as the seeded cells. The temporary multilayered cell sheet structure is constructed by using RAD16-I peptide hydrogel. Finally, the cell sheet is cultured with a dynamic perfusion system to stabilize the three-dimensional (3D) structure, and the cell sheet could be obtained following a 48-hour culture in vitro. This protocol provides an efficient and feasible method for constructing a multilayered stem cell sheet, and the cell sheet could be developed as a favorable stem cell therapy product in the future.

This article provides an efficient and feasible method for constructing multilayered stem cell sheets with favorable stem cell property.

Construção de uma folha de células-tronco mesenquimais em várias camadas com um sistema de cultura dinâmica 3D

Stem cell therapy shows a promising future in regenerating injured organ and tissues, and the cell sheet technique has been developed to improve the low ...

A Human 3D Extracellular Matrix-Adipocyte Culture Model for Studying Matrix-Cell Metabolic Crosstalk

The extracellular matrix (ECM) plays a central role in regulating tissue homeostasis, engaging in crosstalk with cells and regulating multiple aspects of cellular function. The ECM plays a particularly important role in adipose tissue function in obesity, and alterations in adipose tissue ECM deposition and composition are associated with metabolic disease in mice and humans. Tractable in vitro models that permit dissection of the roles of the ECM and cells in contributing to global tissue phenotype are sparse. We describe a novel 3D in vitro model of human ECM-adipocyte culture that permits study of the specific roles of the ECM and adipocytes in regulating adipose tissue metabolic phenotype. Human adipose tissue is decellularized to isolate ECM, which is subsequently repopulated with preadipocytes that are then differentiated within the ECM into mature adipocytes. This method creates ECM-adipocyte constructs that are metabolically active and retain characteristics of the tissues and patients from which they are derived. We have used this system to demonstrate disease-specific ECM-adipocyte crosstalk in human adipose tissue. This culture model provides a tool for dissecting the roles of the ECM and adipocytes in contributing to global adipose tissue metabolic phenotype and permits study of the role of the ECM in regulating adipose tissue homeostasis.

We describe a 3D human extracellular matrix-adipocyte in vitro culture system that permits dissection of the roles of the matrix and adipocytes in contributing to adipose tissue metabolic phenotype.

Um modelo de cultura de matriz-adipócito extracelular humano para estudar crosstalk metabólico de matriz e células

The extracellular matrix (ECM) plays a central role in regulating tissue homeostasis, engaging in crosstalk with cells and regulating multiple aspects of ...

Large-Scale, Automated Production of Adipose-Derived Stem Cell Spheroids for 3D Bioprinting

Adipose-derived stromal/stem cells (ASCs) are a subpopulation of cells found in the stromal vascular fraction of human subcutaneous adipose tissue recognized as a classical source of mesenchymal stromal/stem cells. Many studies have been published with ASCs for scaffold-based tissue engineering approaches, which mainly explored the behavior of these cells after their seeding on bioactive scaffolds. However, scaffold-free approaches are emerging to engineer tissues in vitro and in vivo, mainly by using spheroids, to overcome the limitations of scaffold-based approaches.
Spheroids are 3D microtissues formed by the self-assembly process. They can better mimic the architecture and microenvironment of native tissues, mainly due to the magnification of cell-to-cell and cell-to-extracellular matrix interactions. Recently, spheroids are mainly being explored as disease models, drug screening studies, and building blocks for 3D bioprinting. However, for 3D bioprinting approaches, numerous spheroids, homogeneous in size and shape, are necessary to biofabricate complex tissue and organ models. In addition, when spheroids are produced automatically, there is little chance for microbiological contamination, increasing the reproducibility of the method.
The large-scale production of spheroids is considered the first mandatory step for developing a biofabrication line, which continues in the 3D bioprinting process and finishes in the full maturation of the tissue construct in bioreactors. However, the number of studies that explored the large-scale ASC spheroid production are still scarce, together with the number of studies that used ASC spheroids as building blocks for 3D bioprinting. Therefore, this article aims to show the large-scale production of ASC spheroids using a non-adhesive micromolded hydrogel technique spreading ASC spheroids as building blocks for 3D bioprinting approaches.

Here, we describe the large-scale production of adipose-derived stromal/stem cell (ASC) spheroids using an automated pipetting system to seed the cell suspension, thus ensuring homogeneity of spheroid size and shape. These ASC spheroids can be used as building blocks for 3D bioprinting approaches.

Produção automatizada em larga escala de esferoides de células-tronco derivados de adiposo para bioimpressão 3D

Adipose-derived stromal/stem cells (ASCs) are a subpopulation of cells found in the stromal vascular fraction of human subcutaneous adipose tissue ...

Generation of Multicue Cellular Microenvironments by UV-Photopatterning of Three-Dimensional Cell Culture Substrates

The extracellular matrix is an important regulator of cell function. Environmental cues existing in the cellular microenvironment, such as ligand distribution and tissue geometry, have been increasingly shown to play critical roles in governing cell phenotype and behavior. However, these environmental cues and their effects on cells are often studied separately using in vitro platforms that isolate individual cues, a strategy that heavily oversimplifies the complex in vivo situation of multiple cues. Engineering approaches can be particularly useful to bridge this gap, by developing experimental setups that capture the complexity of the in vivo microenvironment, yet retain the degree of precision and manipulability of in vitro systems.
This study highlights an approach combining ultraviolet (UV)-based protein patterning and lithography-based substrate microfabrication, which together enable high-throughput investigation into cell behaviors in multicue environments. By means of maskless UV-photopatterning, it is possible to create complex, adhesive protein distributions on three-dimensional (3D) cell culture substrates on chips that contain a variety of well-defined geometrical cues. The proposed technique can be employed for culture substrates made from different polymeric materials and combined with adhesive patterned areas of a broad range of proteins. With this approach, single cells, as well as monolayers, can be subjected to combinations of geometrical cues and contact guidance cues presented by the patterned substrates. Systematic research using combinations of chip materials, protein patterns, and cell types can thus provide fundamental insights into cellular responses to multicue environments.

Traditionally, cell culture is performed on planar substrates that poorly mimic the natural environment of cells in vivo. Here we describe a method to produce cell culture substrates with physiologically relevant curved geometries and micropatterned extracellular proteins, allowing systematic investigations into cellular sensing of these extracellular cues.