DOZ é apoiado por uma subvenção concedida à Fundação de Genebra. SN foi apoiado por uma bolsa pós-doutorado da Iniciativa Engenharia de Tecidos Pittsburgh.

1. Isolando derivadas de tecido adiposo células-tronco (ASC) Nota: Todos os procedimentos foram realizados à temperatura ambiente, a menos que indicado de outra forma. <ol><li> Isolar adiposo epididimal e perirenal rato e lavar com solução de Hank estéril tamponada de sal (HBSS) contendo 1% de soro fetal bovino (FBS), como descrito anteriormente 6. </li><li> Picar o tecido e transferir 1-2 g em 25 mL de HBSS contendo FBS a 1% para um tubo de 50 mL e centrifugação a 500 g durante 8 minutos à temperatura ambiente. </li><li> Recolher o de flutuação livre camada de tecido adiposo e transferência para 125 mL balão Erlenmeyer e trata-se com 25 mL de colagenase tipo II (200 U / mL) em HBSS durante 45 min a 37 ° C num agitador orbital (125 rpm). </li><li> Cuidadosamente remover a fracção de líquido (abaixo de óleo e da camada adiposo) e filtrar sequencialmente através de um filtro 100-iM e 70 mícrons de nylon de malha. Centrifugar o filtrado a 500 g durante 10 min à temperatura ambiente, aspirar o supernatant, e lavar a pelete duas vezes com 25 ml de HBSS. </li><li> Ressuspender o sedimento de células em 50 mL de meio de crescimento (Meio MesenPRO RS Basal) suplementado com MesenPRO Suplemento de Crescimento RS, antibiótico-antimicótico (100 U / mL de penicilina G, 100 ug / mL de sulfato de estreptomicina, e 0,25 ug / mL Anfotericina B) , e 2 mM de L-glutamina e as células de pipeta em 2 T75 frascos (25 ml balão /). </li><li> Cultura da ASC em um 5% de CO 2 incubadora humidificada a 37 ° C (passagem 2-4 ASC são utilizados para todas as experiências). </li></ol> 2. Preparação de microesferas (CSM) Nota: Todos os procedimentos foram realizados à temperatura ambiente, a menos que indicado de outra forma. <ol><li> CSM são preparados por um processo de emulsificação de água-em-óleo, juntamente com uma técnica de coacervação iónica usando o nosso protocolo anterior 6. Emulsionar uma solução aquosa de quitosano (6 mL de 3% w / v de quitosano em ácido acético 0,5 M) em 100 ml de uma mistura de fase de óleo consistindo de sojaóleo, n-octanol (1:2 v / v) e 5% de sorbitano-mono-oleato de emulsionante (Span 80), utilizando sobrecarga (1700 rpm) e agitação magnética (1000 rpm), simultaneamente, em direcções opostas. Este método de dupla resultará uma mistura que micelas formadas no início antes de reticulação ocorre podem permanecer em solução e não assentam no fundo. Além disso, a barra de agitação magnética SIDA em DE-agregação de quitosano durante micela formação e rigidization. </li><li> A mistura é agitada continuamente durante aproximadamente 1 hora até uma emulsão de água-em-óleo estável é obtido. Reticulação iónica é iniciada com a adição de 1,5 mL de 1% de hidróxido de w / v de potássio em n-octanol min a cada 15 durante 4 h (24 ml no total). </li><li> Depois de se completar a reacção de reticulação, lentamente decantar a fase de óleo da mistura contendo CSM e imediatamente adicionar as esferas a 100 mL de acetona. Lave as esferas com acetona até que a fase de óleo é completamente removido. </li><li> Secam-se as esferas recuperados em um exsicador de vácuo e analyze inalterado. O tamanho médio de partícula CSM, área de superfície por miligrama e da unidade de volume cúbico foi determinada utilizando analisador de tamanho de partícula. </li><li> Para as experiências subsequentes, lavar CSM três vezes com água estéril para remover os sais residuais e esterilizar com álcool absoluto. </li></ol> 3. Determinando o número de grupos amino livres no CSM Nota: Todos os procedimentos foram realizados à temperatura ambiente, a menos que indicado de outra forma. <ol><li> Determinar o número de grupos amino livres presentes na CSM após reticulação iónica usando o ensaio de ácido benzenossulfónico trinitro (TNBS), de Bubins e Ofner 7. Incubar 5 mg de microesferas com 1 mL de 0,5% de solução de TNBS em um tubo de vidro de 50 mL durante 4 h, a 40 ° C e hidrolisar com a adição de 3 mL de HCl 6N a 60 ° C durante 2h. </li><li> Arrefecer as amostras à temperatura ambiente, e extrair os TNBS livres por adição de 5 mL de água desionizada e 10 mL de acetatoéter. </li><li> Aquecer uma alíquota de 5 ml da fase aquosa para 40 ° C num banho de água durante 15 min para evaporar qualquer éter residual, arrefecer até à temperatura ambiente, e diluir com 15 mL de água. </li><li> Medir a absorvância a 345 nm com um espectrofotómetro com solução TNBS sem quitosana como em branco eo quitosano utilizado para a preparação CSM para determinar o número total de grupos amino. Estimar o número de grupos amino livres da MSC em relação ao quitosano. </li></ol> 4. Carregando ASC no CSM Nota: Todos os procedimentos foram realizados à temperatura ambiente, a menos que indicado de outra forma. <ol><li> Equilibrar 5 mg de CSM esterilizado de seção 2,5 em HBSS estéril durante a noite e adicionar um poro tamanho 8 mícrons membrana inserção placa de cultura (24-bem placa). </li><li> Após o CSM se estabeleceram para a membrana, aspirar cuidadosamente os HBSS e adicionam-se 300 uL de meio de crescimento para o interior da inserção e 700 uL de meio de crescimento para the fora da pastilha. </li><li> Ressuspender o ASC na concentração apropriada (1 x 10 4 a 4 x 10 4) em 200 uL de meio de crescimento e de sementes ao longo do CSM dentro do inserto placa de cultura. O volume final de meio de cultura dentro da inserção, após a semeadura, é de 500 uL. </li><li> Incubar a seeded ASC à CSM por 24 h em um 5% de CO 2 incubadora humidificada a 37 ° C. </li></ol> 5. Determinação da porcentagem de ASC Carregando e viabilidade celular em CSM Nota: Todos os procedimentos foram realizados à temperatura ambiente, a menos que indicado de outra forma. <ol><li> Após a incubação, recolher o CSM ASC-carregado num tubo de microcentrífuga de 1,5 ml estéril, sem perturbar as células que migraram para a membrana de inserção. </li><li> Remover o meio residual e adicionar 250 uL de meio de crescimento fresco para o tubo. </li><li> Para cada tubo 25 uL de MTT [3 - (4,5-dimethylthiozole-2-il) -2,5-difeniltetrazólio]solução (5 mg / mL) e incubar durante 4 h em um 5% de CO 2 incubadora humidificada a 37 ° C. </li><li> Após a incubação, o meio de remover, adicionar 250 uL de sulfóxido de dimetilo, e vórtice a mistura durante 2-5 minutos para solubilizar o formazan complexo. </li><li> Centrifugar a CSM em 2700 X g durante 5 min, e determinar a absorvância sobrenadante medida a 570 nm 630 nm, utilizando como referência. </li><li> Determinar o número de células associado com o MSC em relação ao valor de absorvância obtidos a partir de um número conhecido de ASC viável. </li></ol> 6. Caracterizando ASC-CSM-incorporado gel de colágeno Nota: Todos os procedimentos foram realizados à temperatura ambiente, a menos que indicado de outra forma. <ol><li> Mistura ASC-carregado CSM (5 mg contendo ≈ 2 x 10 4 células) com colagénio de tipo 1 (7,5 mg / mL), extraído a partir de tendão da cauda de rato de acordo com o método de Bornstein 8 e fibrilam depois de ajustar o pH para 6,8 utilizando 2 N de NaOH. </li&gt; <li> Adicionar a mistura de colagénio-ASC-CSM fibrilada para uma placa de 12 poços e incubar durante 30 min a uma em 5% de CO 2 incubadora humidificada a 37 ° C. </li><li> Depois de fibrilação completa, incubar os géis de colagénio-ASC-CSM-se até 14 dias, em um 5% de CO 2 incubadora humidificada a 37 ° C. </li><li> Libertação e migração de células de CSM no gel foram observadas utilizando técnicas de microscopia padrão. </li></ol> 7. Os resultados representativos No presente estudo, nós desenvolvemos uma estratégia in vitro para proporcionar células-tronco de microesferas de quitosano (CSM) em um gel de colagénio andaime. CSM poroso de tamanho uniforme (175-225 um de diâmetro) e composição foram preparados e utilizados como transportadores de células (Figura 2). Após a incubação com a ASC CSM, as células ligado a uma concentração de 2 x 10 4 cells/5mg de MSC. As células foram capazes de espalhar sobre a microesfera, enquanto estende filopodiosnas fendas porosas do microesfera (Figura 3). Uma vez que a célula CSM-carregado foram misturadas com o gel de colagénio, as células imediatamente começou a migrar para os géis (Figura 4). <img alt="Tabela 1" src="/files/ftp_upload/3624/3624table1.jpg" /> Tabela 1. Vantagens biológicos para o uso de quitosano e de colagénio em um sistema de entrega de células estaminais. <img alt="A Figura 1" src="/files/ftp_upload/3624/3624fig1.jpg" /> Figura 1. Esquemático que representa a estratégia geral para a utilização dupla de ASC-CSM andaimes de colagénio carregados. Figuras 2, 3 e 4 são anotadas no interior da esquemática para auxiliar com a interpretação das imagens. <img alt="A Figura 2" src="/files/ftp_upload/3624/3624fig2.jpg" /> Figura 2. Representação esquemática representando o processo de semear as células estaminais para quitosano. O process envolve co-cultura com ASC CSM em um 8 - mM tamanho dos poros da membrana de inserção placa de cultura. Após 24 horas, as microesferas são removidos do inserto e estão prontos para incorporação numa matriz biomaterial. <img alt="A Figura 3" src="/files/ftp_upload/3624/3624fig3.jpg" /> Figura 3. Caracterização morfológica de CSM-carregado com ASC. O painel A representa uma micrografia de luz de ASC-carregado CSM, enquanto o painel B mostra o mesmo campo de visão, sobreposto com uma imagem obtida por microscopia de fluorescência confocal. ASC foram pré-carregado com calceína AM (verde). O painel C mostra uma imagem de uma imagem SEM de uma microesfera descarregado, enquanto o painel D mostra células carregadas no microesfera (asteriscos). A imagem MET em E painel mostra uma secção transversal de uma microesfera descarregado. Uma multidão de poros e fendas estão localizados ao longo da microesfera. Painel F mostra uma microesfera transversalmente com as células (setas) ligado e estendendo filopodia na CREvícios. Ampliações originais: A &amp; B = 70X; C = 500x, D = 2.000 x; E &amp; F = 2.500 x. <img alt="A Figura 4" src="/files/ftp_upload/3624/3624fig4.jpg" /> Figura 4. A migração de ASC a partir do CSM para o colagénio tridimensional andaime. Os painéis A e B representam a CSM com células migrando do microesfera e para dentro da matriz de colagénio no dia 3 (A setas,). O painel B mostra uma cultura semelhante depois de 12 dias. Microscopia electrónica de transmissão (TEM) imagens são representadas em C, D e E. Os asteriscos em C e D mostram uma microesfera que tem sido transversalmente com as células de migrar para longe da microesfera (setas). Maior ampliação de painel D está representado na painel E, e mostra filopodia célula ligado às fibrilas de colagénio (inserção). Aumento original: A &amp; B = 100x; C &amp; D = 6.000 x; E = 20.000 x, inset = 150.000 x. <img alt="A Figura 5" src="/files/ftp_upload/3624/3624fig5.jpg" /> Figura 5.Esquema representando os usos vastas CSM na medicina regenerativa e entrega da droga.

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Não há interesses conflitantes financeiros existem. Alerta As opiniões ou afirmações contidas neste documento são as opiniões pessoais dos autores e não devem ser interpretadas como oficial ou refletindo as opiniões do Departamento de Defesa ou o Governo dos EUA. Os autores são funcionários do governo dos EUA, e este trabalho foi elaborado como parte das suas funções oficiais. Todo o trabalho foi apoiado pelo EUA Pesquisa Médica do Exército e do Comando de Material. Este estudo foi realizado ao abrigo de um protocolo revisto e aprovado pelo Comitê de Ética Médica EUA Exército e do Comando de Material Conselho de Revisão Institucional, e de acordo com o protocolo aprovado.

Um grande obstáculo na terapia de células-tronco base é o desenvolvimento de métodos eficientes para a entrega de células para as regiões especificadas para a reparação. Devido ao paciente a variabilidade do paciente, o tipo de tecido, tamanho da lesão e da profundidade, a metodologia de células estaminais entrega deve ser determinada numa base de caso-a-caso. Embora a incorporação de células-tronco dentro de uma matriz e entregá-los para o local da ferida parece ser uma abordagem lógico seguinte para a e...

<table border="1" ><tbody><tr><td> Nome do reagente / equipamentos </td><td> Companhia </td><td> Número de catálogo </td><td> Comentários </td></tr><tr><td> Hanks BalancedSalt Solução (HBSS) </td><td> Gibco </td><td> 14175 </td><td> Consumível </td></tr><tr><td> Soro Fetal Bovino </td><td> Hyclone </td><td> SH30071.03 </td><td> Consumível </td></tr><tr><td> Colagenase do Tipo II </td><td> Sigma-Aldrich </td><td> C6685 </td><td> Consumível </td></tr><tr><td> 70-iM de nylon de malha de filtro </td><td> BD Biosciences </td><td> 352350 </td><td> Consumível </td></tr><tr><td> 100-iM de nylon de malha de filtro </td><td> BD Biosciences </td><td> 352360 </td><td> Consumível </td></tr><tr><td> MesenPRO Sistema Meio de Crescimento </td><td> Invitrogen </td><td> 12746-012 </td><td> Consumível </td></tr><tr><td> L-glutamina </td><td> Gibco </td><td> 25030 </td><td> Consumível </td></tr><tr><td> T75 frasco de cultura de tecidos </td><td> BD Biosciences </td><td> 137787 </td><td> Consumível </td></tr><tr><td> Chitosan </td><td> Sigma-Aldrich </td><td> 448869 </td><td> Consumível </td></tr><tr><td> Ácido Acético </td><td> Sigma-Aldrich </td><td> 320099 </td><td> Consumível </td></tr><tr><td> N-octanol </td><td> Acros Organics </td><td> 150630025 </td><td> Consumível </td></tr><tr><td> Sorbitano-mono-oleato </td><td> Sigma-Aldrich </td><td> S6760 </td><td> Consumível </td></tr><tr><td> Hidróxido de Potássio </td><td> Sigma-Aldrich </td><td> P1767 </td><td> Consumível </td></tr><tr><td> Acetona </td><td> Fisher Scientific </td><td> L-4859 </td><td> Consumível </td></tr><tr><td> Etanol </td><td> Sigma-Aldrich </td><td> 270741 </td><td> Consumível </td></tr><tr><td> Trinitro benzenossulfónico </td><td> Sigma-Aldrich </td><td> P2297 </td><td> Consumível </td></tr><tr><td> Ácido clorídrico </td><td> Sigma-Aldrich </td><td> 320331 </td><td> Consumível </td></tr><tr><td> Éter etílico </td><td> Sigma-Aldrich </td><td> 472-484 </td><td> Consumível </td></tr><tr><td> 8 m de tecido Placa Insere Cultura </td><td> BD Biosciences </td><td> 353097 </td><td> Consumível </td></tr><tr><td> 1,5 ml tubos de microcentrífuga </td><td> Pescador </td><td> 05-408-129 </td><td> Consumível </td></tr><tr><td> Reagente MTT </td><td> Invitrogen </td><td> M6494 </td><td> Consumível </td></tr><tr><td> Sulfóxido de dimetilo </td><td> Sigma-Aldrich </td><td> D8779 </td><td> Consumível </td></tr><tr><td> Qtracker celular Labeling Kit (Q rastreador 655) </td><td> Sondas moleculares </td><td> Q2502PMP </td><td> Consumível </td></tr><tr><td> Colágeno tipo 1 </td><td> Travigen </td><td> 3447-020-01 </td><td> Consumível </td></tr><tr><td> Hidróxido de Sódio </td><td> Sigma-Aldrich </td><td> S8045 </td><td> Consumível </td></tr><tr><td> 12-Bem Cultura Pratos Tecido </td><td> BD Biosciences </td><td> 353043 </td><td> Consumível </td></tr><tr><td> Centrifugar </td><td> Eppendorf </td><td> 5417R </td><td> Equipamento </td></tr><tr><td> Orbital Shaker </td><td> New Brunswick Scienctific </td><td> C24 </td><td> Equipamento </td&gt; </tr><tr><td> Incubadora de CO umidificado com Air-5 2% </td><td> Thermo Scientific </td><td> Modelo 370 </td><td> Equipamento </td></tr><tr><td> Agitador </td><td> IKA </td><td> Visc6000 </td><td> Equipamento </td></tr><tr><td> Agitador Magnético </td><td> Corning </td><td> PC-210 </td><td> Equipamento </td></tr><tr><td> Exsicador de vácuo </td><td> - </td><td> - </td><td> Equipamento </td></tr><tr><td> Analisador de Tamanho de Partícula </td><td> Malvern </td><td> STP2000 Spraytec </td><td> Equipamento </td></tr><tr><td> Banho de água </td><td> Fisher Scientific </td><td> Isotemp210 </td><td> Equipamento </td&gt; </tr><tr><td> Espectrofotômetro </td><td> Beckman </td><td> Beckman Coulter Espectrofotômetro DU800UV/Visible </td><td> Equipamento </td></tr><tr><td> Vórtice </td><td> Diagger </td><td> 3030a </td><td> Equipamento </td></tr><tr><td> Leitora </td><td> Molecular Devices </td><td> Spectramax M2 </td><td> Equipamento </td></tr><tr><td> Luz / microscópio de fluorescência </td><td> Olimpo </td><td> IX71 </td><td> Equipamento </td></tr><tr><td> Microscópio confocal </td><td> Olimpo </td><td> FV-500 Laser Scanning microscópio confocal </td><td> Equipamento </td></tr><tr><td> Microscópio Eletrônico de Varredura </td><td> Carl Zeiss MicroImaging </td><td> Leo 435 VP </td><td> Equipamento </td></tr><tr><td> Microscópio eletrônico de transmissão </td><td> JEOL </td><td> JEOL 1230 </td><td> Equipamento </td></tr></tbody></table>

constructing a collagen hydrogel for the delivery of stem cell-loaded chitosan microspheres

As células estaminais multipotenciais têm sido mostrados para ser extremamente útil no campo da medicina regenerativa 1-3. No entanto, a fim de utilizar essas células eficazmente para a regeneração de tecidos, um número de variáveis ​​devem ser tidos em conta. Estas variáveis ​​incluem: o volume total e área de superfície do local de implantação, as propriedades mecânicas do tecido e do microambiente do tecido, que inclui a quantidade de vascularização e os componentes da matriz extracelular. Portanto, os materiais que estão sendo utilizados para entregar estas células deve ser biocompatível com uma composição química definida, mantendo uma força mecânica que imita o tecido hospedeiro. Estes materiais também deve ser permeável ao oxigénio e nutrientes para proporcionar um microambiente favorável para as células para anexar e proliferar. A quitosana, um polissacárido catiónico com excelente biocompatibilidade, pode ser facilmente modificada quimicamente e tem uma elevada afinidade para se ligarem a in vivo macromolecules 4-5. A quitosana imita a porção de glicosaminoglicano da matriz extracelular, permitindo-lhe funcionar como um substrato para a migração de adesão celular, e proliferação. Neste estudo, utilizam quitosano na forma de microesferas para entregar células-tronco adiposas (ASC) em uma base de colagénio tridimensional andaime 6. Uma razão de célula-a-microesfera ideal foi determinada com respeito ao tempo de incubação e densidade celular para atingir o número máximo de células que poderiam ser carregados. Uma vez ASC são semeados no microesferas de quitosano (CSM), eles são incorporados em um andaime de colagénio e pode ser mantido em cultura durante períodos prolongados. Em resumo, este estudo fornece um método para entregar precisamente células-tronco dentro de um andaime tridimensional biomaterial.

Watch this Scientific Journal Video about Constructing a Collagen Hydrogel for the Delivery of Stem Cell-loaded Chitosan Microspheres at JoVE.com

Constructing a Collagen Hydrogel for the Delivery of Stem Cell-loaded Chitosan Microspheres

Um grande obstáculo em terapias com células-tronco atuais é determinar o método mais eficaz para entregar essas células para tecidos do hospedeiro. Aqui, nós descrevemos um método de entrega de quitosana-base que é eficiente e simples na abordagem, ao mesmo tempo permitindo que as células-tronco adiposas para manter a sua multipotency.

Construindo um hidrogel de colágeno para a entrega de células-tronco carregado microesferas

Multipotent stem cells have been shown to be extremely useful in the field of regenerative medicine1-3. However, in order to use these cells effectively ...

constructing-collagen-hydrogel-for-delivery-stem-cell-loaded-chitosan

Research

JoVE Journal

Bioengineering

16.7K visualizações.  United States Army Institute of Surgical Research. Um grande obstáculo em terapias com células-tronco atuais é determinar o método mais eficaz para entregar essas células para tecidos do hospedeiro. Aqui, nós descrevemos um método de entrega de quitosana-base que é eficiente e simples na abordagem, ao mesmo tempo permitindo que as células-tronco adiposas para manter a sua multipotency.

Vídeo: Constructing a Collagen Hydrogel for the Delivery of Stem Cell-loaded Chitosan Microspheres

Engineering a Bilayered Hydrogel to Control ASC Differentiation

Natural polymers over the years have gained more importance because of their host biocompatibility and ability to interact with cells in vitro and in vivo. An area of research that holds promise in regenerative medicine is the combinatorial use of novel biomaterials and stem cells. A fundamental strategy in the field of tissue engineering is the use of three-dimensional scaffold (e.g., decellularized extracellular matrix, hydrogels, micro/nano particles) for directing cell function. This technology has evolved from the discovery that cells need a substrate upon which they can adhere, proliferate, and express their differentiated cellular phenotype and function 2-3. More recently, it has also been determined that cells not only use these substrates for adherence, but also interact and take cues from the matrix substrate (e.g., extracellular matrix, ECM)4. Therefore, the cells and scaffolds have a reciprocal connection that serves to control tissue development, organization, and ultimate function. Adipose-derived stem cells (ASCs) are mesenchymal, non-hematopoetic stem cells present in adipose tissue that can exhibit multi-lineage differentiation and serve as a readily available source of cells (i.e. pre-vascular endothelia and pericytes). Our hypothesis is that adipose-derived stem cells can be directed toward differing phenotypes simultaneously by simply co-culturing them in bilayered matrices1. Our laboratory is focused on dermal wound healing. To this end, we created a single composite matrix from the natural biomaterials, fibrin, collagen, and chitosan that can mimic the characteristics and functions of a dermal-specific wound healing ECM environment.

This protocol focuses on utilizing the inherent ability of stem cells to take cue from their surrounding extracellular matrix and be induced to differentiate into multiple phenotypes. This methods manuscript extends our description and characterization of a model utilizing a bilayered hydrogel, composed of PEG-fibrin and collagen, to simultaneously co-differentiate adipose-derived stem cells1.

Engenharia de um hidrogel de camada dupla para controlar a diferenciação ASC

Natural polymers over the years have gained more importance because of their host biocompatibility and ability to interact with cells in vitro and in ...

Bioengenharia

An Improved Method for the Preparation of Type I Collagen From Skin

Soluble type 1 collagen (COL1) is used extensively as an adhesive substrate for cell cultures and as a cellular scaffold for regenerative applications. Clinically, this protein is widely used for cosmetic surgery, dermal injections, bone grafting, and reconstructive surgery. The sources of COL1 for these procedures are commonly nonhuman, which increases the potential for inflammation and rejection as well as xenobiotic disease transmission. In view of this, a method to efficiently and quickly purify COL1 from limited quantities of autologously-derived tissues would circumvent many of these issues; however, standard isolation protocols are lengthy and often require large quantities of collagenous tissues. Here, we demonstrate an efficient COL1 extraction method that reduces the time needed to isolate and purify this protein from about 10 days to less than 3 hr. We chose the dermis as our tissue source because of its availability during many surgical procedures. This method uses traditional extraction buffers combined with forceful agitation and centrifugal filtration to obtain highly-pure, soluble COL1 from small amounts of corium. Briefly, dermal biopsies are washed thoroughly in ice-cold dH2O after removing fat, connective tissue, and hair. The skin samples are stripped of noncollagenous proteins and polysaccharides using 0.5 M sodium acetate and a high speed bench-top homogenizer. Collagen from residual solids is subsequently extracted with a 0.075 M sodium citrate buffer using the homogenizer. These extracts are purified using 100,000 MW cut-off centrifugal filters that yield COL1 preparations of comparable or superior quality to commercial products or those obtained using traditional procedures. We anticipate this method will facilitate the utilization of autologously-derived COL1 for a multitude of research and clinical applications.

Traditional procedures for the isolation of soluble type 1 collagen (COL1) require about 10 days from start to finish because of lengthy buffer incubations and laborious resuspensions of fibrils. Here, we describe a means to purify COL1 from small dermal biopsies in less than 3 hr.

Um método aperfeiçoado para a preparação de colágeno tipo I Da Pele

Soluble type 1 collagen (COL1) is used extensively as an adhesive substrate for cell cultures and as a cellular scaffold for regenerative applications. ...

Imaging Denatured Collagen Strands In vivo and Ex vivo via Photo-triggered Hybridization of Caged Collagen Mimetic Peptides

Collagen is a major structural component of the extracellular matrix that supports tissue formation and maintenance. Although collagen remodeling is an integral part of normal tissue renewal, excessive amount of remodeling activity is involved in tumors, arthritis, and many other pathological conditions. During collagen remodeling, the triple helical structure of collagen molecules is disrupted by proteases in the extracellular environment. In addition, collagens present in many histological tissue samples are partially denatured by the fixation and preservation processes. Therefore, these denatured collagen strands can serve as effective targets for biological imaging. We previously developed a caged collagen mimetic peptide (CMP) that can be photo-triggered to hybridize with denatured collagen strands by forming triple helical structure, which is unique to collagens. The overall goals of this procedure are i)&#160;to image denatured collagen strands resulting from normal remodeling activities in vivo, and ii) to visualize collagens in ex vivo tissue sections using the photo-triggered caged CMPs. To achieve effective hybridization and successful in vivo and ex vivo imaging, fluorescently labeled caged CMPs are either photo-activated immediately before intravenous injection, or are directly activated on tissue sections. Normal skeletal collagen remolding in nude mice and collagens in prefixed mouse cornea tissue sections are imaged in this procedure. The imaging method based on the CMP-collagen hybridization technology presented here could lead to deeper understanding of the tissue remodeling process, as well as allow development of new diagnostics for diseases associated with high collagen remodeling activity.

Imaging Denatured Collagen Strands In vivo and Ex vivo via Photo-triggered Hybridization of Caged Collagen Mimetic Peptides

This procedure demonstrates in vivo near IR fluorescence imaging of collagen remodeling activities in mice as well as ex vivo staining of collagens in tissue sections using caged collagen mimetic peptides that can be photo-triggered to hybridize with denatured collagen strands.

Imagiologia desnaturadas colágeno Vertentes<em&gt; In vivo</em&gt; E<em&gt; Ex vivo</em&gt; Via foto desencadeada Hibridização do Caged Colágeno mimético Peptídeos

Collagen is a major structural component of the extracellular matrix that supports tissue formation and maintenance. Although collagen remodeling is an ...

Development of Amelogenin-chitosan Hydrogel for In Vitro Enamel Regrowth with a Dense Interface

Biomimetic enamel reconstruction is a significant topic in material science and dentistry as a novel approach for the treatment of dental caries or erosion. Amelogenin has been proven to be a critical protein for controlling the organized growth of apatite crystals. In this paper, we present a detailed protocol for superficial enamel reconstruction by using a novel amelogenin-chitosan hydrogel. Compared to other conventional treatments, such as topical fluoride and mouthwash, this method not only has the potential to prevent the development of dental caries but also promotes significant and durable enamel restoration. The organized enamel-like microstructure regulated by amelogenin assemblies can significantly improve the mechanical properties of etched enamel, while the dense enamel-restoration interface formed by an in situ regrowth of apatite crystals can improve the effectiveness and durability of restorations. Furthermore, chitosan hydrogel is easy to use and can suppress bacterial infection, which is the major risk factor for the occurrence of dental caries. Therefore, this biocompatible and biodegradable amelogenin-chitosan hydrogel shows promise as a biomaterial for the prevention, restoration, and treatment of defective enamel.

Development of Amelogenin-chitosan Hydrogel for In Vitro Enamel Regrowth with a Dense Interface

In this article, we describe a protocol for fabricating an amelogenin-chitosan hydrogel for superficial enamel reconstruction. Organized in situ growth of apatite crystals in the hydrogel formed a dense enamel-restoration interface, which will improve the effectiveness and durability of restorations.

Desenvolvimento de Amelogenina-quitosana Hidrogel para<em&gt; In Vitro</em&gt; Esmalte Regrowth Com uma interface Densa

Biomimetic enamel reconstruction is a significant topic in material science and dentistry as a novel approach for the treatment of dental caries or ...

Microscale Vortex-assisted Electroporator for Sequential Molecular Delivery

Electroporation has received increasing attention in the past years, because it is a very powerful technique for physically introducing non-permeant exogenous molecular probes into cells. This work reports a microfluidic electroporation platform capable of performing multiple molecule delivery to mammalian cells with precise and molecular-dependent parameter control. The system&#8217;s ability to isolate cells with uniform size distribution allows for less variation in electroporation efficiency per given electric field strength; hence enhanced sample viability. Moreover, its process visualization feature allows for observation of the fluorescent molecular uptake process in real-time, which permits prompt molecular delivery parameter adjustments in situ for efficiency enhancement. To show the vast capabilities of the reported platform, macromolecules with different sizes and electrical charges (e.g., Dextran with MW of 3,000 and 70,000 Da) were delivered to metastatic breast cancer cells with high delivery efficiencies (&#62;70%) for all tested molecules. The developed platform has proven its potential for use in the expansion of research fields where on-chip electroporation techniques can be beneficial.

A microfluidic vortex assisted electroporation platform was developed for sequential delivery of multiple molecules into identical cell populations with precise and independent dosage control. The system&#8217;s size based target cell purification step preceding electroporation aided to enhance molecular delivery efficiency and processed cell viability.

Microescala Electroporator para entrega Sequential Molecular assistida por Vortex

Electroporation has received increasing attention in the past years, because it is a very powerful technique for physically introducing non-permeant ...

Recombinant Collagen I Peptide Microcarriers for Cell Expansion and Their Potential Use As Cell Delivery System in a Bioreactor Model

Tissue engineering is a promising field, focused on developing solutions for the increasing demand on tissues and organs regarding transplantation purposes. The process to generate such tissues is complex, and includes an appropriate combination of specific cell types, scaffolds, and physical or biochemical stimuli to guide cell growth and differentiation. Microcarriers represent an appealing tool to expand cells in a three-dimensional (3D) microenvironment, since they provide higher surface-to volume ratios and mimic more closely the in vivo situation compared to traditional two-dimensional methods. The vascular system, supplying oxygen and nutrients to the cells and ensuring waste removal, constitutes an important building block when generating engineered tissues. In fact, most constructs fail after being implanted due to lacking vascular support. In this study, we present a protocol for endothelial cell expansion on recombinant collagen-based microcarriers under dynamic conditions in spinner flask and bioreactors, and we explain how to determine in this setting cell viability and functionality. In addition, we propose a method for cell delivery for vascularization purposes without additional detachment steps necessary. Furthermore, we provide a strategy to evaluate the cell vascularization potential in a perfusion bioreactor on a decellularized&#160;biological matrix. We believe that the use of the presented methods could lead to the development of new cell-based therapies for a large range of tissue engineering applications in the clinical practice.

We propose a cell expansion protocol on macroporous microcarriers and their use as delivery system in a perfusion bioreactor to seed a decellularized tissue matrix. We also include different techniques to determine cell proliferation and viability of cells cultured on microcarriers. Furthermore, we demonstrate functionality of cells after bioreactor cultures.

Recombinante colágeno peptídeo Microcarriers para expansão da célula e seu potencial uso como sistema de entrega de células em um bioreator modelo

Tissue engineering is a promising field, focused on developing solutions for the increasing demand on tissues and organs regarding transplantation ...

Fabricating a Kidney Cortex Extracellular Matrix-Derived Hydrogel

Extracellular matrix (ECM) provides important biophysical and biochemical cues to maintain tissue homeostasis. Current synthetic hydrogels offer robust mechanical support for in vitro cell culture but lack the necessary protein and ligand composition to elicit physiological behavior from cells. This manuscript describes a fabrication method for a kidney cortex ECM-derived hydrogel with proper mechanical robustness and supportive biochemical composition. The hydrogel is fabricated by mechanically homogenizing and solubilizing decellularized human kidney cortex ECM. The matrix preserves native kidney cortex ECM protein ratios while also enabling gelation to physiological mechanical stiffnesses. The hydrogel serves as a substrate upon which kidney cortex-derived cells can be maintained under physiological conditions. Furthermore, the hydrogel composition can be manipulated to model a diseased environment which enables the future study of kidney diseases.

Here we present a protocol to fabricate a kidney cortex extracellular matrix-derived hydrogel to retain the native kidney extracellular matrix (ECM) structural and biochemical composition. The fabrication process and its applications are described. Finally, a perspective on using this hydrogel to support kidney-specific cellular and tissue regeneration and bioengineering is discussed.

Fabricando um rim córtex Extracellular Matrix-derivado hidrogel

Extracellular matrix (ECM) provides important biophysical and biochemical cues to maintain tissue homeostasis. Current synthetic hydrogels offer robust ...

Doxycycline Loaded Collagen-Chitosan Composite Scaffold for the Accelerated Healing of Diabetic Wounds

One major complication of diabetes mellitus is diabetic wounds (DW). The prolonged phase of inflammation in diabetes obstructs the further stages of an injury leading to delayed wound healing. We selected doxycycline (DOX), as a potential drug of choice, due to its anti-bacterial properties along with its reported anti-inflammatory properties. The current study aims to formulate DOX loaded collagen-chitosan non-crosslinked (NCL) &amp; crosslinked (CL) scaffolds and evaluate their healing ability in diabetic conditions. The characterization result of scaffolds reveals that the DOX-CL scaffold holds ideal porosity, a low swelling &amp; degradation rate, and a sustained release of DOX compared to the DOX-NCL scaffold. The in vitro studies reveal that the DOX-CL scaffold was biocompatible and enhanced cell growth compared with CL scaffold treated and control groups. The anti-bacterial studies have shown that the DOX-CL scaffold was more effective than the CL scaffold against the most common bacteria found in DW. Using the streptozotocin and high-fat diet-induced DW model, a significantly (p&#8804;0.05) faster rate of wound contraction in the DOX-CL scaffold treated group was observed compared to those in CL scaffold treated and control groups. The use of the DOX-CL scaffold can prove to be a promising approach for local treatment for DWs.

The prepared DOX-CL scaffold satisfied the prerequisites of an ideal DW dressing in mechanical strength, porosity, water absorption, degradation rate, sustained release, anti-bacterial, biocompatibility, and anti-inflammatory properties, which are considered to be essential for the recovery of damaged tissue in DWs.

Doxycycline carregado de colágeno-chitosan andaime composto para a cura acelerada de feridas diabéticas

One major complication of diabetes mellitus is diabetic wounds (DW). The prolonged phase of inflammation in diabetes obstructs the further stages of an ...

Preparation and Characterization of Graphene-Based 3D Biohybrid Hydrogel Bioink for Peripheral Neuroengineering

Peripheral neuropathies can occur as a result of axonal damage, and occasionally due to demyelinating diseases. Peripheral nerve damage is a global problem that occurs in 1.5%-5% of emergency patients and may lead to significant job losses. Today, tissue engineering-based approaches, consisting of scaffolds, appropriate cell lines, and biosignals, have become more applicable with the development of three-dimensional (3D) bioprinting technologies. The combination of various hydrogel biomaterials with stem cells, exosomes, or bio-signaling molecules is frequently studied to overcome the existing problems in peripheral nerve regeneration. Accordingly, the production of injectable systems, such as hydrogels, or implantable conduit structures formed by various bioprinting methods has gained importance in peripheral neuro-engineering. Under normal conditions, stem cells are the regenerative cells of the body, and their number and functions do not decrease with time to protect their populations; these are not specialized cells but can differentiate upon appropriate stimulation in response to injury. The stem cell system is under the influence of its microenvironment, called the stem cell niche. In peripheral nerve injuries, especially in neurotmesis, this microenvironment cannot be fully rescued even after surgically binding severed nerve endings together. The composite biomaterials and combined cellular therapies approach increases the functionality and applicability of materials in terms of various properties such as biodegradability, biocompatibility, and processability. Accordingly, this study aims to demonstrate the preparation and use of graphene-based biohybrid hydrogel patterning and to examine the differentiation efficiency of stem cells into nerve cells, which can be an effective solution in nerve regeneration.

In this manuscript, we demonstrate the preparation of a biohybrid hydrogel bioink containing graphene for use in peripheral tissue engineering. Using this 3D biohybrid material, the neural differentiation protocol of stem cells is performed. This can be an important step in bringing similar biomaterials to the clinic.

Preparação e caracterização de biotinta de hidrogel biohíbrido 3D à base de grafeno para neuroengenharia periférica

Peripheral neuropathies can occur as a result of axonal damage, and occasionally due to demyelinating diseases. Peripheral nerve damage is a global ...

Fabrication of Size-Controlled and Emulsion-Free Chitosan-Genipin Microgels for Tissue Engineering Applications

Chitosan microgels are of significant interest in tissue engineering due to their wide range of applications, low cost, and immunogenicity. However, chitosan microgels are commonly fabricated using emulsion methods that require organic solvent rinses, which are toxic and harmful to the environment. The present protocol presents a rapid, non-cytotoxic, non-emulsion-based method for fabricating chitosan-genipin microgels without the need for organic solvent rinses. The microgels described herein can be fabricated with precise size control. They exhibit sustained release of biomolecules, making them highly relevant for tissue engineering, biomaterials, and regenerative medicine. Chitosan is crosslinked with genipin to form a hydrogel network, then passed through a syringe filter to produce the microgels. The microgels can be filtered to create a range of sizes, and they show pH-dependent swelling and degrade over time enzymatically. These microgels have been employed in a rat growth plate injury model and were demonstrated to promote increased cartilage tissue repair and to show complete degradation at 28 days in vivo. Due to their low cost, high convenience, and ease of fabrication with cytocompatible materials, these chitosan microgels present an exciting and unique technology in tissue engineering.

The present protocol describes a non-emulsion-based method for the fabrication of chitosan-genipin microgels. The size of these microgels can be precisely controlled, and they can display pH-dependent swelling, degrade in vivo,&#160;and be loaded with therapeutic molecules that release over time in a sustained manner, making them highly relevant for tissue engineering applications.

Fabricação de microgéis chitosan-genipin controlados por tamanho e sem emulsão para aplicações de engenharia de tecidos

Chitosan microgels are of significant interest in tissue engineering due to their wide range of applications, low cost, and immunogenicity. However, ...

Methods Article

Construindo um hidrogel de colágeno para a entrega de células-tronco carregado microesferas