This work was supported by the EC within the framework of the STIFF-FLOP FP7-ICT-2011.2.1 European Project (#287728).

Nota: Este protocolo descreve as fases de fabricação de um único módulo, que inclui as câmaras de fluidos, canal de endurecimento, condutas de actuação e a bainha externa. O procedimento a seguir deve ser executado sob um exaustor e vestindo casaco e luvas de laboratório por razões de segurança. Como mencionado anteriormente, o processo de fabrico da unidade elastomérica baseia-se na utilização sequencial de moldes concebidos com software de CAD. Eles são compostos das 13 peças mostradas na Figura 2 e listados na Tabela 1. 1. Preparação do silicone <ol><li> Pesar 12 g de componente A e 12 g de parte B do mesmo copo de plástico ou uma placa de Petri e misturá-los juntos, mexendo. Nota: as proporções de materiais podem variar dependendo de o silicone específico utilizado, neste caso, consiste em duas partes: Parte A (a base) e parte B (o catalisador). Eles são utilizados em proporções 1A: 1B em peso. </li><li> Coloque o vidro contendo a misturamateriais de silicone ed em uma máquina desgaseificador a vácuo pressão de 1 bar. Mantenha o vidro sob vácuo até que todas as bolhas são removidas do material de silicone. Para o silicone utilizado no processo de desgaseificação leva cerca de 10 minutos. Uma vez que os materiais são completamente livre da presença de bolhas, restaurar a pressão atmosférica dentro da máquina e utilizar o silicone. </li></ol> 2. Fabrico do Módulo silicónicos <ol><li> Montagem do molde. <ol><li> Inserir o cilindro de endurecimento e a parte superior das câmaras em cap_A (Figura 3a). </li><li> Fechar as conchas em torno da segunda camada de cap_A. </li></ol></li><li> Primeiro fundição de silicone. <ol><li> Verter a de silicone no interior do molde se montado na borda das conchas (Figura 3B). </li><li> Coloque o molde numa estufa a 60 ° C durante cerca de 30 min. </li></ol></li><li> O rearranjo do molde. <ol><li> Retirar as conchas externas e cap_A (Figura 3c). </li><li> Insira os cilindros das bases das câmaras e do cilindro de reforço dentro cap_B (Figura 3D). </li><li> Feche os escudos de novo em torno do módulo, deslizando-as para cima de 10 mm, a fim de ter uma folga de 10 mm entre a superfície de topo do módulo e as bordas das conchas (Figura 3E). </li></ol></li><li> Segundo fundição de silicone. <ol><li> Verter a de silicone no interior do molde até rearranjada para a borda das conchas sobre o lado superior (isto é, também para cima para o cilindro de endurecimento) (Figura 3F). </li><li> Coloque o molde num forno a 60 ° C durante cerca de 30 min. </li><li> Remover os invólucros externos, cap_B e as câmaras (à excepção do cilindro de endurecimento) (Figura 3G). </li></ol></li></ol> 3. A inserção dos tubos <ol><li> Cortar 3 tubos com o mesmo comprimento desejado (300 mm, por exemplo). </li><li> Colocar cola Siliconic em torno de uma extremidade de cada tubo de 10 mm, sem obtrução de tubos. </li><li> Insira os tubos dentro dos 2 mm canais na unidade Siliconic (Figura 3h) dedicados. </li><li> Permitir um tempo de cura de 12 min à temperatura ambiente ou colocar o módulo no interior de um forno a uma temperatura mais elevada (50 ° - 60 °) para acelerar o processo de secagem. </li></ol> 4. Fabricação do Crimped Trançado bainha <ol><li> Cortar 700 mm de uma bainha entrelaçada expansível (cerca de 15 vezes a altura do módulo). </li><li> Inserir um cilindro metálico de 30 mm de diâmetro e 250 mm de comprimento no interior da bainha. </li><li> Empurrar para baixo e forçar a bainha de deslizar ao longo do cilindro, a fim de criar ondulações. </li><li> Mecanicamente fixar a bainha no lugar com um grampo e ao calor com uma pistola de aquecimento a 350 ° C durante 2-3 minutos até uma deformação permanente é obtido. </li><li> Deixe a bainha esfriar e retire o cilindro interno. </li></ol> 5. Integração da bainha externa <ol><li> Passe otubos através dos orifícios de cap_C. </li><li> Pour 3 g de silicone em cap_C. </li><li> Grampo cap_C a um apoio que é mais elevada do que o plano de trabalho. </li><li> Insira o lado inferior do módulo previamente fabricado em cap_C. </li><li> Deslize a bainha frisado em torno do módulo. </li><li> Empurre as primeiras ondulações da bainha dentro cap_C e mergulhá-los para o silicone recentemente derramado (Figura 3i). </li><li> Coloque o molde num forno a 60 ° C durante cerca de 20 min. </li><li> Repetir o mesmo procedimento a partir do ponto de 5,1-5,6 para fixar a bainha no lado superior, utilizando cap_D (Figura 3j). </li><li> Remover cap_C e cap_D. </li><li> Remover o cilindro central (figura 3K). </li></ol> 6. Fabricação de o Granular Jamming Membrane <ol><li> Pour 5 g de látex líquido num copo de plástico. </li><li> Mergulha-se o cilindro para a membrana (última peça mostrada na Figura 2) no interior do látex líquido até que a superfícieé completamente coberto. </li><li> Deixe secar sob um capuz para 20 min. </li><li> Repita os pontos 6.2 e 6.3. </li><li> Remover a membrana a partir do molde. </li></ol> 7. Inserção do Granular Jamming Membrane <ol><li> Corte um tubo (2 mm de diâmetro) para o comprimento desejado (300 mm no exemplo). </li><li> Corte um pedaço quadrado de cerca de 100 mm 2 de tecido de nylon e fechar uma extremidade do tubo com este tecido, utilizando uma película de plástico ou de parafina supercola. </li><li> Pesar 4 g de pó de café e encher a membrana. </li><li> Inserir o tubo (a extremidade com o filtro) no interior da membrana cheia e corrigi-lo em torno do tubo por meio de uma película de plástico de parafina. </li><li> Aplicar um vácuo do outro lado do tubo (a membrana torna-se mais duro). </li><li> Inserir a membrana no interior do canal central vazia do módulo Siliconic (Figura 3l). </li><li> Cole as extremidades da membrana de endurecimento para o módulo de silicone. </li><li> Feche os anéis ao redor do topolado do módulo (figura 3m). </li><li> Pour 2 g de silicone para os anéis, a fim de nivelar a superfície. </li><li> Deixe que a seco de silicone sob a capa ou numa estufa a 60 °. </li><li> Remover os anéis. </li><li> Repita a partir de pontos de 7,8 a 7,11 para o lado inferior (Figura 3 N). </li></ol>

<ol>
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The authors have nothing to disclose.

The technique described in this protocol enables the fabrication of a pneumatically actuated soft unit usable for modular compliant structures. Thanks to the design of the molds and their simple assembly, it is possible to fabricate one complete module in about 4 hours with 7 main steps. The process of fabrication involves specific materials, which are easily available, and work should be carried out under a fume hood. An external set up including air valves, air compressor and vacuum pump is necessary to activate the mo...

As tendências recentes no campo da medicina estão pressionando por uma redução da capacidade de invasão de operações cirúrgicas. Cirurgia minimamente invasiva (MIS) foi melhorado com sucesso nos últimos anos para operações abdominais. Procedimentos MIS baseiam-se na utilização de ferramentas introduzidas através de quatro ou de cinco pontos de acesso (Trocars) colocados na parede abdominal. A fim de reduzir o número de trocartes, os instrumentos podem ser inseridos por laparoscopia porta única (SPL) ou cirurgia endoscópica Translumenal orifício natural (NOTAS) 1. Estes procedimentos evitar cicatrizes visíveis externos, mas aumentar a dificuldade para os clínicos na execução da cirurgia. Esta limitação deve-se principalmente aos pontos reduzidos de acesso e à natureza rígida e semi-rígidas dos instrumentos, que não são capazes de evitar ou passar em torno de órgãos 2, 3. Destreza e motilidade pode ser melhorada usando articulada e hiper-redundantes robôs que podem cobrir uma área de trabalho mais amplo e complexo, thpermitindo-nos um alvo específico no corpo para ser alcançada mais facilmente 4, 5, 6 e para funcionar como sistemas de retracção quando necessárias 7. Um manipulador flexível pode melhorar a adesão do tecido, tornando assim o contato mais seguro do que pelas ferramentas tradicionais. No entanto, estes manipuladores muitas vezes a falta de estabilidade quando o alvo é atingido e, geralmente, eles não podem controlar o contacto com os tecidos circundantes 8, 9. Estudos sobre estruturas biológicas, como o braço polvo 10 e a tromba de elefante 11, inspiraram recentemente o projeto de manipuladores flexíveis, deformáveis ​​e compatíveis com um número redundante de graus de liberdade (dofs) e rigidez controlável 12. Estes tipos de dispositivos utilizam molas passivas, materiais inteligentes, elementos pneumáticos ou tendões, 13, 14, 15. Geralmente, manipuladores fabricadas com materiais macios e flexíveis não garante a geração de forças elevadas. Tele STIFF-FLOP (rigidez manipulador flexível e pode ser aprendida controlável para operações cirúrgicas) manipulador foi recentemente apresentado como um dispositivo cirúrgico romance para notas e SPL inspirados pelas capacidades do polvo. A fim de superar as limitações dos manipuladores moles anteriores, que tem um corpo mole, bem como elevada destreza, de alta força e rigidez controlável 16. A arquitectura do manipulador baseia-se numa abordagem modular: múltiplas unidades, com a mesma estrutura e funcionalidades, são integrados em conjunto. A única unidade é mostrado na Figura 1. Baseia-se um cilindro elastomérico obtido por uma fabricação multifásico. As etapas de montagem dos componentes de moldes e processos de fundição permitir três câmaras vazias (para atuação de fluidos) e um canal central oca 17 (para a habitação um mecanismo baseado em empastelamento granular 18) a serem incorporados. As câmaras são colocadas em 120 °, de modo que oinflação combinado ir produz movimento omnidirecional e alongamento. Além disso, um invólucro externo trançado é colocado externamente para limitar a expansão radial para fora das câmaras de fluidos quando pressurizado, optimizando assim o efeito da câmara de accionamento no movimento módulo (alongamento e flexão). O canal central aloja um dispositivo cilíndrico composto por uma membrana externa cheia com material granular. Quando uma pressão de vácuo é aplicada, que altera as suas propriedades elásticas que causa um endurecimento que afecta as propriedades de todo o módulo. Desempenhos de movimento e de rigidez são controladas por uma configuração externa incluindo um compressor de ar e três válvulas de pressão para accionar as câmaras e uma bomba de vácuo para activar o vácuo no canal de endurecimento. Uma interface intuitiva permite o controle de acionamento e do vácuo pressões dentro do módulo. Este artigo detalha o fabricatioprocesso n do módulo único deste manipulador e relatórios os resultados mais significativos sobre capacidades básicas de movimento. Considerando a natureza modular do dispositivo, a avaliação do desempenho de fabricação e de apenas um único módulo permite também os resultados para ser estendido e para prever o comportamento básico de um manipulador multi-módulo de integração de dois ou mais módulos.

<table border="0">
	<tbody>
		<tr>
			<td>Ecoflex 00-50 Trial Kit</td>
			<td>SmoothOn</td>
			<td></td>
			<td>Used for the fabrication of the soft unit, combining equal amounts of liquid parts A (the base) and B (the catalyst)</td>
		</tr>
		<tr>
			<td>Latex</td>
			<td>Antichit&#224; Belsito</td>
			<td></td>
			<td>Used for the fabrication of the granular jamming membrane</td>
		</tr>
		<tr>
			<td>Peroxide-Cured Silicone Tubing</td>
			<td>Cole Parmer</td>
			<td>T-06411-59</td>
			<td>Used for actuating the chambers and applying vacuum</td>
		</tr>
		<tr>
			<td>PET expandable braided sleeving</td>
			<td>RS</td>
			<td>408-249</td>
			<td>Used for the fabrication of the external braided sheath</td>
		</tr>
		<tr>
			<td>Silicone Rubber</td>
			<td>Momentive</td>
			<td>127374</td>
			<td>Used to fix the actuation tubes to the module</td>
		</tr>
		<tr>
			<td>Parafilm</td>
			<td>Cole Parmer</td>
			<td>EW-06720-40</td>
			<td>Used to fix the latex membrane to the vacuum tube</td>
		</tr>
		<tr>
			<td>Fume hood Secuflow</td>
			<td>Groupe Waldner</td>
			<td></td>
			<td>Working space</td>
		</tr>
		<tr>
			<td>Precision scale</td>
			<td>KERN EW</td>
			<td></td>
			<td>Used to weight silicone, latex and coffee powder</td>
		</tr>
		<tr>
			<td>Oven/degasser</td>
			<td>Heraeus</td>
			<td></td>
			<td>Used to degass the silicone and reduce its cure time</td>
		</tr>
		<tr>
			<td>Vacuum pump</td>
			<td>DVP Vacuum Technology</td>
			<td></td>
			<td>Used to apply vacuum to the latex membrane</td>
		</tr>
	</tbody>
</table>

design and fabrication of an elastomeric unit for soft modular robots in minimally invasive surgery

Nos últimos anos, as tecnologias de robótica macios têm despertado crescente interesse na área médica devido a sua interação intrinsecamente segura em ambientes não estruturados. Ao mesmo tempo, novos procedimentos e técnicas têm sido desenvolvidas para reduzir a capacidade invasiva de operações cirúrgicas. Cirurgia minimamente invasiva (MIS) foi empregada com sucesso para intervenções abdominais, no entanto procedimentos padrão MIS baseiam-se principalmente em instrumentos rígidos ou semi-rígidos que limitam a habilidade do clínico. Este artigo apresenta um manipulador hábil suave e alta para MIS. O manipulador foi inspirado pelas capacidades biológicas do braço polvo, e é projetado com uma abordagem modular. Cada módulo apresenta as mesmas características funcionais, conseguindo alta habilidade e versatilidade quando mais módulos são integrados. Detalhes O papel do desenho, processo de fabrico e os materiais necessários para o desenvolvimento de uma única unidade, que é fabricada por casting silicone dentro de moldes específicos. O resultado consiste em um cilindro elastomérico incluindo três actuadores pneumáticos flexíveis que permitem o alongamento e flexão omnidireccional da unidade. Uma bainha entrelaçada externo melhora o movimento do módulo. No centro de cada módulo um mecanismo de bloqueio à base de granulado varia a rigidez da estrutura durante as tarefas. Os testes demonstram que o módulo é capaz de dobrar-se para 120 ° C e a alongar-se para 66% do comprimento inicial. O módulo gera uma força máxima de 47 N, e a sua rigidez pode aumentar até 36%.

As várias fases do fabrico, descrito no protocolo, são ilustradas na Figura 3. A fim de avaliar a eficácia da técnica e os resultados do protótipo final, o módulo foi testado em diferentes condições de trabalho. Uma configuração externa permite o controle de ambos o accionamento e a rigidez do módulo. Ele inclui um compressor de ar que activa três válvulas. Eles estão ligados aos tubos silicónicos integradas nas câmaras e permitir a sua press...

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Design and Fabrication of an Elastomeric Unit for Soft Modular Robots in Minimally Invasive Surgery

This paper describes the design and fabrication of a soft unit for surgical manipulators. The base module includes three flexible fluidic actuators to achieve omnidirectional bending and elongation, and a granular jamming-based mechanism to enable stiffness control. A complete mechanical characterization is also reported.

Projeto e fabricação de uma Unidade de elastômero para robôs modulares moles em Cirurgia Minimamente Invasiva

In recent years, soft robotics technologies have aroused increasing interest in the medical field due to their intrinsically safe interaction in ...

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8.9K visualizações.  Scuola Superiore Sant'Anna. This paper describes the design and fabrication of a soft unit for surgical manipulators. The base module includes three flexible fluidic actuators to achieve omnidirectional bending and elongation, and a granular jamming-based mechanism to enable stiffness control. A complete mechanical characterization is also reported. 

Vídeo: Design and Fabrication of an Elastomeric Unit for Soft Modular Robots in Minimally Invasive Surgery

Elastomeric PGS Scaffolds in Arterial Tissue Engineering

Cardiovascular disease is one of the leading cause of mortality in the US and especially, coronary artery disease increases with an aging population and increasing obesity1. Currently, bypass surgery using autologous vessels, allografts, and synthetic grafts are known as a commonly used for arterial substitutes2. However, these grafts have limited applications when an inner diameter of arteries is less than 6 mm due to low availability, thrombotic complications, compliance mismatch, and late intimal hyperplasia3,4. To overcome these limitations, tissue engineering has been successfully applied as a promising alternative to develop small-diameter arterial constructs that are nonthrombogenic, robust, and compliant. Several previous studies have developed small-diameter arterial constructs with tri-lamellar structure, excellent mechanical properties and burst pressure comparable to native arteries5,6. While high tensile strength and burst pressure by increasing collagen production from a rigid material or cell sheet scaffold, these constructs still had low elastin production and compliance, which is a major problem to cause graft failure after implantation. Considering these issues, we hypothesized that an elastometric biomaterial combined with mechanical conditioning would provide elasticity and conduct mechanical signals more efficiently to vascular cells, which increase extracellular matrix production and support cellular orientation.
The objective of this report is to introduce a fabrication technique of porous tubular scaffolds and a dynamic mechanical conditioning for applying them to arterial tissue engineering. We used a biodegradable elastomer, poly (glycerol sebacate) (PGS)7 for fabricating porous tubular scaffolds from the salt fusion method. Adult primary baboon smooth muscle cells (SMCs) were seeded on the lumen of scaffolds, which cultured in our designed pulsatile flow bioreactor for 3 weeks. PGS scaffolds had consistent thickness and randomly distributed macro- and micro-pores. Mechanical conditioning from pulsatile flow bioreactor supported SMC orientation and enhanced ECM production in scaffolds. These results suggest that elastomeric scaffolds and mechanical conditioning of bioreactor culture may be a promising method for arterial tissue engineering.

Elastomeric PGS scaffolds with vascular smooth muscle cells cultured in a pulsatile flow bioreactor may lead to promising small-diameter arterial constructs with native ECM production in a relatively short culture period.

PGS elastomérico Andaimes em Engenharia de Tecidos Arterial

Cardiovascular disease is one of the leading cause of mortality in the US and especially, coronary artery disease increases with an aging population and ...

Bioengenharia

Polymeric Microneedle Array Fabrication by Photolithography

This manuscript describes the fabrication of polymeric microneedle (MN) arrays by photolithography. It involves a simple mold-free process by using a photomask consisting of embedded micro-lenses. Embedded micro-lenses were found to influence MN geometry (sharpness). Robust MN arrays with tip diameters ranging between 41.5 &#181;m &#177; 8.4 &#181;m and 71.6 &#181;m &#177; 13.7 &#181;m, with two different lengths (1,336 &#181;m &#177; 193 &#181;m and 957 &#181;m &#177; 171 &#181;m) were fabricated. These MN arrays may provide potential applications in delivery of low molecular and macromolecular therapeutic agents through skin.

Here, we present a protocol describing a mold-free fabrication process of the polymeric microneedles by photolithography.

Polimérico Fabrication matriz Microneedle por fotolitografia

This manuscript describes the fabrication of polymeric microneedle (MN) arrays by photolithography. It involves a simple mold-free process by using a ...

Rod-based Fabrication of Customizable Soft Robotic Pneumatic Gripper Devices for Delicate Tissue Manipulation

Soft compliant gripping is essential in delicate surgical manipulation for minimizing the risk of tissue grip damage caused by high stress concentrations at the point of contact. It can be achieved by complementing traditional rigid grippers with soft robotic pneumatic gripper devices. This manuscript describes a rod-based approach that combined both 3D-printing and a modified soft lithography technique to fabricate the soft pneumatic gripper. In brief, the pneumatic featureless mold with chamber component is 3D-printed and the rods were used to create the pneumatic channels that connect to the chamber. This protocol eliminates the risk of channels occluding during the sealing process and the need for external air source or related control circuit. The soft gripper consists of a chamber filled with air, and one or more gripper arms with a pneumatic channel in each arm connected to the chamber. The pneumatic channel is positioned close to the outer wall to create different stiffness in the gripper arm. Upon compression of the chamber which generates pressure on the pneumatic channel, the gripper arm will bend inward to form a close grip posture because the outer wall area is more compliant. The soft gripper can be inserted into a 3D-printed handling tool with two different control modes for chamber compression: manual gripper mode with a movable piston, and robotic gripper mode with a linear actuator. The double-arm gripper with two actuatable arms was able to pick up objects of sizes up to 2 mm and yet generate lower compressive forces as compared to elastomer-coated and non-coated rigid grippers. The feasibility of having other designs, such as single-arm or hook gripper, was also demonstrated, which further highlighted the customizability of the soft gripper device, and it's potential to be used in delicate surgical manipulation to reduce the risk of tissue grip damage.

This protocol describes a rod-based approach, combining 3D-printing and soft lithography techniques for fabricating the soft gripper devices. This approach eliminates the need for an external air source by incorporating a chamber component and reduces the chance of occlusion during the sealing process, particularly for miniaturized pneumatic channels.

Fabricação baseada em vara de customizáveis ​​macias robóticos pneumáticas Gripper Aparelhos para a manipulação de tecidos delicados

Soft compliant gripping is essential in delicate surgical manipulation for minimizing the risk of tissue grip damage caused by high stress concentrations ...

Automated Robotic Liquid Handling Assembly of Modular DNA Devices

Recent advances in modular DNA assembly techniques have enabled synthetic biologists to test significantly more of the available &#34;design space&#34; represented by &#34;devices&#34; created as combinations of individual genetic components. However, manual assembly of such large numbers of devices is time-intensive, error-prone, and costly. The increasing sophistication and scale of synthetic biology research necessitates an efficient, reproducible way to accommodate large-scale, complex, and high throughput device construction.
Here, a DNA assembly protocol using the Type-IIS restriction endonuclease based Modular Cloning (MoClo) technique is automated on two liquid-handling robotic platforms. Automated liquid-handling robots require careful, often times tedious optimization of pipetting parameters for liquids of different viscosities (e.g. enzymes, DNA, water, buffers), as well as explicit programming to ensure correct aspiration and dispensing of DNA parts and reagents. This makes manual script writing for complex assemblies just as problematic as manual DNA assembly, and necessitates a software tool that can automate script generation. To this end, we have developed a web-based software tool, http://mocloassembly.com, for generating combinatorial DNA device libraries from basic DNA parts uploaded as Genbank files. We provide access to the tool, and an export file from our liquid handler software which includes optimized liquid classes, labware parameters, and deck layout. All DNA parts used are available through Addgene, and their digital maps can be accessed via the Boston University BDC ICE Registry. Together, these elements provide a foundation for other organizations to automate modular cloning experiments and similar protocols.
The automated DNA assembly workflow presented here enables the repeatable, automated, high-throughput production of DNA devices, and reduces the risk of human error arising from repetitive manual pipetting. Sequencing data show the automated DNA assembly reactions generated from this workflow are ~95% correct and require as little as 4% as much hands-on time, compared to manual reaction preparation.

Here, an automated workflow to perform modular DNA &#34;device&#34; assembly using a modular cloning DNA assembly method on liquid-handling robots is presented. The protocol uses an intuitive software tool for generating liquid handler picklists for combinatorial DNA device library generation, which we demonstrate using two liquid handling platforms.

Robótico líquido manipulação montagem de dispositivos modulares DNA automática

Recent advances in modular DNA assembly techniques have enabled synthetic biologists to test significantly more of the available &#34;design space&#34; ...

Biomechanical Characterization of Human Soft Tissues Using Indentation and Tensile Testing

Regenerative medicine aims to engineer materials to replace or restore damaged or diseased organs. The mechanical properties of such materials should mimic the human tissues they are aiming to replace; to provide the required anatomical shape, the materials must be able to sustain the mechanical forces they will experience when implanted at the defect site. Although the mechanical properties of tissue-engineered scaffolds are of great importance, many human tissues that undergo restoration with engineered materials have not been fully biomechanically characterized. Several compressive and tensile protocols are reported for evaluating materials, but with large variability it is difficult to compare results between studies. Further complicating the studies is the often destructive nature of mechanical testing. Whilst an understanding of tissue failure is important, it is also important to have knowledge of the elastic and viscoelastic properties under more physiological loading conditions.
This report aims to provide a minimally destructive protocol to evaluate the compressive and tensile properties of human soft tissues. As examples of this technique, the tensile testing of skin and the compressive testing of cartilage are described. These protocols can also be directly applied to synthetic materials to ensure that the mechanical properties are similar to the native tissue. Protocols to assess the mechanical properties of human native tissue will allow a benchmark by which to create suitable tissue-engineered substitutes.

Tissue biomechanics is important for maintaining cell shape and function and for determining phenotype. This report demonstrates non-destructive mechanical protocols for characterizing elastic and viscoelastic properties of human soft tissues, which can be directly applied to tissue-engineered substrates to allow a close matching of engineered materials to native tissue.

Caracterização biomecânica de tecidos moles Humanos Usando recuo e testes de tração

Regenerative medicine aims to engineer materials to replace or restore damaged or diseased organs. The mechanical properties of such materials should ...

An In Vitro Organ Culture Model of the Murine Intervertebral Disc

Intervertebral disc (IVD) degeneration is a significant contributor to low back pain. The IVD is a fibrocartilaginous joint that serves to transmit and dampen loads in the spine. The IVD consists of a proteoglycan-rich nucleus pulposus (NP) and a collagen-rich annulus fibrosis (AF) sandwiched by cartilaginous end-plates. Together with the adjacent vertebrae, the vertebrae-IVD structure forms a functional spine unit (FSU). These microstructures contain unique cell types as well as unique extracellular matrices. Whole organ culture of the FSU preserves the native extracellular matrix, cell differentiation phenotypes, and cellular-matrix interactions. Thus, organ culture techniques are particularly useful for investigating the complex biological mechanisms of the IVD. Here, we describe a high-throughput approach for culturing whole lumbar mouse FSUs that provides an ideal platform for studying disease mechanisms and therapies for the IVD. Furthermore, we describe several applications that utilize this organ culture method to conduct further studies including contrast-enhanced microCT imaging and three-dimensional high-resolution finite element modeling of the IVD.

An In Vitro Organ Culture Model of the Murine Intervertebral Disc

Whole organ culture of the intervertebral disc (IVD) preserves the native extracellular matrix, cell phenotypes, and cellular-matrix interactions. Here we describe an IVD culture system using mouse lumbar and caudal IVDs in their functional spinal units and several applications utilizing this system.

A<em&gt; In Vitro</em&gt; Modelo Cultura Órgão da Murino Intervertebral Disc

Intervertebral disc (IVD) degeneration is a significant contributor to low back pain. The IVD is a fibrocartilaginous joint that serves to transmit and ...

A Novel Surgical Technique As a Foundation for In Vivo Partial Liver Engineering in Rat

Organ engineering is a novel strategy to generate liver organ substitutes that can potentially be used in transplantation. Recently, in vivo liver engineering, including in vivo organ decellularization followed by repopulation, has emerged as a promising approach over ex vivo liver engineering. However, postoperative survival was not achieved. The aim of this study is to develop a novel surgical technique of in vivo selective liver lobe perfusion in rats as a prerequisite for in vivo liver engineering. We generate a circuit bypass only through the left lateral lobe. Then, the left lateral lobe is perfused with heparinized saline. The experiment is performed with 4 groups (n = 3 rats per group) based on different perfusion times of 20 min, 2 h, 3 h, and 4 h. Survival, as well as the macroscopically visible change of color and the histologically determined absence of blood cells in the portal triad and the sinusoids, is taken as an indicator for a successful model establishment. After selective perfusion of the left lateral lobe, we observe that the left lateral lobe, indeed, turned from red to faint yellow. In a histological assessment, no blood cells are visible in the branch of the portal vein, the central vein, and the sinusoids. The left lateral lobe turns red after reopening the blocked vessels. 12/12 rats survived the procedure for more than one week. We are the first to report a surgical model for in vivo single liver lobe perfusion with a long survival period of more than one week. In contrast to the previously published report, the most important advantage of the technique presented here is that perfusion of 70% of the liver is maintained throughout the whole procedure. The establishment of this technique provides a foundation for in vivo partial liver engineering in rats, including decellularization and recellularization.

A Novel Surgical Technique As a Foundation for In Vivo Partial Liver Engineering in Rat

We establish a novel surgical technique for an in vivo single liver lobe perfusion model in rat as a prerequisite for further studying in vivo partial liver engineering in the future.

Uma nova técnica cirúrgica como fundamento na Vivo parcial engenharia fígado de rato

Organ engineering is a novel strategy to generate liver organ substitutes that can potentially be used in transplantation. Recently, in vivo liver ...

Bioinspired Soft Robot with Incorporated Microelectrodes

Bioinspired soft robotic systems that mimic living organisms using engineered muscle tissue and biomaterials are revolutionizing the current biorobotics paradigm, especially in biomedical research. Recreating artificial life-like actuation dynamics is crucial for a soft-robotic system. However, the precise control and tuning of actuation behavior still represents one of the main challenges of modern soft robotic systems. This method describes a low-cost, highly scalable, and easy-to-use procedure to fabricate an electrically controllable soft robot with life-like movements that is activated and controlled by the contraction of cardiac muscle tissue on a micropatterned sting ray-like hydrogel scaffold. The use of soft photolithography methods makes it possible to successfully integrate multiple components in the soft robotic system, including micropatterned hydrogel-based scaffolds with carbon nanotubes (CNTs) embedded gelatin methacryloyl (CNT-GelMA), poly(ethylene glycol) diacrylate (PEGDA), flexible gold (Au) microelectrodes, and cardiac muscle tissue. In particular, the hydrogels alignment and micropattern are designed to mimic the muscle and cartilage structure of the sting ray. The electrically conductive CNT-GelMA hydrogel acts as a cell scaffold that improves the maturation and contraction behavior of cardiomyocytes, while the mechanically robust PEGDA hydrogel provides structural cartilage-like support to the whole soft robot. To overcome the hard and brittle nature of metal-based microelectrodes, we designed a serpentine pattern that has high flexibility and can avoid hampering the beating dynamics of cardiomyocytes. The incorporated flexible Au microelectrodes provide electrical stimulation across the soft robot, making it easier to control the contraction behavior of cardiac tissue.

A bioinspired scaffold is fabricated by a soft photolithography technique using mechanically robust and electrically conductive hydrogels. The micropatterned hydrogels provide directional cardiomyocyte cell alignment, resulting in a tailored direction of actuation. Flexible microelectrodes are also integrated into the scaffold to bring electrical controllability for a self-actuating cardiac tissue.

Robô macio bioinspirado com microeletrodos incorporados

Bioinspired soft robotic systems that mimic living organisms using engineered muscle tissue and biomaterials are revolutionizing the current biorobotics ...

Simple, Affordable, and Modular Patterning of Cells using DNA

The relative positioning of cells is a key feature of the microenvironment that organizes cell-cell interactions. To study the interactions between cells of the same or different type, micropatterning techniques have proved useful. DNA Programmed Assembly of Cells (DPAC) is a micropatterning technique that targets the adhesion of cells to a substrate or other cells using DNA hybridization. The most basic operations in DPAC begin with decorating cell membranes with lipid-modified oligonucleotides, then flowing them over a substrate that has been patterned with complementary DNA sequences. Cells adhere selectively to the substrate only where they find a complementary DNA sequence. Non-adherent cells are washed away, revealing a pattern of adherent cells. Additional operations include further rounds of cell-substrate or cell-cell adhesion, as well as transferring the patterns formed by DPAC to an embedding hydrogel for long-term culture. Previously, methods for patterning oligonucleotides on surfaces and decorating cells with DNA sequences required specialized equipment and custom DNA synthesis, respectively. We report an updated version of the protocol, utilizing an inexpensive benchtop photolithography setup and commercially available cholesterol modified oligonucleotides (CMOs) deployed using a modular format. CMO-labeled cells adhere with high efficiency to DNA-patterned substrates. This approach can be used to pattern multiple cell types at once with high precision and to create arrays of microtissues embedded within an extracellular matrix. Advantages of this method include its high resolution, ability to embed cells into a three-dimensional microenvironment without disrupting the micropattern, and flexibility in patterning any cell type.

Here we present a protocol to micropattern cells at single-cell resolution using DNA-programmed adhesion. This protocol uses a benchtop photolithography platform to create patterns of DNA oligonucleotides on a glass slide and then labels cell membranes with commercially available complementary oligonucleotides. Hybridization of the oligos results in programmed cell adhesion.

Padronização simples, acessível e modular de células usando DNA

The relative positioning of cells is a key feature of the microenvironment that organizes cell-cell interactions. To study the interactions between cells ...

Voxel Printing Anatomy: Design and Fabrication of Realistic, Presurgical Planning Models through Bitmap Printing

Most applications of 3-dimensional (3D) printing for presurgical planning have been limited to bony structures and simple morphological descriptions of complex organs due to the fundamental limitations in accuracy, quality, and efficiency of the current modeling paradigm. This has largely ignored the soft tissue critical to most surgical specialties where the interior of an object matters and anatomical boundaries transition gradually. Therefore, the needs of the biomedical industry to replicate human tissue, which displays multiple scales of organization and varying material distributions, necessitate new forms of representation. 
Presented here is a novel technique to create 3D models directly from medical images, which are superior in spatial and contrast resolution to current 3D modeling methods and contain previously unachievable spatial fidelity and soft tissue differentiation. Also presented are empirical measurements of novel, additively manufactured composites that span the gamut of material stiffnesses seen in soft biological tissues from MRI and CT. These unique volumetric design and printing methods allow for deterministic and continuous adjustment of material stiffness and color. This capability enables an entirely new application of additive manufacturing to presurgical planning: mechanical realism. As a natural complement to existing models that provide appearance matching, these new models also allow medical professionals to "feel" the spatially varying material properties of a tissue simulant-a critical addition to a field in which tactile sensation plays a key role.

This method demonstrates a voxel-based 3D printing workflow, which prints directly from medical images with exact spatial fidelity and spatial/contrast resolution. This enables the precise, graduated control of material distributions through morphologically complex, graduated materials correlated to radiodensity without loss or alteration of data.

Anatomia de Impressão Voxel: Design e Fabricação de Modelos realistas de planejamento pré-cirúrgico através da impressão bitmap

Most applications of 3-dimensional (3D) printing for presurgical planning have been limited to bony structures and simple morphological descriptions of ...