The authors thank Sungwon Lim for intellectual contributions to device and mold design as well as Jambu Jambulingam and Rebecca Grossman-Kahn for creating intravaginal silicone probes using this process. This work is supported by the Bill and Melinda Gates Foundation, the Vodafone Americas Foundation, and the FDA (2P50FD003793).

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IEEE Technical Applications Conference and Workshops Northcon. , 305&#8211;310, doi:10.1109/NORTHC.1995.485087. , (1995).</li><li>Hilton, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Rapid Tooling: Technologies and Industrial Applications., 288, Press: Boca. , (2000).</li><li>Ahn, S. -. H., Montero, M., Odell, D., Roundy, S., Wright, P. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anisotropic+material+properties+of+fused+deposition+modeling+ABS.">Anisotropic material properties of fused deposition modeling ABS.</a> Rapid Prototyping Journal. 8 (4), 248-257 (2002).</li><li>Cheah, C. M., Tan, L. H., Feng, C., Lee, C. W., Chua, C. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+investment+casting:+direct+and+indirect+approaches+via+fused+deposition+modelling.">Rapid investment casting: direct and indirect approaches via fused deposition modelling.</a> The International Journal of Advanced Manufacturing Technology. 23 (1-2), 1-2 (2004).</li><li>Harris, A., Wild, P., Stopak, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Silicone+Rubber+Substrata:+A+New+Wrinkle+in+the+Study+of+Cell+Locomotion.">Silicone Rubber Substrata: A New Wrinkle in the Study of Cell Locomotion.</a> Science. 208 (4440), (1980).</li><li>Moisan, M., Barbeau, J., Moreau, S., Pelletier, J., Tabrizian, M., Yahia, L. 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(1-2), 226-221 (2001).</li><li>Etemadi, M., Chung, P., Heller, J., Liu, J., Rand, L., Roy, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Towards+BirthAlert+-+A+Clinical+Device+Intended+for+Early+Preterm+Birth+Detection.">Towards BirthAlert - A Clinical Device Intended for Early Preterm Birth Detection.</a> IEEE Trans Biomed Eng. 10, (2013).</li><li>Etemadi, M., Chung, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+device+to+trend+impedance+and+fluorescence+of+the+cervix+for+preterm+birth+detection.">Novel device to trend impedance and fluorescence of the cervix for preterm birth detection.</a> Conf Proc IEEE Eng Med Biol Soc. 2013, 176&#8211;9, doi:10.1109/EMBC.2013.6609466. , (2013).</li><li>Owen, S. R., Harper, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical,+microscopical+and+fire+retardant+studies+of+ABS+polymers.">Mechanical, microscopical and fire retardant studies of ABS polymers.</a> Polymer Degradation and Stability. 64, 449-455 (1999).</li><li>Cassidy, P. E., Mores, M., Kerwick, D. J., Koeck, D. J., Verschoor, K. L., White, D. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemical+Resistance+of+Geosynthetic+Materials.">Chemical Resistance of Geosynthetic Materials.</a> Geotextiles and Geomembranes. 11, 61-98 (1992).</li><li>Akay, M., Ozden, 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+influence+of+residual+stresses+on+the+mechanical+and+thermal+properties+of+injection+moulded+ABS+copolymer.">The influence of residual stresses on the mechanical and thermal properties of injection moulded ABS copolymer.</a> Journal of Materials Science. 30 (13), (1995).</li></ol>

Ninguno de los autores tiene ningún intereses financieros en competencia con respecto a los trabajos previstos en el presente artículo.

De todos los pasos descritos, diseño de moldes cuidado es el más crítico para el éxito. El maestro molde debe ser creado como un cuerpo sólido con geometrías externas iguales al dispositivo final. Estas geometrías deben ajustarse para tener en cuenta cualquier contracción del material debido al elastómero elegido así como la resolución y las tolerancias impresora 3D. La colocación de las líneas de separación del molde y los agujeros pasantes para varillas roscadas y tornillos son dependientes uno del otro....

Moldeo por inyección de líquido (LIM) (también conocido como moldeo por inyección de reacción) se utiliza a menudo para la fabricación de dispositivos elastoméricos de elastómeros termoendurecibles, pero los altos costos de herramientas y equipos requieren una gran cantidad de inversión de capital inicial 1. Además, LIM puede ser técnicamente difícil y costoso de implementar en los casos con la geometría y los requisitos para overmolding compleja. Como resultado de ello, es normalmente poco práctico utilizar LIM tradicional en volúmenes de ultra-bajas o con diseños de dispositivos en fase inicial que a menudo incurren revisiones iterativos. El procedimiento típico para materiales elastómeros de moldeo por inyección consiste en inyectar monómeros líquidos a presiones de alrededor de 150 psi en un molde utilizando maquinaria de moldeo especializada 2. Las temperaturas y presiones se controlan para asegurar el flujo laminar y evitar que el aire quede atrapado en el molde 3. Las materias primas son típicamente sistemas de curado de dos partes, como la silicona platino cura, tsombrero se mantienen en cámaras controladas por separado y temperatura antes de la inyección. Ambos componentes de la materia prima se bombean a una cámara de mezcla de alta presión que alimenta a continuación en la cavidad del molde. El curado se consigue por la presencia de un catalizador, así como temperaturas de alrededor de 150-200 ° C 4. Los moldes están típicamente mecanizados a partir de acero o de aluminio para tolerancias precisas para crear un buen sellado alrededor de los bordes de despedida 3,5. Desafortunadamente, este proceso es generalmente más adecuado para mayores de fabricación escala dada costes de herramientas alta del molde, así como el requisito de que los sistemas de inyección y de control de realimentación especializados. Para una rápida creación de prototipos de poliuretano (PU) partes, es posible utilizar la estereolitografía (SLA) para crear un archivo maestro de molde y producir un molde de caucho de silicona 6,7. Sin embargo, esta técnica no es adecuado para sobremoldeo, ya que es difícil de lograr una alineación precisa de los componentes sobremoldeados, como la silicona es, pordiseño, no es una estructura rígida. Además, la producción de los dispositivos con geometrías complejas, tales como invaginaciones o secciones fuera ahuecados, es difícil o imposible. El requisito para las líneas de separación del molde complejas o precisas y elementos rígidos delgadas son más a menudo que no, incompatible con el proceso de moldeo de caucho líquido. Los procesos de creación de prototipos antes mencionado a escala de producción o en etapa tardía suelen ser poco práctico para las primeras etapas del desarrollo de dispositivos médicos en los que unos pocos dispositivos necesitan ser producido como prueba de concepto y la viabilidad de los estudios en humanos, como suele ser el caso en el laboratorio académico y puesta en marcha entornos de empresa. La falta de alternativas a menudo significa que incluso el desarrollo de las primeras etapas de un coste alto, que requiere muchos desarrolladores de dispositivos para limitar la funcionalidad del dispositivo o de poner el desarrollo en espera mientras que los fondos adicionales se elevan. Esto contribuye a una disminución dramática del proceso de desarrollo ya que una gran parte de los dispositivos médicos re<html> aplicación requieren de características complejas. También es difícil de financiar el costoso desarrollo de este tipo de dispositivos ya que los datos de prueba de concepto es a menudo aún no establecido. Nos encontramos con este obstáculo en un proyecto reciente en este laboratorio, que implicó el desarrollo de una sonda intravaginal de silicona con sensores eléctricos y ópticos sobremoldeadas que requerían una punta en forma de copa para adaptarse a geometrías cervicales especificados. El proceso descrito en este artículo documenta nuestro intento de evitar este círculo vicioso y rápidamente llegar a una prueba de concepto para dispositivos médicos LIM. La técnica que se muestra en la Figura 1 deconstruye el proceso LIM en 5 actividades principales: (1) diseño de moldes y la producción, (2) de montaje del molde (3) de mezcla de elastómero, (4) de inyección de elastómero, y (5) de elastómero curado y desmoldantes. pg &quot;width =&quot; 600 &quot;/&gt; .. Figura 1 Protocolo Descripción general del protocolo, que consiste en: (1 bis) la creación de un molde utilizando herramientas de diseño asistido por ordenador, (1b) 3D la impresión de las piezas del molde, (2) el montaje de las piezas del molde utilizando varillas roscadas y tornillos, ( 3) la mezcla de elastómero líquido y lo carga en una jeringa, (4) inyectar el elastómero líquido en el molde usando un desecador modificado, (5a) curar el elastómero en un horno de temperatura controlada, y (5b) del dispositivo de desmoldeo elastómero curado desde las piezas de molde. Diseño de moldes implica el desarrollo de un maestro de molde en el diseño asistido por ordenador (CAD), la resta del maestro molde a partir de un bloque sólido y la definición de líneas de separación del molde. Piezas del molde se crean y luego se ensamblan con tornillos, varillas y nueces con componentes sobremoldeadas ubicadas en el interior del molde. Mixin Elastómerog implica la combinación de las partes A y B de la materia prima y la desgasificación para eliminar los posibles espacios vacíos en el material. A continuación, la inyección de elastómero implica el llenado a presión impulsado de la cavidad del molde, seguido de curado elastómero en un horno de temperatura controlada para asegurar la reticulación química de las cadenas poliméricas. Romper el proceso de moldeo por inyección en estos pasos nos permite renunciar equipo LIM tradicional a favor de alternativas de bajo costo. Por ejemplo, en lugar de mecanizado de un molde de fundición de metal o de un molde de goma de silicona de un maestro molde, los moldes creados a partir de el protocolo descrito en este manuscrito se crean a partir de acrilonitrilo butadieno estireno (ABS) de plástico usando un modelado fusionado-deposición (FDM) 3D 8,9 impresora. En comparación con la construcción de moldes de metal o moldes de SLA, FDM es generalmente un proceso más barato y más rápido. Moldes bastante complejas se pueden imprimir de forma rápida en una impresora 3D de la casa, o de bajo costo producido por uno de los muchos contratos Printin 3Dservicios g disponibles. Por ejemplo, se utilizó una de ocho pieza de molde 3D ​​impreso complejo para echar la sonda intravaginal demostrado en la sección de resultados representativo y se muestra en las Figuras 14 y 15. Todas las partes de este molde se pueden imprimir en aproximadamente 1,5 días en una impresora 3D en casa. Los tiempos de entrega para moldes simples pueden ser un par de horas. La longitud total de tiempo necesario para crear prototipos de un dispositivo que utiliza impresoras FDM 3D para crear moldes es similar al tiempo requerido para emitir un molde de caucho de silicona y crear un prototipo de poliuretano. Sin embargo, el uso de impresoras FDM 3D para crear moldes permite varias cosas que no pueden fácilmente llevar a cabo usando un molde de silicona: (1) muchos elastómeros termoestables se pueden usar siempre y cuando el molde 3D-impreso puede tolerar las temperaturas de curado requeridos, (2) geometrías complejas se puede crear con el uso de diferentes piezas de molde y líneas de separación, y (3) el uso de piezas de molde rígidas permite precisa y reproducialineación ble de componentes sobremoldeados dentro de la cavidad del molde. En lugar de utilizar una máquina tradicional LIM, que combina la mezcla, la inyección, y el curado, es posible utilizar un mezclador de laboratorio para asegurar una mezcla homogénea, un desecador modificado para inyección, y un horno estándar de temperatura controlada para el curado. El sistema de inyección se ha creado usando componentes fuera de la plataforma e implica la adición de una línea de suministro de presión positiva en el desecador que se conecta a una jeringa llena con elastómero mixto. Presurización de la cámara en las principales desecadores de banco suele ser controlada por una válvula de tres vías entre las cámaras, una línea de suministro de vacío y la atmósfera. El desecador modificado añade una línea de suministro de presión positiva de alimentación a la parte posterior de un émbolo de la jeringa. Esto permite la creación de un diferencial de presión de 40-50 psi que es suficiente para la inyección de material líquido en la cavidad del molde. Esta técnica nos permitió Produce silicona sondas intravaginales con sensores eléctricos y ópticos sobremoldeadas para recolectar prueba-de-concepto de datos para un estudio de fase I de ensayos clínicos. De silicona se seleccionó debido a la necesidad de inercia biológica, así como la capacidad para esterilizar con una variedad de métodos 10,11. Además, el dispositivo requiere una geometría en forma de copa complejo y poco convencional en la punta de la sonda donde se encuentran los sensores para interactuar con el cuello del útero. Sin el uso de la técnica descrita, que habría sido un proceso mucho más largo y costoso para producir estos dispositivos. Esta adaptación del proceso LIM reduce costos y los requisitos de equipo en comparación con el proceso tradicional LIM, por lo que es práctico para adoptar un enfoque rápido e iterativo para el diseño de dispositivos elastoméricos.

<table border="0" cellpadding="0" cellspacing="0" width="1434">
	<tbody>
		<tr>
			<td>ABS Model Material</td>
			<td>Stratasys</td>
			<td>P430</td>
			<td>Model Material for uPrint Plus SE (Step: Mold Design &#38; Production)</td>
		</tr>
		<tr>
			<td>Soluble Support Material</td>
			<td>Stratasys</td>
			<td>SR-30</td>
			<td>Support Material for uPrint Plus SE (Step: Mold Design &#38; Production)</td>
		</tr>
		<tr>
			<td>Underwater Silicone Sealant, 2.8 Oz Tube, Clear</td>
			<td>McMaster-Carr Supply Company</td>
			<td>7327A21</td>
			<td>Silicone RTV for sealing gaps at mold parting lines (Step: Mold Assembly)</td>
		</tr>
		<tr>
			<td>Tubing, 1/8&#34; ID, 1/4&#34; OD, 1/16&#34; Wall Thickness, Ultra-chemical-resistant Tygon PVC, Clear</td>
			<td>McMaster-Carr Supply Company</td>
			<td>5046K11</td>
			<td>Forms runner/sprue adapter between mold and syringe with elastomer (Step: Elastomer Mixing)</td>
		</tr>
		<tr>
			<td>Coupling, Adapter, Straight, Male Quick-turn (Luer lock) X 1/8&#34; Tube Barb, Nylon</td>
			<td>McMaster-Carr Supply Company</td>
			<td>51525K123</td>
			<td>Connect runner/sprue between mold and syringe with elastomer (Step: Elastomer Mixing)</td>
		</tr>
		<tr>
			<td>Coupling, Adapter, Staight, Female Quick-turn (Luer lock) X 1/8&#34; Tube Barb, Nylon</td>
			<td>McMaster-Carr Supply Company</td>
			<td>51525K213</td>
			<td>Connect runner/sprue between mold and syringe with elastomer (Step: Elastomer Mixing)</td>
		</tr>
		<tr>
			<td>Cap, Female Quick-turn (Luer lock), Nylon</td>
			<td>McMaster-Carr Supply Company</td>
			<td>51525K315</td>
			<td>Cap to prevent silicone from leaking out of mold after injection (Step: Elastomer Mixing)</td>
		</tr>
		<tr>
			<td>Liquid Silicone Rubber (LSR) 30 - 10:1, Implant Grade</td>
			<td>Applied Silicone Corporation</td>
			<td>PN40029</td>
			<td>Substitute with the elastomer of your choice.&#160; This is the one used for the intravaginal probe (Step: Elastomer Mixing)</td>
		</tr>
		<tr>
			<td>Syringes (BD), 1mL Slip-Tip, non-sterile clean, bulk</td>
			<td>Cole-Parmer</td>
			<td>WU-07945-00</td>
			<td>Syringes for transfering elastomer material (Step: Elastomer Mixing)</td>
		</tr>
		<tr>
			<td>Syringes (BD), 1mL Slip-Tip, non-sterile clean, bulk</td>
			<td>Cole-Parmer</td>
			<td>WU-07945-04</td>
			<td>Syringes for transfering elastomer material (Step: Elastomer Mixing)</td>
		</tr>
		<tr>
			<td>Syringe, 20mL, Open Bore, Solid Ring Plunger and Grip</td>
			<td>Qosina Corporation</td>
			<td>C1200</td>
			<td>Syringes for transfering elastomer material.&#160; Open bore is used for very viscous elastomers. (Step: Elastomer Mixing)</td>
		</tr>
		<tr>
			<td>Needle (BD), Non-sterile Clean with Shields, 18 gauge X 1.5&#34; Lg., Stainless Steel, BD Bulk&#160;</td>
			<td>Cole-Parmer</td>
			<td>WU-07945-76</td>
			<td>Used for removing air column between syringe plunger and elastomer (Step: Elastomer Mixing)</td>
		</tr>
		<tr>
			<td>Plastic Cups, 12 Oz., Clear</td>
			<td>Safeway</td>
			<td>N/A</td>
			<td>Used for mixing silicone in THINKY Mixer (Step: Elastomer Mixing)</td>
		</tr>
		<tr>
			<td>Polyethylene Bag, Open-Top, Flat, 5&#34; Width X 6&#34; Height, 2-MIL Thk.</td>
			<td>McMaster-Carr Supply Company</td>
			<td>1928T68</td>
			<td>Used for mixing silicone in THINKY Mixer (Step: Elastomer Mixing)</td>
		</tr>
		<tr>
			<td>Rubber Band, Latex Free, Orange, Size 64, 3-1/2&#34; L X 1/4&#34; W</td>
			<td>McMaster-Carr Supply Company</td>
			<td>12205T96</td>
			<td>Used for mixing silicone in THINKY Mixer (Step: Elastomer Mixing)</td>
		</tr>
		<tr>
			<td>Parafilm Wrap, 4&#34;W</td>
			<td>Cole-Parmer</td>
			<td>EW-06720-40</td>
			<td>Used for mixing silicone in THINKY Mixer (Step: Elastomer Mixing)</td>
		</tr>
		<tr>
			<td>Syringe Barrels with Stoppers, Luer Lock, Air Operated,&#160; 50mL</td>
			<td>EWD Solutions</td>
			<td>JEN-JG50A-15</td>
			<td>Smaller syringes can be used if less elastomer is required, but make sure it is compatible with Air Operated Syringe Adapter in injection chamber (Step: Elastomer Mixing)</td>
		</tr>
		<tr>
			<td>Sealant Tape, Pipe Thread, 50&#39;Lg X 1/4&#34; W, .0028&#34; Thk, 0.5 G/CC Specific Gravity&#160;</td>
			<td>McMaster-Carr Supply Company</td>
			<td>4591K11</td>
			<td>Teflon Tape for air-tight seals around at threads (Step: Elastomer Injection)</td>
		</tr>
		<tr>
			<td>Scalpel Blades, Disposable, No. 22</td>
			<td>VWR</td>
			<td>21909-646</td>
			<td>Used for cutting tubing and demolding (Step: Curing &#38; Demolding)</td>
		</tr>
		<tr>
			<td>Kimwipes</td>
			<td>VWR</td>
			<td>21903-005</td>
			<td>&#160;(Step: Curing &#38; Demolding)</td>
		</tr>
		<tr>
			<td>2-Propanol, J. T. Baker</td>
			<td>VWR</td>
			<td>JT9334-3</td>
			<td>&#160;(Step: Curing &#38; Demolding)</td>
		</tr>
		<tr>
			<td>uPrint Plus SE 3D Printer</td>
			<td>Stratasys</td>
			<td>uPrint Plus SE</td>
			<td>Other 3D printers can be used (Step: Mold Design &#38; Production)</td>
		</tr>
		<tr>
			<td>Screw, Cap, Hex Head,&#160; 1/4&#34;-28 , 2-1/2&#34; Lg, 18-8 Stainless Steel</td>
			<td>McMaster-Carr Supply Company</td>
			<td>92198A115</td>
			<td>Screws used with nuts to compress mold (Step: Mold Assembly)</td>
		</tr>
		<tr>
			<td>Nut, Hex, 1/4&#34;-28, 7/16&#34; Wd, 7/32&#34; Height, 18-8 Stainless Steel&#160;</td>
			<td>McMaster-Carr Supply Company</td>
			<td>91845A105</td>
			<td>Screws used with nuts to compress mold (Step: Mold Assembly)</td>
		</tr>
		<tr>
			<td>Stud, Fully Threaded, 1/4&#34;-28, 1&#34; Lg, 18-8 Stainless Steel&#160;</td>
			<td>McMaster-Carr Supply Company</td>
			<td>95412A567</td>
			<td>Threaded-rods can be cut to desired length and are used with nutes to compress mold (Step: Mold Assembly)</td>
		</tr>
		<tr>
			<td>Planetary Centrifugal Mixer</td>
			<td>THINKY USA Inc.</td>
			<td>ARE-310</td>
			<td>Mixers are strongly recommended for fine mixing and to reduce degassing time, but hand mixing is fine (Step: Elastomer Mixing)</td>
		</tr>
		<tr>
			<td>Laboratory Weigh Scale</td>
			<td>Mettler-Toledo International Inc.</td>
			<td>EL602</td>
			<td>&#160;(Step: Elastomer Mixing)</td>
		</tr>
		<tr>
			<td>Desiccant Vacuum Canister, Reusable,&#160; 10-3/4&#34; OD</td>
			<td>McMaster-Carr Supply Company</td>
			<td>2204K7</td>
			<td>This desiccator is used for degassing the elastomer (Step: Elastomer Mixing)</td>
		</tr>
		<tr>
			<td>Custom 3D-Printed Mixer-to-Cup Adapter</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Modeled in Solidworks CAD and 3D printed (Step: Elastomer Mixing)</td>
		</tr>
		<tr>
			<td>Tubing, Smooth Bore, 1/4&#34; ID, 1/2&#34; OD, 1/8&#34; Wall Thickness, High Purity Tygon PVC, Clear</td>
			<td>McMaster-Carr Supply Company</td>
			<td>5624K51</td>
			<td>Tubing outside of Desiccator (Step: Elastomer Injection)</td>
		</tr>
		<tr>
			<td>Tubing, Smooth Bore, 3/8&#34; ID, 5/8&#34; OD, 1/8&#34; Wall Thickness, High Purity Tygon PVC, Clear</td>
			<td>McMaster-Carr Supply Company</td>
			<td>5624K52</td>
			<td>Tubing to adapt to Air/Vacuum Supply (Step: Elastomer Injection)</td>
		</tr>
		<tr>
			<td>Coupling, Reducer, Straight, Vacuum Barb 3/8&#34; Tube ID X Vacuum Barb 1/4&#34; Tube ID, Brass</td>
			<td>McMaster-Carr Supply Company</td>
			<td>44555K188</td>
			<td>Adapt Tubing outside Desiccator to Tubing leading to Air/Vacuum Supply (Step: Elastomer Injection)</td>
		</tr>
		<tr>
			<td>Clamp, Hose &#38; Tube, Worm-Drive, for 7/32&#34; to 5/8&#34; OD tube, 5/16&#34; Wd., 316 SS</td>
			<td>McMaster-Carr Supply Company</td>
			<td>5011T141</td>
			<td>Used on tubing to create Air/Vacuum-tight seal at junctions (Step: Elastomer Injection)</td>
		</tr>
		<tr>
			<td>Clamp, Hose, Smooth-Band Worm-Drive, for 1/2&#34; to 3/4&#34; OD tube, 3/8&#34; Wd., 304 SS</td>
			<td>McMaster-Carr Supply Company</td>
			<td>5574K13</td>
			<td>Used on tubing to create Air/Vacuum-tight seal at junctions (Step: Elastomer Injection)</td>
		</tr>
		<tr>
			<td>Coupling, Tee, Vacuum Barb 1/4&#34; Tube ID, Brass</td>
			<td>McMaster-Carr Supply Company</td>
			<td>44555K138</td>
			<td>Tee Junction between Vacuum, Three-way T-valve on Desiccator, and Three-way L-valve (Step: Elastomer Injection)</td>
		</tr>
		<tr>
			<td>Coupling, Tee, 1/4 NPT Female X Female X Male, Brass</td>
			<td>McMaster-Carr Supply Company</td>
			<td>50785K222</td>
			<td>Tee Junction between Pressure Gauge, Chamber, and Three-way L-valve (Step: Elastomer Injection)</td>
		</tr>
		<tr>
			<td>Valve, Ball, Straight, T-Handle, 1/4 NPT Female X Male, Brass</td>
			<td>McMaster-Carr Supply Company</td>
			<td>4082T42</td>
			<td>Three-way L-valve (Step: Elastomer Injection)</td>
		</tr>
		<tr>
			<td>Coupling, Adapter, Straight, Vacuum Barb 1/4&#34; ID Tube X 1/4 NPT Male, Brass</td>
			<td>McMaster-Carr Supply Company</td>
			<td>44555K132</td>
			<td>Adapter for Three-way L-valve-to-Tubing (Step: Elastomer Injection)</td>
		</tr>
		<tr>
			<td>Saw, Hole, Bimetal. 1-3/8&#34; OD, 1-1/2&#34; Cutting Depth</td>
			<td>McMaster-Carr Supply Company</td>
			<td>4066A25</td>
			<td>Used to cut holes in Desiccator for throughwall fittings (Step: Elastomer Injection)</td>
		</tr>
		<tr>
			<td>Arbor, 9/16&#34; to 1-3/16&#34; Saw, 1/4&#34; Hex</td>
			<td>McMaster-Carr Supply Company</td>
			<td>4066A76</td>
			<td>Used to cut holes in Desiccator for throughwall fittings (Step: Elastomer Injection)</td>
		</tr>
		<tr>
			<td>Arbor Adapter for 1-1/4&#34; Thru 6&#34; Dia Hole Saws</td>
			<td>McMaster-Carr Supply Company</td>
			<td>4066A77</td>
			<td>Used to cut holes in Desiccator for throughwall fittings (Step: Elastomer Injection)</td>
		</tr>
		<tr>
			<td>Coupling, Straight, Through-Wall, 1/2 NPT Female, Polypropylene</td>
			<td>McMaster-Carr Supply Company</td>
			<td>36895K141</td>
			<td>Throughwall fittings leading to Pressure/Vacuum Gauges (Step: Elastomer Injection)</td>
		</tr>
		<tr>
			<td>Coupling, Adapter, Straight, Reducing,&#160; Bushing, Hex, 1/2 NPT Male X 1/4 NPT Female, Brass</td>
			<td>McMaster-Carr Supply Company</td>
			<td>4429K422</td>
			<td>Reducing tube diameter inside the Desiccator to adapt to Air-operated Syringe System (Step: Elastomer Injection)</td>
		</tr>
		<tr>
			<td>Coupling, Adapter, Straight, Reducing, Bushing, Hex, 1/4 NPT Male X 1/8 NPT Female, Brass</td>
			<td>McMaster-Carr Supply Company</td>
			<td>4757T91</td>
			<td>Reducing tube diameter inside the Desiccator to adapt to Air-operated Syringe System (Step: Elastomer Injection)</td>
		</tr>
		<tr>
			<td>Coupling, Adapter, Straight, Vacuum Barb 1/4&#34; ID Tube X 1/8 NPT Female, Brass</td>
			<td>McMaster-Carr Supply Company</td>
			<td>44555K124</td>
			<td>Reducing tube diameter inside the Desiccator to adapt to Air-operated Syringe System (Step: Elastomer Injection)</td>
		</tr>
		<tr>
			<td>Syringe Adapters, Air Operated, 30/50mL</td>
			<td>EWD Solutions</td>
			<td>JEN-JG30A-X6</td>
			<td>Air operated syringe adapter on the inside of the Desiccator; must be compatible with syringes used to hold elastomer (Step: Elastomer Injection)</td>
		</tr>
		<tr>
			<td>Gauge, Dual-Scale Vacuum, 2-1/2&#34; Dial, 1/4 NPT Male, Bottom Connector, 30&#34; Hg-0, Steel Case</td>
			<td>McMaster-Carr Supply Company</td>
			<td>4002K11</td>
			<td>Vacuum Gauge (Step: Elastomer Injection)</td>
		</tr>
		<tr>
			<td>Gauge, Dual-Scale Vacuum and Compound, 3-1/2&#34; Dial, 1/4 NPT Male, Center Back, 30&#34; Hg-0, 100 PSI, Steel Case</td>
			<td>McMaster-Carr Supply Company</td>
			<td>4004K616</td>
			<td>Pressure Gauge leading to Air-operated Syringe System (Step: Elastomer Injection)</td>
		</tr>
		<tr>
			<td>Oven, Vacuum, Isotemp, Economy&#160;</td>
			<td>Fisher Scientific</td>
			<td>280A</td>
			<td>Standard non-vacuum oven can be used (Step: Curing &#38; Demolding)</td>
		</tr>
		<tr>
			<td>Solidworks CAD</td>
			<td>Dassault Syst&#232;mes</td>
			<td>Solidworks Research Subscription</td>
			<td>Other CAD Software can be used for mold master and mold design (Step: Mold Design &#38; Production)</td>
		</tr>
	</tbody>
</table>

rapid and low-cost prototyping of medical devices using 3d printed molds for liquid injection molding

Elastómeros biológicamente inertes tales como la silicona son materiales favorables para la fabricación del dispositivo médico, pero la formación y el curado de estos elastómeros usando procesos de moldeo por inyección de líquido tradicionales pueden ser un proceso costoso debido a los costes de herramientas y equipos. Como resultado, ha sido tradicionalmente poco práctico utilizar moldeo por inyección de líquido para bajo coste, aplicaciones de prototipado rápido. Hemos ideado un método para la producción rápida y de bajo costo de los dispositivos de inyección de líquidos elastómero moldeado que utiliza impresoras modelado por deposición fundida 3D para el diseño de moldes y un secador modificado como un sistema de inyección. Bajos costos y tiempo de respuesta rápido en esta técnica disminuyen la barrera para el diseño de forma iterativa y prototipado dispositivos elastoméricos complejos. Además, los modelos CAD desarrollados en este proceso puede ser más tarde adaptar para el diseño de herramientas de molde de metal, lo que permite una fácil transición a un proceso de moldeo por inyección tradicional. Hemos utilizado esta técnica para la fabricación de intravagsondas de nal que implican geometrías complejas, así como sobremoldeo sobre las piezas de metal, con herramientas corrientes en un laboratorio de investigación académica. Sin embargo, esta técnica se puede adaptar fácilmente para crear dispositivos moldeados de inyección de líquidos para muchas otras aplicaciones.

El molde y la sonda intravaginal en las figuras 14 y 15 demuestran los resultados representativos del procedimiento presentado en este artículo. <img alt="Figura 14" fo:content-width="5in" src="/files/ftp_upload/51745/51745fig14highres.jpg" width="500" /> Figura 14. Molde montado completamente. Totalmente montado molde para dispositivo de sonda intravaginal. <p class="jove_content" fo:keep-toge...

Watch this Scientific Journal Video about Rapid and Low-cost Prototyping of Medical Devices Using 3D Printed Molds for Liquid Injection Molding at JoVE.com

Rapid and Low-cost Prototyping of Medical Devices Using 3D Printed Molds for Liquid Injection Molding

Hemos ideado un método de bajo coste y rápida de prototipos de dispositivos moldeados por inyección de caucho elastómero líquido mediante el uso de las impresoras 3D de modelado por deposición fundida de diseño de moldes y un secador modificado como un sistema de inyección de líquido.

Prototipado rápido y de bajo costo de los dispositivos médicos Utilizando 3D Impreso Moldes para moldeo por inyección de líquido

Biologically inert elastomers such as silicone are favorable materials for medical device fabrication, but forming and curing these elastomers using ...

rapid-low-cost-prototyping-medical-devices-using-3d-printed-molds-for

Research

JoVE Journal

Bioengineering

19.7K vistas.  University of California, San Francisco.  Hemos ideado un método de bajo coste y rápida de prototipos de dispositivos moldeados por inyección de caucho elastómero líquido mediante el uso de las impresoras 3D de modelado por deposición fundida de diseño de moldes y un secador modificado como un sistema de inyección de líquido. 

Video: Rapid and Low-cost Prototyping of Medical Devices Using 3D Printed Molds for Liquid Injection Molding

High Throughput Microfluidic Rapid and Low Cost Prototyping Packaging Methods

In this work, 3 different packaging and assembly techniques are presented. They can be classified into two categories: one-time use and reusable packaging techniques.
The one-time use packaging technique employs UV-based and temperature curing epoxies to connect microtubes to access holes, wire-bonding for integrated circuit connections, and silver epoxy for electrical connections. This method is based on a robust assembly technique that can support relatively high pressure close to 1 psi and does not need any support to strengthen the microfluidic architecture.
Reusable packaging techniques consist of PDMS-based microtube interconnectors and anisotropic adhesive films for electrical connections. These devices are more sensitive and fragile. Consequently, Plexiglas support is added to the microfluidic structure to improve the electrical contact when anisotropic adhesive films are used, and also to strengthen the microfluidic architecture. In addition, a micromanipulator is needed to maintain tubes while using a thin PDMS layer to connect them to the access holes. Different PDMS layer thicknesses, ranging from 0.45-3 mm, are tested to compare the best adherence versus injection rates. Applied injection rates are varied from 50-300 &#956;l/hr for 0.45-3 mm PDMS layers, respectively. These techniques are mainly applicable for low-pressure applications. However, they can be extended for high-pressure ones through plasma-oxygen process to permanently seal the PDMS to glass substrates. The main advantage of this technique, besides the fact that it is reusable, consists of keeping the device observable when the microchannel length is very short (in the range of 3 mm or lower).

In this article we describe different techniques for microfluidic rapid prototyping platforms. The proposed techniques are based on ultraviolet (UV) sensitive and temperature curing epoxies, polydimethylsiloxane (PDMS) based tubing, wire-bonding, and anisotropic adhesive films. The assembling procedures presented are developed for both one-time use devices as well as reusable microfluidic systems.

In this work, 3 different packaging and assembly techniques are presented. They can be classified into two categories: one-time use and reusable packaging ...

Investigación

Bioingeniería

Using Adhesive Patterning to Construct 3D Paper Microfluidic Devices

We demonstrate the use of patterned aerosol adhesives to construct both planar and nonplanar 3D paper microfluidic devices. By spraying an aerosol adhesive through a metal stencil, the overall amount of adhesive used in assembling paper microfluidic devices can be significantly reduced. We show on a simple 4-layer planar paper microfluidic device that the optimal adhesive application technique and device construction style depends heavily on desired performance characteristics. By moderately increasing the overall area of a device, it is possible to dramatically decrease the wicking time and increase device success rates while also reducing the amount of adhesive required to keep the device together. Such adhesive application also causes the adhesive to form semi-permanent bonds instead of permanent bonds between paper layers, enabling single-use devices to be non-destructively disassembled after use. Nonplanar 3D origami devices also benefit from the semi-permanent bonds during folding, as it reduces the likelihood that unrelated faces may accidently stick together. Like planar devices, nonplanar structures see reduced wicking times with patterned adhesive application vs uniformly applied adhesive.

We demonstrate the use of patterned aerosol adhesives to construct 3D paper microfluidic devices. This method of adhesive application forms semi-permanent bonds between layers, enabling single-use devices to be non-destructively disassembled after use and to ease folding complex nonplanar structures.

El uso de adhesivo Patrones para construir dispositivos de microfluidos de papel 3D

We demonstrate the use of patterned aerosol adhesives to construct both planar and nonplanar 3D paper microfluidic devices. By spraying an aerosol ...

High-throughput Identification of Bacteria Repellent Polymers for Medical Devices

Medical devices are often associated with hospital-acquired infections, which place enormous strain on patients and the healthcare system as well as contributing to antimicrobial resistance. One possible avenue for the reduction of device-associated infections is the identification of bacteria-repellent polymer coatings for these devices, which would prevent bacterial binding at the initial attachment step. A method for the identification of such repellent polymers, based on the parallel screening of hundreds of polymers using a microarray, is described here. This high-throughput method resulted in the identification of a range of promising polymers that resisted binding of various clinically relevant bacterial species individually and also as multi-species communities. One polymer, PA13 (poly(methylmethacrylate-co-dimethylacrylamide)), demonstrated significant reduction in attachment of a number of hospital isolates when coated onto two commercially available central venous catheters. The method described could be applied to identify polymers for a wide range of applications in which modification of bacterial attachment is important.

A high-throughput microarray method for the identification of polymers which reduce bacterial surface binding on medical devices is described.

De alto rendimiento de identificación de bacterias polímeros repelentes para dispositivos médicos

Medical devices are often associated with hospital-acquired infections, which place enormous strain on patients and the healthcare system as well as ...

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.

Automatizado de montaje robotizada manipulación líquido de dispositivos modulares de la DNA

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

Scaling of Engineered Vascular Grafts Using 3D Printed Guides and the Ring Stacking Method

Coronary artery disease remains a leading cause of death, affecting millions of Americans. With the lack of autologous vascular grafts available, engineered grafts offer great potential for patient treatment. However, engineered vascular grafts are generally not easily scalable, requiring manufacture of custom molds or polymer tubes in order to customize to different sizes, constituting a time-consuming and costly practice. Human arteries range in lumen diameter from about 2.0-38 mm and in wall thickness from about 0.5-2.5 mm. We have created a method, termed the "Ring Stacking Method," in which variable size rings of tissue of the desired cell type, demonstrated here with vascular smooth muscle cells (SMCs), can be created using guides of center posts to control lumen diameter and outer shells to dictate vessel wall thickness. These tissue rings are then stacked to create a tubular construct, mimicking the natural form of a blood vessel. The vessel length can be tailored by simply stacking the number of rings required to constitute the length needed. With our technique, tissues of tubular forms, similar to a blood vessel, can be readily manufactured in a variety of dimensions and lengths to meet the needs of the clinic and patient.

Scalable engineered blood vessels would improve clinical applicability. Using easily sizable 3D-printed guides, rings of vascular smooth muscle were created and stacked into a tubular form, forming a vascular graft. Grafts can be sized to meet the range of human coronary artery dimensions by simply changing the 3D-printed guide size.

El escalado de Engineered injertos vasculares Usando 3D Impreso guías y el método de anillo de apilamiento

Coronary artery disease remains a leading cause of death, affecting millions of Americans. With the lack of autologous vascular grafts available, ...

Synthesis of Biocompatible Liquid Crystal Elastomer Foams as Cell Scaffolds for 3D Spatial Cell Cultures

Here, we present a step-by-step preparation of a 3D, biodegradable, foam-like cell scaffold. These scaffolds were prepared by cross-linking star block co-polymers featuring cholesterol units as side-chain pendant groups, resulting in smectic-A (SmA) liquid crystal elastomers (LCEs). Foam-like scaffolds, prepared using metal templates, feature interconnected microchannels, making them suitable as 3D cell culture scaffolds. The combined properties of the regular structure of the metal foam and of the elastomer result in a 3D cell scaffold that promotes not only higher cell proliferation compared to conventional porous templated films, but also better management of mass transport (i.e., nutrients, gases, waste, etc.). The nature of the metal template allows for the easy manipulation of foam shapes (i.e., rolls or films) and for the preparation of scaffolds of different pore sizes for different cell studies while preserving the interconnected porous nature of the template. The etching process does not affect the chemistry of the elastomers, preserving their biocompatible and biodegradable nature. We show that these smectic LCEs, when grown for extensive time periods, enable the study of clinically relevant and complex tissue constructs while promoting the growth and proliferation of cells.

This study presents a methodology to prepare 3D, biodegradable, foam-like cell scaffolds based on biocompatible side-chain liquid crystal elastomers (LCEs). Confocal microscopy experiments show that foam-like LCEs allow for cell attachment, proliferation, and the spontaneous alignment of C2C12s myoblasts.

Síntesis de biocompatibles de cristal líquido de elastómero Espumas como andamios celulares para 3D espaciales Cultivos Celulares

Here, we present a step-by-step preparation of a 3D, biodegradable, foam-like cell scaffold. These scaffolds were prepared by cross-linking star block ...

Fabrication of Custom Agarose Wells for Cell Seeding and Tissue Ring Self-assembly Using 3D-Printed Molds

Engineered tissues are being used clinically for tissue repair and replacement, and are being developed as tools for drug screening and human disease modeling. Self-assembled tissues offer advantages over scaffold-based tissue engineering, such as enhanced matrix deposition, strength, and function. However, there are few available methods for fabricating 3D tissues without seeding cells on or within a supporting scaffold. Previously, we developed a system for fabricating self-assembled tissue rings by seeding cells into non-adhesive agarose wells. A polydimethylsiloxane (PDMS) negative was first cast in a machined polycarbonate mold, and then agarose was gelled in the PDMS negative to create ring-shaped cell seeding wells. However, the versatility of this approach was limited by the resolution of the tools available for machining the polycarbonate mold. Here, we demonstrate that 3D-printed plastic can be used as an alternative to machined polycarbonate for fabricating PDMS negatives. The 3D-printed mold and revised mold design is simpler to use, inexpensive to produce, and requires significantly less agarose and PDMS per cell seeding well. We have demonstrated that the resulting agarose wells can be used to create self-assembled tissue rings with customized diameters from a variety of different cell types. Rings can then be used for mechanical, functional, and histological analysis, or for fabricating larger and more complex tubular tissues.

This protocol describes a platform for fabricating self-assembled tissue rings in variable sizes using a customized 3D-printed plastic mold. PDMS negatives are cured in the 3D-printed mold; then agarose is cast in the cured PDMS negatives. Cells are seeded into the resulting agarose wells where they aggregate into tissue rings.

Fabricación de pozos de agarosa personalizado para la siembra de células y tejido anillo autoensamblaje con moldes impresa en 3D

Engineered tissues are being used clinically for tissue repair and replacement, and are being developed as tools for drug screening and human disease ...

Design of an Open-Source, Low-Cost Bioink and Food Melt Extrusion 3D Printer

Three-dimensional (3D) printing is an increasingly popular manufacturing technique that allows highly complex objects to be fabricated with no retooling costs. This increasing popularity is partly driven by falling barriers to entry such as system set-up costs and ease of operation. The following protocol presents the design and construction of an Additive Manufacturing Melt Extrusion (ADDME) 3D printer for the fabrication of custom parts and components. ADDME has been designed with a combination of 3D-printed, laser-cut, and online-sourced components. The protocol is arranged into easy-to-follow sections, with detailed diagrams and parts lists under the headings of framing, y-axis and bed, x-axis, extrusion, electronics, and software. The performance of ADDME is evaluated through extrusion testing and 3D printing of complex objects using viscous cream, chocolate, and Pluronic F-127 (a model for bioinks). The results indicate that ADDME is a capable platform for the fabrication of materials and constructs for use in a wide range of industries. The combination of detailed diagrams and video content facilitates access to low-cost, easy-to-operate equipment for individuals interested in 3D printing of complex objects from a wide range of materials.

The aim of this work is to design and construct a reservoir-based melt extrusion three-dimensional printer made from open-source and low-cost components for applications in the biomedical and food printing industries.

Diseño de una impresora 3D de extrusión de biotinta y fusión de alimentos de código abierto y bajo costo

Three-dimensional (3D) printing is an increasingly popular manufacturing technique that allows highly complex objects to be fabricated with no retooling ...

Rapid Fabrication of Custom Microfluidic Devices for Research and Educational Applications

Microfluidic devices allow for the manipulation of fluids, particles, cells, micro-sized organs or organisms in channels ranging from the nano to submillimeter scales. A rapid increase in the use of this technology in the biological sciences has prompted a need for methods that are accessible to a wide range of research groups. Current fabrication standards, such as PDMS bonding, require expensive and time consuming lithographic and bonding techniques. A viable alternative is the use of equipment and materials that are easily affordable, require minimal expertise and allow for the rapid iteration of designs. In this work we describe a protocol for designing and producing PET-laminates (PETLs), microfluidic devices that are inexpensive, easy to fabricate, and consume significantly less time to generate than other approaches to microfluidics technology. They consist of thermally bonded film sheets, in which channels and other features are defined using a craft cutter. PETLs solve field-specific technical challenges while dramatically reducing obstacles to adoption. This approach facilitates the accessibility of microfluidics devices in both research and educational settings, providing a reliable platform for new methods of inquiry.

Here we present a protocol to design and fabricate custom microfluidic devices with minimal financial and time investment. The aim is to facilitate the adoption of microfluidic technologies in biomedical research laboratories and educational settings.

Fabricación rápida de dispositivos microfluídicos personalizados para investigación y aplicaciones educativas

Microfluidic devices allow for the manipulation of fluids, particles, cells, micro-sized organs or organisms in channels ranging from the nano to ...

Low-Cost, Volume-Controlled Dipstick Urinalysis for Home-Testing

Dipstick urinalysis provides quick and affordable estimations of multiple physiological conditions but requires good technique and training to use accurately. Manual performance of dipstick urinalysis relies on good human color vision, proper lighting control, and error-prone, time-sensitive comparisons to chart colors. By automating the key steps in the dipstick urinalysis test, potential sources of error can be eliminated, allowing self-testing at home. We describe the steps necessary to create a customizable device to perform automated urinalysis testing in any environment. The device is cheap to manufacture and simple to assemble. We describe the key steps involved in customizing it for the dipstick of choice and for customizing a mobile phone app to analyze the results. We demonstrate its use to perform urinalysis and discuss the critical measurements and fabrication steps necessary to ensure robust operation. We then compare the proposed method to the dip-and-wipe method, the gold standard technique for dipstick urinalysis.

Dipstick urinalysis is a quick and affordable method of assessing one&#8217;s personal state of health. We present a method to perform accurate, low-cost dipstick urinalysis that removes the primary sources of error associated with traditional dip-and-wipe protocols and is simple enough to be performed by lay users at home.