This work has been supported by the COMET K1 ASSIC Austrian Smart Systems Integration Research Center. The COMET-Competence Centers for Excellent Technologies-Program is supported by BMVIT, BMWFW, and the federal provinces of Carinthia and Styria.

CAUTION: Before using the considered inks and adhesives, please consult the relevant Material Safety Data Sheets (MSDS). The employed nanoparticle ink and adhesives may be toxic or carcinogenic, dependent on the filler. Please use all appropriate safety practices when performing inkjet printing or the preparation of samples and make sure to wear appropriate personal protective equipment (safety glasses, gloves, lab coat, full-length pants, closed-toe shoes).
NOTE: The protocol can be paused after any step except steps 6.3 - 6.6 and steps 9.2 - 9.5.
1. Preparation of 3D-printed Substrates
<ol>
	<li>Prepare computer-aided design (CAD) drawings, ideally using the stereolithography .stl file format. 
	NOTE: The used designs are illustrated in Supplementary Figure 2 and Supplementary Figure 3.</li>
	<li>Choose the AM process based on the material properties required by the target application (see Table 1 for the respective process limitations). 
	NOTE: In this work, we used samples made of 3D-printed copper, as well as 3D-printed ceramics.</li>
	<li>Fabricate the copper substrate by 3D-printing with wax and lost wax casting39.</li>
	<li>Fabricate the ceramic substrate by lithography-based ceramic manufacturing (LCM) technology40&#160;(see Video 1).</li>
	<li>Fabricate the acrylate substrate using a high-resolution polymer 3D-printer37 and remove the supporting wax from the printed part.
	<ol>
		<li>Put the printed part inside an oven at 65 &#176;C for 1 h to melt the supporting wax.</li>
		<li>After removing the printed part from the oven, put it inside an ultrasonic oil bath at 65 &#176;C to remove the wax from holes, small openings, etc.</li>
	</ol>
	</li>
	<li>Clean the substrates using a wiper wetted with acetone, as possible surface impurities greatly affect the later inkjet print quality. 
	NOTE: The preparation of AM substrates can be done using different equipment and processes. Depending on the fabrication strategy, the surface and bulk properties may vary as well. It is, therefore, crucial to control these properties using the inspection techniques recommended later (see, for instance, section 4 of this protocol).</li>
</ol>
2. Fabrication of Interconnects
NOTE: The fabrication of interconnects differs depending on the type (conductive/nonconductive) of substrate.
<ol>
	<li>Fabricate interconnects on nonconductive (ceramic) substrates.
	<ol>
		<li>Dispense the low temperature curable conductive adhesive with a time-pressure microdispenser mounted on a microassembly station into the appropriate vias of the printed parts.</li>
		<li>Leave the fabricated interconnects to dry for 10 min at 23 &#176;C and with ambient pressure. 
		NOTE: For the ceramic substrate, the interconnects can also be fabricated using solder paste and high-temperature curing.</li>
	</ol>
	</li>
	<li>Fabricate interconnects on conductive substrates.
	<ol>
		<li>Dispense the insulating ink all over the vias&#8217; (holes/holes in the substrate) circumference via a time-pressure microdispenser.</li>
		<li>Perform the photonic curing using intense pulsed light as suggested by the ink supplier.
		<ol>
			<li>Open the tray of the photonic curing equipment containing the substrate table.</li>
			<li>Move the copper sample to the substrate table of the photonic curing equipment and fix it using the provided magnetic fixtures.</li>
			<li>Adjust the height of the equipment&#8217;s substrate table to move the sample to the focus plane of the curing equipment.</li>
			<li>Close the tray and adjust the curing profile as recommended by the material&#8217;s supplier for the printed material in the equipment&#8217;s software interface and press the start button.</li>
		</ol>
		</li>
		<li>Fill the via with low-temperature curing conductive paste (Table of Materials). 
		NOTE: In general, it is possible to use all forms of one-component, epoxy-based conductive adhesives which are temperature activated.</li>
		<li>Dry the fabricated interconnects for 10 min at 23 &#176;C.</li>
	</ol>
	</li>
</ol>
3. Preparation of the Inkjet Printing System
<ol>
	<li>Clean/purge the print head nozzles with the purge setting in the printer software, using the appropriate chemical for the respective ink: use isopropanol for insulating inks; use triethylene glycol monomethyl ether for the conductive ink. Purge the nozzles by pressing the purge button in the printer&#8217;s software interface until the solution ejected from the respective nozzles is clear. 
	NOTE: The amount of chemical necessary depends on the printer, nozzle, and chemical. In this experiment, approximately 2 mL was used.</li>
	<li>Fill the ink containers with approximately 1.5 mL of nanoparticles silver ink with 50 wt.% metal loading and an average particle size of 110 nm using a syringe, for instance, with a 3 mL barrel, and an 18 G Luer lock dispensing needle.</li>
	<li>Use one print head to jet the ink by pressing the Start head button in the printer&#8217;s software interface.</li>
	<li>Use the pre-adjusted jetting profile of the printer for the jetting of the conductive ink.
	<ol>
		<li>Move the print head to the dropview position using the Go to dropview position option in the printer software interface and observe the jetting of the ink.</li>
		<li>Change the parameters of the voltage profile that is preinstalled for the print head and the print head temperature in order to adjust the drop velocity, shape, and volume. Adjust the ink pressure to avoid any spilling of the ink and to reduce the formation of satellite droplets. 
		NOTE: For the printing system used in this protocol, the operational maximum jetting voltage was set to 40 V and a jetting profile of 1 &#181;s rise/fall time with 10 - 14 &#181;s hold time was used. The silver ink was jetted at 45 &#176;C. The optimum ink pressure is dependent on the ink level. The voltage in the voltage profile has to be increased or reduced depending on the state (e.g., temperature, viscosity) of the ink and the current temperature of the head, as well as the state of the used print head. To achieve proper jetting, we recommend changing the voltage upward in small steps of 1 V. If there is no improvement in the drop shape, reduce the voltage in small steps of 1 V. Follow this procedure until a stable dropping is achieved.</li>
	</ol>
	</li>
	<li>Adjust the printing parameters for the insulating ink in the same manner as done for the silver ink.
	<ol>
		<li>Use another print head to jet the low-k dielectric material, which is a mixture of acrylate-type monomers. 
		NOTE: Again, an operational jetting voltage of 40 V and a 1 &#181;s rise/fall time with 8 &#181;s hold time was used in this protocol. The dielectric ink could be jetted at 50 &#176;C. The optimum ink pressure is dependent on the actual ink level. Generally, the used parameters highly depend on the properties of the ink, as well as of the substrate or layer onto which it should be printed. During the fabrication process, the printing parameters might have to be adjusted dynamically. Please refer to the user manual of the printing system on how to properly adjust printer parameters.</li>
	</ol>
	</li>
</ol>
4. Inspection of the Surface Properties of the Respective Substrates for Printability and the Adjustment of Printer Parameters for the First Layer
<ol>
	<li>Perform profilometer measurements to determine the surface roughness.
	<ol>
		<li>Put the sample on the substrate table (stage) of the profilometer.</li>
		<li>If not homed, home the stage using the home button in the software interface.</li>
		<li>Choose the respective resolution and area which is mapped in the software interface.</li>
		<li>Place the measurement head at the starting position and start the measurement using the jog option and start button in the software interface.</li>
		<li>After the measurement is finished, check the result for consistency (e.g., are the shown heights plausible for the number of printed layers) and save the data.</li>
	</ol>
	</li>
	<li>Perform SEM inspections as per the user manual to analyze the surface quality.</li>
	<li>Perform contact angle measurements as described in the user manual of the SEM station to determine the wettability properties.</li>
	<li>Fix the substrate on the substrate table using adhesive tape and mark its position appropriately.</li>
	<li>Adjust the nozzle and printing parameters in the settings of the software interface by editing the properties of the print head in the printer&#8217;s software interface.
	<ol>
		<li>Again, move the print head to the dropview position using the Go to dropview position option in the printer&#8217;s software interface and observe the jetting of the ink. If necessary, adjust the printing parameters to optimize the jetting.</li>
		<li>Choose a nozzle which ejects well-defined and homogeneous drops of ink for printing.</li>
		<li>Enter the number of the chosen nozzle in the printer&#8217;s preferences.</li>
	</ol>
	</li>
	<li>Perform the drop size tests to determine the size of one printed drop on the respective substrate.
	<ol>
		<li>Print a drop pattern, using a known printer configuration.</li>
		<li>Determine the achieved drop size using a calibrated microscope or the inbuilt camera system of the printer.</li>
		<li>Ensure that the subsequently used printing resolution is appropriate for the observed ink wetting to fabricate a homogeneous and closed surface (e.g., choose a printing resolution of 900 - 1,000 dpi for a drop size of 40 - 50 &#181;m).</li>
	</ol>
	</li>
	<li>Perform an FIB analysis (Table of Materials), as per the manufacturer&#8217;s instruction, to ensure a sufficient bulk homogeneity for conductive substrates.</li>
</ol>
5. Curing Parameter Adjustments for the First Layer
<ol>
	<li>Print multiple structures, using a layer of the ink used for the first device layer, onto a dummy substrate (i.e., a sample of the same material which can later be disposed and is used for testing purposes only).</li>
	<li>Use thermal curing in an oven at 130 &#176;C for at least 30 min at ambient pressure for the printed conductive silver patterns on a ceramic substrate. 
	NOTE: Depending on the size of the sample, use a pod to hold the sample inside the oven.</li>
	<li>Use the photonic curing for the insulating ink on the metal substrate.
	<ol>
		<li>Open the tray of the photonic curing equipment containing the substrate table.</li>
		<li>Move the sample to the substrate table of the photonic curing equipment and fix it accordingly (using, for instance, provided magnetic fixtures).</li>
		<li>Adjust the height of the equipment&#8217;s substrate table, using the table spindle to move the sample to the focus plane of the curing equipment.</li>
		<li>Close the tray and adjust the curing profile as recommended by the supplier for the printed material in the equipment&#8217;s software interface and press the start button.</li>
	</ol>
	</li>
	<li>Control the homogeneity of the surface qualitatively using a microscope and quantitatively using a profilometer.
	<ol>
		<li>Put the sample on the substrate table (stage) of the profilometer.</li>
		<li>If not homed, home the stage using the respective button in the software.</li>
		<li>Choose the respective resolution and area which should be mapped.</li>
		<li>Place the measurement head at the starting position and start the measurement.</li>
		<li>After the measurement is finished, check the result for consistency and save the data.</li>
	</ol>
	</li>
	<li>Repeat photonic or thermal curing procedures using adopted curing parameters if necessary.
	<ol>
		<li>Increase the used photonic energy in small steps of, for instance, 5 V in the software interface of the photonic curing equipment if the achieved resistance is too high. Decrease the used energy if the sample shows signs of burning.</li>
	</ol>
	</li>
	<li>Adjust the equipment parameters for the curing of the first functional device layer so that a conductivity sufficient for the application at hand is reached, but yet no burning of the printed structure occurs.</li>
</ol>
6. Inkjet Printing and Curing of the First Device Layer
<ol>
	<li>Fix the substrate on the substrate table using adhesive tape and mark its position appropriately.</li>
	<li>As the first layer is conductive, for the ceramic and acrylate type substrate, use substrate table heating of 60 &#176;C. 
	NOTE: The temperature must not exceed a temperature which might affect the respective substrate (e.g., the acrylate tolerates only up to 65 &#176;C). This adjustment can be done in the printer settings.</li>
	<li>Adjust the nozzle and printing parameters in the settings of the software interface.
	<ol>
		<li>Move the print head to the dropview position and observe the jetting of the ink.</li>
		<li>Choose a nozzle which ejects well-defined and homogeneous drops of ink for printing.</li>
		<li>Enter the number of the chosen nozzle in the printer&#8217;s preferences.</li>
	</ol>
	</li>
	<li>Adjust the used resolution of the print head to deposit a homogeneous layer of ink according to the previously determined substrate properties: for low-wettability substrates, for instance, a large contact angle and small drop size increase the printing resolution. Lower the resolution for high-wettability substrates. 
	 
	NOTE: The adjustment of the printing parameters can be done in the printer settings.</li>
	<li>Select the appropriate reference point to print the pattern and store its coordinates.</li>
	<li>Load the respective scalable vector graphic (.svg) file and select an appropriate resolution and size, dependent on the desired pattern and the dimensions of the substrate in the printer software.</li>
	<li>Perform printing. Repeat the printing of one layer of ink until the homogeneity of the print is satisfying.</li>
	<li>Control the homogeneity of the printed layer using a calibrated microscope or using the inbuilt camera system of the printer.
	<ol>
		<li>Move the camera of the printer to the print position and observe the quality of the print given in the printer&#8217;s software interface.</li>
	</ol>
	</li>
	<li>Cure the first layer using the parameters determined in section 5 of this protocol.
	<ol>
		<li>For silver ink on a polymer substrate (acrylate, foil), use a 1 ms pulse at 250 V with a reduced amount of energy (525 mJ/cm2).</li>
		<li>For silver ink on a ceramic substrate, use heat curing in an oven as recommended with the ink (e.g., 130 &#176;C for 30 min).</li>
		<li>Cure the printed dielectric ink at 200 V with 1 ms pulses and repeat the pulses 8x at the frequency of 1 Hz. 
		NOTE: The spectra of the emitted light used in photonic curing is quite broad (ultra-violet&#8211;near-infrared [UV-NIR]). Still, the amount of UV light is sufficient to initiate the photopolymerization and cure the insulating layer.</li>
	</ol>
	</li>
</ol>
7. Inspection of the Surface Properties of the Respective Substrates for Printability and the Adjustment of Printer Parameters for Subsequent Layers
NOTE: Please refer to the user manuals of the measurement equipment to perform the profilometer measurements and microscopy inspections.
<ol>
	<li>Perform profilometer measurements to determine the roughness and thickness of the printed layer.
	<ol>
		<li>Put the sample on the substrate table of the profilometer.</li>
		<li>If not homed, home the stage using the respective button in the software.</li>
		<li>Choose the respective resolution and area which needs to be mapped.</li>
		<li>Place the measurement head at the starting position and start the measurement.</li>
		<li>After the measurement is finished, check the result for consistency and save the data.</li>
	</ol>
	</li>
	<li>Perform contact angle measurements to determine the wettability properties. 
	NOTE: Refer to the user manual of the measurement equipment at hand on how to properly perform contact angle measurements.</li>
	<li>Perform drop size tests to determine the size of one printed drop on the respective substrate.
	<ol>
		<li>Print a drop pattern using a known printer configuration.</li>
		<li>Determine the achieved drop size using a calibrated microscope or the printer&#8217;s inbuilt inspection system.</li>
	</ol>
	</li>
	<li>Adjust the used resolution of the print head to achieve a homogeneous layer of ink: for low-wettability substrates, for instance, a large contact angle and small drop size increase the printing resolution. Lower the resolution for high-wettability substrates.</li>
	<li>Control the electrical properties of the first layer: for a conductive first layer, use the four-point probe to determine the achieved conductivity.
	<ol>
		<li>Put the sample on the substrate table.</li>
		<li>Lower the measurement head onto the conductive track, making sure the probe has good contact with the printed structure, to be analyzed.</li>
	</ol>
	</li>
	<li>For an insulating first layer, make sure the surface homogenously covers the conductor below. Use a microscope for confirming. Verify the insulating properties using a multimeter.</li>
</ol>
8. Curing Parameter Adjustments for Subsequent Layers
<ol>
	<li>Print multiple structures, using a layer of the ink used for the next device layer, onto a dummy substrate with an equivalent previous layer.</li>
	<li>Use only photonic curing for all substrates.</li>
	<li>After curing, control the electrical and structural properties of the printed layer: to determine if the conductivity is sufficient, use a four-point probe measurement.</li>
	<li>Control the homogeneity of the surface qualitatively using a microscope and quantitatively using the profilometer.</li>
	<li>Repeat photonic curing procedures if necessary.</li>
	<li>Adjust the equipment parameters for the curing of the subsequent functional device layer.</li>
</ol>
9. Inkjet Printing and Curing of Subsequent Device Layers
<ol>
	<li>Fix the substrate on the substrate table appropriately at the previously marked position.</li>
	<li>Adjust the nozzle and printing parameters as determined from the previous step.</li>
	<li>Select the appropriate reference point to print the pattern and make sure the printed patterns are well-aligned with each other to ensure proper functionality of the device afterward.</li>
	<li>Load the respective .svg file with appropriate resolution and size.</li>
	<li>Perform printing. Repeat the printing of one layer of ink until the homogeneity of the print is satisfying.</li>
	<li>Control the homogeneity of the printed layer under a microscope (here, the inbuilt camera system of the printer is used).</li>
	<li>Use photonic curing only for the curing of this layer. Use the parameters determined beforehand for an insulating layer or a conductive layer on the insulator.</li>
	<li>After curing, control the electrical and structural properties of the printed layer: to determine if the conductivity range of the conductive layer is acceptable, use a multimeter.</li>
</ol>

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Application to Immunodetection of a Cancer Biomarker Protein.</a> Physical Chemistry Chemical Physics. 13 (11), 4888-4894 (2011).</li><li>Lesch, A., 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=Large+Scale+Inkjet-Printing+of+Carbon+Nanotubes+Electrodes+for+Antioxidant+Assays+in+Blood+Bags.">Large Scale Inkjet-Printing of Carbon Nanotubes Electrodes for Antioxidant Assays in Blood Bags.</a> Journal of Electroanalytical Chemistry. 717, 61-68 (2014).</li><li>Sarfraz, J., 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=A+Printed+H2S+Sensor+with+Electro-Optical+Response.">A Printed H2S Sensor with Electro-Optical Response.</a> Sensors and Actuators B: Chemical. 191, 821-827 (2014).</li><li>Sarfraz, J., 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=Printed+Copper+Acetate+Based+H2S+Sensor+on+Paper+Substrate.">Printed Copper Acetate Based H2S Sensor on Paper Substrate.</a> Sensors and Actuators B: Chemical. 173, 868-873 (2012).</li><li>Huang, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Novel+Paper-Based+Flexible+Ammonia+Gas+Sensor+via+Silver+and+SWNT-PABS+Inkjet+Printing.">A Novel Paper-Based Flexible Ammonia Gas Sensor via Silver and SWNT-PABS Inkjet Printing.</a> SWNT-PABS Inkjet Printing. Sensors and Actuators B: Chemical. 197, 308-313 (2014).</li><li>Kamyshny, A., Steinke, J., Magdassi, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metal-based+inkjet+inks+for+printed+electronics.">Metal-based inkjet inks for printed electronics.</a> Open Applied Physics Journal. 4, 19-36 (2011).</li><li>Perelaer, J., de Gans, B. J., Schubert, U. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ink-jet+Printing+and+Microwave+Sintering+of+Conductive+Silver+Tracks.">Ink-jet Printing and Microwave Sintering of Conductive Silver Tracks.</a> Advanced Materials. 18, 2101-2104 (2006).</li><li>Hummelgard, M., Zhang, R., Nilsson, H. -. E., Olin, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrical+sintering+of+silver+nanoparticle+ink+studied+by+in+situ+TEM+probing.">Electrical sintering of silver nanoparticle ink studied by in situ TEM probing.</a> PLoS One. 6, (2011).</li><li>Kumpulainen, T., 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=Low+temperature+nanoparticle+sintering+with+continuous+wave+and+pulse+lasers.">Low temperature nanoparticle sintering with continuous wave and pulse lasers.</a> Optics and Laser Technology. 43, 570-576 (2011).</li><li>Schr&#246;der, K., McCool, S., Furlan, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Broadcast+Photonic+Curing+of+Metallic+Nanoparticle+Films.">Broadcast Photonic Curing of Metallic Nanoparticle Films.</a> Technical Proceedings of the 2006 NSTI Nanotechnology Conference and Trade Show. 3, 198-201 (2006).</li><li>Lopes, A. J., Lee, I. H., MacDonald, E., Quintana, R., Wicker, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laser+Curing+of+Silver-Based+Conductive+Inks+for+In-Situ+3D+Structural+Electronics+Fabrication+in+Stereolithography.">Laser Curing of Silver-Based Conductive Inks for In-Situ 3D Structural Electronics Fabrication in Stereolithography.</a> Journal Materials Processing Technology. 214 (9), 1935-1945 (2014).</li><li>Faller, L. -. M., Mitterer, T., Leitzke, J. P., Zangl, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+and+Evaluation+of+a+Fast,+High-Resolution+Sensor+Evaluation+Platform+Applied+to+MEMS+Position+Sensing.">Design and Evaluation of a Fast, High-Resolution Sensor Evaluation Platform Applied to MEMS Position Sensing.</a> IEEE Transactions on Instrumentation and Measurement. 67 (5), 1014-1027 (2018).</li><li>Faller, L. -. M., Zangl, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Feasibility+Considerations+on+an+Inkjet-Printed+Capacitive+Position+Sensor+for+Electrostatically+Actuated+Resonant+MEMS-Mirror+Systems.">Feasibility Considerations on an Inkjet-Printed Capacitive Position Sensor for Electrostatically Actuated Resonant MEMS-Mirror Systems.</a> Journal of Microelectromechanical Systems. 26 (3), 559-568 (2017).</li><li>Faller, L. -. M., Zangl, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Robust+design+of+an+inkjet-printed+capacitive+sensor+for+position+tracking+of+a+MOEMS-mirror+in+a+Michelson+interferometer+setup.">Robust design of an inkjet-printed capacitive sensor for position tracking of a MOEMS-mirror in a Michelson interferometer setup.</a> Proceedings of SPIE 10246, Smart Sensors, Actuators, and MEMS VIII. , (2017).</li><li>Faller, L. -. M., Zangl, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Robust+design+of+a+3D-+and+inkjet-printed+capacitive+force/pressure+sensor.">Robust design of a 3D- and inkjet-printed capacitive force/pressure sensor.</a> 2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE). , (2016).</li><li>Wang, P. -. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+inkjet+printing+of+catalyst+Pd+ink+for+selective+metallization+apply+to+product+antenna+on+PC/ABS+substrate.">The inkjet printing of catalyst Pd ink for selective metallization apply to product antenna on PC/ABS substrate.</a> 2013 8th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT). , (2013).</li><li>Quintero, A. V., 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=Printing+and+encapsulation+of+electrical+conductors+on+polylactic+acid+(PLA)+for+sensing+applications.">Printing and encapsulation of electrical conductors on polylactic acid (PLA) for sensing applications.</a> 2014 IEEE 27th International Conference on Micro Electro Mechanical Systems (MEMS). , (2014).</li><li>Unnikrishnan, D., Kaddour, D., Tedjini, S., Bihar, E., Saadaoui, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CPW-Fed+Inkjet+Printed+UWB+Antenna+on+ABS-PC+for+Integration+in+Molded+Interconnect+Devices+Technology.">CPW-Fed Inkjet Printed UWB Antenna on ABS-PC for Integration in Molded Interconnect Devices Technology.</a> IEEE Antennas and Wireless Propagation Letters. 14, 1125-1128 (2015).</li><li>. Lost Wax Printing &amp; Casting Available from: <a target="_blank" href="https://i.materialise.com/en/3d-printing-technologies/lost-wax-printing-casting">https://i.materialise.com/en/3d-printing-technologies/lost-wax-printing-casting</a> (2018)</li><li>Faller, L. -. M., Krivec, M., Abram, A., Zangl, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=AM+Metal+Substrates+for+Inkjet-Printing+of+Smart+Devices.">AM Metal Substrates for Inkjet-Printing of Smart Devices.</a> Materials Characterization. , (2018).</li><li>Hutchings, I. M., Martin, G. D., Hutchings, I. M., Martin, G. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Introduction+to+Inkjet+Printing+for+Manufacturing.">Introduction to Inkjet Printing for Manufacturing.</a> Inkjet Technology for Digital Fabrication. , 1-20 (2013).</li><li>Baek, M. I., Hong, M., Korvink, J. G., Smith, P. J., Shin, D. -. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Equalization+of+Jetting+Performance.">Equalization of Jetting Performance.</a> Inkjet-Based Micromanufacturing. , 159-172 (2012).</li><li>Zhang, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Methods for Fabricating Printed Electronics with High Conductivity and High Resolution. , (2014).</li><li>Suganuma, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Introduction to Printed Electronics. , (2014).</li><li>Baxter, L. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Capacitive Sensors: Design and Applications. , (1997).</li></ol>

The authors have nothing to disclose.

A way to fabricate multilayer sensor structures on 3D-printed substrates and on foil is demonstrated. AM metal, as well as ceramic and acrylate type and foil substrates are shown to be suitable for multilayer inkjet printing, as the adhesion between the substrate and the different layers is sufficient, as well as the respective conductivity or insulation capability. This could be shown by printing layers of conductive structures on insulating material. Furthermore, the printing and curing processes for all layers was suc...

Additive manufacturing (AM) is standardized as a process where materials are joined to make objects from 3D model data. This is usually done layer upon layer and, thus, contrasts with subtractive manufacturing technologies, such as semiconductor fabrication. Synonyms include 3D-printing, additive fabrication, additive process, additive techniques, additive layer manufacturing, layer manufacturing, and freeform fabrication. These synonyms are reproduced from the standardization by the American Society of Testing and Materials (ASTM)1 to provide a unique definition. In the literature, 3D-printing is referred to as the process where thickness of the printed objects is in the range of centimeters to even meters2.
More common processes, such as stereolithography3, enable the printing of polymers, but the 3D-printing of metal is also already commercially available. The AM of metals is employed in manifold areas, such as for the automotive, aerospace4, and medical5 sectors. An advantage for aerospace structures is the possibility to print lighter devices through simple structural changes (e.g., by using a honeycomb design). Consequently, materials with, for instance, greater mechanical strength, that would otherwise add a significant amount of weight (e.g.,&#160;titanium instead of aluminum)6, can be employed.
While the 3D-printing of polymers is already well established, metal 3D-printing is still a vibrant research topic, and a variety of processes have been developed for the 3D-printing of metal structures. Basically, the available methods can be combined into four groups7,8, namely 1) using a laser or electron beam for cladding in a wire-fed process, 2) sintering systems using a laser or electron beam, 3) selectively melting powder using a laser or electron beam (powder bed fusion), and 4) a binder jetting process where, commonly, an inkjet print head moves over a powder substrate and dispenses binding agent.
Depending on the process, the respective manufactured samples will exhibit different surface and structural properties7. These different properties will have to be considered in further efforts to further functionalize the printed parts (e.g., by fabricating sensors on their surfaces).
In contrast to 3D-printing, the printing processes to achieve such a functionalization (e.g., screen and inkjet printing) cover only limited object heights from less than 100 nm9 up to a few micrometers and are, thus, often also referred to as 2.5D-printing. Alternatively, laser-based solutions for high-resolution patterning have also been proposed10,11. A comprehensive review of the printing processes, the thermally dependent melt temperature of nanoparticles, and the applications is given by Ko12.
Although screen printing is well established in the literature13,14, inkjet printing provides an improved upscaling ability, together with an increased resolution for the printing of smaller feature sizes. Besides that, it is a digital, noncontact printing method enabling the flexible deposition of functional materials on three-dimensional. Consequently, our work is focused on inkjet printing.
Inkjet printing technology has already been employed in the fabrication of metal (silver, gold, platinum, etc.) sensing electrodes. Application areas include temperature measurement15,16, pressure and strain sensing17,18,19, and biosensing20,21, as well as gas or vapor analysis22,23,24. The curing of such printed structures with limited height extension can be done using various techniques, based on thermal25, microwave26, electrical27, laser28, and photonic29 principles.
Photonic curing for inkjet-printed structures allows researchers to use high-energy, curable, conductive inks on substrates with a low-temperature resistance. Exploiting this circumstance, the combination of 2.5D- and 3D-printing processes can be employed to fabricate highly flexible prototypes in the area of smart packaging30,31,32 and smart sensing.
The conductivity of 3D-printed metal substrates is of interest to the aerospace sector, as well as for the medical sector. It does not just improve the mechanical stability of certain parts but is beneficial in near-field as well as capacitive sensing. A 3D-printed metal housing provides additional shielding/guarding of the sensor&#39;s front-end since it can be electrically connected.
The aim is to fabricate devices using AM technology. These devices should provide a sufficiently high resolution in the measurement they are employed for (often at micro- or nanoscale) and, at the same time, they should fulfill high standards regarding reliability and quality.
It has been shown that AM technology presents the user with enough flexibility to fabricate optimized designs33,34 which improve the overall measurement quality that can be achieved. Additionally, the combination of polymers and single-layer inkjet printing has been presented in previous research35,36,37,38.
In this work, available studies are extended, and a review about the physical properties of AM substrates, with a focus on metals,and their compatibility with multilayer inkjet printing and photonic curing is provided. An exemplary multilayer coil design is provided in Supplementary Figure 1. The results are used for providing strategies for the inkjet printing of multilayer sensor structures on AM metal substrates.

<table>
	<tbody>
		<tr>
			<td>PiXDRO LP 50</td>
			<td>Meyer Burger AG</td>
			<td></td>
			<td>Inkjet-Printer with dual-head assembly.</td>
		</tr>
		<tr>
			<td>SM-128 Spectra S-class</td>
			<td>Fujifilm Dimatix</td>
			<td></td>
			<td>Printheads with nozzle diameter of 50 &#181;m, 50 pL calibrated dropsize and 800 dpi maximum resolution.</td>
		</tr>
		<tr>
			<td>DMC-11610/DMC-11601</td>
			<td>Fujifilm Dimatix</td>
			<td></td>
			<td>Disposable printheads with nozzle diameter 21.5 &#181;m, 1 or 10 pL calibrated dropsize</td>
		</tr>
		<tr>
			<td>Sycris I50DM-119</td>
			<td>PV Nanocell</td>
			<td></td>
			<td>Conductive silver nanoparticle ink with 50 wt.% silver loading, with an average particle size of 120 nm, in triethylene glycol monomethyl ether.</td>
		</tr>
		<tr>
			<td>Solsys EMD6200</td>
			<td>SunChemical</td>
			<td></td>
			<td>Insulating, low-k dielectric ink which is a mixture of acrylate-type monomers. Viscosity is 7-9 cps.</td>
		</tr>
		<tr>
			<td>Dycotec DM-IN-7002-I</td>
			<td>Dycotec</td>
			<td></td>
			<td>UV curable insulator, Surface Tension: 37.4 mN/m</td>
		</tr>
		<tr>
			<td>Dycotec DM-IN-7003C-I</td>
			<td>Dycotec</td>
			<td></td>
			<td>UV curable insulator, Surface Tension: 29.7 mN/m</td>
		</tr>
		<tr>
			<td>Dycotec DM-IN-7003-I</td>
			<td>Dycotec</td>
			<td></td>
			<td>UV curable insulator, Surface Tension: 31.4 mN/m</td>
		</tr>
		<tr>
			<td>Dycotec DM-IN-7004-I</td>
			<td>Dycotec</td>
			<td></td>
			<td>UV curable insulator, Surface Tension: 27.9 mN/m</td>
		</tr>
		<tr>
			<td>Pulseforge 1200</td>
			<td>Novacentrix</td>
			<td></td>
			<td>Photonic curing/sintering equipment.</td>
		</tr>
		<tr>
			<td>DektatkXT</td>
			<td>Bruker</td>
			<td></td>
			<td>Stylus Profiler with stylus tip of 12.5 &#181;m diameter and constant force of 4 mg.</td>
		</tr>
		<tr>
			<td>C4S</td>
			<td>Cascade Microtech</td>
			<td></td>
			<td>Four-point-probe measurement head.</td>
		</tr>
		<tr>
			<td>2000</td>
			<td>Keithley</td>
			<td></td>
			<td>Multimeter to evaluate the measurements using the four-point-probe.</td>
		</tr>
		<tr>
			<td>Helios NanoLab600i</td>
			<td>FEI</td>
			<td></td>
			<td>Focused Ion Beam analysis station which provides high-energy gallium ion milling.</td>
		</tr>
		<tr>
			<td>SeeSystem</td>
			<td>Advex Instruments</td>
			<td></td>
			<td>Water contact angle measurement device.</td>
		</tr>
		<tr>
			<td>Projet 3500 HDMax</td>
			<td>3D Systems</td>
			<td></td>
			<td>Professional high-resolution polymer 3D-printer. See also (accessed Sep. 2018): https://www.3dsystems.com/sites/default/files/projet_3500_plastic_0115_usen_web.pdf</td>
		</tr>
		<tr>
			<td>Polytec PU 1000</td>
			<td>Polytec PT</td>
			<td></td>
			<td>Electrically conductive adhesive based on Polyurethane, available</td>
		</tr>
		<tr>
			<td>Microdispenser</td>
			<td>Musashi</td>
			<td></td>
			<td>Needle for microdispensing.</td>
		</tr>
		<tr>
			<td>Micro-assembly station</td>
			<td>Finetech</td>
			<td></td>
			<td>Equipment for assembly of, e.g., printed circuit boards (PCBs) and placing of chemicals (e.g. solder) and SMD parts.</td>
		</tr>
	</tbody>
</table>

hybrid printing for the fabrication of smart sensors

A method to combine additively manufactured substrates or foils and multilayer inkjet printing for the fabrication of sensor devices is presented. First, three substrates (acrylate, ceramics, and copper) are prepared. To determine the resulting material properties of these substrates, profilometer, contact angle, scanning electron microscope (SEM), and focused ion beam (FIB) measurements are done. The achievable printing resolution and suitable drop volume for each substrate are, then, found through the drop size tests. Then, layers of insulating and conductive ink are inkjet printed alternately to fabricate the target sensor structures. After each printing step, the respective layers are individually treated by photonic curing. The parameters used for the curing of each layer are adapted depending on the printed ink, as well as on the surface properties of the respective substrate. To confirm the resulting conductivity and to determine the quality of the printed surface, four-point probe and profilometer measurements are done. Finally, a measurement set-up and results achieved by such an all-printed sensor system are shown to demonstrate the achievable quality.

From the SEM images shown in Figure 1, conclusions on the printability on the respective substrates can be drawn. The scale bars are different due to the different ranges of the surface roughness. In Figure 1a, the surface of the copper substrate is shown, which is by far the smoothest. Figure 1c, on the other hand, shows steel, a substrate which is not usable for inkjet printing due to the high poro...

Watch this Scientific Journal Video about Hybrid Printing for the Fabrication of Smart Sensors at JoVE.com

Hybrid Printing for the Fabrication of Smart Sensors

Here we present a protocol for the fabrication of inkjet-printed multilayer sensor structures on additively manufactured substrates and foil.

A method to combine additively manufactured substrates or foils and multilayer inkjet printing for the fabrication of sensor devices is presented. First, ...

hybrid-printing-for-the-fabrication-of-smart-sensors

Research

JoVE Journal

Engineering

8.0K Views.  Alpen-Adria-Universität Klagenfurt. Here we present a protocol for the fabrication of inkjet-printed multilayer sensor structures on additively manufactured substrates and foil.

Video: Hybrid Printing for the Fabrication of Smart Sensors

Fabrication of VB2/Air Cells for Electrochemical Testing

A technique to investigate the properties and performance of new multi-electron metal/air battery systems is proposed and presented. A method for synthesizing nanoscopic VB2 is presented as well as step-by-step procedure for applying a zirconium oxide coating to the VB2 particles for stabilization upon discharge. The process for disassembling existing zinc/air cells is shown, in addition construction of the new working electrode to replace the conventional zinc/air cell anode with a the nanoscopic VB2 anode. Finally, discharge of the completed VB2/air battery is reported. We show that using the zinc/air cell as a test bed is useful to provide a consistent configuration to study the performance of the high-energy high capacity nanoscopic VB2 anode.

Fabrication of VB2/Air Cells for Electrochemical Testing

A protocol is presented to study multi-electron metal/air battery systems by using previous technology developed for the zinc/air cell. Electrochemical testing is then performed on fabricated batteries to evaluate performance.

A technique to investigate the properties and performance of new multi-electron metal/air battery systems is proposed and presented. A method for ...

Patterning via Optical Saturable Transitions - Fabrication and Characterization

This protocol describes the fabrication and characterization of nanostructures using a novel nanolithographic technique called Patterning via Optical Saturable Transitions (POST). In this technique the chemical properties of organic photochromic molecules that undergo single-photon reactions are exploited, enabling rapid top-down nanopatterning over large areas at low light intensities, thereby, allowing for the circumvention of the far-field diffraction barrier.4 Simple, cost-effective, high throughput and resolution alternatives to nanopatterning are being explored, such as, two-photon polymerization5,6, beam pen lithography (BPL)7, scanning electron beam lithography (SEBL), and focused ion beam (FIB) patterning. However, multi-photon approaches require high light intensities, which limit their potential for high throughput and offer low image contrast. Although, electron and ion beam lithographic processes offer increased resolution, the serial nature of the process is limited to slow writing speeds, which also prevents patterning of features over large areas. Beam-pen lithography is an approach towards parallel near-field optical lithography. However, the gap between the source of the beam and the surface of the photoresist needs to be controlled extremely precisely for good pattern uniformity and this is very challenging to accomplish for large arrays of beams. Patterning via Optical Saturable Transitions (POST) is an alternative optical nanopatterning technique for patterning sub-wavelength features1-3. Since this technique uses single photons instead of electrons, it is extremely fast and does not require high light intensities1-3, opening the door to massive parallelization.

We report that the diffraction limit of conventional optical lithography can be overcome by exploiting the transitions of organic photochromic derivatives induced by their photoisomerization at low light intensities.1-3 This paper outlines our fabrication technique and two locking mechanisms, namely: dissolution of one photoisomer and electrochemical oxidation.

This protocol describes the fabrication and characterization of nanostructures using a novel nanolithographic technique called Patterning via Optical ...

Experiments on Ultrasonic Lubrication Using a Piezoelectrically-assisted Tribometer and Optical Profilometer

Friction and wear are detrimental to engineered systems. Ultrasonic lubrication is achieved when the interface between two sliding surfaces is vibrated at a frequency above the acoustic range (20 kHz). As a solid-state technology, ultrasonic lubrication can be used where conventional lubricants are unfeasible or undesirable. Further, ultrasonic lubrication allows for electrical modulation of the effective friction coefficient between two sliding surfaces. This property enables adaptive systems that modify their frictional state and associated dynamic response as the operating conditions change. Surface wear can also be reduced through ultrasonic lubrication. We developed a protocol to investigate the dependence of friction force reduction and wear reduction on the linear sliding velocity between ultrasonically lubricated surfaces. A pin-on-disc tribometer was built which differs from commercial units in that a piezoelectric stack is used to vibrate the pin at 22 kHz normal to the rotating disc surface. Friction and wear metrics including effective friction force, volume loss, and surface roughness are measured without and with ultrasonic vibrations at a constant pressure of 1 to 4 MPa and three different sliding velocities: 20.3, 40.6, and 87 mm/sec. An optical profilometer is utilized to characterize the wear surfaces. The effective friction force is reduced by 62% at 20.3 mm/sec. Consistently with existing theories for ultrasonic lubrication, the percent reduction in friction force diminishes with increasing speed, down to 29% friction force reduction at 87 mm/sec. Wear reduction remains essentially constant (49%) at the three speeds considered.

We present a protocol for using a piezoelectrically-assisted tribometer and optical profilometer to investigate the dependence of ultrasonic wear and friction reduction on linear velocity, contact pressure, and surface properties.

Friction and wear are detrimental to engineered systems. Ultrasonic lubrication is achieved when the interface between two sliding surfaces is vibrated at ...

Printing Fabrication of Bulk Heterojunction Solar Cells and In Situ Morphology Characterization

Polymer-based materials hold promise as low-cost, flexible efficient photovoltaic devices. Most laboratory efforts to achieve high performance devices have used devices prepared by spin coating, a process that is not amenable to large-scale fabrication. This mismatch in device fabrication makes it difficult to translate quantitative results obtained in the laboratory to the commercial level, making optimization difficult. Using a mini-slot die coater, this mismatch can be resolved by translating the commercial process to the laboratory and characterizing the structure formation in the active layer of the device in real time and in situ as films are coated onto a substrate. The evolution of the morphology was characterized under different conditions, allowing us to propose a mechanism by which the structures form and grow. This mini-slot die coater offers a simple, convenient, material efficient route by which the morphology in the active layer can be optimized under industrially relevant conditions. The goal of this protocol is to show experimental details of how a solar cell device is fabricated using a mini-slot die coater and technical details of running in situ structure characterization using the mini-slot die coater.

Printing Fabrication of Bulk Heterojunction Solar Cells and In Situ Morphology Characterization

Here, we present a protocol to fabricate organic thin film solar cells using a mini-slot die coater and related in-line structure characterizations using synchrotron scattering techniques.

Polymer-based materials hold promise as low-cost, flexible efficient photovoltaic devices. Most laboratory efforts to achieve high performance devices ...

Nanostructured Ag-zeolite Composites as Luminescence-based Humidity Sensors

Small silver clusters confined inside zeolite matrices have recently emerged as a novel type of highly luminescent materials. Their emission has high external quantum efficiencies (EQE) and spans the whole visible spectrum. It has been recently reported that the UV excited luminescence of partially Li-exchanged sodium Linde type A zeolites [LTA(Na)] containing luminescent silver clusters can be controlled by adjusting the water content of the zeolite. These samples showed a dynamic change in their emission color from blue to green and yellow upon an increase of the hydration level of the zeolite, showing the great potential that these materials can have as luminescence-based humidity sensors at the macro and micro scale. Here, we describe the detailed procedure to fabricate a humidity sensor prototype using silver-exchanged zeolite composites. The sensor is produced by suspending the luminescent Ag-zeolites in an aqueous solution of polyethylenimine (PEI) to subsequently deposit a film of the material onto a quartz plate. The coated plate is subjected to several hydration/dehydration cycles to show the functionality of the sensing film.

A protocol for the synthesis of moisture-responsive luminescent Ag-zeolite composites is described in this report.

Small silver clusters confined inside zeolite matrices have recently emerged as a novel type of highly luminescent materials. Their emission has high ...

3D Printing of Biomolecular Models for Research and Pedagogy

The construction of physical three-dimensional (3D) models of biomolecules can uniquely contribute to the study of the structure-function relationship. 3D structures are most often perceived using the two-dimensional and exclusively visual medium of the computer screen. Converting digital 3D molecular data into real objects enables information to be perceived through an expanded range of human senses, including direct stereoscopic vision, touch, and interaction. Such tangible models facilitate new insights, enable hypothesis testing, and serve as psychological or sensory anchors for conceptual information about the functions of biomolecules. Recent advances in consumer 3D printing technology enable, for the first time, the cost-effective fabrication of high-quality and scientifically accurate models of biomolecules in a variety of molecular representations. However, the optimization of the virtual model and its printing parameters is difficult and time consuming without detailed guidance. Here, we provide a guide on the digital design and physical fabrication of biomolecule models for research and pedagogy using open source or low-cost software and low-cost 3D printers that use fused filament fabrication technology.

Physical models of biomolecules can facilitate an understanding of their structure-function for the researcher, aid in communication between researchers, and serve as an educational tool in pedagogical endeavors. Here, we provide detailed guidance for the 3D printing of accurate models of biomolecules using fused filament fabrication desktop 3D printers.

The construction of physical three-dimensional (3D) models of biomolecules can uniquely contribute to the study of the structure-function relationship. 3D ...

Design and Evaluation of Smart Glasses for Food Intake and Physical Activity Classification

This study presents a series of protocols of designing and manufacturing a glasses-type wearable device that detects the patterns of temporalis muscle activities during food intake and other physical activities. We fabricated a 3D-printed frame of the glasses and a load cell-integrated printed circuit board (PCB) module inserted in both hinges of the frame. The module was used to acquire the force signals, and transmit them wirelessly. These procedures provide the system with higher mobility, which can be evaluated in practical wearing conditions such as walking and waggling. A performance of the classification is also evaluated by distinguishing the patterns of food intake from those physical activities. A series of algorithms were used to preprocess the signals, generate feature vectors, and recognize the patterns of several featured activities (chewing and winking), and other physical activities (sedentary rest, talking, and walking). The results showed that the average F1 score of the classification among the featured activities was 91.4%. We believe this approach can be potentially useful for automatic and objective monitoring of ingestive behaviors with higher accuracy as practical means to treat ingestive problems.

This study presents a protocol of designing and manufacturing a glasses-type wearable device that detects the patterns of food intake and other featured physical activities using load cells inserted in both hinges of the glasses.

This study presents a series of protocols of designing and manufacturing a glasses-type wearable device that detects the patterns of temporalis muscle ...

Scalable Stamp Printing and Fabrication of Hemiwicking Surfaces

Hemiwicking is a process where a fluid wets a patterned surface beyond its normal wetting length due to a combination of capillary action and imbibition. This wetting phenomenon is important in many technical fields ranging from physiology to aerospace engineering. Currently, several different techniques exist for fabricating hemiwicking structures. These conventional methods, however, are often time consuming and are difficult to scale-up for large areas or are difficult to customize for specific, nonhomogeneous patterning geometries. The presented protocol provides researchers with a simple, scalable, and cost-effective method for fabricating micro-patterned hemiwicking surfaces. The method fabricates wicking structures through the use of stamp printing, polydimethylsiloxane (PDMS) molding, and thin-film surface coatings. The protocol is demonstrated for hemiwicking with ethanol on PDMS micropillar arrays coated with a 70 nm thick aluminum thin-film.

A simple protocol is provided for the fabrication of hemiwicking structures of varying sizes, shapes, and materials. The protocol uses a combination of physical stamping, PDMS molding, and thin-film surface modifications via common materials deposition techniques.

Hemiwicking is a process where a fluid wets a patterned surface beyond its normal wetting length due to a combination of capillary action and imbibition. ...

Multimodal 3D Printing of Phantoms to Simulate Biological Tissue

Biomedical optical imaging is playing an important role in diagnosis and treatment of various diseases. However, the accuracy and the reproducibility of an optical imaging device are greatly affected by the performance characteristics of its components, the test environment, and the operations. Therefore, it is necessary to calibrate these devices by traceable phantom standards. However, most of the currently available phantoms are homogeneous phantoms that cannot simulate multimodal and dynamic characteristics of biological tissue. Here, we show the fabrication of heterogeneous tissue-simulating phantoms using a production line integrating a spin coating module, a polyjet module, a fused deposition modeling (FDM) module, and an automatic control framework. The structural information and the optical parameters of a &#34;digital optical phantom&#34; are defined in a prototype file, imported to the production line, and fabricated layer-by-layer with sequential switch between different printing modalities. Technical capability of such a production line is exemplified by the automatic printing of skin-simulating phantoms that comprise the epidermis, dermis, subcutaneous tissue, and an embedded tumor.

Spin coating, polyjet printing, and fused deposition modeling are integrated to produce multilayered heterogeneous phantoms that simulate structural and functional properties of biological tissue.

Biomedical optical imaging is playing an important role in diagnosis and treatment of various diseases. However, the accuracy and the reproducibility of ...

Fabrication of Compressed Hosiery and Measurement of its Pressure Characteristic Exerted on the Lower Limbs

This article reports the pressure characteristic measurement of compressed hosiery via direct and indirect methods. In the direct method, an interface sensor is used to measure the pressure value exerted on the lower limbs. In the indirect method, the necessary parameters mentioned by the cone and cylinder model are tested to calculate the pressure value. The necessary parameters involve course density, wales density, circumference, length, thickness, tension, and deformation of the compressed hosiery. Compared with the results of the direct method, the cone model in the indirect method is more suitable for calculating the pressure value because the cone model considers the change in radius of the lower limb from the knee to the ankle. Based on this measurement, the relationship among fabrication, structure, and pressure is further investigated in this study. We find that graduation is the main influence that can change the wales density. On the other hand, elastic motors directly affect the course density and the circumference of the stockings. Our reported work provides the fabrication-structure-pressure relationship and a design guide for gradually compressed hosiery.

This article reports fabrication, structure and pressure measurement of compressed hosiery by employing direct and indirect methods.

This article reports the pressure characteristic measurement of compressed hosiery via direct and indirect methods. In the direct method, an interface ...