The work was supported by the National Natural Science Foundation of China (Grant Nos. 11002139 and 81327803) and the Fundamental Research Funds for the Central Universities. We thank Zachary J. Smith of the University of Science and Technology for providing the audio voiceover.

1. Preparing materials for 3D printing
NOTE: Our optical phantom production line uses a variety of printing materials to simulate the structural and functional heterogeneities of biological tissue. The selection of the printing materials also depends on the manufacturing processes.
<ol>
	<li>Material preparation for spin coating printing
	<ol>
		<li>Add 100 mg of titanium dioxide (TiO2) powder into a beaker containing 100 mL of stereolithography (SLA) photopolymer resin.</li>
		<l...

<ol>
	<li>Lu, G., Fei, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Medical+hyperspectral+imaging:+a+review.">Medical hyperspectral imaging: a review.</a> Journal of Biomedical Optics. 19 (1), 010901 (2014).</li><li>Wang, K., 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=Development+of+a+non-uniform+discrete+Fourier+transform+based+high+speed+spectral+domain+optical+coherence+tomography+system.">Development of a non-uniform discrete Fourier transform based high speed spectral domain optical coherence tomography system.</a> Optics Express. 17 (14), 12121-12131 (2009).</li><li>Zhao, H., Gao, F., Tanikawa, Y., Homma, K., Yamada, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Time-resolved+diffuse+optical+tomographic+imaging+for+the+provision+of+both+anatomical+and+functional+information+about+biological+tissue.">Time-resolved diffuse optical tomographic imaging for the provision of both anatomical and functional information about biological tissue.</a> Applied Optics. 44 (10), 1905-1916 (2005).</li><li>Ding, Z., Ren, H., Zhao, Y., Nelson, J. S., Chen, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-resolution+optical+coherence+tomography+over+a+large+depth+range+with+an+axicon+lens.">High-resolution optical coherence tomography over a large depth range with an axicon lens.</a> Optics Letters. 27 (4), 243-245 (2002).</li><li>Iida, H., 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=Three-dimensional+brain+phantom+containing+bone+and+grey+matter+structures+with+a+realistic+head+contour.">Three-dimensional brain phantom containing bone and grey matter structures with a realistic head contour.</a> Annals of Nuclear Medicine. 27 (1), 25-36 (2013).</li><li>Mobashsher, A. T., Abbosh, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional+human+head+phantom+with+realistic+electrical+properties+and+anatomy.">Three-dimensional human head phantom with realistic electrical properties and anatomy.</a> IEEE Antennas and Wireless Propagation Letters. 13, 1401-1404 (2014).</li><li>Li, J. B., 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+new+head+phantom+with+realistic+shape+and+spatially+varying+skull+resistivity+distribution.">A new head phantom with realistic shape and spatially varying skull resistivity distribution.</a> IEEE Transactions on Biomedical Engineering. 61 (2), 254-263 (2013).</li><li>Bykov, 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=Multilayer+tissue+phantoms+with+embedded+capillary+system+for+OCT+and+DOCT+imaging.">Multilayer tissue phantoms with embedded capillary system for OCT and DOCT imaging.</a> Life Sciences. (International Society for Optics and Photonics). , 73760 (2011).</li><li>Bykov, A. V., Popov, A. P., Priezzhev, A. V., Myllyl&#228;, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Skin+phantoms+with+realistic+vessel+structure+for+OCT+measurements+in+Laser+Applications.">Skin phantoms with realistic vessel structure for OCT measurements in Laser Applications.</a> European Conference on Biomedical Optics. , 80911 (2010).</li><li>Park, 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=Fabrication+of+double+layer+optical+tissue+phantom+by+spin+coating+method:+mimicking+epidermal+and+dermal+layer.">Fabrication of double layer optical tissue phantom by spin coating method: mimicking epidermal and dermal layer.</a> Design and Performance Validation of Phantoms Used in Conjunction with Optical Measurement of Tissue V. , 85830 (2013).</li><li>Wr&#243;bel, M. S., 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=Use+of+optical+skin+phantoms+for+preclinical+evaluation+of+laser+efficiency+for+skin+lesion+therapy.">Use of optical skin phantoms for preclinical evaluation of laser efficiency for skin lesion therapy.</a> Journal of Biomedical Optics. 20 (8), 085003 (2015).</li><li>Sheng, S., Wu, Q., Han, Y., Dong, E., Xu, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabricating+optical+phantoms+to+simulate+skin+tissue+properties+and+microvasculature.">Fabricating optical phantoms to simulate skin tissue properties and microvasculature.</a> Design and Performance Validation of Phantoms Used in Conjunction with Optical Measurement of Tissue Vii. , 932507 (2015).</li><li>Lurie, K. L., Smith, G. T., Khan, S. A., Liao, J. C., Ellerbee, A. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional,+distendable+bladder+phantom+for+optical+coherence+tomography+and+white+light+cystoscopy.">Three-dimensional, distendable bladder phantom for optical coherence tomography and white light cystoscopy.</a> Journal of Biomedical Optics. 19 (3), 36009 (2014).</li><li>Hahn, C., Noghanian, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heterogeneous+breast+phantom+development+for+microwave+imaging+using+regression+models.">Heterogeneous breast phantom development for microwave imaging using regression models.</a> Journal of Biomedical Imaging. 2012, 6 (2012).</li><li>Ansari, M. A., Mohajerani, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimation+of+optical+abnormalities+in+breast+phantom+by+diffuse+equation.">Estimation of optical abnormalities in breast phantom by diffuse equation.</a> Optik-International Journal for Light and Electron Optics. 125 (20), 5978-5981 (2014).</li><li>Roman, M., Gonzalez, J., Carrasquilla, J., Erickson, S. J., Godavarty, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Gen-2+Hand-Held+Optical+Imager:+Phantom+and+Preliminary+in-vivo+Breast+Imaging+Studies.">A Gen-2 Hand-Held Optical Imager: Phantom and Preliminary in-vivo Breast Imaging Studies.</a> 29th Southern Biomedical Engineering Conference. , 103-104 (2013).</li><li>Michaelsen, K. E., 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=Anthropomorphic+breast+phantoms+with+physiological+water,+lipid,+and+hemoglobin+content+for+near-infrared+spectral+tomography.">Anthropomorphic breast phantoms with physiological water, lipid, and hemoglobin content for near-infrared spectral tomography.</a> Journal of Biomedical Optics. 19 (2), 026012 (2014).</li><li>Park, 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=Optical+tissue+phantoms+based+on+spin+coating+method.">Optical tissue phantoms based on spin coating method.</a> Design and Performance Validation of Phantoms Used in Conjunction with Optical Measurement of Tissue VII. , 93250 (2015).</li><li>Mustari, 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=Agarose-based+tissue+mimicking+optical+phantoms+for+diffuse+reflectance+spectroscopy.">Agarose-based tissue mimicking optical phantoms for diffuse reflectance spectroscopy.</a> Journal of Visualized Experiments. (138), e57578 (2018).</li><li>Luciano, N. 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=Utilizing+3D+printing+technology+to+merge+MRI+with+histology:+A+protocol+for+brain+sectioning.">Utilizing 3D printing technology to merge MRI with histology: A protocol for brain sectioning.</a> Journal of Visualized Experiments. (118), e54780 (2016).</li><li>Dong, E., 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=Three-dimensional+fuse+deposition+modeling+of+tissue-simulating+phantom+for+biomedical+optical+imaging.">Three-dimensional fuse deposition modeling of tissue-simulating phantom for biomedical optical imaging.</a> Journal of Biomedical Optics. 20 (12), 121311 (2015).</li><li>Beltrame, E. D. 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=3D+Printing+of+Biomolecular+Models+for+Research+and+Pedagogy.">3D Printing of Biomolecular Models for Research and Pedagogy.</a> Journal of Visualized Experiments. (121), e55427 (2017).</li><li>Bentz, B. Z., Chavan, A. V., Lin, D., Tsai, E. H., Webb, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication+and+application+of+heterogeneous+printed+mouse+phantoms+for+whole+animal+optical+imaging.">Fabrication and application of heterogeneous printed mouse phantoms for whole animal optical imaging.</a> Applied Optics. 55 (2), 280-287 (2016).</li><li>Liu, G., 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=Fabrication+of+a+multilayer+tissue-mimicking+phantom+with+tunable+optical+properties+to+simulate+vascular+oxygenation+and+perfusion+for+optical+imaging+technology.">Fabrication of a multilayer tissue-mimicking phantom with tunable optical properties to simulate vascular oxygenation and perfusion for optical imaging technology.</a> Applied Optics. 57 (23), 6772-6780 (2018).</li></ol>

In the fabrication of the multilayered phantom, the material used for spin coating is a kind of light-curable material instead of PDMS. The intermediate layer is printed with the polyjet printing method, which uses the light-curable resin as raw material. Although thin PDMS phantoms can be made by spin coating after adding tert-butyl alcohol, a PDMS layer cannot effectively bind to the light-curable material during polyjet printing. Therefore, we chose the light-curable resin for spin coating.
<p class="jove_content"...

Biomedical optical imaging represents a family of medical imaging tools that detect diseases and tissue anomalies based on light interactions with biological tissue. In comparison with other imaging modalities, such as magnetic resonance imaging (MRI) and computed tomography (CT), biomedical optical imaging takes the advantage of noninvasive measurement of tissue structural, functional, and molecular characteristics using low-cost and portable devices1,2,3,4. However, despite its superiority in cost and portability, optical imaging has not been widely accepted for clinical diagnosis and therapeutic guidance, partially due to its poor reproducibility and lack of quantitative mapping between optical and biological parameters. The main reason for this limitation is the lack of traceable standards for quantitative calibration and validation of biomedical optical imaging devices.
In the past, a variety of tissue-simulating phantoms were developed for biomedical optical imaging research in various tissue types, such as brain5,6,7, skin8,9,10,11,12, bladder13, and breast tissues14,15,16,17. These phantoms are primarily produced by one of the following fabrication processes: 1) spin coating10,18 (for simulating homogenous and thin-layered tissue); 2) molding19 (for simulating bulky tissue with geometric features); and 3) three-dimensional (3D) printing20,21,22 (for simulating multilayered heterogeneous tissue). Skin phantoms produced by molding are able to mimic the bulk optical properties of skin tissue but cannot simulate the lateral optical heterogeneities19. Bentz et al. used a two-channel FDM 3D printing method to mimic different optical properties of biological tissue23. However, using two materials cannot sufficiently simulate tissue optical heterogeneity and anisotropy. Lurie et al. created a bladder phantom for optical coherence tomography (OCT) and cystoscopy by combining 3D printing and spin coating13. However, heterogeneous features of the phantom, such as blood vessels, had to be hand painted.
Among the above phantom fabrication processes, 3D printing provides the most flexibility for simulating the structural and functional heterogeneities of biological tissue. However, many biological tissue types, such as skin tissue, consist of multilayered and multiscaled components that cannot be effectively duplicated by a single 3D printing process. Therefore, integration of multiple manufacturing processes is necessary. We propose a 3D printing production line that integrates multiple manufacturing processes for automatic production of multilayered and multiscaled tissue simulating phantoms as a traceable standard for biomedical optical imaging (Figure 1). Although spin coating, polyjet printing, and FDM are automated in our 3D printing production line, each modality retains the same functional characteristics as the established processes. Therefore, this paper provides a general guideline for producing multiscaled, multilayered, and heterogeneous tissue-simulation phantoms without the need for physical integration of multiple processes in a single apparatus.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/60563/60563fig1.jpg" /> 
Figure 1: The CAD diagram of the 3D printing production line. (A) The 3D printing production line with the top shell removed. (B) The schematic of the spin coating module and the mechanical hand module. (C) The schematic of the polyjet printing module. (D) The schematic of the FDM printing module (the UV lamp belongs to the polyjet printing module). <a href="https://www.jove.com/files/ftp_upload/60563/60563fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>2-Hydroxy-2-methylpropiophenone</td>
			<td>aladdin</td>
			<td>H110280-500g</td>
			<td>Light initiator 
			<a href="http://www.aladdin-e.com/" target="_blank">http://www.aladdin-e.com/</a></td>
		</tr>
		<tr>
			<td>3D printing control system</td>
			<td>USTC</td>
			<td>USTC-3DPrinter_control1.0</td>
			<td>custom-made 
			github: 
			<a href="https://github.com/macanzhen/3D_printing_control_system_of_USTC" target="_blank">https://github.com/macanzhen/</a></td>
		</tr>
		<tr>
			<td>3D printing system</td>
			<td>USTC</td>
			<td>USTC-3DPrinter1.0</td>
			<td>custom-made</td>
		</tr>
		<tr>
			<td>AcroRip color</td>
			<td>Human Plus</td>
			<td>AcroRip v8.2.6</td>
			<td></td>
		</tr>
		<tr>
			<td>All-in-one nozzle slicing script</td>
			<td>Shenzhen CBD Technology Co.,Ltd.</td>
			<td></td>
			<td>github: 
			<a href="https://github.com/macanzhen/3D_printing_Cura_all-in-one-nozzle-slicing-script" target="_blank">https://github.com/macanzhen/</a></td>
		</tr>
		<tr>
			<td>Chinese Red Dye</td>
			<td>Juents</td>
			<td></td>
			<td>Oil-soluble</td>
		</tr>
		<tr>
			<td>Cura</td>
			<td>Ultimaker</td>
			<td>Cura_15.04.6</td>
			<td></td>
		</tr>
		<tr>
			<td>Gel Wax</td>
			<td>Shanghai Lida Industry Co.,ltd.</td>
			<td>LP</td>
			<td>melting point: 56 &#176;C</td>
		</tr>
		<tr>
			<td>Graphite</td>
			<td>aladdin</td>
			<td>G103922-100g</td>
			<td>Change object optical absorption parameters 
			<a href="http://www.aladdin-e.com/" target="_blank">http://www.aladdin-e.com/</a></td>
		</tr>
		<tr>
			<td>PDMS</td>
			<td>Dow Corning</td>
			<td>184</td>
			<td></td>
		</tr>
		<tr>
			<td>Titanium dioxide</td>
			<td>ALDRICH</td>
			<td>24858-100G</td>
			<td>347 nm</td>
		</tr>
		<tr>
			<td>Triethylene glycol dimethacrylate</td>
			<td>aladdin</td>
			<td>T101642-250ml</td>
			<td>Photocured monomer 
			<a href="http://www.aladdin-e.com/" target="_blank">http://www.aladdin-e.com/</a></td>
		</tr>
		<tr>
			<td>UV ink SLA Photopolymer Resin</td>
			<td>time80s</td>
			<td>RESIN-A</td>
			<td><a href="http://www.time80s.com/zlxz" target="_blank">http://www.time80s.com/zlxz</a></td>
		</tr>
	</tbody>
</table>

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.

Phantom fabricated by spin coating 
The spin coating evenly distributes the droplets on the substrate by rotating the turntable, and a single layer of the original body is fabricated after curing. The rotational speed of the substrate and the time of rotation not only affect the surface quality of the phantom, but also determine the thickness of each layer of the phantom. Phantoms of different thicknesses can be fabricated by repetitive spin coating layer-by-layer. The optical parameters of the phan...

Watch this Scientific Journal Video about Multimodal 3D Printing of Phantoms to Simulate Biological Tissue at JoVE.com

Multimodal 3D Printing of Phantoms to Simulate Biological Tissue

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 ...

Spin-coating, polyjet printing and fused deposition modeling are integrated to produce multilayered heterogenous phantoms that simulate structural and functional properties of biologic tissue. Lack of traceable phantom standards that simulate structural and functional heterogeneity of biologic tissue has become the bottleneck for development and validation of biomedical optical devices. This video shows layer by layer fabrication of heterogeneous tissue simulating phantoms by integrating multiple additive manufacturing processes such as spin coating, PolyJet printing and FDM in a production line of 3D printing.Technical capability of such a production line is exemplified by the automatic printing of skin-simulating phantoms that comprise epidermis, dermis, subcutaneous tissue and an embedded tumor. Material preparation for spin coating printing. Add titanium dioxide powder into SLA photopolymer Resin, stir for 30 minutes on a magnetic stir.Seal with tin foil and sonicate. Vacuum for 10 minutes. Load it into the storage syringe Material preparation for polyjet printing.Add material, sonicate, add Chinese Red Dye, load them into the cartridges, put cartridges into the printer. Material preparation for FDM printing. Heat low-density gel wax on a magnetic stir.Add titanium dioxide powder, add graphite powder into the second beaker. Vacuum load them into the extruder of the hybrid three nozzle module. Design of digital optical phantom of skin Setting up parameters for spin-coating.Set up the parameters of rotating speed and duration in the control software. setup the amount of spin-coating material and the time of light-curing. Preparation of source file for polyjet printing, Import the blood vessel image into the software, set the print position and set the inkjet parameters generate the PRN file needed for printing after the setup is complete preparation of G-code for FDM printing, import the tumor model into the Cura software add the all in one nozzle slicing script into the Cura software and slice the model to generate the G-code required for printing Documents import of the printing control software.Click the File menu item in the menu bar. Load the UV printing PRN files. import the G-code.Click the Start printing button. The mechanical hand moves the substrate on the loading station to the center center of the spin-coater sample stage. The glue dispenser controls a syringed drip the material to the center of the substrate.The spin-coater starts to work. Drop the UV lamp and turn it on and the skin epidermis will be printed. Move the substrate to the 3D mobile platform.Move the substrate to the initial position of the UV printing, push the inkjet printer to the working position. The inkjet printer prints the picture. The UV lamp is pushed by the cylinder and moved down to the position above the substrate, turn on the UV lamp.Repeat for the next layer of printing until the multilayer printing is complete. The mixing nozzle is moved to the working position by the push of the cylinder print according to the instructions of the G-code. The print is completed until the subcutaneous tissue portion of the tumor portion is printed.Move the substrate back to the loading station cast the subcutaneous layer phantom with the help of a mold Representative results. Result of automated printing production line. By integrating the 3D printing methods, the system could create a tumor like phantom by following the steps in the protocol.Taking the simplified multilayer skin model is an example. The epidermis layer, dermis layer and subcutaneous tissue layer with different thicknesses and different optical properties are fabricated by the spin coating method, polyjet printing method and FDM printing method. Through the model the possibility of combining spin coating, polyjet printing and FDM printing to produce optical phantoms was verified it is proved that the system has the potential to produce tissue optical phantom with optical simulation characteristics and structural simulation characteristics.

multimodal-3d-printing-of-phantoms-to-simulate-biological-tissue

Research

JoVE Journal

Engineering

7.2K visualizações.  University of Science and Technology of China. O spin-coating, a impressão de polijato e a modelagem de deposição fundida são integrados para produzir fantasmas heterogêneos multicamadas que simulam propriedades estruturais e funcionais do tecido biológico. A falta de padrões fantasmas rastreáveis que simulam a heterogeneidade estrutural e funcional do tecido biológico tornou-se o gargalo para o desenvolvimento e validação de dispositivos ópticos biomédicos. Este vídeo mostra a fabricação camada por camada de tecido hetero...