Name: 3d printing and in situ surface modification via type i photoinitiated reversible addition-fragmentation chain transfer polymerization
Uploaded: 2022-02-18T14:45:00
Description: Watch this Scientific Journal Video about 3D Printing and In Situ Surface Modification via Type I Photoinitiated Reversible Addition-Fragmentation Chain Transfer Polymerization at JoVE.com

The authors acknowledge funding from the Australian Research Council and UNSW Australia via the Discovery Research program (DP210100094).

1. Preparation of 3D printing program and 3D printer
<ol>
	<li>Design the digital model for 3D printing following the steps below.
	<ol>
		<li>Open a computer-assisted design program (see Table of Materials).</li>
		<li>In the x-y plane, create a rectangle centered on the origin having dimensions of 80 mm x 40 mm, then extrude along the positive z-axis for 1.5 mm to make a solid rectangular prism, called the base object.</li>
		<li>Above the base object, i.e., at z = 1.5 mm, draw the d...

<ol>
	<li>Ligon, S. C., Liska, R., Stampfl, J., Gurr, M., M&#252;lhaupt, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polymers+for+3D+printing+and+customized+additive+manufacturing.">Polymers for 3D printing and customized additive manufacturing.</a> Chemical Reviews. 117 (15), 10212-10290 (2017).</li><li>Lewis, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+ink+writing+of+3D+functional+materials.">Direct ink writing of 3D functional materials.</a> Advanced Functional Materials. 16 (17), 2193-2204 (2006).</li><li>Kumar, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selective+laser+sintering:+A+qualitative+and+objective+approach.">Selective laser sintering: A qualitative and objective approach.</a> JOM. 55 (10), 43-47 (2003).</li><li>Jung, 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=Designing+with+light:+Advanced+2D,+3D,+and+4D+materials.">Designing with light: Advanced 2D, 3D, and 4D materials.</a> Advanced Materials. 32 (18), 1903850 (2020).</li><li>Lim, K. 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=Fundamentals+and+applications+of+photo-cross-linking+in+bioprinting.">Fundamentals and applications of photo-cross-linking in bioprinting.</a> Chemical Reviews. 120 (19), 10662-10694 (2020).</li><li>Chen, 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=Photoinitiators+derived+from+natural+product+scaffolds:+Monochalcones+in+three-component+photoinitiating+systems+and+their+applications+in+3D+printing.">Photoinitiators derived from natural product scaffolds: Monochalcones in three-component photoinitiating systems and their applications in 3D printing.</a> Polymer Chemistry. 11 (28), 4647-4659 (2020).</li><li>Chen, 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=Novel+D-&#960;-A+and+A-&#960;-D-&#960;-A+three-component+photoinitiating+systems+based+on+carbazole/triphenylamino+based+chalcones+and+application+in+3D+and+4D+printing.">Novel D-&#960;-A and A-&#960;-D-&#960;-A three-component photoinitiating systems based on carbazole/triphenylamino based chalcones and application in 3D and 4D printing.</a> Polymer Chemistry. 11 (40), 6512-6528 (2020).</li><li>Zhang, J., Xiao, P. <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+photopolymers.">3D printing of photopolymers.</a> Polymer Chemistry. 9 (13), 1530-1540 (2018).</li><li>Zhu, Y., Ramadani, E., Egap, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thiol+ligand+capped+quantum+dot+as+an+efficient+and+oxygen+tolerance+photoinitiator+for+aqueous+phase+radical+polymerization+and+3D+printing+under+visible+light.">Thiol ligand capped quantum dot as an efficient and oxygen tolerance photoinitiator for aqueous phase radical polymerization and 3D printing under visible light.</a> Polymer Chemistry. 12 (35), 5106-5116 (2021).</li><li>Jiang, P., Ji, Z., Wang, X., Zhou, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+functionalization+-+a+new+functional+dimension+added+to+3D+printing.">Surface functionalization - a new functional dimension added to 3D printing.</a> Journal of Materials Chemistry C. 8 (36), 12380-12411 (2020).</li><li>Gonzalez, G., Chiappone, A., Dietliker, K., Pirri, C. F., Roppolo, I. <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+functionalization+of+3D+printed+polydimethylsiloxane-based+microfluidic+devices+obtained+through+digital+light+processing.">Fabrication and functionalization of 3D printed polydimethylsiloxane-based microfluidic devices obtained through digital light processing.</a> Advanced Materials Technologies. 5 (9), 2000374 (2020).</li><li>Yao, X., Song, Y., Jiang, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Applications+of+bio-inspired+special+wettable+surfaces.">Applications of bio-inspired special wettable surfaces.</a> Advanced Materials. 23 (6), 719-734 (2011).</li><li>Bose, S., Robertson, S. F., Bandyopadhyay, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+modification+of+biomaterials+and+biomedical+devices+using+additive+manufacturing.">Surface modification of biomaterials and biomedical devices using additive manufacturing.</a> Acta Biomaterialia. 66, 6-22 (2018).</li><li>Wang, X., 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=i3DP,+a+robust+3D+printing+approach+enabling+genetic+post-printing+surface+modification.">i3DP, a robust 3D printing approach enabling genetic post-printing surface modification.</a> Chemical Communications. 49 (86), 10064-10066 (2013).</li><li>Lee, K., Corrigan, N., Boyer, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+high-resolution+3D+printing+and+surface+functionalization+via+type+I+photoinitiated+raft+polymerization.">Rapid high-resolution 3D printing and surface functionalization via type I photoinitiated raft polymerization.</a> Angewandte Chemie International Edition. 60 (16), 8839-8850 (2021).</li><li>Zhang, Z., Corrigan, N., Bagheri, A., Jin, J., Boyer, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+versatile+3D+and+4D+printing+system+through+photocontrolled+raft+polymerization.">A versatile 3D and 4D printing system through photocontrolled raft polymerization.</a> Angewandte Chemie International Edition. 58 (50), 17954-17963 (2019).</li><li>Corrigan, N., 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=Reversible-deactivation+radical+polymerization+(controlled/living+radical+polymerization):+From+discovery+to+materials+design+and+applications.">Reversible-deactivation radical polymerization (controlled/living radical polymerization): From discovery to materials design and applications.</a> Progress in Polymer Science. 111, 101311 (2020).</li><li>Moad, G., Rizzardo, E., Thang, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Living+radical+polymerization+by+the+raft+process+-+A+third+update.">Living radical polymerization by the raft process - A third update.</a> Australian Journal of Chemistry. 65 (8), 985-1076 (2012).</li><li>Chiefari, 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=Living+free-radical+polymerization+by+reversible+addition&#8722;Fragmentation+chain+transfer:+The+RAFT+process.">Living free-radical polymerization by reversible addition&#8722;Fragmentation chain transfer: The RAFT process.</a> Macromolecules. 31 (16), 5559-5562 (1998).</li><li>Fromel, M., 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=User-friendly+chemical+patterning+with+digital+light+projection+polymer+brush+photolithography.">User-friendly chemical patterning with digital light projection polymer brush photolithography.</a> European Polymer Journal. 158, 110652 (2021).</li><li>Fromel, M., Li, M., Pester, C. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+engineering+with+polymer+brush+photolithography.">Surface engineering with polymer brush photolithography.</a> Macromolecular Rapid Communications. 41 (18), 2000177 (2020).</li><li>Wang, C. -. G., Chen, C., Sakakibara, K., Tsujii, Y., Goto, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Facile+fabrication+of+concentrated+polymer+brushes+with+complex+patterning+by+photocontrolled+organocatalyzed+living+radical+polymerization.">Facile fabrication of concentrated polymer brushes with complex patterning by photocontrolled organocatalyzed living radical polymerization.</a> Angewandte Chemie International Edition. 57 (41), 13504-13508 (2018).</li><li>Zoppe, J. O., 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=Surface-initiated+controlled+radical+polymerization:+state-of-the-art,+opportunities,+and+challenges+in+surface+and+interface+engineering+with+polymer+brushes.">Surface-initiated controlled radical polymerization: state-of-the-art, opportunities, and challenges in surface and interface engineering with polymer brushes.</a> Chemical Reviews. 117 (3), 1105 (2017).</li><li>Pester, C. W., 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=Ambiguous+antifouling+surfaces:+Facile+synthesis+by+light-mediated+radical+polymerization.">Ambiguous antifouling surfaces: Facile synthesis by light-mediated radical polymerization.</a> Journal of Polymer Science Part A: Polymer Chemistry. 54 (2), 253-262 (2016).</li><li>Poelma, J. E., Fors, B. P., Meyers, G. F., Kramer, J. W., Hawker, C. 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The present protocol demonstrates a process for 3D printing of polymer materials with independently tunable bulk and interfacial properties. The procedure is performed via a two-step method by 3D printing the base substrate and subsequently modifying the surface layer of the 3D printed object using a different functional resin but using the same 3D printing hardware. While the 3D printers used in this work are designed to print crosslinked materials in a layer-by-layer fashion, the surface functionalization can ...

Additive manufacturing and 3D printing have revolutionized material manufacturing by providing more efficient and facile routes for the fabrication of geometrically complex materials1. Apart from the enhanced design freedoms in 3D printing, these technologies produce less waste than traditional subtractive manufacturing processes via the judicious use of precursor materials in a layer-by-layer manufacturing process. Since the 1980s, a wide range of different 3D printing techniques has been developed to fabricate polymeric, metal, and ceramic components1. The most commonly employed methods include extrusion-based 3D printing such as fused filament fabrication and direct ink writing techniques2, sintering techniques such as selective laser sintering3, as well as resin-based photoinduced 3D printing techniques such as laser and projection-based stereolithography and masked digital light processing techniques4. Among the many 3D printing techniques in existence today, photoinduced 3D printing techniques provide some advantages compared to other methods, including higher resolution and faster printing speeds, as well as the ability to perform solidification of the liquid resin at room temperature, which opens the possibility to advanced biomaterial 3D printing4,5,6,7,8,9.
While these advantages have allowed the widespread adoption of 3D printing in many fields, the limited ability to independently tailor the 3D printed material properties restricts future applications10. In particular, the inability to easily tailor the bulk mechanical properties independently of the interfacial properties limits applications such as implants, which require finely tailored biocompatible surfaces and often vastly differing bulk properties, as well as antifouling and antibacterial surfaces, sensor materials, and other smart materials11,12,13. Researchers have proposed surface modification of 3D printed materials to overcome these issues to provide more independently tailorable bulk and interfacial properties10,14,15.
Recently, our group developed a photoinduced 3D printing process that exploits reversible addition-fragmentation chain transfer (RAFT) polymerization to mediate network polymer synthesis15,16. RAFT polymerization is a type of reversible deactivation radical polymerization that provides a high degree of control over the polymerization process and allows for the production of macromolecular materials with finely tuned molecular weights and topologies, and broad chemical scope17,18,19. Notably, the thiocarbonylthio compounds, or RAFT agents, used during RAFT polymerization are retained after polymerization. They can thus be reactivated to modify further the chemical and physical properties of the macromolecular material. Thus, after 3D printing, these dormant RAFT agents on the surfaces of the 3D printed material can be reactivated in the presence of functional monomers to provide tailored material surfaces20,21,22,23,24,25,26. The secondary surface polymerization dictates the interfacial material properties and can be performed in a spatially controlled fashion via photochemical initiation.
The present protocol describes a method for 3D printing polymeric materials via a photoinduced RAFT polymerization process and the subsequent in situ surface modification to modulate the interfacial properties independently of the bulk material mechanical properties. Compared to previous 3D printing and surface modification approaches, the current protocol does not require deoxygenation or other stringent conditions and is thus highly accessible for non-specialists. Furthermore, the use of 3D printing hardware to perform both the initial material fabrication and the surface post-functionalization provides spatial control over the material properties and can be performed without the tedious alignment of several different photomasks to make complex patterns.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>1-pyrenemethyl methacrylate</td>
			<td>Sigma-Aldrich</td>
			<td>765120</td>
			<td></td>
		</tr>
		<tr>
			<td>2-(n-butylthiocarbonothioylthio) propanoic acid</td>
			<td>Boron Molecular</td>
			<td>BM1640</td>
			<td></td>
		</tr>
		<tr>
			<td>3D Printer</td>
			<td>Photon</td>
			<td>Mono S</td>
			<td>light intensity at digital mask surface = 0.81 mW cm-2</td>
		</tr>
		<tr>
			<td>3D Printing Slicing Software</td>
			<td>Photon</td>
			<td>Photon Workshop V2.1.19</td>
			<td></td>
		</tr>
		<tr>
			<td>40 kHz Ultrasonic Bath</td>
			<td>Thermoline</td>
			<td>UB-410</td>
			<td></td>
		</tr>
		<tr>
			<td>Compressed Air</td>
			<td>Coregas</td>
			<td>230142</td>
			<td>Tank operating at 130 kPa</td>
		</tr>
		<tr>
			<td>Computer Assisted Design Program</td>
			<td>SpaceClaim</td>
			<td>SpaceClaim Design Manager V19.1</td>
			<td></td>
		</tr>
		<tr>
			<td>Diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide</td>
			<td>Sigma-Aldrich</td>
			<td>415952</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol Undenatured 100% AR</td>
			<td>ChemSupply</td>
			<td>EL043-2.5L-P</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol Wash bottle</td>
			<td>Rowe Scientific</td>
			<td>AZLWGF541P</td>
			<td></td>
		</tr>
		<tr>
			<td>Fluorescence Imager</td>
			<td>Bio-Rad</td>
			<td>Gel Doc XR+</td>
			<td>Uses a 302 nm gas discharge lamp as emission source</td>
		</tr>
		<tr>
			<td>Light intensity power meter</td>
			<td>Newport</td>
			<td>843-R</td>
			<td></td>
		</tr>
		<tr>
			<td>Mechanical Tester</td>
			<td>Mark&#8211;10</td>
			<td>ESM303</td>
			<td>1 kN force gauge M5&#8211;200</td>
		</tr>
		<tr>
			<td>Moldable plastic film</td>
			<td>Parafilm</td>
			<td>PM992</td>
			<td></td>
		</tr>
		<tr>
			<td>N,N-dimethlacrylamide</td>
			<td>Sigma-Aldrich</td>
			<td>274135</td>
			<td></td>
		</tr>
		<tr>
			<td>N,N-Dimethylformamide HPLC</td>
			<td>ChemSupply</td>
			<td>LC1051-G4L</td>
			<td></td>
		</tr>
		<tr>
			<td>Poly(ethylene glycol) diacrylate average Mn 250</td>
			<td>Sigma-Aldrich</td>
			<td>475629</td>
			<td></td>
		</tr>
		<tr>
			<td>Post Cure Lamp</td>
			<td>Leoway</td>
			<td>&#8206;B0869BY79P</td>
			<td>60 W 405 nm</td>
		</tr>
		<tr>
			<td>Standards document</td>
			<td>ASTM</td>
			<td>ASTM Standard D638-14</td>
			<td></td>
		</tr>
		<tr>
			<td>Tensile testing machine</td>
			<td>Mark-10</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>UV Light</td>
			<td>Fisher Scientific</td>
			<td>11-982-30</td>
			<td>6 W Spectroline E-Series, Gas discharge lamp</td>
		</tr>
		<tr>
			<td>Vortex Mixer IKA Vortex 3</td>
			<td>LabTek</td>
			<td>3340000I</td>
			<td></td>
		</tr>
	</tbody>
</table>

3d printing and in situ surface modification via type i photoinitiated reversible addition-fragmentation chain transfer polymerization

3D printing provides facile access to geometrically complex materials. However, these materials have intrinsically linked bulk and interfacial properties dependent on the chemical composition of the resin. In the current work, 3D printed materials are post-functionalized using the 3D printer hardware via a secondary surface-initiated polymerization process, thus providing independent control over the bulk and interfacial material properties. This process begins with preparing liquid resins, which contain a monofunctional monomer, a crosslinking multifunctional monomer, a photochemically labile species that enables initiation of polymerization, and critically, a thiocarbonylthio compound which facilitates reversible addition-fragmentation chain transfer (RAFT) polymerization. The thiocarbonylthio compound, known commonly as a RAFT agent, mediates the chain growth polymerization process and provides polymeric materials with more homogeneous network structures. The liquid resin is cured in a layer-by-layer fashion using a commercially available digital light processing 3D printer to give three-dimensional materials having spatially controlled geometries. The initial resin is removed and replaced with a new mixture containing functional monomers and photoinitiating species. The 3D printed material is then exposed to light from the 3D printer in the presence of the new functional monomer mixture. This allows photoinduced surface-initiated polymerization to occur from the latent RAFT agent groups on the surface of the 3D printed material. Given the chemical flexibility of both resins, this process allows a wide range of 3D printed materials to be produced with tailorable bulk and interfacial properties.

The general procedure for 3D printing and surface functionalization is shown in Figure 1. In this protocol, a network polymer is initially synthesized via a photoinduced RAFT polymerization process15, using a 3D printer to fabricate an object in a layer-by-layer process (Figure 1A). The bulk resin used to form the polymer network contains a photolabile initiating species (TPO), which generates radicals upon exposure to 405 nm lig...

Watch this Scientific Journal Video about 3D Printing and In Situ Surface Modification via Type I Photoinitiated Reversible Addition-Fragmentation Chain Transfer Polymerization at JoVE.com

3D Printing and In Situ Surface Modification via Type I Photoinitiated Reversible Addition-Fragmentation Chain Transfer Polymerization

The present protocol describes the digital light processing-based 3D printing of polymeric materials using type I photoinitiated reversible addition-fragmentation chain transfer polymerization and the subsequent in situ material post-functionalization via surface-mediated polymerization. Photoinduced 3D printing provides materials with independently tailored and spatially controlled bulk and interfacial properties.

3D Printing and In Situ Surface Modification via Type I Photoinitiated Reversible Addition-Fragmentation Chain Transfer Polymerization

3D printing provides facile access to geometrically complex materials. However, these materials have intrinsically linked bulk and interfacial properties ...

This protocol allows the bulk and interfacial properties of 3D-printed materials to be independently tuned. This gives greater flexibility to design and fabricate complex 3D-printed materials. This technique doesn't require stringent reaction conditions and can be performed using commercially available equipment.As a result, this technique makes it significantly easier to fabricate complex 3D-printed materials. To begin, prepare the bulk resin by weighing 0.36 grams of BTPA into a clean 50 milliliter amber vial. Add 13.63 milliliters of polyethylene glycol diacrylate and 14.94 milliliters of DMAm to the amber vial using a micropipette.In a separate 20 milliliter clean glass vial covered with aluminum foil, add 0.53 grams of TPO. Using a micropipette, add 10 milliliters of DMAm to the 20 milliliter glass vial containing the TPO and seal the vial using the cap. Thoroughly homogenize the solution of TPO in DMAm by mixing using a vortex mixer for 10 seconds and then using a standard laboratory sonic bath to sonicate the mixture for 2 minutes at room temperature.Using a glass pipette and rubber pipette bulb, transfer the solution from the 20 milliliter glass vial to the 50 milliliter amber vial and seal the vial with a cap and moldable plastic film. Gently shake the 50 milliliter amber vial and then placed the vial in a sonic bath for 2 minutes at room temperature to ensure the mixture is homogenous. Place the sealed amber vial filled with the bulk resin in a fume hood for later use.Prepare the surface resin as described previously for the preparation of the bulk resin. After preparing the surface resin, place the sealed amber vile filled with the surface resin in a fume hood for later use. To perform 3D printing, pour the previously prepared bulk resin into the 3D printer vat, ensuring that the solution completely covers the bottom film in the vat without any air bubbles or other inhomogeneities, and then close the 3D printer case.Navigate the USB using the 3D printer screen and select the sliced model file by clicking on the triangle Play button to begin the 3D printing process. By watching the 3D printer screen, take careful note of the number of layers printed and pause the printing program by pressing the two vertical lines Pause button during 3D printing of the last layer of the base substrate. Remove the entire build stage and gently rinse the build stage and printed material with undenatured 100%ethanol from a wash bottle for 10 seconds to remove residual bulk resin from the 3D-printed material and the build stage.Using compressed air, gently dry the 3D-printed material and build stage to remove residual ethanol and then reinsert the build stage into the 3D printer. Remove the vat from the 3D printer and pour the remaining bulk resin into an amber vile, and store the vile in a cool, dark place. Using undenatured 100%ethanol from a wash bottle, carefully rinse the vat to remove any residual bulk resin.Dry the vat using a stream of compressed air to remove any residual ethanol and reinsert the vat into the 3D printer. To perform surface functionalization, pour the previously prepared surface resin into the 3D printer vat, ensuring that the solution completely covers the bottom film without any air bubbles or other inhomogeneities, and then close the 3D printer case. Resume the 3D printing program by clicking on the triangle Play button to allow the predetermined surface patterning to occur.Once the printing program has been completed, remove the build stage from the 3D printer and wash for 10 seconds with undenatured 100%ethanol using a wash bottle to remove residual surface resin from the 3D-printed material and the build stage. Using compressed air, gently dry the 3D-printed material and build stage to remove residual ethanol. While still attached to the build stage, post-cure the material by inverting the entire build stage and placing it under 405 nanometer light for 15 minutes.Gently remove the surface-functionalized 3D-printed material from the build stage using a thin metal plate or paint scraper. To perform the fluorescence analysis, place the 3D-printed surface-functionalized material under a 312 nanometer ultraviolet gas discharge lamp in a dark place, ensuring the surface-functionalized layer is facing up. Turn the lamp on to continuously irradiate the surface layer with 312 nanometer light and observe the fluorescent pattern.To perform the tensile property analysis, place the dog bone-shaped specimens between the grips of a tensile testing machine, ensuring the 3D-printed material is equally placed at a distance of 50.3 millimeters. Start the program to acquire force versus travel data. After 3D printing and surface functionalization, the material was post-cured under 405 nanometer irradiation.It was observed that the functionalized materials were yellow but highly transparent with well-defined shapes. The functionalized materials show no fluorescence in the dark. However, upon ultraviolet irradiation, spatially-resolved surface fluorescence was observed in the regions irradiated with light during the surface functionalization step, visible as a slightly raised yin-yang pattern.Fluorescence images showed that the underside of the material showed no fluorescence under ultraviolet light irradiation. However, the top side of the material showed strong fluorescence in the yin-yang pattern. The mechanical properties of the 3D-printed dog bone-shaped samples were analyzed and a stress-strain curve was obtained.The material showed an elastic deformation, providing yield stress of approximately 25 megapascal, and then a plastic deformation before failure. The elongation at break was approximately 12%while the stress at break was about 22 megapascal. The Young's modulus was calculated to be approximately 7 megapascal, while the toughness was approximately 115 megajoule per cubic meter.It's important to make sure that the surface resident completely covers the vat film and is free from air bubbles or other imperfections that may lead to deviations from the intended surface pattern.

3d-printing-situ-surface-modification-via-type-i-photoinitiated

Research

JoVE Journal

Chemistry

Facile and Efficient Preparation of Tri-component Fluorescent Glycopolymers via RAFT-controlled Polymerization

Synthetic glycopolymers are instrumental and versatile tools used in various biochemical and biomedical research fields. An example of a facile and efficient synthesis of well-controlled fluorescent statistical glycopolymers using reversible addition-fragmentation chain-transfer (RAFT)-based polymerization is demonstrated. The synthesis starts with the preparation of &#946;-galactose-containing glycomonomer 2-lactobionamidoethyl methacrylamide obtained by reaction of lactobionolactone and N-(2-aminoethyl) methacrylamide (AEMA). 2-Gluconamidoethyl methacrylamide (GAEMA) is used as a structural analog lacking a terminal &#946;-galactoside. The following RAFT-mediated copolymerization reaction involves three different monomers: N-(2-hydroxyethyl) acrylamide as spacer, AEMA as target for further fluorescence labeling, and the glycomonomers. Tolerant of aqueous systems, the RAFT agent used in the reaction is (4-cyanopentanoic acid)-4-dithiobenzoate. Low dispersities (&#8804;1.32), predictable copolymer compositions, and high reproducibility of the polymerizations were observed among the products. Fluorescent polymers are obtained by modifying the glycopolymers with carboxyfluorescein succinimidyl ester targeting the primary amine functional groups on AEMA. Lectin-binding specificities of the resulting glycopolymers are verified by testing with corresponding agarose beads coated with specific glycoepitope recognizing lectins. Because of the ease of the synthesis, the tight control of the product compositions and the good reproducibility of the reaction, this protocol can be translated towards preparation of other RAFT-based glycopolymers with specific structures and compositions, as desired.

An efficient, three-step synthesis of RAFT-based fluorescent glycopolymers, consisting of glycomonomer preparation, copolymerization, and post-modification, is demonstrated. This protocol can be used to prepare RAFT-based statistical glycopolymers with desired structures.

Synthetic glycopolymers are instrumental and versatile tools used in various biochemical and biomedical research fields. An example of a facile and ...

Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization

We demonstrate a method for high-throughput catalyst screening using a parallel pressure reactor starting from the initial synthesis of a nickel &#945;-diimine ethylene polymerization catalyst. Initial polymerizations with the catalyst lead to optimized reaction conditions, including catalyst concentration, ethylene pressure and reaction time. Using gas-uptake data for these reactions, a procedure to calculate the initial rate of propagation (kp) is presented. Using the optimized conditions, the ability of the nickel &#945;-diimine polymerization catalyst to undergo chain transfer with diethylzinc (ZnEt2) during ethylene polymerization was investigated. A procedure to assess the ability of the catalyst to undergo chain transfer (from molecular weight and 13C NMR data), calculate the degree of chain transfer, and calculate chain transfer rates (ke) is presented.

A protocol for the high-throughput analysis of polymerization catalyst, chain transfer polymerizations, polyethylene characterization, and reaction kinetic analysis is presented.

We demonstrate a method for high-throughput catalyst screening using a parallel pressure reactor starting from the initial synthesis of a nickel ...

Assessment of Boron Doped Diamond Electrode Quality and Application to In Situ Modification of Local pH by Water Electrolysis

Boron doped diamond (BDD) electrodes have shown considerable promise as an electrode material where many of their reported properties such as extended solvent window, low background currents, corrosion resistance, etc., arise from the catalytically inert nature of the surface. However, if during the growth process, non-diamond-carbon (NDC) becomes incorporated into the electrode matrix, the electrochemical properties will change as the surface becomes more catalytically active. As such it is important that the electrochemist is aware of the quality and resulting key electrochemical properties of the BDD electrode prior to use. This paper describes a series of characterization steps, including Raman microscopy, capacitance, solvent window and redox electrochemistry, to ascertain whether the BDD electrode contains negligible NDC i.e. negligible sp2 carbon. One application is highlighted which takes advantage of the catalytically inert and corrosion resistant nature of an NDC-free surface i.e. stable and quantifiable local proton and hydroxide production due to water electrolysis at a BDD electrode. An approach to measuring the local pH change induced by water electrolysis using iridium oxide coated BDD electrodes is also described in detail.

Assessment of Boron Doped Diamond Electrode Quality and Application to In Situ Modification of Local pH by Water Electrolysis

A protocol is described for the characterization of the key electrochemical parameters of a boron doped diamond (BDD) electrode and subsequent application for in situ pH generation experiments.

Boron doped diamond (BDD) electrodes have shown considerable promise as an electrode material where many of their reported properties such as extended ...

A Method to Manipulate Surface Tension of a Liquid Metal via Surface Oxidation and Reduction

Controlling interfacial tension is an effective method for manipulating the shape, position, and flow of fluids at sub-millimeter length scales, where interfacial tension is a dominant force. A variety of methods exist for controlling the interfacial tension of aqueous and organic liquids on this scale; however, these techniques have limited utility for liquid metals due to their large interfacial tension.
Liquid metals can form soft, stretchable, and shape-reconfigurable components in electronic and electromagnetic devices. Although it is possible to manipulate these fluids via mechanical methods (e.g., pumping), electrical methods are easier to miniaturize, control, and implement. However, most electrical techniques have their own constraints: electrowetting-on-dielectric requires large (kV) potentials for modest actuation, electrocapillarity can affect relatively small changes in the interfacial tension, and continuous electrowetting is limited to plugs of the liquid metal in capillaries.
Here, we present a method for actuating gallium and gallium-based liquid metal alloys via an electrochemical surface reaction. Controlling the electrochemical potential on the surface of the liquid metal in electrolyte rapidly and reversibly changes the interfacial tension by over two orders of magnitude ( &#820;500 mN/m to near zero). Furthermore, this method requires only a very modest potential (&#60; 1 V) applied relative to a counter electrode. The resulting change in tension is due primarily to the electrochemical deposition of a surface oxide layer, which acts as a surfactant; removal of the oxide increases the interfacial tension, and vice versa. This technique can be applied in a wide variety of electrolytes and is independent of the substrate on which it rests.

We present a method to control the interfacial energy of a liquid metal in an electrolyte via electrochemical deposition (or removal) of a surface oxide layer. This simple method can control the capillary behavior of gallium-based liquid metals by tuning the interfacial energy rapidly, significantly, and reversibly using modest voltages.

Controlling interfacial tension is an effective method for manipulating the shape, position, and flow of fluids at sub-millimeter length scales, where ...

Atom Transfer Radical Polymerization of Functionalized Vinyl Monomers Using Perylene as a Visible Light Photocatalyst

A standardized technique for atom transfer radical polymerization of vinyl monomers using perylene as a visible-light photocatalyst is presented. The procedure is performed under an inert atmosphere using air- and water-exclusion techniques. The outcome of the polymerization is affected by the ratios of monomer, initiator, and catalyst used as well as the reaction concentration, solvent, and nature of the light source. Temporal control over the polymerization can be exercised by turning the visible light source off and on. Low dispersities of the resultant polymers as well as the ability to chain-extend to form block copolymers suggest control over the polymerization, while chain end-group analysis provides evidence supporting an atom-transfer radical polymerization mechanism.

A method for the atom transfer radical polymerization of functionalized vinyl monomers using perylene as a visible-light photocatalyst is described.

A standardized technique for atom transfer radical polymerization of vinyl monomers using perylene as a visible-light photocatalyst is presented. The ...

Synthesis of Protein Bioconjugates via Cysteine-maleimide Chemistry

The chemical linking or bioconjugation of proteins to fluorescent dyes, drugs, polymers and other proteins has a broad range of applications, such as the development of antibody drug conjugates (ADCs) and nanomedicine, fluorescent microscopy and systems chemistry. For many of these applications, specificity of the bioconjugation method used is of prime concern. The Michael addition of maleimides with cysteine(s) on the target proteins is highly selective and proceeds rapidly under mild conditions, making it one of the most popular methods for protein bioconjugation.
We demonstrate here the modification of the only surface-accessible cysteine residue on yeast cytochrome c with a ruthenium(II) bisterpyridine maleimide. The protein bioconjugation is verified by gel electrophoresis and purified by aqueous-based fast protein liquid chromatography in 27% yield of isolated protein material. Structural characterization with MALDI-TOF MS and UV-Vis is then used to verify that the bioconjugation is successful. The protocol shown here is easily applicable to other cysteine - maleimide coupling of proteins to other proteins, dyes, drugs or polymers.

Synthesis of Protein Bioconjugates via Cysteine-maleimide Chemistry

This protocol details the important steps required for the bioconjugation of a cysteine containing protein to a maleimide, including reagent purification, reaction conditions, bioconjugate purification and bioconjugate characterization.

The chemical linking or bioconjugation of proteins to fluorescent dyes, drugs, polymers and other proteins has a broad range of applications, such as the ...

Microfluidic Dry-spinning and Characterization of Regenerated Silk Fibroin Fibers

The protocol demonstrates a method for mimicking the spinning process of silkworm. In the native spinning process, the contracting spinning duct enables the silk proteins to be compact and ordered by shearing and elongation forces. Here, a biomimetic microfluidic channel was designed to mimic the specific geometry of the spinning duct of the silkworm. Regenerated silk fibroin (RSF) spinning doped with high concentration, was extruded through the microchannel to dry-spin fibers at ambient temperature and pressure. In the post-treated process, the as-spun fibers were drawn and stored in ethanol aqueous solution. Synchrotron radiation wide-angle X-ray diffraction (SR-WAXD) technology was used to investigate the microstructure of single RSF fibers, which were fixed to a sample holder with the RSF fiber axis normal to the microbeam of the X-ray. The crystallinity, crystallite size, and crystalline orientation of the fiber were calculated from the WAXD data. The diffraction arcs near the equator of the two-dimensional WAXD pattern indicate that the post-treated RSF fiber has a high orientation degree.

A protocol for the microfluidic spinning and microstructure characterization of regenerated silk fibroin monofilament is presented.

The protocol demonstrates a method for mimicking the spinning process of silkworm. In the native spinning process, the contracting spinning duct enables ...

Synthesis of Substrate-Bound Au Nanowires Via an Active Surface Growth Mechanism

Advancing synthetic capabilities is important for the development of nanoscience and nanotechnology. The synthesis of nanowires has always been a challenge, as it requires asymmetric growth of symmetric crystals. Here, we report a distinctive synthesis of substrate-bound Au nanowires. This template-free synthesis employs thiolated ligands and substrate adsorption to achieve the continuous asymmetric deposition of Au in solution at ambient conditions. The thiolated ligand prevented the Au deposition on the exposed surface of the seeds, so the Au deposition only occurs at the interface between the Au seeds and the substrate. The side of the newly deposited Au nanowires is immediately covered with the thiolated ligand, while the bottom facing the substrate remains ligand-free and active for the next round of Au deposition. We further demonstrate that this Au nanowire growth can be induced on various substrates, and different thiolated ligands can be used to regulate the surface chemistry of the nanowires. The diameter of the nanowires can also be controlled with mixed ligands, in which another &#34;bad&#34; ligand could turn on the lateral growth. With the understanding of the mechanism, Au nanowire-based nanostructures can be designed and synthesized.

We report a solution-based method to synthesize substrate-bound Au nanowires. By tuning the molecular ligands used during the synthesis, the Au nanowires can be grown from various substrates with different surface properties. Au nanowire-based nanostructures can also be synthesized by adjusting the reaction parameters.

Advancing synthetic capabilities is important for the development of nanoscience and nanotechnology. The synthesis of nanowires has always been a ...

Stereolithographic 3D Printing with Renewable Acrylates

The accessibility of cost-competitive renewable materials and their application in additive manufacturing is essential for an efficient biobased economy. We demonstrate the rapid prototyping of sustainable resins using a stereolithographic 3D printer. Resin formulation takes place by straightforward mixing of biobased acrylate monomers and oligomers with a photoinitiatior and optical absorber. Resin viscosity is controlled by the monomer to oligomer ratio and is determined as a function of shear rate by a rheometer with parallel plate geometry. A stereolithographic apparatus charged with the biobased resins is employed to produce complex shaped prototypes with high accuracy. The products require a post-treatment, including alcohol rinsing and UV irradiation, to ensure complete curing. The high feature resolution and excellent surface finishing of the prototypes is revealed by scanning electron microscopy.

A protocol for additive manufacturing with renewable photopolymer resins on a stereolithography apparatus is presented.

The accessibility of cost-competitive renewable materials and their application in additive manufacturing is essential for an efficient biobased economy. ...

Surface Properties of Synthesized Nanoporous Carbon and Silica Matrices

In this work, we report the synthesis and characterization of ordered nanoporous carbon material (also called ordered mesoporous carbon material [OMC]) with a 4.6 nm pore size, and ordered silica porous matrix, SBA-15, with a 5.3 nm pore size. This work describes the surface properties of nanoporous molecular sieves, their wettability, and the melting behavior of D2O confined in the differently ordered porous materials with similar pore sizes. For this purpose, OMC and SBA-15 with highly ordered nanoporous structures are synthesized via impregnation of the silica matrix by applying a carbon precursor and by the sol-gel method, respectively. The porous structure of investigated systems is characterized by an N2 adsorption-desorption analysis at 77 K. To determine the electrochemical character of the surface of synthesized materials, potentiometric titration measurements are conducted; the obtained results for OMC shows a significant pHpzc shift toward the higher values of pH, relative to SBA-15. This suggests that investigated OMC has surface properties related to oxygen-based functional groups. To describe the surface properties of the materials, the contact angles of liquids penetrating the studied porous beds are also determined. The capillary rise method has confirmed the increased wettability of the silica walls relative to the carbon walls and an influence of the pore roughness on the fluid/wall interactions, which is much more pronounced for silica than for carbon mesopores. We have also studied the melting behavior of D2O confined in OMC and SBA-15 by applying the dielectric method. The results show that the depression of the melting temperature of D2O in the pores of OMC is about 15 K higher relative to the depression of the melting temperature in SBA-15 pores with a comparable 5 nm size. This is caused by the influence of adsorbate/adsorbent interactions of the studied matrices.

Here we report the synthesis and characterization of ordered nanoporous carbon (with a 4.6 nm pore size) and SBA-15 (with a 5.3 nm pore size). The work describes the surface and textural properties of nanoporous molecular sieves, their wettability, and the melting behavior of D2O confined in the materials.

In this work, we report the synthesis and characterization of ordered nanoporous carbon material (also called ordered mesoporous carbon material [OMC]) ...