Name: facile synthesis of worm-like micelles by visible light mediated dispersion polymerization using photoredox catalyst
Uploaded: 2016-06-08T15:00:00
Description: Watch this Scientific Journal Video about Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst Video at JoVE.com

CB is thankful for his Future Fellowship from Australian Research Council (ARC-FT12010096) and UNSW Australia.

1. Synthesis and Characterization of POEGMA Macro-CTA
<ol>
	<li>Add oligo(ethylene glycol) methyl ether methacrylate (OEGMA) (12 g, 4 &#215; 10-2 mol), 4-cyano-4-(phenylcarbonothioylthio)pentanoic acid (CPADB) (0.224 g, 8 &#215; 10-4 mol), 2,2&#8242;-azobis(2-methylpropionitrile) (AIBN) (16.4 mg, 0.1 mmol) and 50 ml acetonitrile (MeCN) to a 100 ml round bottom flask.</li>
	<li>Seal the flask with an appropriately sized rubber septum and steel wire and cool the flask from room temperature to &#60; ...

<ol>
	<li>Yu, Y., Eisenberg, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Control+of+Morphology+through+Polymer&#8722;Solvent+Interactions+in+Crew-Cut+Aggregates+of+Amphiphilic+Block+Copolymers.">Control of Morphology through Polymer&#8722;Solvent Interactions in Crew-Cut Aggregates of Amphiphilic Block Copolymers.</a> J. Am. Chem. Soc. 119 (35), 8383-8384 (1997).</li><li>Zhang, L., Eisenberg, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermodynamic+vs+Kinetic+Aspects+in+the+Formation+and+Morphological+Transitions+of+Crew-Cut+Aggregates+Produced+by+Self-Assembly+of+Polystyrene-b-poly(acrylic+acid)+Block+Copolymers+in+Dilute+Solution.">Thermodynamic vs Kinetic Aspects in the Formation and Morphological Transitions of Crew-Cut Aggregates Produced by Self-Assembly of Polystyrene-b-poly(acrylic acid) Block Copolymers in Dilute Solution.</a> Macromolecules. 32 (7), 2239-2249 (1999).</li><li>Zhang, L., Eisenberg, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiple+Morphologies+of+'Crew-Cut'+Aggregates+of+Polystyrene-b-poly(acrylic+acid)+Block+Copolymers.">Multiple Morphologies of 'Crew-Cut' Aggregates of Polystyrene-b-poly(acrylic acid) Block Copolymers.</a> Science. 268 (5218), 1728-1731 (1995).</li><li>Yu, K., Zhang, L., Eisenberg, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+Morphologies+of+&amp;#34;Crew-Cut&amp;#34;+Aggregates+of+Amphiphilic+Diblock+Copolymers+in+Dilute+Solution.">Novel Morphologies of &amp;#34;Crew-Cut&amp;#34; Aggregates of Amphiphilic Diblock Copolymers in Dilute Solution.</a> Langmuir. 12 (25), 5980-5984 (1996).</li><li>Blanazs, A., Ryan, A. J., Armes, S. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Predictive+Phase+Diagrams+for+RAFT+Aqueous+Dispersion+Polymerization:+Effect+of+Block+Copolymer+Composition,+Molecular+Weight,+and+Copolymer+Concentration.">Predictive Phase Diagrams for RAFT Aqueous Dispersion Polymerization: Effect of Block Copolymer Composition, Molecular Weight, and Copolymer Concentration.</a> Macromolecules. 45 (12), 5099-5107 (2012).</li><li>Ladmiral, V., Semsarilar, M., Canton, I., Armes, S. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polymerization-induced+self-assembly+of+galactose-functionalized+biocompatible+diblock+copolymers+for+intracellular+delivery.">Polymerization-induced self-assembly of galactose-functionalized biocompatible diblock copolymers for intracellular delivery.</a> J. Am. Chem. Soc. 135 (36), 13574-13581 (2013).</li><li>Sugihara, S., Blanazs, A., Armes, S. P., Ryan, A. J., Lewis, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aqueous+Dispersion+Polymerization:+A+New+Paradigm+for+in+Situ+Block+Copolymer+Self-Assembly+in+Concentrated+Solution.">Aqueous Dispersion Polymerization: A New Paradigm for in Situ Block Copolymer Self-Assembly in Concentrated Solution.</a> J. Am. Chem. Soc. 133 (39), 15707-15713 (2011).</li><li>Wan, W. M., Hong, C. Y., Pan, C. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=One-pot+synthesis+of+nanomaterials+via+RAFT+polymerization+induced+self-assembly+and+morphology+transition.">One-pot synthesis of nanomaterials via RAFT polymerization induced self-assembly and morphology transition.</a> Chem. Comm. (39), 5883-5885 (2009).</li><li>Semsarilar, M., Jones, E. R., Blanazs, A., Armes, S. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+Synthesis+of+Sterically-Stabilized+Nano-Objects+via+RAFT+Dispersion+Polymerization+of+Benzyl+Methacrylate+in+Alcoholic+Media.">Efficient Synthesis of Sterically-Stabilized Nano-Objects via RAFT Dispersion Polymerization of Benzyl Methacrylate in Alcoholic Media.</a> Adv. Mater. 24 (25), 3378-3382 (2012).</li><li>Karagoz, 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=Polymerization-Induced+Self-Assembly+(PISA)+-+control+over+the+morphology+of+nanoparticles+for+drug+delivery+applications.">Polymerization-Induced Self-Assembly (PISA) - control over the morphology of nanoparticles for drug delivery applications.</a> Polym. Chem. 5 (2), 350-355 (2014).</li><li>Geng, Y., 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=Shape+effects+of+filaments+versus+spherical+particles+in+flow+and+drug+delivery.">Shape effects of filaments versus spherical particles in flow and drug delivery.</a> Nat Nano. 2 (4), 249-255 (2007).</li><li>Blanazs, 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=Sterilizable+gels+from+thermoresponsive+block+copolymer+worms.">Sterilizable gels from thermoresponsive block copolymer worms.</a> J. Am. Chem. Soc. 134 (23), 9741-9748 (2012).</li><li>Pei, Y., Thurairajah, L., Sugita, O. R., Lowe, A. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RAFT+Dispersion+Polymerization+in+Nonpolar+Media:+Polymerization+of+3-Phenylpropyl+Methacrylate+in+n-Tetradecane+with+Poly(stearyl+methacrylate)+Homopolymers+as+Macro+Chain+Transfer+Agents.">RAFT Dispersion Polymerization in Nonpolar Media: Polymerization of 3-Phenylpropyl Methacrylate in n-Tetradecane with Poly(stearyl methacrylate) Homopolymers as Macro Chain Transfer Agents.</a> Macromolecules. 48 (1), 236-244 (2015).</li><li>Fielding, L. A., Lane, J. A., Derry, M. J., Mykhaylyk, O. O., Armes, S. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermo-responsive+Diblock+Copolymer+Worm+Gels+in+Non-polar+Solvents.">Thermo-responsive Diblock Copolymer Worm Gels in Non-polar Solvents.</a> J. Am. Chem. Soc. 136 (15), 5790-5798 (2014).</li><li>Yeow, J., Xu, 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=Polymerization-Induced+Self-Assembly+Using+Visible+Light+Mediated+Photoinduced+Electron+Transfer-Reversible+Addition-Fragmentation+Chain+Transfer+Polymerization.">Polymerization-Induced Self-Assembly Using Visible Light Mediated Photoinduced Electron Transfer-Reversible Addition-Fragmentation Chain Transfer Polymerization.</a> ACS Macro Lett. 4 (9), 984-990 (2015).</li><li>Xu, J., Jung, K., Corrigan, N. A., 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=Aqueous+photoinduced+living/controlled+polymerization:+tailoring+for+bioconjugation.">Aqueous photoinduced living/controlled polymerization: tailoring for bioconjugation.</a> Chem. Sci. 5 (9), 3568-3575 (2014).</li><li>Pei, Y., 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=RAFT+dispersion+polymerization+of+3-phenylpropyl+methacrylate+with+poly[2-(dimethylamino)ethyl+methacrylate]+macro-CTAs+in+ethanol+and+associated+thermoreversible+polymorphism.">RAFT dispersion polymerization of 3-phenylpropyl methacrylate with poly[2-(dimethylamino)ethyl methacrylate] macro-CTAs in ethanol and associated thermoreversible polymorphism.</a> Soft Matter. 10 (31), 5787-5796 (2014).</li></ol>

This visualized protocol demonstrates the ability to monitor the formation of worm-like micelles simply by observing the onset of gel-like behavior. The utility of this approach lies in the ability to monitor worm formation during the polymerization in comparison to other methods. This procedure can be performed using a two-step polymerization of two commercially available monomers (OEGMA and BzMA) to yield self-assembled POEGMA-b-PBzMA amphiphilic diblock copolymers.
It should be not...

The synthesis of nonspherical (and other) nanoparticle morphologies has traditionally been accomplished using a multistep self-assembly procedure starting with the synthesis and purification of well-defined amphiphilic diblock (or multiblock) copolymers. One of the most common self-assembly techniques was popularized by Eisenberg in the 1990s and involves the dissolution of the amphiphilic block copolymer in a common solvent for both polymer blocks followed by the slow addition of a solvent selective for one of the blocks1-3. As the selective solvent (typically water) is added, the block copolymer undergoes self-assembly to form polymeric nanoparticles. The final morphology (or mixtures of morphologies) of the nanoparticles are determined by a large number of factors such as the relative lengths of each polymer block, rate of water addition and the nature of the common solvent. However, this approach generally only allows for the production of nanoparticles at relatively low solids content (less than 1 wt%) and so limits its practical scalability4. In addition, the reproducible formation of &#34;intermediate&#34; phases such as worm-like micelles can be difficult owing to the narrow range of parameters required to stabilize this nonspherical morphology5.
The polymerization-induced self-assembly (PISA) approach partially addresses the drawbacks of the Eisenberg approach by utilizing the polymerization process itself to drive self-assembly in situ allowing for nanoparticle synthesis at much higher solids content (typically 10-30 wt%)6-8. In a typical PISA approach, a living polymerization process is used to chain extend a solvent soluble macroinitiator (or macro-CTA) with a monomer that is initially soluble in the reaction medium but forms an insoluble polymer. The PISA approach has been used to synthesize worm-like micelles by systematically testing a number of experimental parameters and using detailed phase diagrams as a synthetic &#34;roadmap&#34;5,9.
Despite their challenging synthesis, there is great interest in worm-like nanoparticles due to their interesting properties relative to their spherical counterparts. For example, we have demonstrated that drug loaded short and long worm-like micelles synthesized using a PISA approach have significantly higher in vitro cytotoxicity compared to spherical micelles or vesicles10. Others have shown a correlation between nanoparticle aspect ratio and blood circulation time in in vivo models11. Others have shown that the synthesis of worm-like nanoparticles using an appropriate PISA methodology yields a macroscopic gel due to the nanoscale entanglement of the nanoparticle filaments. These gels have demonstrated potential as sterilizable gels owing to their thermoreversible sol-gel behavior12.
This protocol describes a method allowing for the in situ monitoring of the formation of worm-like micelles by simply observing the solution viscosity during the polymerization. Previous studies of similar worm-like micellar gels have demonstrated that above a critical temperature, these nanoparticles undergo a reversible worm-sphere transition and so form free-flowing dispersions at elevated temperatures. To date, these systems have utilized a thermally sensitive azo compound to initiate the controlled polymerization13,14 and so gelation may not be readily observed in these systems during the thermal polymerization. From these studies, it was hypothesized that synthesizing PISA derived nanoparticles at lower temperatures may allow for observation of this gelation behavior in situ.
Recently we reported the use of a facile room temperature photopolymerization technique to mediate the PISA process to yield nanoparticles of different morphologies15. Here, a visualized protocol is presented for the reproducible synthesis of worm-like micelles by observing the solution viscosity behavior during the polymerization. The dispersion polymerization proceeds readily using commercially available light-emitting diodes (LEDs) (&#955; = 460 nm, 0.7 mW/cm2).

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>4-Cyano-4-(phenylcarbonothioylthio)pentanoic acid (CPADB)</td>
			<td>Sigma-Aldrich</td>
			<td>722995-5G</td>
			<td></td>
		</tr>
		<tr>
			<td>Oligo(ethylene glycol) methyl ether methacrylate (OEGMA)</td>
			<td>Sigma-Aldrich</td>
			<td>447935-500ML</td>
			<td>Average Mn 300, contains 100&#160;ppm MEHQ as inhibitor, 300&#160;ppm BHT as inhibitor</td>
		</tr>
		<tr>
			<td>2,2&#8242;-Azobis(2-methylpropionitrile) (AIBN)</td>
			<td>Sigma-Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ru(bpy)3Cl2.6H2O</td>
			<td>Sigma-Aldrich</td>
			<td>544981-1G</td>
			<td></td>
		</tr>
		<tr>
			<td>Benzyl methacrylate (BzMA)</td>
			<td>Sigma-Aldrich</td>
			<td>409448-1L</td>
			<td>Contains monomethyl ether hydroquinone as inhibitor</td>
		</tr>
		<tr>
			<td>Aluminium oxide (basic)</td>
			<td>Chem-Supply Pty Ltd Australia</td>
			<td>AL08371000</td>
			<td></td>
		</tr>
		<tr>
			<td>95% Ethanol (EtOH)</td>
			<td>Sucrogen Bio Ethanol</td>
			<td>80889</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetonitrile (MeCN)</td>
			<td>Chem-Supply Pty Ltd Australia</td>
			<td>RP1005-G2.5L</td>
			<td></td>
		</tr>
		<tr>
			<td>Tetrahydrofuran (THF)</td>
			<td>Chem-Supply Pty Ltd Australia</td>
			<td>TA011-2.5L</td>
			<td></td>
		</tr>
		<tr>
			<td>Petroleum Spirits (40-60oC)</td>
			<td>Chem-Supply Pty Ltd Australia</td>
			<td>PA044-2.5L</td>
			<td></td>
		</tr>
		<tr>
			<td>Diethyl Ether</td>
			<td>Chem-Supply Pty Ltd Australia</td>
			<td>EA0362.5L</td>
			<td></td>
		</tr>
		<tr>
			<td>Dimethylacetamide (DMAc)</td>
			<td>VWR International Australia</td>
			<td>ALFA22916.M1</td>
			<td>For GPC analysis</td>
		</tr>
		<tr>
			<td>Pasteur pipettes (230 mm)</td>
			<td>Labtek</td>
			<td>355.050.503</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass beakers</td>
			<td>Labtek</td>
			<td>025.01.902 (2L)/ 2110654 (1L)</td>
			<td>2L beaker is for attaching LED strips to form the circular reactor</td>
		</tr>
		<tr>
			<td>Commercial LED strip</td>
			<td>EcoLab</td>
			<td>n/a</td>
			<td>&#955; = 460 nm, 4.8 W/m</td>
		</tr>
		<tr>
			<td>4 mL Glass Vials</td>
			<td>Labtek</td>
			<td>APC502214B</td>
			<td></td>
		</tr>
		<tr>
			<td>0.9 mL Quartz Cuvette</td>
			<td>Starna Scientific Ltd</td>
			<td>21/Q/2</td>
			<td></td>
		</tr>
		<tr>
			<td>Needle (0.8 mm x 38 mm)</td>
			<td>Beckton Dickson</td>
			<td>302017</td>
			<td>For deoxygenating reactions</td>
		</tr>
		<tr>
			<td>Needle (0.8 mm x 120 mm)</td>
			<td>B Braun Australia</td>
			<td>4665643</td>
			<td>For deoxygenating reactions</td>
		</tr>
		<tr>
			<td>Sleeve stopper septa (rubber septum)</td>
			<td>Sigma-Aldrich</td>
			<td>z564680/z564702</td>
			<td></td>
		</tr>
		<tr>
			<td>Stirring hotplates</td>
			<td>VWR International Australia/In Vitro Technologies</td>
			<td>97018-488/RADRR91200</td>
			<td></td>
		</tr>
		<tr>
			<td>Vortex mixer</td>
			<td>VWR International Australia</td>
			<td>412-0098</td>
			<td></td>
		</tr>
		<tr>
			<td>Vacuum oven</td>
			<td>In Vitro Technologies</td>
			<td>MEMVO200</td>
			<td></td>
		</tr>
	</tbody>
</table>

facile synthesis of worm-like micelles by visible light mediated dispersion polymerization using photoredox catalyst

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins with the synthesis of a hydrophilic poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) homopolymer using reversible addition-fragmentation chain-transfer (RAFT) polymerization. Under mild visible light irradiation (&#955; = 460 nm, 0.7 mW/cm2), this macro-chain transfer agent (macro-CTA) in the presence of a ruthenium based photoredox catalyst, Ru(bpy)3Cl2 can be chain extended with a second monomer to form a well-defined block copolymer in a process known as Photoinduced Electron Transfer RAFT (PET-RAFT). When PET-RAFT is used to chain extend POEGMA with benzyl methacrylate (BzMA) in ethanol (EtOH), polymeric nanoparticles with different morphologies are formed in situ according to a polymerization-induced self-assembly (PISA) mechanism. Self-assembly into nanoparticles presenting POEGMA chains at the corona and poly(benzyl methacrylate) (PBzMA) chains in the core occurs in situ due to the growing insolubility of the PBzMA block in ethanol. Interestingly, the formation of highly pure worm-like micelles can be readily monitored by observing the onset of a highly viscous gel in situ due to nanoparticle entanglements occurring during the polymerization. This process thereby allows for a more reproducible synthesis of worm-like micelles simply by monitoring the solution viscosity during the course of the polymerization. In addition, the light stimulus can be intermittently applied in an ON/OFF manner demonstrating temporal control over the nanoparticle morphology.

In this study, two-step polymerization protocol is used for the synthesis of worm-like micelles using a PISA approach (Figure 1). In the first step, the polymerization of OEGMA is performed yielding a POEGMA macro-CTA which can be used as a stabilizer in the subsequent polymerization step. The PET-RAFT polymerization proceeds under dispersion conditions owing to the insolubility of PBzMA in ethanol which ultimately leads to nanoparticle formation. During the polymerizatio...

Watch this Scientific Journal Video about Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst Video at JoVE.com

Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst Video (Video) | JoVE

This article describes a process for producing polymeric self-assembled nanoparticles using visible light mediated dispersion polymerization. Using low energy visible light to control the polymerization allows for the reproducible formation of self-assembled worm-like micelles at high solids content.

Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins ...

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