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; 4 &#176;C in an ice-water bath.</li>
	<li>Deoxygenate the flask for 30 min by bubbling nitrogen directly into the reaction mixture through a 21 G needle (0.8 mm x 120 mm) with a second 21 G needle (0.8 mm x 38 mm) acting as a vent.</li>
	<li>Place the flask in an oil bath at 70 &#176;C for 5.5 hr before quenching the polymerization by immersion in an ice-water bath and exposing the contents to air.</li>
	<li>Remove the MeCN by agitation under a continuous stream of compressed air and re-dissolve the crude mixture in ~40 ml tetrahydrofuran (THF).</li>
	<li>Add the contents of the flask dropwise to 400 ml of a rapidly stirred mixture of petroleum spirits (b.p. 40-60 &#176;C) and diethyl ether (70:30, v/v) and continue to stir until the supernatant is no longer cloudy. 
	Note: Cooling in an ice-bath may be used to accelerate the precipitation process.</li>
	<li>Decant the supernatant and re-dissolve the polymer residue in ~40 ml THF.</li>
	<li>Repeat the precipitation process (steps 1.5-1.7) at least two more times to ensure complete removal of the residual OEGMA monomer. Remove the excess solvent from the purified POEGMA macro-CTA firstly by agitation under a continuous stream of compressed air and drying in a vacuum oven (20 &#176;C, 10 mbar) for 4 hr.</li>
	<li>Determine the number average molecular weight of the POEGMA macro-CTA by Nuclear Magnetic Resonance (NMR) (Mn, NMR) using a previously reported method15. Using gel permeation chromatography15 (GPC) (dimethylacetamide as mobile phase and appropriate standards for calibration) calculate the polymer dispersity (&#208;). 
	Note: Using the above synthesis (steps 1.1-1.8) should yield a POEGMA macro-CTA with Mn, NMR = 9,000, and &#208; &#60; 1.15. If the molecular weight (and dispersity) of the synthesized POEGMA macro-CTA differs from the synthesis presented here (between 7,000 - 1,000 g/mol), the formation of worm-like micelles (as indicated by in situ gelation) can still occur using the subsequent PISA methodology presented in (section 2) albeit at a slightly altered reaction time.</li>
</ol>
2. Preparation of POEGMA-b-PBzMA Nanoparticles Using PISA
<ol>
	<li>Prepare a 1 mg/ml stock solution of Ru(bpy)3Cl2 .6H2O in ethanol (EtOH). Store the stock solution in the refrigerator to minimize solvent evaporation.</li>
	<li>Plug a Pasteur pipette with a small wad of cotton wool using a second pipette to help pack it tightly. Pour basic aluminum oxide into the pipette with the cotton wool plug to give a column of approximately 5 cm. Remove the monomethyl ether hydroquinone inhibitor in commercial BzMA by passing ~3 ml of BzMA through the column and collecting the deinhibited BzMA eluent.</li>
	<li>Add POEGMA macroCTA (~9,000 g/mol; 76.9 mg, 8.5 &#215; 10-6 mol), deinhibited BzMA (0.301 g, 1.71 &#215; 10-3 mol), Ru(bpy)3Cl2.6H2O (128 &#181;g, 1.71&#215;10-7 mol, 128 &#181;l of a 1 mg/ml ethanolic stock solution), 0.383 ml MeCN and 1.402 ml EtOH (1.913 ml total solvent, 80 wt%, 20 v/v% MeCN) to a 4 ml glass vial.</li>
	<li>Perform the deoxygenation procedure as outlined in steps 1.2-1.3.</li>
	<li>Place the vial in a 2,000 ml glass beaker (Figure 2) lined with blue LED strips (&#955;max = 460 nm, 0.7 mW/cm2) and irradiate at room temperature with magnetic stirring. Monitor the reaction vial routinely after 20 hr and remove it from the reactor when the high viscosity solution forms a free standing gel when the vial is inverted (Figure 3). 
	Note: The total time to yield a free-standing gel should be about 24 hr of blue light irradiation using the conditions presented here. Small differences in the light irradiation reactors (physical dimensions, intensity, etc.) may require slightly altered conditions (specifically reaction time) to achieve the in situ formation of worm-like micelles.</li>
	<li>After removing from the reactor, quench the polymerization by exposing the nanoparticle gel to air for a few minutes and storing the closed vial upright in the dark.</li>
</ol>
3. Transmission Electron Microscopy (TEM) Imaging of Nanoparticle Morphology
<ol>
	<li>Place approximately 40 mg of the crude nanoparticle gel (from section 2) in a 4 ml glass vial.</li>
	<li>Continuously agitate the nanoparticle gel using a vortex mixer and add 4 ml of EtOH dropwise over a period of at least 5 min. The gel should become a free-flowing solution during the solvent addition. 
	Note: If the gel is diluted with EtOH too rapidly or not agitated adequately, some precipitation of the nanoparticles may occur. See step 3.3.</li>
	<li>Remove any macroscopic aggregates from the diluted nanoparticles by filtering through glass wool.</li>
	<li>Perform TEM imaging (with uranyl acetate staining) of the diluted sample according to a previously reported procedure.15</li>
</ol>

<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>

The authors have nothing to disclose.

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 at JoVE.com

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

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.

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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9.4K Views.  The University of New South Wales. 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.

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

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 ...

Facile Preparation of Internally Self-assembled Lipid Particles Stabilized by Carbon Nanotubes

We present a facile method to prepare nanostructured lipid particles stabilized by carbon nanotubes (CNTs). Single-walled (pristine) and multi-walled (functionalized) CNTs are used as stabilizers to produce Pickering type oil-in-water (O/W) emulsions. Lipids namely, Dimodan U and Phytantriol are used as emulsifiers, which in excess water self-assemble into the bicontinuous cubic Pn3m phase. This highly viscous phase is fragmented into smaller particles using a probe ultrasonicator in presence of conventional surfactant stabilizers or CNTs as done here. Initially, the CNTs (powder form) are dispersed in water followed by further ultrasonication with the molten lipid to form the final emulsion. During this process the CNTs get coated with lipid molecules, which in turn are presumed to surround the lipid droplets to form a particulate emulsion that is stable for months. The average size of CNT-stabilized nanostructured lipid particles is in the submicron range, which compares well with the particles stabilized using conventional surfactants. Small angle X-ray scattering data confirms the retention of the original Pn3m cubic phase in the CNT-stabilized lipid dispersions as compared to the pure lipid phase (bulk state). Blue shift and lowering of the intensities in characteristic G and G&#39; bands of CNTs observed in Raman spectroscopy characterize the interaction between CNT surface and lipid molecules. These results suggest that the interactions between the CNTs and lipids are responsible for their mutual stabilization in aqueous solutions. As the concentrations of CNTs employed for stabilization are very low and lipid molecules are able to functionalize the CNTs, the toxicity of CNTs is expected to be insignificant while their biocompatibility is greatly enhanced. Hence the present approach finds a great potential in various biomedical applications, for instance, for developing hybrid nanocarrier systems for the delivery of multiple functional molecules as in combination therapy or polytherapy.

We report on a smart application of carbon nanotubes for kinetic stabilization of lipid particles that contain self-assembled nanostructures in their cores. The preparation of lipid particles requires rather low concentrations of carbon nanotubes permitting their use in biomedical applications such as drug delivery.

We present a facile method to prepare nanostructured lipid particles stabilized by carbon nanotubes (CNTs). Single-walled (pristine) and multi-walled ...

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 ...

Facile Preparation of 4-Substituted Quinazoline Derivatives

Reported in this paper is a very simple method for direct preparation of 4-substituted quinazoline derivatives from a reaction between substituted 2-aminobenzophenones and thiourea in the presence of dimethyl sulfoxide (DMSO). This is a unique complementary reaction system in which thiourea undergoes thermal decomposition to form carbodiimide and hydrogen sulfide, where the former reacts with 2-aminobenzophenone to form 4-phenylquinazolin-2(1H)-imine intermediate, whilst hydrogen sulfide reacts with DMSO to give methanethiol or other sulfur-containing molecule which then functions as a complementary reducing agent to reduce 4-phenylquinazolin-2(1H)-imine intermediate into 4-phenyl-1,2-dihydroquinazolin-2-amine. Subsequently, the elimination of ammonia from 4-phenyl-1,2-dihydroquinazolin-2-amine affords substituted quinazoline derivative. This reaction usually gives quinazoline derivative as a single product arising from 2-aminobenzophenone as monitored by GC/MS analysis, along with small amount of sulfur-containing molecules such as dimethyl disulfide, dimethyl trisulfide, etc. The reaction usually completes in 4-6 hr at 160 &#186;C in small scale but may last over 24 hr when carried out in large scale. The reaction product can be easily purified by means of washing off DMSO with water followed by column chromatography or thin layer chromatography.

A protocol for facile preparation of 4-substituted quinazoline derivatives from 2-aminobenzophenones, thiourea and dimethyl sulfoxide is presented.

Reported in this paper is a very simple method for direct preparation of 4-substituted quinazoline derivatives from a reaction between substituted ...

HKUST-1 as a Heterogeneous Catalyst for the Synthesis of Vanillin

Vanillin (4-hydoxy-3-methoxybenzaldehyde) is the main component of the extract of vanilla bean. The natural vanilla scent is a mixture of approximately 200 different odorant compounds in addition to vanillin. The natural extraction of vanillin (from the orchid Vanilla planifolia, Vanilla tahitiensis and Vanilla pompon) represents only 1% of the worldwide production and since this process is expensive and very long, the rest of the production of vanillin is synthesized. Many biotechnological approaches can be used for the synthesis of vanillin from lignin, phenolic stilbenes, isoeugenol, eugenol, guaicol, etc., with the disadvantage of harming the environment since these processes use strong oxidizing agents and toxic solvents. Thus, eco-friendly alternatives on the production of vanillin are very desirable and thus, under current investigation. Porous coordination polymers (PCPs) are a new class of highly crystalline materials that recently have been used for catalysis. HKUST-1 (Cu3(BTC)2(H2O)3, BTC = 1,3,5-benzene-tricarboxylate) is a very well known PCP which has been extensively studied as a heterogeneous catalyst. Here, we report a synthetic strategy for the production of vanillin by the oxidation of trans-ferulic acid using HKUST-1 as a catalyst.

The conversion of trans-ferulic acid to vanillin was achieved by heterogeneous catalysis. HKUST-1 was employed in this synthesis and the essential step in the catalytic process was the generation of unsaturated metal sites. Thus, when the catalyst was activated under vacuum, full vanillin conversion (yield of 95%) was obtained.

Vanillin (4-hydoxy-3-methoxybenzaldehyde) is the main component of the extract of vanilla bean. The natural vanilla scent is a mixture of approximately ...

Anionic Polymerization of an Amphiphilic Copolymer for Preparation of Block Copolymer Micelles Stabilized by &#960;-&#960; Stacking Interactions

In this study, an amphiphilic copolymer that includes a core-forming block with phenyl groups was synthesized by living anionic polymerization of phenyl glycidyl ether (PheGE) on methoxy-polyethylene glycol (mPEG-b-PPheGE). Characterization of the copolymer revealed a narrow molecular distribution (PDI &#60; 1.03) and confirmed the degree of polymerization of mPEG122-b-(PheGE)15. The critical micelle concentration of the copolymer was evaluated using an established fluorescence method with the aggregation behavior evaluated by dynamic light scattering and transmission electronic microscopy. The potential of the copolymer for use in drug delivery applications was evaluated in a preliminary manner including in vitro biocompatibility, loading and release of the hydrophobic anti-cancer drug doxorubicin (DOX). A stable micelle formulation of DOX was prepared with drug loading levels up to 14% (wt%), drug loading efficiencies &#62; 60% (w/w) and sustained release of drug over 4 days under physiologically relevant conditions (acidic and neutral pH, presence of albumin). The high drug loading level and sustained release is attributed to stabilizing &#960;-&#960; interactions between DOX and the core-forming block of the micelles.

The key steps of living anionic polymerization of phenyl glycidyl ether (PheGE) on methoxy-polyethylene glycol (mPEG-b-PPheGE) are described. The resulting block copolymer micelles (BCMs) were loaded with doxorubicin 14% (wt%) and sustained release of drug over 4 days under physiologically relevant conditions was obtained.

In this study, an amphiphilic copolymer that includes a core-forming block with phenyl groups was synthesized by living anionic polymerization of phenyl ...

Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate

Direct cross-coupling between two alkenes via vinylic C-H bond activation represents an efficient strategy for the synthesis of butadienes with high atomic and step economy. However, this functionality-directed cross-coupling reaction has not been developed, as there are still limited directing groups in practical use. In particular, a stoichiometric amount of oxidant is usually required, producing a large amount of waste. Due to our interest in novel 1,3-butadiene synthesis, we describe the ruthenium-catalyzed olefination of electron-deficient alkenes using allyl acetate and without external oxidant. The reaction of 2-phenyl acrylamide and allyl acetate was chosen as a model reaction, and the desired diene product was obtained in 80% isolated yield with good stereoselectivity (Z,E/Z,Z = 88:12) under optimal conditions: [Ru(p-cymene) Cl2]2 (3 mol %) and AgSbF6 (20 mol %) in DCE at 110 &#186;C for 16 h. With the optimized catalytic conditions in hand, representative &#945;- and/or &#946;-substituted acrylamides were investigated, and all reacted smoothly, regardless of aliphatic or aromatic groups. Also, differently N-substituted acrylamides have proven to be good substrates. Moreover, we examined the reactivity of different allyl derivatives, suggesting that the chelation of acetate oxygen to the metal is crucial for the catalytic process. Deuterium-labeled experiments were also conducted to investigate the reaction mechanism. Only Z-selective H/D exchanges on acrylamide were observed, indicating a reversible cyclometalation event. In addition, a kinetic isotope effect (KIE) of 3.2 was observed in the intermolecular isotopic study, suggesting that the olefinic C-H metalation step is probably involved in the rate-determining step.

Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate

The ruthenium-catalyzed olefination of electron-deficient alkenes with allyl acetate is described here. By using aminocarbonyl as a directing group, this external oxidant-free protocol has high efficiency and good stereo- and regioselectivity, opening a novel synthetic route to (Z,E)-butadiene skeletons.

Direct cross-coupling between two alkenes via vinylic C-H bond activation represents an efficient strategy for the synthesis of butadienes with high ...

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes

Here, we describe an effective protocol that combines photoredox Ni/Ir catalysis with the use of a Zn-alkoxide for efficient ring-opening polymerization, allowing for the synthesis of isotactic poly(&#945;-hydroxy acids) with expected molecular weights (&#62;140 kDa) and narrow molecular weight distributions (Mw/Mn &#60; 1.1). This ring-opening polymerization is mediated by Ni and Zn complexes in the presence of an alcohol initiator and a photoredox Ir catalyst, irradiated by a blue LED (400 - 500 nm). The polymerization is performed at a low temperature (-15 &#176;C) to avoid undesired side reactions. The complete monomer consumption can be achieved within 4 - 8 hours, providing a polymer close to the expected molecular weight with narrow molecular weight distribution. The resulted number-average molecular weight shows a linear correlation with the degree of polymerization up to 1000. The homodecoupling 1H NMR study confirms that the obtained polymer is isotactic without epimerization. This polymerization reported herein offers a strategy for achieving rapid, controlled O-carboxyanhydrides polymerization to prepare stereoregular poly(&#945;-hydroxy acids) and its copolymers bearing various functional side-chain groups.

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes

A protocol for the controlled photoredox ring-opening polymerization of O-carboxyanhydrides mediated by Ni/Zn complexes is presented.

Here, we describe an effective protocol that combines photoredox Ni/Ir catalysis with the use of a Zn-alkoxide for efficient ring-opening polymerization, ...

Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction

This protocol presents both the synthesis method of the Ni single atom catalyst, and the electrochemical testing of its catalytic activity and selectivity in aqueous CO2 reduction. Different from traditional metal nanocrystals, the synthesis of metal single atoms involves a matrix material that can confine those single atoms and prevent them from aggregation. We report an electrospinning and thermal annealing method to prepare Ni single atoms dispersed and coordinated in a graphene shell, as active centers for CO2 reduction to CO. During the synthesis, N dopants play a critical role in generating graphene vacancies to trap Ni atoms. Aberration-corrected scanning transmission electron microscopy and three-dimensional atom probe tomography were employed to identify the single Ni atomic sites in graphene vacancies. Detailed setup of electrochemical CO2 reduction apparatus coupled with an on-line gas chromatography is also demonstrated. Compared to metallic Ni, Ni single atom catalyst exhibit dramatically improved CO2 reduction and suppressed H2 evolution side reaction.

Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction

Here, we present a protocol for the synthesis and electrochemical testing of transition metal single atoms coordinated in graphene vacancies as active centers for selective carbon dioxide reduction to carbon monoxide in aqueous solutions.

This protocol presents both the synthesis method of the Ni single atom catalyst, and the electrochemical testing of its catalytic activity and selectivity ...

Synthesis of a Thiol Building Block for the Crystallization of a Semiconducting Gyroidal Metal-sulfur Framework

We present a method for preparing thioester molecules as the masked form of the thiol linkers and their utilization for accessing a semiconducting and porous metal-dithiolene network in the highly ordered single crystalline state. Unlike the highly reactive free-standing thiols, which tend to decompose and complicate the crystallization of metal-thiolate open frameworks, the thioester reacts in situ to provide the thiol species, serving to mitigate the reaction between the mercaptan units and the metal centers, and to improve crystallization consequently. Specifically, the thioester was synthesized in a one-pot procedure: an aromatic bromide (hexabromotriphenylene) reacted with excess sodium thiomethoxide under vigorous conditions to first form the thioether intermediate product. The thioether was then demethylated by the excess thiomethoxide to provide the thiolate anion that was acylated to form the thioester product. The thioester was conveniently purified by standard column chromatography, and then used directly in the framework synthesis, wherein NaOH and ethylenediamine serve to revert in situ the thioester to the thiol linker for assembling the single-crystalline Pb(II)-dithiolene network. Compared with other methods for thiol synthesis (e.g., by cleaving alkyl thioether using sodium metal and liquid ammonia), the thioester synthesis here uses simple conditions and economical reagents. Moreover, the thioester product is stable and can be conveniently handled and stored. More importantly, in contrast to the generic difficulty in accessing crystalline metal-thiolate open frameworks, we demonstrate that using the thioester for in situ formation of the thiol linker greatly improves the crystallinity of the solid-state product. We intend to encourage broader research efforts on the technologically important metal-sulfur frameworks by disclosing the synthetic protocol for the thioester as well as the crystalline framework solid.

Here, we present a one-pot, transition-metal-free synthesis of thiols and thioesters from aromatic halides and sodium thiomethoxide, followed by the preparation of single crystals of a metal-dithiolene network using thiol species generated in situ from the more stable and tractable thioester.

We present a method for preparing thioester molecules as the masked form of the thiol linkers and their utilization for accessing a semiconducting and ...