This work was supported by JCO A*STAR Investigatorship grant (Project no. 1437C00135), A*STAR Science &amp; Engineering Research Council Public Sector Funding (Project no. 1421200076), and a JSPS-NUS Joint Research Projects grant (WBS R143-000-611-133).

1. Preparation of Precursor Stock Solutions
<ol>
	<li>TOP-Se stock solution.
	<ol>
		<li>In a nitrogen atmosphere glovebox, weigh out 11.84 g of selenium pellets into a 150-mL conical flask and place a magnetic stir bar in the flask.</li>
		<li>Add 100 mL of tri-n-octylphosphine (TOP) to the conical flask and seal the flask with a rubber septum.</li>
		<li>Stir the mixture overnight at 800 RPM. 
		NOTE: Once the selenium pellets have dissolved fully into the TOP, the TOP-Se stock solution (1.5 M) is ready to be used in further reactions.</li>
	</ol>
	</li>
	<li>TOP-S stock solution.
	<ol>
		<li>Weigh out 0.611 g of sulfur powder into a 20-mL single-necked round-bottom flask (RBF) and place a magnetic stir bar in the flask.</li>
		<li>Add 10 mL of TOP to the sulfur powder and seal the RBF with a rubber septum. Place it under a nitrogen atmosphere and stir at 800 RPM.</li>
		<li>Once the sulfur powder has dissolved and the solution is clear, use the TOP-S stock solution in further reactions.</li>
	</ol>
	</li>
</ol>
2. Synthesis of CdSe Quantum Dot (QD) Stock Solution
<ol>
	<li>Wurtzite CdSe QDs. 
	Note: See5.
	<ol>
		<li>Mix 9 g of tri-n-octylphosphine oxide (TOPO), 6 g of hexadecyl amine (HDA), and 0.25 mL of diisooctylphosphonic acid (DIPA) in a three-necked RBF. Add a magnetic stir bar to the mixture and insert a temperature probe into the RBF through a punctured rubber septum.
		<ol>
			<li>Mount a reflux condenser over the RBF and connect it to a Schlenk line via an adapter. Apply high vacuum grease at all glass-to-glass joints.</li>
		</ol>
		</li>
		<li>Degas the solution at 100 &#176;C for 2 h under constant stirring at 800 RPM.</li>
		<li>Separately, mix 0.320 g of cadmium acetylacetonate (Cd(acac)2), 0.570 g of hexadecanediol (HDDO), and 6 mL of 1-octadecene (ODE) in a single-necked RBF. Add a magnetic stir bar and degas the mixture under constant stirring over an oil bath for 2 h at 120 &#176;C and 800 RPM.</li>
		<li>After degassing for 2 h, increase the temperature of the three-necked RBF to 345 &#176;C. Concurrently, let the cadmium precursor mixture cool to room temperature and add 4 mL of TOP-Se stock solution to the single-necked RBF.</li>
		<li>Swiftly inject the entire cadmium and selenium precursor solution into the three-necked RBF once its temperature reaches 345 &#176;C. Remove the heating mantle immediately after injecting the precursor solution and allow the reaction mixture to cool to room temperature under ambient conditions.</li>
		<li>Add 15 mL of toluene to the crude reaction mixture and process the synthesized QDs by centrifuging for 3 min at 2,240 x g. Discard the precipitate and add an excess of methanol to the recovered supernatant. Centrifuge the mixture at 2,325 x g for 8 min and discard the supernatant.</li>
		<li>Add 5 mL of toluene to the precipitate to disperse the QDs. Carry out further processing cycles via the precipitation of the QDs using 30 mL of methanol, centrifuge the suspension at 2,240 x g for 3 min, discard the supernatant, and disperse the QDs in 5 mL of toluene.
		<ol>
			<li>Following two cycles of processing, disperse the QDs in a minimal amount (~2-3 mL) of toluene (henceforth referred to as the QD stock solution) for further use.</li>
		</ol>
		</li>
		<li>Determine the concentration of QDs in solution by taking 20 &#181;L of the stock solution and adding it to 3 mL of toluene. Measure the absorbance at 350 nm and calculate the concentration using the known molar absorptivity at 350 nm6. Scale the concentration accordingly to take into account the dilution of the stock solution. 
		NOTE: It is important to maintain vigorous stirring of the solution and to immediately remove the heating mantle after the swift injection of the precursor solution in step 2.1.5 to obtain highly size-monodisperse QDs.</li>
	</ol>
	</li>
	<li>Zinc-blende CdSe QDs. 
	Note: See7.
	<ol>
		<li>Mix 0.0384 g of cadmium oxide (CdO), 0.137 g of myristic acid (MA), and 5 mL of ODE in a three-necked RBF. Add a magnetic stir bar to the mixture and insert a temperature probe into the RBF through a punctured rubber septum. Mount a reflux condenser over the RBF and connect it to a Schlenk line via an adapter. Seal the remaining port with a rubber septum. Apply high vacuum grease at all glass-to-glass joints.</li>
		<li>Degas the solution at 90 &#176;C under constant stirring at 800 RPM.</li>
		<li>Separately, degas a mixture of 0.05 mL of oleic acid (OA), 0.5 mL of oleylamine (OM), and 2 mL of ODE in a single-necked RBF under constant stirring at 75 &#176;C and 800 RPM.</li>
		<li>Increase the temperature of the cadmium precursor solution to 250 &#176;C and maintain it for 15 min. Observe a color change in the solution, from dark brown to colorless, indicating the formation of cadmium myristate.</li>
		<li>Cool the reaction mixture to 90 &#176;C and add 12 mL of ODE. Degas the mixture again for 1 h.</li>
		<li>Let the reaction mixture cool to room temperature. Add 0.012 g of selenium powder and degas the mixture for 20 min.</li>
		<li>Increase the temperature of the reaction mixture to 240 &#176;C under N2. Observe a color change, from colorless to yellow at 150 &#176;C and then to orange-red upon reaching 240 &#176;C, signifying the formation of zb-CdSe QDs.</li>
		<li>Grow the QDs for 5 min at 240 &#176;C and then cool the mixture to room temperature. Add the degassed mixture of OM, OA, and ODE dropwise to the reaction solution. Leave the solution to cool to room temperature under ambient conditions.</li>
		<li>Process the synthesized QDs by adding acetone to the growth solution until the total volume is about 50 mL. Centrifuge the resulting suspension at 2,240 x g for 3 min. Subsequently, discard the supernatant.</li>
		<li>Add 5 mL of toluene to the precipitate to disperse the QDs. Carry out further processing cycles: precipitate the QDs using 30 mL of methanol, centrifuge the suspension at 2,240 x g for 3 min, discard the supernatant, and disperse the QDs in 5 mL of toluene.
		<ol>
			<li>Following two cycles of processing, disperse the QDs in a minimal amount (~2-3 mL) of toluene (henceforth referred to as the QD stock solution) for further use.</li>
		</ol>
		</li>
		<li>Determine the concentration of CdSe QDs in the stock solution by taking 20 &#181;L of the processed nanoparticles and adding it to 3 mL of toluene. Measure the absorbance at 350 nm and calculate the concentration using the known molar absorptivity at 350 nm6. Scale the concentration accordingly to take into account the dilution of the stock solution. 
		NOTE: For the successful synthesis of monodisperse QDs, it is critical to ensure that all the selenium powder is added to the reaction mixture and that none of it is left stuck to the neck and sidewalls of the RBF.</li>
	</ol>
	</li>
</ol>
3. Synthesis of CdSe-seeded CdS NRs
Note: See8.
<ol>
	<li>Mix 3 g of TOPO, 0.90 g of CdO, 0.80 g of hexylphosphonic acid (HPA), and 0.29 g of octadecylphosphonic acid (ODPA) in a 50-mL three-necked RBF. Add a magnetic stir bar to the mixture and insert a temperature probe through a punctured rubber septum.</li>
	<li>Mount a reflux condenser over the RBF and connect it to a Schlenk line via an adapter. Seal the remaining port with a rubber septum. Apply high vacuum grease at all glass-to-glass joints. Heat the RBF to 150 &#176;C and place it under a vacuum for 1.5 h to degas, with stirring at 800 RPM.</li>
	<li>Place 1.8 mL of the TOP-S stock solution into a 10-mL single-necked RBF and seal it with a rubber septum. Add 80 nmol of wurtzite CdSe QDs in toluene to the TOP-S solution and subsequently remove the toluene under vacuum at 70 &#176;C. Allow the solution to degas under stirring at 800 RPM for a further 30 min.</li>
	<li>Place the RBF containing the Cd precursor under nitrogen and raise the temperature to 350 &#176;C. At 320 &#176;C, add 1.8 mL of TOP to the RBF through the rubber septum.</li>
	<li>At 350 &#176;C, draw the TOP-S solution containing the w-CdSe QDs into a syringe and rapidly inject it into the RBF containing the Cd precursor. Allow the solution to stir at 800 RPM for an additional 6 min to allow for the growth of the NRs. Subsequently, remove the heating mantle and cool the solution to room temperature under ambient conditions.</li>
	<li>To process the solution of NRs, add 2 mL of toluene to the growth solution and place the entire mixture into a 50-mL centrifuge tube. Add 30 mL of methanol. Subsequently, centrifuge the resulting suspension at 2,240 x g for 3 min and then discard the supernatant.</li>
	<li>Add 5 mL of toluene to the precipitate to disperse the NRs. Carry out further processing cycles: precipitate the NRs using 30 mL of methanol, centrifuge the suspension at 2,240 x g for 3 min, discard the supernatant, and disperse the NRs in 5 mL of toluene.
	<ol>
		<li>Following 2-3 cycles of processing, disperse the NRs in 5 mL of toluene (henceforth referred to as the NR stock solution) for further use.</li>
	</ol>
	</li>
	<li>Prepare the sample for TEM analysis.5
	<ol>
		<li>Place a drop of the NR solution onto a 300-mesh copper grid covered with a continuous carbon film for electron microscopy analysis.</li>
		<li>Remove the excess solution with an adsorbent paper and dry the sample at room temperature.</li>
	</ol>
	</li>
	<li>Perform TEM imaging (and analysis) to obtain the dimensions of the NR so that the average volume of the NR and the number of moles of CdS per NR can be determined.
	<ol>
		<li>Determine the concentration of CdSe-seeded CdS NRs in the stock solution by taking 20 &#181;L of the processed NRs and adding it to 3 mL of toluene. Measure the absorbance at 350 nm and calculate the concentration of NRs using the known molar absorptivity at that wavelength (assumed to be dominated by CdS)9. Scale the concentration accordingly to account for the dilution of the stock solution. 
		NOTE: For a typical synthesis, the yield of NRs is nearly 100%, with very few byproducts such as branched structures.</li>
	</ol>
	</li>
</ol>
4. Synthesis of CdSe-seeded CdSe NRs
Note: See8.
<ol>
	<li>Mix 1.035 g of CdO, 0.1657 g of HPA, 0.1543 g of n-tetradecylphosphonic acid (TDPA), and 3 g of TOPO in a three-necked RBF. Add a magnetic stir bar to the mixture and insert a temperature probe into the RBF through a punctured rubber septum. Mount a reflux condenser over the RBF and connect it to a Schlenk line via an adapter. Seal the remaining port with a rubber septum. Apply high vacuum grease at all glass-to-glass joints.</li>
	<li>Degas the solution at 150 &#176;C for 1.5 h under constant stirring at 800 RPM.</li>
	<li>Separately, mix 2 mL of the TOPSe stock solution and 10 nmol of w-CdSe QDs (dispersed in toluene) in a single-necked RBF and degas under constant stirring over an oil bath at 800 RPM and 90 &#176;C until all the toluene is removed.</li>
	<li>After degassing, increase the temperature of the cadmium precursor mixture to 340 &#176;C. As the temperature increases, observe a color change in the solution, from dark brown to colorless, indicating the formation of the cadmium-alkyl phosphonic acid complex.</li>
	<li>As the temperature of cadmium precursor reaches 340 &#176;C, swiftly inject 1.8 mL of TOP into the mixture and allow the temperature to recover to 340 &#176;C.</li>
	<li>Upon reaching 340 &#176;C, swiftly inject 1.8 mL of the TOP-Se/CdSe QD mixture into the three-necked RBF, whereupon the temperature will drop to 320 &#176;C. Upon recovery to 340 &#176;C, maintain the reaction solution at this temperature for ~3 min before removing the heating mantle and allowing the solution to cool to room temperature under ambient conditions.</li>
	<li>After the reaction solution has cooled to room temperature, add 2 mL of toluene and transfer the entire solution to a 50-mL centrifuge tube. Top up the centrifuge tube with methanol (99%) to 50 mL and centrifuge the resulting suspension at 2,240 x g for 3 min. Subsequently, discard the supernatant.</li>
	<li>Add 5 mL of toluene to the precipitate to disperse the NRs. Carry out further processing cycles: precipitate the NRs using 30 mL of methanol (99%), centrifuge the suspension at 2,240 x g for 3 min, discard the supernatant, and disperse the NRs in 5 mL of toluene.
	<ol>
		<li>Following 2-3 cycles of processing, disperse the NRs in 5 mL of toluene (henceforth referred to as the NR stock solution) for further use.</li>
	</ol>
	</li>
	<li>Place a drop of NR solution onto a 300-mesh copper grid covered with a continuous carbon film for electron microscopy analysis. Remove the excess solution with an adsorbent paper and dry the sample at room temperature.</li>
	<li>Perform TEM imaging and analysis to obtain the dimensions of the NRs so that the average volume of the NR and the number of moles of CdSe per NR can be determined.
	<ol>
		<li>Determine the concentration of NRs in solution by taking 20 &#181;L of the stock solution and adding it to 3 mL of toluene. Measure the absorbance at 350 nm and calculate the concentration using the known molar absorptivity at that wavelength6. Scale the concentration accordingly to take into account the dilution of the stock solution. 
		NOTE: For a typical synthesis, the yield of NRs is close to 100%, with very few byproducts such as branched structures.</li>
	</ol>
	</li>
</ol>
5. Synthesis of CdSe-seeded CdSe TPs
Note: See10.
<ol>
	<li>Mix 0.43 g of CdO, 3.8 mL of OA, 2.2 mL ODE, and 0.3 mL of TOP in a three-necked RBF. Add a magnetic stir bar to the mixture and insert a temperature probe into the RBF through a punctured rubber septum. Mount a reflux condenser over the RBF and connect it to a Schlenk line via an adapter. Seal the remaining port with a rubber septum. Apply high vacuum grease at all glass-to-glass joints.</li>
	<li>Degas the solution at 90 &#176;C for 1 h under constant stirring at 800 RPM and then increase the temperature to 265 &#176;C. As the temperature reaches 265 &#176;C, observe the color of the solution changing, from dark brown to colorless, indicating the formation of the cadmium oleate complex.</li>
	<li>Reduce the temperature to 50 &#176;C and add 1.7 mL of 2 M TOPSe (separately prepared by sonicating, at 37 kHz and 320 W, a mixture of 0.316 g of Se powder in 2 mL of TOP in an 8-mL glass vial) and 0.017 g of hexadecyltrimethylammonium bromide (CTAB).</li>
	<li>Separately, mix 7 mL of ODE, 0.025 g of CTAB, 0.5 mL of TOP, 0.75 mL of OA, and 100 nmol of zinc-blende CdSe QDs (dispersed in toluene) in a three-necked RBF. Add a magnetic stir bar to the mixture and insert a temperature probe into the RBF through a punctured rubber septum.
	<ol>
		<li>Mount a condenser over the RBF and connect it to the Schlenk line via an adapter. Seal the remaining port with a rubber septum. Apply high vacuum grease at all glass-to-glass joints.</li>
	</ol>
	</li>
	<li>Degas the mixture prepared in step 5.4 at 90 &#176;C and 800 RPM under constant stirring for ~45 min until all the toluene is removed.</li>
	<li>Increase the temperature of the reaction mixture containing the zinc-blende CdSe QDs to 260 &#176;C. When the temperature reaches 260 &#176;C, add 8 mL of the cadmium precursor solution to the mixture containing zinc-blende CdSe QDs at an injection rate of 0.25 mL/min using a syringe pump. After the addition is completed, allow the solution to cool to room temperature under ambient conditions.</li>
	<li>After the solution has cooled to room temperature, transfer it to a 50-mL centrifuge tube. Add 40 mL of acetone (99%) to precipitate the TPs and centrifuge the suspension at 1,340 x g for 10 min. Subsequently, discard the supernatant.</li>
	<li>Add 5 mL of toluene to the precipitate of TPs to disperse them. Carry out further processing cycles: precipitate the TPs using 30 mL of methanol (99%), centrifuge the suspension at 2,240 x g for 3 min, discard the supernatant, and disperse the TPs in 5 mL of toluene.
	<ol>
		<li>Following 2-3 cycles of processing, disperse the TPs in 5 mL of toluene (henceforth referred to as the TP stock solution) for further use.</li>
	</ol>
	</li>
	<li>Place a drop of the TP solution onto a 300-mesh copper grid covered with a continuous carbon film for electron microscopy analysis. Remove the excess solution with adsorbent paper and dry the sample at room temperature.</li>
	<li>Perform TEM imaging and analysis to obtain the dimensions of the TPs so that the average volume of the TP and the number of moles of CdSe per TP can be determined.
	<ol>
		<li>Determine the concentration of QDs in solution by taking 20 &#181;L of the stock solution and adding it to 3 mL of toluene.</li>
		<li>Measure the absorbance at 350 nm and calculate the concentration using the known molar absorptivity at that wavelength6. Scale the concentration accordingly to account for the dilution of the stock solution. 
		Note: For a typical synthesis, the yield for the TPs is ~80%, with ~20% being bipods and tripods.</li>
	</ol>
	</li>
</ol>
6. Facet Activation and the Linking of Nanostructures
<ol>
	<li>Preparation of a dodecylamine (DDA) stock solution.
	<ol>
		<li>Prepare a DDA stock solution by adding 0.140 g of DDA to 5 mL of ethanol. Sonicate the solution at 37 kHz and 320 W for ~5 min to ensure that the DDA is fully dissolved.</li>
	</ol>
	</li>
	<li>Cation exchange and linking.
	<ol>
		<li>Prepare a 1-mL solution of NC (NR or TP) at the appropriate concentration (see Table 1). Add 6 mg of ODPA to the 1 mL of NC solution and sonicate for 10 min at 37 kHz and 320 W.</li>
		<li>Separately, mix 1 mL of DDA stock solution and 1 mL of Ag+ solution at the appropriate concentration (see Table 1) in a vial. Add a magnetic stir bar and stir the solution vigorously at 800 RPM.</li>
		<li>While stirring, add 1 mL of the NC solution to the vial and allow the reaction to proceed for the corresponding amount of time, as listed in Table 1.</li>
		<li>At the end of the reaction, stop the stirring and allow the solution to phase-separate. Extract and remove the bottom aqueous layer. Add 5 mL of methanol to the organic layer, to precipitate out the NCs. Centrifuge the vial for 3 min at 2,240 x g.</li>
		<li>After centrifugation, discard the supernatant and add 1 mL of toluene to re-disperse the product for further characterization. 
		NOTE: The cation exchange reaction occurs at different rates for different materials. Table 1 summarizes the set of conditions under which the synthesis of linked nanostructures of other materials and morphologies are synthesized. The volume of NC solution (1 mL), aqueous Ag+ solution (1 mL), and ethanol-DDA solution (1 mL) and the amount of ODPA (6 mg) added are kept the same, as mentioned above, for each set of reactions.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Figuerola, 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=End-to-End+Assembly+of+Shape-Controlled+Nanocrystals+via+a+Nanowelding+Approach+Mediated+by+Gold+Domains.">End-to-End Assembly of Shape-Controlled Nanocrystals via a Nanowelding Approach Mediated by Gold Domains.</a> Adv. Mat. 21, 550-554 (2009).</li><li>Tang, Z., Kotov, N. A., Giersig, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spontaneous+Organization+of+Single+CdTe+Nanoparticles+into+Luminescent+Nanowires.">Spontaneous Organization of Single CdTe Nanoparticles into Luminescent Nanowires.</a> Science. 297, 237-240 (2002).</li><li>Kim, D., Kim, W. D., Kang, M. S., Kim, S. -. H., Lee, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-Organization+of+Nanorods+into+Ultra-Long+Range+Two-Dimensional+Monolayer+End-to-End+Network.">Self-Organization of Nanorods into Ultra-Long Range Two-Dimensional Monolayer End-to-End Network.</a> Nano Lett. 15, 714-720 (2015).</li><li>Schliehe, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrathin+PbS+Sheets+by+Two-Dimensional+Oriented+Attachment.">Ultrathin PbS Sheets by Two-Dimensional Oriented Attachment.</a> Science. 329, 550-553 (2010).</li><li>Chakrabortty, 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=Facet+to+facet+Linking+of+Shape+Anisotropic+Inorganic+Nanocrystals+with+Site+Specific+and+Stoichiometric+Control.">Facet to facet Linking of Shape Anisotropic Inorganic Nanocrystals with Site Specific and Stoichiometric Control.</a> Nano Lett. 16, 6431-6436 (2016).</li><li>Leatherdale, C. A., Woo, W. K., Mikulec, F. V., Bawendi, M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On+the+Absorption+Cross+Section+of+CdSe+Nanocrystal+Quantum+Dots.">On the Absorption Cross Section of CdSe Nanocrystal Quantum Dots.</a> J Phys Chem B. 106, 7619-7622 (2002).</li><li>Dabbousi, B. 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=(CdSe)ZnS+Core-Shell+Quantum+Dots:+Synthesis+and+Characterization+of+a+Size+Series+of+Highly+Luminescent+Nanocrystallites.">(CdSe)ZnS Core-Shell Quantum Dots: Synthesis and Characterization of a Size Series of Highly Luminescent Nanocrystallites.</a> J Phys Chem B. 101, 9463-9475 (1997).</li><li>Carbone, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+Micrometer-Scale+Assembly+of+Coilloidal+CdSe/CdS+Nanorods+Prepared+by+Seeded+Grwoth+Approach.">Synthesis and Micrometer-Scale Assembly of Coilloidal CdSe/CdS Nanorods Prepared by Seeded Grwoth Approach.</a> Nano Lett. 7, 2942-2950 (2007).</li><li>Shaviv, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Absorption+properties+of+Metal-Semiconductor+Hybrid+Nanoparticles.">Absorption properties of Metal-Semiconductor Hybrid Nanoparticles.</a> ACS Nano. 5, 4712-4719 (2011).</li><li>Lim, 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=Controlled+Synthesis+of+CdSe+Tetrapods+with+High+Morphological+Uniformity+by+the+Persistent+Kinetic+Growth+and+the+Halide-Mediated+Phase+Transformation.">Controlled Synthesis of CdSe Tetrapods with High Morphological Uniformity by the Persistent Kinetic Growth and the Halide-Mediated Phase Transformation.</a> Chem Mat. 25, 1443-1449 (2013).</li></ol>

We do not have anything to disclose.

The linking technique described in this work allows for shape-anisotropic cadmium chalcogenide nanoparticles that can undergo cation exchange with Ag+ to be joined, facet-to-facet, into assemblies such as linear chains or branched networks. Failure to form well-dispersed, extensive assemblies of facet-to-facet linked nanoparticles is often because of two reasons: (i) the ODPA is not dispersed well in the NR-containing solution, which can be addressed by sonicating the mixture for the prescribed amount of time ...

The directed assembly of colloidal semiconductor NCs offers a synthetic pathway to the fabrication of nanostructures whose physicochemical properties are either the collective sum of or radically different from their individual NC building blocks1,2,3,4. Among the various approaches to nanoparticle assembly, the method of oriented attachment - in which NCs are essentially fused with each other - stands out as one that allows for interparticle electronic coupling. However, conventional oriented attachment typically requires the delicate balancing of particle dipole-, ligand- and solvent-based interactions that are generally difficult to execute and make applicable to different NC systems.
We have recently developed a wet-chemical method of covalently joining shape-anisotropic cadmium chalcogenide NCs by introducing a reactive inorganic intermediate through a site-selective nucleation process. The particles are subsequently linked by the spontaneous fusion of the reactive inorganic intermediate domains5. Although the technique is still based on an oriented attachment mechanism, there is much less need to consider weak interparticle interactions, thus allowing for more flexibility and control. The linking of shape-anisotropic cadmium chalcogenide NCs is carried out by first converting their tip facets to silver chalcogenide via a partial cation exchange process (in solution); this is followed by the selective removal of ligands passivating the surface. The NCs then come together via the fusion of the exposed silver chalcogenide facets, resulting in assemblies of cadmium chalcogenide NCs that are linked end-to-end.
In this protocol, we demonstrate that the linking technique can be applied to a variety of shape-anisotropic cadmium chalcogenide NCs (i.e., CdSe-seeded CdS NRs and CdSe-seeded CdSe NRs or TPs), yielding long linear NR chains or highly branched TP networks. These results suggest that the technique can be extended to a wide variety of NC shapes and metal chalcogenides amenable to silver cation exchange.

<table width="724">
	<colgroup>
		<col />
		<col span="2" />
		<col />
	</colgroup>
	<tbody>
		<tr height="22">
			<td height="22" style="width:288px;height:22px;">Cadmium oxide (CdO), 99.5%</td>
			<td style="width:123px;">Sigma Aldrich</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Highly toxic</td>
		</tr>
		<tr height="43">
			<td height="43" style="width:288px;height:43px;">Tri-n-octylphosphine oxide (TOPO), 90 % and 99%</td>
			<td style="width:123px;">Sigma Aldrich</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Technical and analytical grade</td>
		</tr>
		<tr height="47">
			<td height="47" style="width:288px;height:47px;">Cadmium acetylacetonate (Cd(acac)2), 99.9%</td>
			<td style="width:123px;">Sigma Aldrich</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Highly toxic</td>
		</tr>
		<tr height="22">
			<td height="22" style="width:288px;height:22px;">Hexadecanediol (HDDO), 90%</td>
			<td style="width:123px;">Sigma Aldrich</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Technical grade</td>
		</tr>
		<tr height="22">
			<td height="22" style="width:288px;height:22px;">1-octadecene (ODE), 90%</td>
			<td style="width:123px;">Sigma Aldrich</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Technical grade</td>
		</tr>
		<tr height="22">
			<td height="22" style="width:288px;height:22px;">Dodecylamine (DDA), 98%</td>
			<td style="width:123px;">Sigma Aldrich</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Toxic</td>
		</tr>
		<tr height="47">
			<td height="47" style="width:288px;height:47px;">Cadmium nitrate tetrahydrate ((CdNO3)2.4H2O), 98%</td>
			<td style="width:123px;">Sigma Aldrich</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Highly toxic</td>
		</tr>
		<tr height="22">
			<td height="22" style="width:288px;height:22px;">Myristic acid (MA), 99%</td>
			<td style="width:123px;">Sigma Aldrich</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Analytical grade</td>
		</tr>
		<tr height="22">
			<td height="22" style="width:288px;height:22px;">Octyl phosphonic acid (OPA), 97%</td>
			<td style="width:123px;">Sigma Aldrich</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Analytical grade</td>
		</tr>
		<tr height="22">
			<td height="22" style="width:288px;height:22px;">Oleylamine (Oly), 70%</td>
			<td style="width:123px;">Sigma Aldrich</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Technical grade</td>
		</tr>
		<tr height="43">
			<td height="43" style="width:288px;height:43px;">Hexadecyltrimethylammonium bromide (CTAB), 95%</td>
			<td style="width:123px;">Sigma Aldrich</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Toxic</td>
		</tr>
		<tr height="22">
			<td height="22" style="width:288px;height:22px;">Selenium pellets (Se, 5 mm), 99.99%</td>
			<td style="width:123px;">Sigma Aldrich</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Analytical grade</td>
		</tr>
		<tr height="22">
			<td height="22" style="width:288px;height:22px;">Hexadecylamine (HDA), 90%</td>
			<td style="width:123px;">Alfa Aesar</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Technical grade, toxic</td>
		</tr>
		<tr height="22">
			<td height="22" style="width:288px;height:22px;">n-tetradecylphosphonic acid (TDPA), 98%&#160;</td>
			<td style="width:123px;">Alfa Aesar</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Analytical grade</td>
		</tr>
		<tr height="26">
			<td height="26" style="width:288px;height:26px;">Silver nitrate (AgNO3), 99.9%</td>
			<td style="width:123px;">Alfa Aesar</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Analytical grade</td>
		</tr>
		<tr height="22">
			<td height="22" style="width:288px;height:22px;">Oleic acid (OA), 90%</td>
			<td style="width:123px;">Alfa Aesar</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Technical grade</td>
		</tr>
		<tr height="43">
			<td height="43" style="width:288px;height:43px;">Tri-n-octylphosphine (TOP), 97%</td>
			<td style="width:123px;">Strem</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Analytical grade, toxic, air sensitive</td>
		</tr>
		<tr height="22">
			<td height="22" style="width:288px;height:22px;">n-hexylphosphonic acid (HPA), 97%</td>
			<td style="width:123px;">Strem</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Analytical grade</td>
		</tr>
		<tr height="22">
			<td height="22" style="width:288px;height:22px;">n-octadecylphosphonic acid (ODPA), 97%</td>
			<td style="width:123px;">Strem</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Analytical grade</td>
		</tr>
		<tr height="22">
			<td height="22" style="width:288px;height:22px;">Tellurium powder (Te), 99.9%</td>
			<td style="width:123px;">Strem</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Air sensitive</td>
		</tr>
		<tr height="43">
			<td height="43" style="width:288px;height:43px;">Tri-n-butylphosphine (TBP), 99%</td>
			<td style="width:123px;">Strem</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Analytical grade, highly toxic, air sensitive</td>
		</tr>
		<tr height="22">
			<td height="22" style="width:288px;height:22px;">Diisooctylphosphonic acid (DIPA), 90%</td>
			<td style="width:123px;">Fluka</td>
			<td style="width:123px;"></td>
			<td style="width:191px;">Technical grade, toxic</td>
		</tr>
	</tbody>
</table>

facet-to-facet linking of shape-anisotropic colloidal cadmium chalcogenide nanostructures

Here, we describe a protocol that allows for shape-anisotropic cadmium chalcogenide nanocrystals (NCs), such as nanorods (NRs) and tetrapods (TPs), to be covalently and site-specifically linked via their end facets, resulting in polymer-like linear or branched chains. The linking procedure begins with a cation-exchange process in which the end facets of the cadmium chalcogenide NCs are first converted to silver chalcogenide. This is followed by the selective removal of ligands at their surface. This results in cadmium chalcogenide NCs with highly reactive silver chalcogenide end facets that spontaneously fuse upon contact with each other, thereby establishing an interparticle facet-to-facet attachment. Through the judicious choice of precursor concentrations, an extensive network of linked NCs can be produced. Structural characterization of the linked NCs is carried out via low- and high-resolution transmission electron microscopy (TEM), as well as energy-dispersive X-ray spectroscopy, which confirm the presence of silver chalcogenide domains between chains of cadmium chalcogenide NCs.

Using CdSe-seeded CdS NRs as a model system, as illustrated in Figure 1(a), we demonstrated that we can use a partial Ag+ exchange process to specifically transform the facets at the NR tips to Ag2S. The Ag2S facets are capped by DDA, which reacts with ODPA via an acid-base reaction to form an insoluble salt5. This causes the DDA ligands to be removed from the Ag2S facets, ca...

Watch this Scientific Journal Video about Facet-to-facet Linking of Shape-anisotropic Colloidal Cadmium Chalcogenide Nanostructures at JoVE.com

Facet-to-facet Linking of Shape-anisotropic Colloidal Cadmium Chalcogenide Nanostructures

A protocol detailing how shape-anisotropic colloidal cadmium chalcogenide nanocrystals can be covalently linked via their end facets is presented here.

Here, we describe a protocol that allows for shape-anisotropic cadmium chalcogenide nanocrystals (NCs), such as nanorods (NRs) and tetrapods (TPs), to be ...

facet-to-facet-linking-shape-anisotropic-colloidal-cadmium

Research

JoVE Journal

Chemistry

7.6K Views.  National University of Singapore. A protocol detailing how shape-anisotropic colloidal cadmium chalcogenide nanocrystals can be covalently linked via their end facets is presented here.

Video: Facet-to-facet Linking of Shape-anisotropic Colloidal Cadmium Chalcogenide Nanostructures

Gyroid Nickel Nanostructures from Diblock Copolymer Supramolecules

Nanoporous metal foams possess a unique combination of properties - they are catalytically active, thermally and electrically conductive, and furthermore, have high porosity, high surface-to-volume and strength-to-weight ratio. Unfortunately, common approaches for preparation of metallic nanostructures render materials with highly disordered architecture, which might have an adverse effect on their mechanical properties. Block copolymers have the ability to self-assemble into ordered nanostructures and can be applied as templates for the preparation of well-ordered metal nanofoams. Here we describe the application of a block copolymer-based supramolecular complex - polystyrene-block-poly(4-vinylpyridine)(pentadecylphenol) PS-b-P4VP(PDP) - as a precursor for well-ordered nickel nanofoam. The supramolecular complexes exhibit a phase behavior similar to conventional block copolymers and can self-assemble into the bicontinuous gyroid morphology with two PS networks placed in a P4VP(PDP) matrix. PDP can be dissolved in ethanol leading to the formation of a porous structure that can be backfilled with metal. Using electroless plating technique, nickel can be inserted into the template&#39;s channels. Finally, the remaining polymer can be removed via pyrolysis from the polymer/inorganic nanohybrid resulting in nanoporous nickel foam with inverse gyroid morphology.

This article describes the preparation of well-ordered nickel nanofoams via electroless metal deposition onto nanoporous templates obtained from self-assembled diblock copolymer based supramolecules.

Nanoporous metal foams possess a unique combination of properties - they are catalytically active, thermally and electrically conductive, and furthermore, ...

Quantitative and Qualitative Examination of Particle-particle Interactions Using Colloidal Probe Nanoscopy

Colloidal Probe Nanoscopy (CPN), the study of the nano-scale interactive forces between a specifically prepared colloidal probe and any chosen substrate using the Atomic Force Microscope (AFM), can provide key insights into physical interactions present within colloidal systems. Colloidal systems are widely existent in several applications including, pharmaceuticals, foods, paints, paper, soil and minerals, detergents, printing and much more.1-3 Furthermore, colloids can exist in many states such as emulsions, foams and suspensions. Using colloidal probe nanoscopy one can obtain key information on the adhesive properties, binding energies and even gain insight into the physical stability and coagulation kinetics of the colloids present within. Additionally, colloidal probe nanoscopy can be used with biological cells to aid in drug discovery and formulation development. In this paper we describe a method for conducting colloidal probe nanoscopy, discuss key factors that are important to consider during the measurement, and show that both quantitative and qualitative data that can be obtained from such measurements.

Colloidal probe nanoscopy can be used within a variety of fields to gain insight into the physical stability and coagulation kinetics of colloidal systems and aid in drug discovery and formulation sciences using biological systems. The method described within provides a quantitative and qualitative means to study such systems.

Colloidal Probe Nanoscopy (CPN), the study of the nano-scale interactive forces between a specifically prepared colloidal probe and any chosen substrate ...

Synthesis of Indoxyl-glycosides for Detection of Glycosidase Activities

Indoxyl glycosides proved to be valuable and versatile tools for monitoring glycosidase activities. Indoxyls are released by enzymatic hydrolysis and are rapidly oxidized, for example by atmospheric oxygen, to indigo type dyes. This reaction enables fast and easy screening in vivo without isolation or purification of enzymes, as well as rapid tests on agar plates or in solution (e.g., blue-white screening, micro-wells) and is used in biochemistry, histochemistry, bacteriology and molecular biology. Unfortunately the synthesis of such substrates proved to be difficult, due to various side reactions and the low reactivity of the indoxyl hydroxyl function. Especially for glucose type structures low yields were observed. Our novel approach employs indoxylic acid ester as key intermediates. Indoxylic acid esters with varied substitution patterns were prepared on scalable pathways. Phase transfer glycosylations with those acceptors and peracetylated glycosyl halides can be performed under common conditions in high yields. Ester cleavage and subsequent mild silver mediated glycosylation yields the peracetylated indoxyl glycosides in high yields. Finally deprotection is performed according to Zempl&#233;n.

Indoxyl glycosides are well-established and widely used tools for enzyme screening and enzyme activity monitoring. Especially for glucose type structures previous syntheses proved to be challenging and low yielding. Our novel approach employs indoxylic acid esters as precious intermediates to yield a considerable number of indoxyl glycosides in good yields.

Indoxyl glycosides proved to be valuable and versatile tools for monitoring glycosidase activities. Indoxyls are released by enzymatic hydrolysis and are ...

Synthesis and Exfoliation of Discotic Zirconium Phosphates to Obtain Colloidal Liquid Crystals

Due to their abundance in natural clay and potential applications in advanced materials, discotic nanoparticles are of interest to scientists and engineers. Growth of such anisotropic nanocrystals through a simple chemical method is a challenging task. In this study, we fabricate discotic nanodisks of zirconium phosphate [Zr(HPO4)2&#183;H2O] as a model material using hydrothermal, reflux and microwave-assisted methods. Growth of crystals is controlled by duration time, temperature, and concentration of reacting species. The novelty of the adopted methods is that discotic crystals of size ranging from hundred nanometers to few micrometers can be obtained while keeping the polydispersity well within control. The layered discotic crystals are converted to monolayers by exfoliation with tetra-(n)-butyl ammonium hydroxide [(C4H9)4NOH, TBAOH]. Exfoliated disks show isotropic and nematic liquid crystal phases. Size and polydispersity of disk suspensions is highly important in deciding their phase behavior.

A two dimensional model material of discotic zirconium phosphate was developed. The inorganic crystal with lamellar structure was synthesized by hydrothermal, reflux, and microwave-assisted methods. On exfoliation with organic molecules, layered crystals can be converted to monolayers, and nematic liquid crystal phase was formed at sufficient concentration of monolayers.

Due to their abundance in natural clay and potential applications in advanced materials, discotic nanoparticles are of interest to scientists and ...

Visualization of Ambient Mass Spectrometry with the Use of Schlieren Photography

This manuscript outlines how to visualize mass spectrometry ambient ionization sources using schlieren photography. In order to properly optimize the mass spectrometer, it is necessary to characterize and understand the physical principles of the source. Most commercial ambient ionization sources utilize jets of nitrogen, helium, or atmospheric air to facilitate the ionization of the analyte. As a consequence, schlieren photography can be used to visualize the gas streams by exploiting the differences in refractive index between the streams and ambient air for visualization in real time. The basic setup requires a camera, mirror, flashlight, and razor blade. When properly configured, a real time image of the source is observed by watching its reflection. This allows for insight into the mechanism of action in the source, and pathways to its optimization can be elucidated. Light is shed on an otherwise invisible situation.

This paper presents a protocol for the visualization of gaseous streams of an ambient ionization source using schlieren photography and mass spectrometry.

This manuscript outlines how to visualize mass spectrometry ambient ionization sources using schlieren photography. In order to properly optimize the mass ...

Preparation and Characterization of C60/Graphene Hybrid Nanostructures

Physical thermal deposition in a high vacuum environment is a clean and controllable method for fabricating novel molecular nanostructures on graphene. We present methods for depositing and passively manipulating C60 molecules on rippled graphene that advance the pursuit of realizing applications involving 1D C60/graphene hybrid structures. The techniques applied in this exposition are geared towards high vacuum systems with preparation areas capable of supporting molecular deposition as well as thermal annealing of the samples. We focus on C60 deposition at low pressure using a homemade Knudsen cell connected to a scanning tunneling microscopy (STM) system. The number of molecules deposited is regulated by controlling the temperature of the Knudsen cell and the deposition time. One-dimensional (1D) C60 chain structures with widths of two to three molecules can be prepared via tuning of the experimental conditions. The surface mobility of the C60 molecules increases with annealing temperature allowing them to move within the periodic potential of the rippled graphene. Using this mechanism, it is possible to control the transition of 1D C60 chain structures to a hexagonal close packed quasi-1D stripe structure.

Preparation and Characterization of C60/Graphene Hybrid Nanostructures

Here we present a protocol for the fabrication of C60/graphene hybrid nanostructures by physical thermal evaporation. Particularly, the proper manipulation of deposition and annealing conditions allow the control over the creation of 1D and quasi 1D C60 structures on rippled graphene.

Physical thermal deposition in a high vacuum environment is a clean and controllable method for fabricating novel molecular nanostructures on graphene. We ...

The Effect of Ultraviolet Radiation on the Chemical Bath Deposition of Bis(thiourea) Cadmium Chloride Crystals and the Subsequent CdS Obtention

In this work, the effects on the preparation of bis(thiourea) cadmium chloride crystals when illuminated with ultraviolet (UV) light at a wavelength of 367 nm using the chemical bath deposition technique are studied comparatively. Two experiments are performed to make a comparison: one without UV light and the other with the aid of UV light. Both experiments are performed under equal conditions, at a temperature of 343 K and with a pH of 3.2. The precursors used are cadmium chloride (CdCl2) and thiourea [CS(NH2)2], which are dissolved in 50 mL of deionized water with an acidic pH. In this experiment, the interaction of electromagnetic radiation is sought at the moment the chemical reaction is carried out. The results demonstrate the existence of an interaction between the crystals and the UV light; the UV light assistance causes crystal growths in an acicular shape. Also, the final product obtained is cadmium sulfide and shows no evident difference when synthesized with or without the use of UV light.

The Effect of Ultraviolet Radiation on the Chemical Bath Deposition of Bisthiourea Cadmium Chloride Crystals and the Subsequent CdS Obtention

This article presents a protocol for the synthesis of bis(thiourea) cadmium chloride crystals by chemical bath deposition. Two experiments are described: one aided by ultraviolet light compared to one without ultraviolet light.

In this work, the effects on the preparation of bis(thiourea) cadmium chloride crystals when illuminated with ultraviolet (UV) light at a wavelength of ...

Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F&#8722;

Anion photoelectron imaging is a very efficient method for the study of energy states of bound negative ions, neutral species and interactions of unbound electrons with neutral molecules/atoms. State-of-the-art in vacuo anion generation techniques allow application to a broad range of atomic, molecular, and cluster anion systems. These are separated and selected using time-of-flight mass spectrometry. Electrons are removed by linearly polarized photons (photo detachment) using table-top laser sources which provide ready access to excitation energies from the infra-red to the near ultraviolet. Detecting the photoelectrons with a velocity mapped imaging lens and position sensitive detector means that, in principle, every photoelectron reaches the detector and the detection efficiency is uniform for all kinetic energies. Photoelectron spectra extracted from the images via mathematical reconstruction using an inverse Abel transformation reveal details of the anion internal energy state distribution and the resultant neutral energy states. At low electron kinetic energy, typical resolution is sufficient to reveal energy level differences on the order of a few millielectron-volts, i.e., different vibrational levels for molecular species or spin-orbit splitting in atoms. Photoelectron angular distributions extracted from the inverse Abel transformation represent the signatures of the bound electron orbital, allowing more detailed probing of electronic structure. The spectra and angular distributions also encode details of the interactions between the outgoing electron and the residual neutral species subsequent to excitation. The technique is illustrated by the application to an atomic anion (F&#8722;), but it can also be applied to the measurement of molecular anion spectroscopy, the study of low lying anion resonances (as an alternative to scattering experiments) and femtosecond (fs) time resolved studies of the dynamic evolution of anions.

Here, we present a protocol for photoelectron imaging of anionic species. Anions generated in vacuo and separated by mass spectrometry are probed using velocity mapped photoelectron imaging, providing details of anion and neutral energy levels, anion and neutral structure and the nature of the anion electronic state.

Anion photoelectron imaging is a very efficient method for the study of energy states of bound negative ions, neutral species and interactions of unbound ...

Stable DNA Motifs, 1D and 2D Nanostructures Constructed from Small Circular DNA Molecules

This article presents a detailed protocol for synthesis of small circular DNA molecules, annealing of circular DNA motifs, and construction of 1D and 2D DNA nanostructures. Over decades, the rapid development of DNA nanotechnology is attributed to the use of linear DNAs as the source materials. For example, the DAO (double crossover, antiparallel, odd half-turns) tile is well-known as a building block for construction of 2D DNA lattices; the core structure of DAO is made from two linear single-stranded (ss) oligonucleotides, like two ropes making a right hand granny&#160;knot. Herein, a new type of DNA tiles called cDAO (coupled DAO) are built using a small circular ss-DNA of c64nt or c84nt (circular 64 or 84 nucleotides) as the scaffold strand and several linear ss-DNAs as the staple strands. Perfect 1D and 2D nanostructures are assembled from cDAO tiles: infinite nanowires, nanospirals, nanotubes, nanoribbons; and finite nano-rectangles. Detailed protocols are described: 1) preparation by T4 ligase and purification by denaturing PAGE (polyacrylamide gel electrophoresis) of small circular oligonucleotides, 2) annealing of stable circular tiles, followed by native PAGE analysis, 3) assembling of infinite 1D nanowires, nanorings, nanospirals, infinite 2D lattices of nanotubes and nanoribbons, and finite 2D nano-rectangles, followed by AFM (Atomic Force Microscopy) imaging. The method is simple, robust, and affordable for most labs.

This article presents a detailed protocol for T4 ligation and denaturing PAGE purification of small circular DNA molecules, annealing and native PAGE analysis of circular tiles, assembling and AFM imaging of 1D and 2D DNA nanostructures, as well as agarose gel electrophoresis and centrifugation purification of finite DNA nanostructures.

This article presents a detailed protocol for synthesis of small circular DNA molecules, annealing of circular DNA motifs, and construction of 1D and 2D ...

Gene-therapy Inspired Polycation Coating for Protection of DNA Origami Nanostructures

DNA origami nanostructures hold an immense potential to be used for biological and medical applications. However, low-salt conditions and nucleases in physiological fluids induce denaturation and degradation of self-assembled DNA nanostructures. In non-viral gene delivery, enzymatic degradation of DNA is overcome by the encapsulation of the negatively charged DNA in a cationic shell. Herein, inspired by gene delivery advancements, a simple, one-step and robust methodology is presented for the stabilization of DNA origami nanostructures by coating them with chitosan and linear polyethyleneimine. The polycation coating efficiently protects DNA origami nanostructures in Mg-depleted and nuclease-rich media. This method also preserves the full addressability of enzyme- and aptamer-based functionalization of DNA nanostructures.

Here, a protocol for the protection of DNA origami nanostructures in Mg-depleted and nuclease-rich media using natural cationic polysaccharide chitosan and synthetic linear polyethyleneimine (LPEI) coatings is presented.

DNA origami nanostructures hold an immense potential to be used for biological and medical applications. However, low-salt conditions and nucleases in ...