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Continuous In-Flight Synthesis for On-Demand Delivery of Ligand-Free Colloidal Gold Nanoparticles

Maguire, Paul, Rutherford, David, Macias-Montero, Manuel, Mahony, Charles, Kelsey, Colin, Tweedie, M, Perez-Martin, F, McQuaid, Harold, Diver, Declan and Mariotti, Davide (2017) Continuous In-Flight Synthesis for On-Demand Delivery of Ligand-Free Colloidal Gold Nanoparticles. Nano Letters, 17 (3). pp. 1336-1343. [Journal article]

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URL: http://pubs.acs.org/doi/full/10.1021/acs.nanolett.6b03440

DOI: 10.1021/acs.nanolett.6b03440


We demonstrate an entirely new method of nanoparticle chemical synthesis based on liquid droplet irradiation with ultralow (<0.1 eV) energy electrons. While nanoparticle formation via high energy radiolysis or transmission electron microscopy-based electron bombardment is well-understood, we have developed a source of electrons with energies close to thermal which leads to a number of important and unique benefits. The charged species, including the growing nanoparticles, are held in an ultrathin surface reaction zone which enables extremely rapid precursor reduction. In a proof-of-principle demonstration, we obtain small-diameter Au nanoparticles (∼4 nm) with tight control of polydispersity, in under 150 μs. The precursor was almost completely reduced in this period, and the resultant nanoparticles were water-soluble and free of surfactant or additional ligand chemistry. Nanoparticle synthesis rates within the droplets were many orders of magnitude greater than equivalent rates reported for radiolysis, electron beam irradiation, or colloidal chemical synthesis where reaction times vary from seconds to hours. In our device, a stream of precursor loaded microdroplets, ∼15 μm in diameter, were transported rapidly through a cold atmospheric pressure plasma with a high charge concentration. A high electron flux, electron and nanoparticle confinement at the surface of the droplet, and the picoliter reactor volume are thought to be responsible for the remarkable enhancement in nanoparticle synthesis rates. While this approach exhibits considerable potential for scale-up of synthesis rates, it also offers the more immediate prospect of continuous on-demand delivery of high-quality nanomaterials directly to their point of use by avoiding the necessity of collection, recovery, and purification. A range of new applications can be envisaged, from theranostics and biomedical imaging in tissue to inline catalyst production for pollution remediation in automobiles.Paul MaguireDavid RutherfordManuel Macias-MonteroCharles MahonyColin KelseyMark TweedieFatima Perez-MartinHarold McQuaidDeclan DiverDavide Mariotti

Item Type:Journal article
Keywords:Plasma, Nanoparticles, Microdroplets
Faculties and Schools:Faculty of Computing & Engineering
Faculty of Computing & Engineering > School of Engineering
Research Institutes and Groups:Engineering Research Institute
Engineering Research Institute > Nanotechnology & Integrated BioEngineering Centre (NIBEC)
ID Code:37172
Deposited By: Professor Paul Maguire
Deposited On:26 Apr 2017 08:25
Last Modified:06 Jun 2017 14:46

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