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Monitoring Early-Stage Nanoparticle Assembly in Microdroplets by Optical Spectroscopy and SERS.

Published version
Peer-reviewed

Repository DOI


Change log

Authors

Salmon, Andrew R 
Esteban, Ruben 
Taylor, Richard W 
Hugall, James T 
Smith, Clive A 

Abstract

Microfluidic microdroplets have increasingly found application in biomolecular sensing as well as nanomaterials growth. More recently the synthesis of plasmonic nanostructures in microdroplets has led to surface-enhanced Raman spectroscopy (SERS)-based sensing applications. However, the study of nanoassembly in microdroplets has previously been hindered by the lack of on-chip characterization tools, particularly at early timescales. Enabled by a refractive index matching microdroplet formulation, dark-field spectroscopy is exploited to directly track the formation of nanometer-spaced gold nanoparticle assemblies in microdroplets. Measurements in flow provide millisecond time resolution through the assembly process, allowing identification of a regime where dimer formation dominates the dark-field scattering and SERS. Furthermore, it is shown that small numbers of nanoparticles can be isolated in microdroplets, paving the way for simple high-yield assembly, isolation, and sorting of few nanoparticle structures.

Description

Keywords

SERS, dark-field spectroscopy, microdroplets, nanoparticle, Gold, Metal Nanoparticles, Microfluidics, Optical Phenomena, Refractometry, Spectrum Analysis, Raman

Journal Title

Small

Conference Name

Journal ISSN

1613-6810
1613-6829

Volume Title

12

Publisher

Wiley
Sponsorship
Engineering and Physical Sciences Research Council (EP/G060649/1)
Engineering and Physical Sciences Research Council (EP/L027151/1)
European Research Council (320503)
Engineering and Physical Sciences Research Council (EP/K028510/1)
Engineering and Physical Sciences Research Council (EP/H007024/1)
Engineering and Physical Sciences Research Council (EP/G037221/1)
J. J. Baumberg and A. Salmon acknowledge the support of the European Research Council (LINASS 320503), the UK Engineering and Physical Sciences Research Council EP/K028510/1, EP/G037221/1, EP/G060649/1, EP/L027151/1, and the Nano Science and Technology Doctoral Training Centre (NanoDTC) of the University of Cambridge. J. Aizpurua and R. Esteban acknowledge the Spanish Ministry of Economy and Competitiveness (FIS2013-41184-P). R. Esteban acknowledges the Fellow Gipuzkoa Program of the Gipuzkoako Foru Aldundia through FEDER “Una Manera de hacer Europa”.