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. Furthurmore, 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.
- Dark-field spectroscopy
ASJC Scopus subject areas
- Engineering (miscellaneous)
- School of Engineering & Physical Sciences - Associate Professor
- School of Engineering & Physical Sciences, Institute of Biological Chemistry, Biophysics and Bioengineering - Associate Professor
Person: Academic (Research & Teaching)