Issue 7, 2014

Nanoscale spatially resolved infrared spectra from single microdroplets

Abstract

Droplet microfluidics has emerged as a powerful platform allowing a large number of individual reactions to be carried out in spatially distinct microcompartments. Due to their small size, however, the spectroscopic characterisation of species encapsulated in such systems remains challenging. In this paper, we demonstrate the acquisition of infrared spectra from single microdroplets containing aggregation-prone proteins. To this effect, droplets are generated in a microfluidic flow-focussing device and subsequently deposited in a square array onto a ZnSe prism using a micro stamp. After drying, the solutes present in the droplets are illuminated locally by an infrared laser through the prism, and their thermal expansion upon absorption of infrared radiation is measured with an atomic force microscopy tip, granting nanoscale resolution. Using this approach, we resolve structural differences in the amide bands of the spectra of monomeric and aggregated lysozyme from single microdroplets with picolitre volume.

Graphical abstract: Nanoscale spatially resolved infrared spectra from single microdroplets

Supplementary files

Article information

Article type
Paper
Submitted
29 Oct 2013
Accepted
29 Jan 2014
First published
29 Jan 2014
This article is Open Access
Creative Commons BY license

Lab Chip, 2014,14, 1315-1319

Author version available

Nanoscale spatially resolved infrared spectra from single microdroplets

T. Müller, F. S. Ruggeri, A. J. Kulik, U. Shimanovich, T. O. Mason, T. P. J. Knowles and G. Dietler, Lab Chip, 2014, 14, 1315 DOI: 10.1039/C3LC51219C

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