Cover Picture: Analysis of Protein–Protein Interactions by Using Droplet‐Based Microfluidics (ChemBioChem 10/2009)

Abstract

AbstractThe cover picture shows a segmented‐flow microfluidic system that was used to analyse protein–protein interactions in picolitre droplets. The 400 pL aqueous droplets were formed, encapsulated by a carrier fluid, and then transported through a 50 μm‐wide microchannel at a constant velocity. Each droplet contained fluorescently labelled antigens and antibodies, and FRET was used to report protein–protein interactions. Angiogenin (ANG), a small polypeptide implicated in angiogenesis and tumour growth, was selected as a model protein. Specifically, an anti‐ANG antibody (anti‐ANG Ab) and an ANG antigen were labelled with fluorophores to act as donor and acceptor in the FRET measurements. KD values for ANG and anti‐ANG Ab from these experiments (KD=6.4±1.6 nM) agree closely with data from bulk fluorescence polarisation measurements KD=9.0±1.5 nM). We expect that this novel experimental platform will have significant application in high‐throughput protein expression profiling and drug discovery. For further details, see the article by S.‐I. Chang, A. J. deMello et al. on p. 1605 ff.magnified image