Zhang Y, Buell AK, Müller T, De Genst E, Benesch J, Dobson CM, Knowles TP.
Chembiochem. 2016 Oct 17;17(20):1920-1924
Zhang et al again demonstrate the utility of Microfluidic Diffusional Sizing (MDS) to monitor Nanobody binding to ɑ-synuclein, but this time also use MDS to monitor ɑ-synuclein fibril formation. Due to their size, ɑ-synuclein fibrils diffuse very little and are retained in the centre of the channel, while ɑ-synuclein monomers diffuse more freely. The authors observe that after 40 minutes, fluorescence signal corresponding to the monomeric protein was found to increase in the centre of the channel as a consequence of incorporation into aggregates (Figure 1).
In summary, the method rapidly yields qualitative binding information from only a few microlitres of sample. For quantitative studies, a series of measurements under different conditions enables binding constants and stoichiometries to be established.