Treffer: Interfacial protein adsorption behavior can be connected across a wide range of timescales using the microfluidic EDGE (Edge-based droplet GEneration) tensiometer

Hypothesis: Our hypothesis is that dynamic interfacial tension values as measured by the partitioned-Edge-basedDroplet GEneration (EDGE) tensiometry can be connected to those obtained with classical techniques, such as theautomated drop tensiometer (ADT), expanding the range of timescales towards very short ones.Experiments: Oil-water and air–water interfaces are studied, with whey protein isolate solutions (WPI, 2.5 – 10 wt%) as the continuous phase. The dispersed phase consists of pure hexadecane or air. The EDGE tensiometer andADT are used to measure the interfacial (surface) tension at various timescales. A comparative assessment iscarried out to identify differences between protein concentrations as well as between oil–water and air–waterinterfaces.Findings: The EDGE tensiometer can measure at timescales down to a few milliseconds and up to around 10 s,while the ADT provides dynamic interfacial tension values after at least one second from droplet injection andtypically is used to also cover hours. The interfacial tension values measured with both techniques exhibitoverlap, implying that the techniques provide consistent and complementary information. Unlike the ADT, theEDGE tensiometer distinguishes differences in protein adsorption dynamics at protein concentrations as high as10 wt% (which is the highest concentration tested) at both oil–water and air–water interfaces.