Fig. 9

Examples of microfluidic neutrophil chemotaxis devices in clinical applications. a The overview of the gel-based neutrophil chemotaxis device. The gel channel (100 µm high) was used for collagen loading. The cell channel (50 µm high) was used for cell loading. The linear LPS concentration gradient was generated in five migration channels (50 µm high). The directional velocities of healthy, general sepsis, severe sepsis, and septic shock groups were decreased with the seriousness of sepsis. Reprinted from Ref. [33], Copyright (2016), with permission from Elsevier; b the donut-shape neutrophil chemotaxis assay and characterization of neutrophil chemotaxis of adults, term neonates, and preterm neonates. Reprinted from Ref. [92] Copyright (2017), with permission from Elsevier; c the microfluidic method for phenotyping asthma patients. For asthmatic and nonasthmatic patients, no statistically significant difference in neutrophil migration speed (i) and chemotactic index (ii); for asthmatic patients (n = 23), neutrophil chemotaxis velocity (iii) is lower than nonasthmatic patients (n = 11). *P = 0.02. (Figure reproduced from Ref. [39])