Fig. 4.

Autonomous PIP2 sorting in response to physical structures. a Schematic of the procedure of making PMSD pattern. b SEM images of PDMS micropatterns. c Biotinylated-GPMVs were labeled with BODIPY FL-PIP2, TopFluor-TMR PC, or PE and incubated with PDMS triangular and rectangular patterns coated with NeutrAvidin. Images were taken when GPMV were settled onto a specific pattern. Fold changes, defined as the ratio of fluorescence intensity of a given lipid at the pattern contacting regions over non-contacting regions, were measured for all shapes with or without 10 mM NaN₃. n ≥ 30, N = 5. Scale bars, 5 µm. ***p < 0.001 by one-way ANOVA with Scheffé post hoc. d Polystyrene beads with different degrees of crosslinking on glass surfaces were subjected to force-indentation displacement probing with a stiff probe. The values of stiffness (Young’s modulus) were obtained via indentation analysis with Veeco software. n ≥ 12, N = 3. ***p < 0.001 and *p < 0.05 by one-way ANOVA with Scheffé post hoc. e RAW264.7 cells were incubated with 2 µm, biotin-BSA-labeled polystyrene beads with varied degrees of crosslinking for 90 min at 37 °C. The efficiency of phagocytosis was analyzed as per phagocytosis assay. n = 50, N = 4. ***p < 0.001 and **p < 0.01 by one-way ANOVA with Scheffé post hoc. f Correlation analysis of stiffness as shown in d and phagocytosis efficiency as shown in e by non-parametric method. Spearman’s rank correlation coefficient r = 1. p = 0.0083