Figure 1.

Formation and characterization of PDMS-supported bilayers. (a) A schematic representation of the experimental setup and the bilayer formation process is shown. (b and c) Single-molecule diffusion analysis of lipids in the PDMS-supported bilayers is given. (b) Representative MSD plots and fits of data acquired on SLBs formed on 4 kPa (D = 1.3 μm²/s, σ = 0.116 μm², n_Tracks = 264) and 1 MPa PDMS gels (D = 0.8 μm²/s, σ = 0.103 μm², n_Tracks = 452) and glass (D = 1.5 μm²/s, σ = 0.117 μm², n_Tracks = 5430) are shown. Error bars indicate SEM. (c) Comparison of the diffusion coefficients of lipids on SLBs supported by glass and 1 MPa and 4 kPa PDMS gels is shown. Each data point represents one independent measurement of lipid diffusion at room temperature (RT) (n_tracks > 100) each performed on a separate bilayer. (d) Representative FRAP curve and fit from an SLB on 4 kPa PDMS gel are given, with raw data showing the fluorescence recovery after photobleaching, above. Scale bars, 10 μm. (e) Mobile fractions f_mobile and (f) diffusion coefficients measured using FRAP are shown. In (e) and (f), each data point represents one independent experiment, performed at RT. (g–i) Mechanical characterization of SLBs on PDMS via AFM is shown. (g) A schematic representing the AFM cantilever approaching and contacting first the SLB and then the PDMS is given. (h) Representative force curve (green) on a 4 kPa PDMS gel is shown. Push-through events are detected via changes in the gradient of the force curve (black). (i) Boxplots of SLB thickness (z-jump) are given (number of force curves analyzed: 30 (glass), 31 (1 MPa PDMS), and 52 (4 kPa PDMS)) acquired on three separate SLBs per condition. Boxes indicate the 25 and 75% quartile, the horizontal line the mean, and whiskers the 1.5 IQR . The Mann-Whitney U test was used for statistical comparisons. To see this figure in color, go online.