Characterization of the Lateral Distribution of Fluorescent Lipid in Binary-Constituent Lipid Monolayers by Principal Component Analysis
Figure 6
2D-Diagram of fluorescence spectra of binary-constituent lipid monolayers. Each point on the plane represents a fluorescence spectrum of a BODIPY-labeled binary-constituent lipid monolayer. For the jth spectrum and , where and are jth component of the 1st and 2nd eigenvectors, respectively. A zig-zag line of the same color connects points belonging to monolayers comprised of the same lipid constituents. These lines start from the origin representing the spectra of different monolayers with 0 of the monolayer increases with successive dots corresponding to Me4BODIPY-PC mole fractions of 0.01, 0.1, and 0.2. All lines converge to the same final point, representing the spectrum of pure Me4BODIPY-PC monolayer. Panels (a) and (b) represent lateral pressures of 5 and 30 mN/m; whereas, panels (c) and (d) correspond to average cross-sectional molecular areas of 75 and 64 /molecule, respectively. Color codes: Me4BODIPY-PC/POPC (black), Me4BODIPY-PC/DPPC (green), Me4BODIPY-PC/18:1SM (blue), Me4BODIPY-PC/16:0SM (red). The dotted ellipses encircle equivalent Me4BODIPY-PC mole fractions, with the numerical label indicating the fluorophore mole fraction (0.01, 0.1, or 0.2) mixed with each of the four different nonfluorescent lipids (POPC, DPPC, 18:1-SM, or 16:0-SM).
