Growth of Solid Domains in Model Membranes: Quantitative Image Analysis Reveals a Strong Correlation between Domain Shape and Spatial Position

Abstract

The nucleation and growth of solid domains in supported bilayers composed of a binary mixture of equimolar 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) have been studied using combined fluorescence microscopy and AFM. We have found that the formation of the DPPC-enriched solid domains occurs by a combination of homogeneous and heterogeneous nucleation and that the nucleation density is directly proportional to the cooling rate. Furthermore, during cooling the shape of the domains evolve from compact to a branched morphology. This suggests that the growth is controlled by the diffusion of DPPC from the liquid phase toward the solid domain interface. In the late stages of the growth, we observe that the size and overall shape of the domains depend on the position of the nucleation points relative to the surrounding nucleation point positions. To analyze this effect, the nucleation points were used as generators in a Voronoi construction. Associated with each generator is a Voronoi polygon that contains all points closer to this generator than to any other. Through a detailed quantitative analysis of the Voronoi cells and the domains, we have found that their area, orientation, and asymmetry correlate and that the correlation becomes stronger for larger domains. This means that the spatial distribution of the nucleation points regulate the domain shape.

Meniscus-assisted solution printing of large-grained perovskite films for high-efficiency solar cells

“…A two-stage crystal growth is observed, namely, a quadratic increase of crystal area with time at the early stage of growth and a linear increase of crystal area with time at the late stage. It is worth noting that this growth pattern is analogous to the vacuum deposition of organic crystals on substrate3940, except that the atom transferring medium in MASP is a liquid flow. In this context, we examine the perovskite crystal growth kinetics according to the scaling capture zone model4142, in which the crystal growth is essentially governed by the accessible collection area for solutes and the solute diffusion length41.…”

Dendritic Domains with Hexagonal Symmetry Formed by X‐Shaped Bolapolyphiles in Lipid Membranes

“…The dendritic domains are probably formed through a kinetically controlled nucleation and growth mechanism[46] and bear a superficial resemblance to phase-separated structures observed in mixed-lipid GUVs[10] or supported bilayers. [6, 7] The clean sixfold symmetry observed for B12 is remarkable. It suggests a regular packing structure of the BP and lipid components, and most likely reflects its local symmetry.…”

Electrostatic field effects on membrane domain segregation and on lateral diffusion

“…Then, by knowing the factors that underlie the domain shape and distribution, this allows the surface topography of the system and the electrostatic effect of the domain on the particles inserted into the membrane to be controlled. Domain environment, for example, affects the domain size and shape (Bernchou et al 2009), which is illustrated in Fig. 4 (unpublished results).…”