Abstract: Using confocal microscopy and optical microscopy, the formation and evolution of the self-assembly structures from cardiolipin were investigated in NaCl solutions. The results show that, as the solution concentration is close to physiological concentrations, micro-hemispherical cells emerge on the surface of sponge phase cardiolipin, which tend to automatically arrange in a honeycomb-like array. The slow increasing of the brine content in solutions would drive the phase transition from sponge phase to lamellar phase continuously developed toward to the deep-center of sponge phase cardiolipin. On the other hand, the pressure and shear stress from weak flowing of the fluid also can affect the final morphology of these micro-cells, make them appear as honeycomb-like structures, raspberry-like domes and raspberry spheres. Since cardiolipid plays an important role for mitochondrial function, we hope these above results on phase transition and morphology evolution may improve our understanding of the acting mechanisms of cardiolipin.

Key words: Cardiolipin, Honeycomb-like structure, Raspberry-like structure, Sponge phase, Lamellar phase