The influence of the Gaussian bending modulus kg on the shapes of opening-up dumbbell vesicles is studied in the spontaneous-curvature model. Using the shooting method the equilibrium shapes of opening-up vesicles at different kg are calculated by solving the Euler-Lagrange equation under the corresponding boundary conditions at the membrane edge. The effects of kg on two kinds of characteristic opening-up shapes of dumbbell vesicles are investigated. One kind is the shape with large diameter of opening hole, which can be regarded as a ball and another part of the ball connected by a fine neck. For this kind of shape, the Gaussian bending modulus mainly influences the neck radius of the vesicles. Another kind is the shape with a small opening hole, which tends to closing dumbbell shapes. For this type, the variation of kg will change the shape of the opening hole.

spontaneous-curvature model; opening-up vesicles; numerical calculations; Gaussian bending modulus