Buckling of lipid tubules in shrinking liquid droplets

Self-assembled hollow lipid tubules are interesting and potentially useful supramolecular structures. Here, we study the deformation of lipid tubules of 1,2-bis(tricosa-10,12-diynoyl)-sn-glycero-3-phosphocholine (DC8,9PC) trapped inside liquid droplets on glass substrates. The interface tension of the shrinking liquid droplets exerts a compression force on the ends of the trapped lipid tubules, and causes them to buckle. This provides a method to measure their mechanical properties. The Young's modulus of the DC8,9PC lipid tubules is estimated to approximately 1.07 GPa. As the strain energy of the buckled tubules builds up, they poke through the interface of shrinking liquid droplets and then adhere onto glass substrates to form looplike shapes.