Immobilization of intact liposomes on solid surfaces: A quartz crystal microbalance study

Immobilization of model cell membranes (liposomes) on sensing devices is useful for the detection, evaluation, and analysis of interaction between cell membranes and proteins or other biological materials. The method to immobilize the liposomes on the solid surface was investigated by using the quartz crystal microbalance (QCM) method, focusing on the density of immobilized liposomes and their stability. The different liposomes were applied onto the planar surface of the QCM electrode by varying the immobilization method. The results showed that the immobilized liposomes depended not only on the immobilization method but also on the properties of the liposomes. The liposome with low membrane fluidity likely showed intact immobilization on a solid surface. An electrostatic interaction also affected the amount of immobilized liposomes on the functionalized quartz crystal. By using the amino-coupling method, intact liposomes could be immobilized on a solid surface and immobilized liposomes could stabilize for 10 h with frequency changes less than 5%.