Abstract
Premanufactured shelled microbubbles composed of a protein shell are currently licensed as ultrasound imaging contrast agents. Current research is focussing on using the protein shelled microbubbles as transportation mechanisms for localised drug delivery particularly in the treatment of various types of cancer. For the very first time, a theoretical model is developed for an incompressible, gas loaded shelled microbubble with a thin shell composed of a liquid-crystalline material. We show that liquid-crystalline shelled microbubbles exhibit significantly different physical characteristics from commercial protein shelled microbubbles such as Sonovue and Optison. The authors propose that these significantly different physical characteristics may enhance localised drug delivery. We use the technique of linearisation to predict the shelled microbubble’s natural frequency and relaxation time. These physical parameters strongly influence sonoporation which is the mechanism that is used for localised drug delivery. The influence of the material properties of the shell on the natural frequency and relaxation time are discussed. We have discovered that liquid-crystalline shelled microbubbles have a relaxation time that is 10 times longer than Sonovue and Optison.