From Nanovesicles to Nanobubbles Based on Repeated Compression Method

Abstract

Nanobubbles have been increasingly applied in biomedicine, which is attributed to their ability to work as ultrasound imaging contrast agents and powerful gene/drug carriers. Different production techniques or approaches have been developed to generate uniform and stable shelled nanobubbles. However, these shelled nanobubbles are usually prepared based on disordered shell materials, such as free phospholipids and polymers. In recent years, the continuous repeated compression method for a gas−liquid mixture has been developed to produce free and lipid-shelled nanobubbles. In this study, to explore the response of well-organized nanostructures to this method, the repeated compression method was used to treat preprepared liposomes and polymeric nanovesicles. Size distribution, morphologies, and ultrasound image contrast enhancement of these nanovesicles were determined before and after repeated compression. Results demonstrate that the presence of a phospholipid bilayer is vital to form liposome-based nanobubbles. And the low elastic modulus of the polymeric membrane is key to encapsulate gases into polymeric nanovesicles. Overall, it demonstrated the advantages of well-organized nanostructures to produce nanobubble structures, giving new insights into the preparation and understanding of nanobubbles.

One-Step Preparation of Magnetic Lipid Bubbles: Magnetothermal Effect Induces the Simultaneous Formation of Gas Nuclei and Self-Assembly of Phospholipids

“…To overcome this drawback, encapsulated micro-nanobubbles which consist of a gas core and an external membrane shell were adequately studied in previous works. In particular, three kinds of materials (i.e., proteins, − lipids, − and polymers ,− ) usually act as the membrane shell materials to stabilize the MNBs and provide them biocompatibility and echogenicity. − Among the materials, lipids are the most widely used due to their safety, high stability, good biocompatibility, and ease of chemical surface modification. , …”