Synthesis and Characterization of Chitosan Based Micro/Nanobubbles for Potential Biomedical Applications

Abstract Microbubbles (MBs) are gaining increased interest in biomedical applications. They are typically in the range of 1–10 μm, composed of a shell made of polymers, lipids, proteins, or surfactant, encapsulating heavy gas such as; sulfur hexafluoride (SF 6 ), or perfluorocarbons. MBs have a range of medical applications, from ultrasound image enhancement, to drug delivery, and gas delivery. In this study, Chitosan-coated MBs is produced by reacting chitosan and glycerol to produce a shell of crosslinked polymer with SF 6 as the gas core. The population was tested for the presence of Nanobubbles. Moreover, freeze drying has been used to test the capability of the new shell to withstand the freeze-drying conditions. The main point of freeze drying is to allow long term storage of bubbles, facilitate bubble transportation, and change the gas core to oxygen to enhance the benefits of using these MBs. Different characterization techniques have been used, FTIR to confirm that we have developed the hypothesized CS shell for micro/nanobubbles. TEM to test the and image the presence of nanobubbles. The results showed that the produced population included microbubbles and nanobubbles with mean diameter of 3.57 ± 0.71 μm and 55 ± 37 nm respectively. The bubbles have a surface positive charge and high concentration of 1.02 × 10 12 MBs/ml. Moreover, freeze-drying was used to change the gas core to oxygen producing MBs with mean diameter 1 ± 0.7 μm and concentration of 6.5 × 10 9 MBs/ml. These results indicate the potential of using this new formulation for production of bubbles that can be used for various applications. Further investigation is still in progress for extra optimization and application.