Construction Of Bovine Serum Albumin-based Capsules To Simulate Cell Fusion Behavior

Cell is the basic structural and functional unit of the organism,which plays an important role in the biological processes of organism. Several hundred years has passed since the discovery of cells, and one Nobel Prize in Physiology in 2013 was granted for discovering the vesicle transport regulatory mechanism. Although these developments, some behaviors of the cell are still mysterious for us, such as the photosynthesis of the plant cells, the signal transmission between cells and the metabolism etc. Bearing these in mind, mimicking the behaviour of cells, could on one hand this help us a further understanding the function of cells, and on the other hand pay a theoretical foundation for the design of the tissue regeneration material. Microcapsules with a hollow core domain and a similar size to cells, are capable of controlling the release of the loaded material, extending the storage period, modulating membrane permeability and biocompatibility. These features made capsules to be promising candidates applied in this field.Herein, in this thesis, we constructed a proteinosome with encapsulated protein-based hydrogel inside, and the hydrogel self-healing behaviour trigger the fusion between proteinosomes.The cationized bovine serum albumin and poly(N-isopropylacrylamide) were synthesized, respectively. The poly(N-isopropylacrylamide) with a mercapto-thiazoline active ester as one end which allows an easy conjugation between the cationized BSA and the polymer. Such constructed building block, it showed good biocompatibility, temperature sensitivity and post-modification properties. Then taking advantage of Pickering emulsion, via self-assembly at the water droplet/oil interface, a well-defined proteinosome was obtained with a high yield.To achieve the aim of cell fusion, a driving force must be incorporated into the system. In this study, a protein-based hydrogel which was cross-linked by the reaction between the cationized proteins and aldehyde dextran was chosen. Since the protein hydrogel contains a large number of dynamic bond-Schiff bases, this endowed a self-healing behavior to the hydrogel, and also being a driving force of fusion. In addition, considering the same building block of the protein-based hydrogel and proteinosome, the entrapped hydrogel could be well miscible with the proteinosome.Our study not only achieves a biomimetic cell fusion process, but also realizes the regulation of fusion process. By adding both the glucose and glucose oxidase into proteinosomes, the fusion process could be clearly accelerated, and by adding the cinnamaldehyde into the oil phase, the fusion process could be delayed.