A novel biomedical approach based on artificial cells. Microencapsulated genetically engineered bacterial cells: Using E. coli DH5 cells for urea and ammonia removal as an example.

摘要

A novel approach whereby one can use genetically engineered cells for various applications is presented in this thesis. The concept of artificial cell has been used for the purpose. Artificial cells containing genetically engineered bacteria E. coli DH5 cells for the removal of urea and ammonia are taken as an example to establish the feasibility of this approach. Further, this example of removal of urea and ammonia is selected as presently we do not have an efficient and cost effective method to use during kidney failure, liver failure and other diseases when elevated levels of urea and ammonia are commonly experienced. In concurrence to these requirements, several in-vitro and in-vivo methods are designed and discussed in this thesis report. For these studies, alginate-polylysine-alginate microcapsules were used. Process parameters for E. coli DH5 cell microencapsulation, using the drop technique, have been optimized and presented. In the in-vitro studies, the batch reactor and column bioreactor have been used. Results show the possibility of using this type of artificial cells containing genetically engineered bacteria for various applications. For in-vivo experiments uremic rats were used. The details of the procedure for making uremic rat models are given. The artificial cells containing genetically engineered E. coli DH5 cells were administered orally to the uremic rats. Results show, only a very small dosage of artificial cells is required to lower systemic urea and ammonia. Thus, this approach can overcome problems related to the use of free bacterial cells. The efficiency of microencapsulated genetically engineered bacteria was found to be several times greater compared to standard oxystarch and ureasezirconium phosphate methods. This study has shown the primary feasibility of this new approach. The possibility of extending this approach of using artificial cells for the use of other types of genetically engineered cells for various clinical, biotechnological and biomedical applications is, therefore, potent.