| Artificial liver support system is used to provide an environment for liver regeneration and possible spontaneous recovery, to serve as a bridge to liver transplantation, or to support patients with dysfunction after liver resections. Current artificial liver support systems have different pros and cons. Furthermore, these systems usually are expensive, have limited efficiency, and are bulky. Therefore, in this dissertation, an optimal portable artificial liver support device, which integrates advantages of previous systems, is inexpensive, and is able to be attached to any hemodialysis machine to become an artificial liver support system, is developed. This device includes a new circulation system designed to enhance the efficiency of removing protein-bound toxins, and a new adsorption column designed to increase the flexibility of adsorbents. Our experiments compare adsorption capacities to five biomarkers by four adsorbents, i.e. activated charcoal Norit RO 0.8, anion exchange resin Dowex 1x4, neutral resin Amberlite XAD-7 and cation exchange resin Dowex 50wx4. The results show that activated charcoal Norit RO 0.8 and anion exchange resin Dowex 1x4 are better for adsorbent and resin columns, respectively. In order to effectively and largely remove protein-bound toxins, a novel method, called local concentration method (LCM), is developed. In this method, a concentrator is installed before the adsorbent cartridge. The method firstly is validated by experiments, and then a theoretical model is developed to study the effects of concentration ratios and plasma flow rates. The theoretical results show that in order to remove more protein-bound toxins, one should increase plasma flow rates and/or concentration ratios. In order to increase the use efficiency of adsorbents and thereby lower the cost, the feasibility of reusing activated carbon is qualitatively investigated. The results show that the regeneration of activated carbon is possible. The performance of activated charcoal after regeneration is reliable. The regeneration process can be used within one single experiment or coupled with the LCM. These results provide theoretical supports for adding the regeneration process and the LCM in our device in the future. |
