Development of A Light-responsive Artificial Gill

2006 Fiscal Year Final Research Report Summary

• Project/Area Number: 16560685
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Biofunction/Bioprocess
• Research Institution: Waseda University
• Principal Investigator: SAKAI Kiyotaka Waseda University, Faculty of Science and Engineering, Professor, 理工学術院, 教授 (00063727)
• Co-Investigator(Kenkyū-buntansha): KOHORI Fukashi Waseda University, Faculty of Science and Engineering, Assistant Professor, 理工学術院, 講師 (70329093)
• Project Period (FY): 2004 – 2006
• Keywords: Artificial Gill / Gas Carrier Solution / Mo^<IV>O(tmp) / o-xylene / Scale Up / Mass Transfer Coefficient / Membrane Area / Oxygen

Research Abstract

In gas carrier solution-circulating artificial gill, oxygen transfer rate depends on the property of the gas carrier solution. Oxygen transfer rate becomes higher by controlling oxygen affinity of the gas carrier solution. The objective of the present study is to develop a light-responsive artificial gill using the gas carrier solution containing 5,10,15,20-oxo-molybdenum(IV) tetramesitylporphyrin (Mo^<IV>O(tmp)) which absorbs oxygen in a dark place at room temperature and desorbs oxygen by visible light irradiation. Mo^<IV>O(tmp) was synthesized and oxygen absorption and desorption efficiencies were measured. Mo^<IV>O(tmp) absorbed oxygen under a shading condition to be Mo^<IV>O(tmp)(O2) and reversely desorbed oxygen under an irradiation condition to be Mo^<IV>O(tmp). In addition, Mo^<IV>O(tmp) absorbed all of the oxygen dissolved in an aqueous solution in a shading condition and desorbed all of the oxygen after visible light irradiation with a Xe lamp. Mo^<IV>O(tmp) was dissolved int o several kind of solvents and solubility and also oxygen absorption and desorption rates were measured. O-xylene was most suitable for a solvent of the gas carrier solution. Hence, gas carrier solutions were prepared with o-xylene. Oxygen partial pressures by light irradiation were measured with the gas carrier solutions of varying Mo^<IV>O(tmp) concentrations. Mo^<IV>O(tmp) desorbed all of the oxygen at lower concentrations of Mo^<IV>O(tmp), while Mo^<IV>O(tmp) desorbed partial oxygen at higher concentrations of Mo^<IV>O(tmp). These results indicate that detailed studies about light irradiation are required. To perform scale-up of the artificial gill, enhancement factor was calculated from data on film mass transfer coefficient of the gas carrier solutions containing Mo^<IV>O(tmp) of varying concentrations. Much more membrane area was necessary with the Mo^<IV>O(tmp) solutions than with hemoglobin solutions. A reservoir tank containing the Mo^<IV>O(tmp) solutions needs more volume because oxygen absorption rate to Mo^<IV>O(tmp) is low. However, the principal advantage is energy saving because no artificial gill using Mo^<IV>O(tmp) requires thermal energy in oxygen absorption and desorption. In addition, we are able to effectively uptake oxygen from highly concentrated Mo^<IV>O(tmp) solution irrespective of oxygen partial pressure in water. In conclusion, the artificial gill we have developed is very useful for large-scale devices for submarine life space.