Monday, August 2, 2010
Pacific Concourse (Hyatt Regency San Francisco)
Since many medical devices such as pacemaker and neurostimulator are implanted in the human body, it should be supplied with constant voltage by a long-life battery. So, we are developing a enzymatic biofuel cell battery that uses glucose in blood as an energy source. On the principle of a blood glucose biosensor, the bio-anode converts blood glucose to electric current by using enzyme breaking glucose down. Although glucose oxidase (GOX) has been widely used so far, we selected glucose dehydrogenase (GDH) as an alternative enzyme source for some reason. GDH produces non-toxic byproduct, H2O and has low Km enabling utilization of blood glucose unlike GOX. In order to get long-life GDHs, we cloned GDH genes from thermophiles whose protein usually have rigid structures. The GDHs are from Acinetobacter calcoaceticus (ACGDH), Burkholderia cepacia (BCGDH), Thermus thermophilus (TTGDH). The aldose sugar dehydrogenase (YliI) and membrane-bound glucose dehydrogenase (Gcd) were used as reference enzymes. Except for BCGDH, others require pyrroloquinoline quinine (PQQ) for their activity. PQQ is a redox cofactor like nicotinamide or flavin, and has higher reduction potential than others. It is expected to transfer electrons from glucose to electrode more efficiently. BCGDH uses FAD as a cofactor, but has cytochrome c subunit. We look forward to increase conductivity by using the cytochrome c. PAN nanofiber and carbon nanotube are used to to immobilize the GDHs. This work was supported by the Basic Research Program(Grant No. 2009-0082812) of MEST, the EB-NCRC (Grant No. R15-2003-012-02001- 0) and BK21 program of Korea