Tomohiko Ikeuchi

Development of biofuel cells based on gold nanoparticle decorated multi-walled carbon nanotubes.

This study focused on developing the synthesis of Au nanoparticle-decorated functionalized multi-walled carbon nanotubes (Au-NPs/f-MWCNTs) for monosaccharide (bio-fuel) oxidation reactions and practical application in air-biofuel cells. We developed a scalable and straightforward method to synthesize Au-NPs/f-MWCNTs which allow us to control the loading and size of the Au-NPs. The Au-NPs/f-MWCNTs exhibited better catalytic activities and stability than the Au sheet and subsequently resulted in a threefold increase in the power density of the air-glucose fuel cell with an exceptionally high open circuit voltage (~1.3 V). The catalytic efficiency was confirmed by high performance liquid chromatography with the superior of the Au-NPs/f-MWCNTs over a bare gold electrode. In addition, the application of this advanced catalyst to other monosaccharide oxidation reactions figured out that the configuration of -OH groups at C(2) and C(3) of the reactants plays an important role in the initial adsorption process, and thus, affects the required activation energy for further oxidation. The different monosaccharides lead to significantly different fuel cell performances in terms of power density, which coherently corresponds to the difference in the configuration of C(2) and C(3). Because two small air-glucose fuel cells using Au-NPs/f-MWCNTs can run a LED lamp, further applications of other monosaccharides as fuel in biofuel cells for equivalent required power devices may be possible.

Improvement of transformation efficiency by bioactive-beads-mediated gene transfer using DNA-lipofectin complex as entrapped genetic material

The efficiency of bioactive-beads-mediated plant transformation was improved using DNA-lipofectin complex as the entrapped genetic material instead of naked DNA used in the conventional method. In the improved method, beads aggregated and formed clusters around the protoplasts resulting in a 4-fold higher transformation efficiency than that by the conventional method.

PCR-Based Method for Rapid and Minimized Electrochemical Detection of mec A Gene of Methicillin-Resistant Staphylococcus aureus and Methicillin-Resistant Staphylococcus epidermis

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most important pathogens that cause nosocomial infections. However, microbiological culture techniques take a few days to yield results; therefore, a simple, cost-effective, and rapid detection system is required for screening for MRSA and related bacteria: Methicillin-resistant Staphylococcus epidermidis (MRSE) carriers during the hospital admissions process. In this study, we described the simplified method using by one-time use and screen-printed carbon electrodes, relied upon current quantification of Hoechst dyes which bound with DNA amplified via polymerase chain reaction (PCR) targeted for MRSA mecA gene. Amount of DNA-bound Hoechst molecules were measured by the hand-held potentiostat within two minutes. We found that the peak of a Hoechst-mediated current depended upon the number of MRSA isolates, and successfully distinguished between carriers and a non-carrier based on nasal swabs from the patients. This method required only 10 μL for application, and the results could be obtained within total 60 min from sample collection when a minimum of 1×103 MRSA isolates was present. These results suggested that this minimized technique has the potential to become a useful system of active surveillance for MRSA/MRSE carriers.