15:45 〜 16:00
▲ [22p-A105-10] Measurement of adsorption of CNT-bound peptides on carbonaceous electrode.
キーワード：peptide aptamer, EIS, peptide adsorption
We proposed a novel CNT/protein/CNT junction for nanodevices. The outer-surface of a cage shaped protein was genetically modified to bind a CNT and fabricate a heterojunction which improves the thermoelectric properties of CNT composites.[1] We used the Ph.D.-12 phage display system for the aptamer SELEX (Systematic evolution of ligands by exponential enrichment) and panning out high-affinity CNT aptamers. We got 223 sequences from 2 different CNT materials, Meijo D and Tuball. We analyzed the hydrophobicity of obtained peptides with ECS score. In general, the score showed pulsation, suggesting that the hydrophilic and hydrophobic amino acid were located on the opposite sides of an alfa helical structure. 3D structure prediction indicated that the top two peptides (MJD-1 and MJD-2) would have different conformations.[2] We synthesized those short peptide and measured their adsorption using electrochemical impedance spectroscopy (EIS). Measurements were performed in PBS solution, and after equilibration, 1 mg/mL, 3 mg/mL, 5 mg/mL, 10 mg/mL, and 30 mg/mL of the peptides were sequentially added to PBS.
When we used super graphite (SG) as a working electrode (WE), the charge-transfer resistance (Rct) increased with the the addition of MJD-1 and MJD-2. However, when glassy carbon (GC) as the WE, MJD-1 causes an increase in Rct, while MJD-2 did not cause any change (Figure 1a). The G and D peaks of Raman spectroscopy were very different between graphite and GC (Figure 1b), which indicated that their surfaces were different, especially the GC had more defects. The difference in adsorption behavior between MJD-1 and MJD-2 might be due to their different 3D structures, and the different adsorption behavior of MJD-2 to SG and GC might be attributed to the structure of the carbon electrode surface. However, the quantitative precision of these experiments is still low and need more studies.
When we used super graphite (SG) as a working electrode (WE), the charge-transfer resistance (Rct) increased with the the addition of MJD-1 and MJD-2. However, when glassy carbon (GC) as the WE, MJD-1 causes an increase in Rct, while MJD-2 did not cause any change (Figure 1a). The G and D peaks of Raman spectroscopy were very different between graphite and GC (Figure 1b), which indicated that their surfaces were different, especially the GC had more defects. The difference in adsorption behavior between MJD-1 and MJD-2 might be due to their different 3D structures, and the different adsorption behavior of MJD-2 to SG and GC might be attributed to the structure of the carbon electrode surface. However, the quantitative precision of these experiments is still low and need more studies.