T-chip, Electrochemical biosensor platform based on the electron tunneling: Role and effect of the back-filling material

The concept of the electrochemical biosensor platform based on the electron tunneling (T-chip) is suggested. A pair of a probe peptide and a target protease protein (biomarker) which indicates the severity of the disease (carcinoma and tissue tumor) is introduced. The cleaving event of the probe peptide is utilized to detect the existence of the biomarkers and to measure their reaction activity. The redox molecule, Methylene blue (MB), is functionalized at the end of the peptide sequence providing the electron states where the electron flows in and out. The main strategy of detecting biomarkers is measuring the change of the tunneling current between the metal electrode and the MB states. To maintain stable electrical characteristics of the sensor and to optimize detection performance, not only the probe peptide itself but also the back-filling material, Mercapto-ol-series (MCX) is important. In this paper, the key role of the back-filing material and its length effect on the detection performance is investigated.