title: An incremental double-layer capacitance of a planar nano gap and its application in cardiac-troponin T detection.
abstract: Surface potential is one of the most important properties at solid-liquid interfaces. It can be modulated by the voltage applied on the electrode or by the surface properties. Hence, surface potential is a good indicator for surface modifications, such as biomolecular bindings. In this work, we proposed a planar nano-gap structure for surface-potential difference monitoring. Based on the proposed architecture, the variance of surface-potential difference can be determined by electrical double layer capacitance (EDLC) between the nano-gap electrodes. Using cyclic voltammetry method, in this work, we demonstrated a relationship between surface potential and EDLC by chemically modifying surface properties. Finally, we also showed the proposed planar nano-gap device provides the capability for cardiac-troponin T (cTnT) measurements with co-existed 10 µg/ml BSA interference. The detection dynamic range is from 100 pg/ml to 1 µg/ml. Based on experimental results and extrapolation, the detection limit is less than 100 pg/ml in diluted PBS buffer (0.01X PBS). These results demonstrated the planar nano-gap architecture having potentials on biomolecular detection through monitoring of surface-potential variation.
authors.affiliation: Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei 106, Taiwan.
authors.forename: Hsiao-Ting
authors.initials: HT
authors.lastname: Hsueh
authors.affiliation: Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei 106, Taiwan; Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 106, Taiwan. Electronic address: timlin@ntu.edu.tw.
authors.forename: Chih-Ting
authors.initials: CT
authors.lastname: Lin
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation*; D025802:Electric Capacitance; D004566:Electrodes; D004867:Equipment Design; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation; D057230:Limit of Detection; D020107:Troponin T / Q000032:analysis*
chemical_list: D055910:Antibodies, Immobilized; D020107:Troponin T
keywords: Biosensor; Coplanar electrode; Cyclic voltammetry; Electric double layer capacitance; Nano-gap; Surface potential