Detection of amyloid β peptide at physiologic using electrochemical impedance spectroscopy

• Main Authors: Bien-Chen Ku, 顧秉宸
• Other Authors: 吳嘉哲
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/392b54

碩士 === 國立中興大學 === 機械工程學系所 === 102 === Aβ1-42 oligomer accumulations are associated with physiologic alterations in human brain who suffer Alzheimer’s disease. In this study, we demonstrate a nanostructured gold electrode deposited gold nanoparticles (GNPs) with electrochemical impedance spectroscopy (EIS) as detecting Aβ1-42 biosensor. Monoclonal antibody 12F4 as caputare antibody binded in self-assembled monolayers (SAMs) of biosensor. The objective of this study was identified Aβ1-42 monomer and oligomer formations using 12F4. Aβ1-42 aggregative behaviors were controlled in different concentrations. The Aβ1-42 monomer showing only one band in 4.5kDa and the Aβ1-42 oligomer showing multiple bands are evaluated by western bolts of gels running under native conditions. After preparation of Aβ1-42 monomer and Aβ1-42 oligomer,EIS measurement were used to determine the formation of Aβ1-42. An equivalent circuit model was built to fit experiment data. The resistances R_(Aβ1-42) in the equivalent circuit model were measured after Aβ1-42 and theresistances R_(Aβ1-42) in the equivalent circuit model measured after second antibody 12F4 incubating on sensors. ??R?_12F4 is the definition of R_(Aβ1-42) substracting R_(Aβ1-42). ??R?_12F4?R_(Aβ1-42) was probability precntage of reporter antibody 12F4 binding Aβ1-42.The plots determined by calculating ratio of different Aβ1-42 concentration. The line of Aβ1-42 monomer resulted an equation ??R?_12F4?R_(Aβ1-42) =-0.9*log(monomer)+0.0139 was nearly compared line of Aβ1-42 oligomer The line of Aβ1-42 oligomer resulted an equation ??R?_12F4?R_(Aβ1-42) =3.62*log(oligomer)+3.31 with R^2 value of 0.941. The linear detection range was between 10pg ml^(-1)and 100 ng ml^(-1)of Aβ1-42monomer and Aβ1-42oligomer.