Premium
P1‐038: Highly sensitive detection of amyloid beta for Alzheimer's disease diagnosis using bead‐based impedance spectrometry
Author(s) -
Shin Kyeong-Sik,
Ji Jae Hoon,
Park Min Cheol,
Kim Moojong,
Kang Ji Yoon
Publication year - 2015
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2015.06.234
Subject(s) - detection limit , dielectric spectroscopy , bead , materials science , microfluidics , electrode , electrical impedance , magnetic bead , optoelectronics , nanotechnology , biomedical engineering , analytical chemistry (journal) , chromatography , chemistry , electrochemistry , composite material , electrical engineering , medicine , engineering
Background:Alzheimer’s disease (AD) is the most common neurodegenerative disease of dementia, and the development of early diagnosis platform is highly required for effective therapeutics. Recently, amyloid beta (Ab) has been considered as a major biomarker in AD diagnosis. Therefore, many researches have been studied in development of sensors to detect Ab of low concentration by using electrical methods such as field effect transistor and electrochemical impedance spectroscopy (EIS) to overcome the relatively high limit of detection in ELISA. All these devices required immobilization with antibody on the surface of sensing region in device itself. They showed LOD of a few pg/ml. So, we propose a new highly sensitive detection platform to quantify the concentration of Ab with immobilization of detection antibody not on the electrodes of EIS device but on the surface of magnetic beads. Methods:We designed a new detection platform including array of EIS device, fluidic channel and permanent magnet bar on/beneath a slide glass. EIS array device has individual hole on each working-counter electrode pair. The individual hole size is around 6 mm, and the bead size is around 2.8 mm. Therefore, each hole can capture 2 or 3 pre-treated beads that prepared by incubation with antibody. First pre-treated beads were injected into microfluidic channel, and these beads were located in each hole by the magnetic bar under a platform. Then, Ab monomer with different concentration was flown into device for 5 min, then non-specific Ab was removed by washing buffer. Finally, impedance measurement was measured with sweeping frequency. Results: We were able to detect Ab monomer below than 1 pg/ml with very small amount of sample (w4 ml), and total detection time was dramatically reduced to less than 10 minutes. The results were clearly distinguishable among the Ab samples with different concentration in impedance plot. Conclusions:Proposed novel detection method based on magnetic beads could be a feasible tool with high sensitivity for early diagnosis of AD. For further application of our platform, it needs more tests with Ab oligomer and blood samples of AD patients to confirm the usefulness in a diagnosis. P1-039 INHIBITORS OFAMYLOID BETA PEPTIDE