Integration of a miniature quartz crystal microbalance with a microfluidic chip for amyloid beta-Aβ42 quantitation.

Wenyan Tao,Shanming Ke,Xierong Zeng,Peng Lin,Hairui Wang,Qingji Xie

doi:10.3390/s151025746

Wenyan Tao, Shanming Ke + Show 4 more

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https://doi.org/10.3390/s151025746

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Abstract

A miniature quartz crystal microbalance (mQCM) was integrated with a polydimethylsiloxane (PDMS) microfluidic device for on-chip determination of amyloid polypeptide–Aβ42. The integration techniques included photolithography and plasma coupling. Aβ42 antibody was immobilized on the mQCM surface using a cross-linker method, and the resonance frequency of mQCM shifted negatively due to antibody-antigen binding. A linear range from 0.1 µM to 3.2 µM was achieved. By using matrix elimination buffer, i.e., matrix phosphate buffer containing 500 µg/mL dextran and 0.5% Tween 20, Aβ42 could be successfully detected in the presence of 75% human serum. Additionally, high temperature treatments at 150 °C provided a valid method to recover mQCM, and PDMS-mQCM microfluidic device could be reused to some extent. Since the detectable Aβ42 concentration could be as low as 0.1 µM, which is close to cut-off value for Alzheimer patients, the PDMS-mQCM device could be applied in early Alzheimer’s disease diagnosis.

Highlights

Alzheimer’s disease (AD), a kind of irreversible progressive neurodegenerative disease, has been ranked as the 3rd killer of the elderly, only next to angiocardiopathy and cancer
Nowadays there are over 25 million cases of AD around the whole world, with about 5 million of these being found in
Prediction of AD is very important, since it is helpful to slow down the progression of the disease

Summary

Introduction

Alzheimer’s disease (AD), a kind of irreversible progressive neurodegenerative disease, has been ranked as the 3rd killer of the elderly, only next to angiocardiopathy and cancer. Nowadays there are over 25 million cases of AD around the whole world, with about 5 million of these being found in. Prediction of AD is very important, since it is helpful to slow down the progression of the disease. Two amyloid polypeptides–Aβ40 and Aβ42, found in serum and cerebrospinal fluid, are proved to be the biomarkers of Alzheimer disease. The dominant mutation of amyloid polypeptide–Aβ4 protein precursor gene on normal chromosomes 21 and pressenilin-1 or 2 gene on chromosomes 14 is seen in AD patients before the age of 65. Amyloid precursor protein (APP), which belongs to the type I membrane glycoproteins, has at least 10 isomers arising from different splicing of 19 exons.

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