Determination of blood lithium-ion concentration using digital microfluidic whole-blood separation and preloaded paper sensors

Existing microfluidic technologies for blood tests have several limitations, including difficulties in integrating the sample preparation steps, such as blood dilution, and precise metering of tiny samples (microliter) for accurate downstream analyses on a chip. Digital microfluidics (DMF) is a liqu...

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Bibliographic Details
Published in:Biosensors & bioelectronics 2022-01, Vol.195, p.113631-113631, Article 113631
Main Authors: Komatsu, Takeshi, Tokeshi, Manabu, Fan, Shih-Kang
Format: Article
Language:English
Subjects:
Colorimetry
Dielectrophoresis
Digital microfluidics
Lithium ion
Paper-sensor
Plasma separation
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Summary:Existing microfluidic technologies for blood tests have several limitations, including difficulties in integrating the sample preparation steps, such as blood dilution, and precise metering of tiny samples (microliter) for accurate downstream analyses on a chip. Digital microfluidics (DMF) is a liquid manipulation technique that can provide precise volume control of micro or nano-liter liquid droplets. Without using sensitive but complex detection methods for tiny droplets involving fluorescence, luminescence, and electrochemistry, this article presents a DMF device with embedded paper-based sensors to detect blood lithium-ion (Li+) concentration by colorimetry. Dielectrophoresis on the DMF device between two parallel planar electrodes separates plasma droplets (from tens to hundreds of nanoliters in volume) from undiluted whole blood (a few microliters) within 4 min with an efficiency exceeding 90%. The embedded paper sensors contain a detection reagent to absorb the DMF-transported plasma droplets. These droplets change the color of the paper sensors in accordance with the Li+ concentration. Subsequently, colorimetry is used to reveal the Li+ concentration via image analysis. The proposed method meets the detection-sensitivity requirement for clinical diagnosis of bipolar disorder, making the DMF device a potential therapeutic tool for rapid whole-blood Li+ detection. •Plasma droplets can be separated from whole blood via dielectrophoresis with DMF.•Paper sensor–embedded DMF devices can detect lithium ions via colorimetry.•Detection of lithium ions in whole blood can be completed within 4 min.
ISSN:0956-5663
1873-4235
DOI:10.1016/j.bios.2021.113631