Kainz Daniel M, Breiner Bastian J, Früh Susanna M, Hutzenlaub Tobias, Zengerle Roland, Paust Nils
Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
Microsyst Nanoeng. 2021 Sep 6;7:72. doi: 10.1038/s41378-021-00296-5. eCollection 2021.
Despite the widespread application of point-of-care lateral flow tests, the viscosity dependence of these assay results remains a significant challenge. Here, we employ centrifugal microfluidic flow control through the nitrocellulose membrane of the strip to eliminate the viscosity bias. The key feature is the balancing of the sample flow into the cassette of the lateral flow test with the air flow out of the cassette. A viscosity-independent flow rate of 3.01 ± 0.18 µl/min (±6%) is demonstrated for samples with viscosities ranging from 1.1 mPas to 24 mPas, a factor greater than 20. In a model human IgG lateral flow assay, signal-intensity shifts caused by varying the sample viscosity from 1.1 mPas to 2.3 mPas could be reduced by more than 84%.
尽管即时侧向流动检测已得到广泛应用，但这些检测结果对粘度的依赖性仍然是一个重大挑战。在此，我们采用离心微流控技术控制样本通过试纸条硝酸纤维素膜的流动，以消除粘度偏差。关键在于使流入侧向流动检测卡盒的样本流与流出卡盒的空气流达到平衡。对于粘度范围从1.1毫帕秒到24毫帕秒（相差超过20倍）的样本，实现了3.01±0.18微升/分钟（±6%）的与粘度无关的流速。在一个模型化的人IgG侧向流动检测中，样本粘度从1.1毫帕秒变化到2.3毫帕秒所引起的信号强度偏移可减少超过84%。
