Distance-Based Tear Lactoferrin Assay on Microfluidic Paper Device Using Interfacial Interactions on Surface-Modified Cellulose

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• 作者：Kentaro Yamada ; Terence G. Henares ; Koji Suzuki ; Daniel Citterio
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：November 11, 2015
• 年：2015
• 卷：7
• 期：44
• 页码：24864-24875
• 全文大小：704K
• ISSN：1944-8252

文摘

鈥淒istance-based鈥?detection motifs on microfluidic paper-based analytical devices (渭PADs) allow quantitative analysis without using signal readout instruments in a similar manner to classical analogue thermometers. To realize a cost-effective and calibration-free distance-based assay of lactoferrin in human tear fluid on a 渭PAD not relying on antibodies or enzymes, we investigated the fluidic mobilities of the target protein and Tb³⁺ cations used as the fluorescent detection reagent on surface-modified cellulosic filter papers. Chromatographic elution experiments in a tear-like sample matrix containing electrolytes and proteins revealed a collapse of attractive electrostatic interactions between lactoferrin or Tb³⁺ and the cellulosic substrate, which was overcome by the modification of the paper surface with the sulfated polysaccharide 喂-carrageenan. The resulting 渭PAD based on the fluorescence emission distance successfully analyzed 0鈥? mg mL^鈥? of lactoferrin in complex human tear matrix with a lower limit of detection of 0.1 mg mL^鈥? by simple visual inspection. Assay results of 18 human tear samples including ocular disease patients and healthy volunteers showed good correlation to the reference ELISA method with a slope of 0.997 and a regression coefficient of 0.948. The distance-based quantitative signal and the good batch-to-batch fabrication reproducibility relying on printing methods enable quantitative analysis by simply reading out 鈥渃oncentration scale marks鈥?printed on the 渭PAD without performing any calibration and using any signal readout instrument.