Point-of-Care Detection of Interleukin-6 using Quantum Dot-based Immunochromatographic Test Strips

摘要

Interleukin-6 (IL-6) is essential for regulating the immune system and initiating acute inflammatory responses. While normal levels of IL-6 are very low in healthy individuals, current detection methods rely primarily on sophisticated instrumentation in central laboratories. Here, we developed a novel fluorescent immunochromatographic test strip method based on CdSe@ZnS quantum dots for point-of-care testing of IL-6. The test strip takes only 20 min to test the sample. Four analysis methods were developed: a self-developed smartphone application, smartphone photographs analyzed with ImageJ, a self-constructed portable immunoanalyzer, and a commercial immunoanalyzer. The performance of these four methods was evaluated and compared. The commercial immunoanalyzer achieved the best limit of detection (LOD) at 2.65 pg/mL, followed by the portable immunoanalyzer (5.74 pg/mL) and ImageJ (8.25 pg/mL). These LODs were sensitive enough to quantify IL-6 in healthy human serum around the clinically relevant cut-off of 10 pg/mL. Despite a higher LOD of 50 pg/mL, customized smartphone application enabled rapid IL-6 quantification and screening, which is useful in resource-scarce areas and well suited for measuring IL-6 levels. The developed method provides a simple, rapid, and portable tool for diagnosing and monitoring IL-6-related diseases.

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