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Biochemical-immunological hybrid biosensor based on two-dimensional chromatography for on-site sepsis diagnosis

Kim, Seung-Wan, Cho, Il-Hoon, Lim, Guei-Sam, Park, Gi-Na, Paek, Se-Hwan
Biosensors & bioelectronics 2017 v.98 pp. 7-14
C-reactive protein, antibodies, antigen-antibody complex, biosensors, blood serum, chromatography, color, immunoassays, lactic acid, tracer techniques
A hybrid-biosensor system that can simultaneously fulfill the immunoassay for protein markers (e.g., C-reactive protein (CRP) and procalcitonin (PCT)) and the enzyme assay for metabolic substances (e.g., lactate) in the same sepsis-based sample has been devised. Such a challenge was pursued through the installation of an enzyme-reaction zone on the signal pad of the typical immuno-strip for the rapid two-dimensional (2-D)-chromatography test. To minimize the mutual interference in the hybrid assays, a pre-determined membrane site was etched in a pattern and mounted with a biochemical-reaction pad, thereby allowing a loaded sample to enter and then stay in the pad for a colored-signal production over the course of an immunoassay. By employing such a constructed system, a serum sample was analyzed according to the vertical direction flowing along the strip, which supplied lactate to the biochemical-reaction zone and then protein markers to the immunological-binding area that was pre-coated with capture antibodies. Thereafter, the enzyme-signal tracers for the immunoassay and the substrate solution were sequentially furnished using a horizontal path for the tracing of the immune complexes that were formed with CRP or PCT. The color signal that was produced from each assay was detected at a pre-determined time and quantified on a smartphone-based detector. Under the optimal conditions, the dynamic ranges for the analytes covered the respective clinical ranges, and the total coefficient of variation was between 8.6% and 13.3%. The hybrid biosensor further showed a high correlation (R² > 0.95) with the reference systems for the target markers.