Development of a microfluidic point-of-care testing device for biomarker monitoring

Abstract

Die vorliegende Dissertation beschreibt die Entwicklung einer vollautomatisierten mikrofluidischen Plattform zur quantitativen Bestimmung von Blut-Biomarkern des menschlichen Immunsystems. Auf Basis von schnellen, hochsensitiven und reproduzierbaren Magnetic-Beads-Immunoassays wurden mikrofluidische Chips designed und produziert und die Leistungsfähigkeit des entwickelten Systems mit off-chip Magnetic-Beads-Assays verglichen. Um den Anforderungen von Point-of-Care-Systemen zu entsprechen wurden Lösungen für die On-Chip-Aufbewahrung von Reagenzien und ein System für die integrierte Beads-Handhabung entwickelt. Abschließend wurde die Funktionsfähigkeit des Systems durch Messungen von IL-8-Konzentrationen in Blutserumproben von Intensivstationpatienten validiert.

Sepsis represents the main cause for patient death at the intensive care units. For a successful treatment it is essential to identify sepsis at an early stage of the syndrome. By quantifying specific blood biomarkers derived from the immune cells of the patients, early diagnostic signs and the course of sepsis can be determined, which enables an accurately timed therapy. The biomarker concentrations alter quickly during the course of disease and therefore a fast method is preferable. To meet this criterion, a point-of-care test is required. In this thesis, a fully automated microfluidic platform was developed for a rapid and sensitive biomarker quantification. The establishment of fast, low-volume, highly sensitive and reproducible magnetic beads immunoassays for quantitative measurements of the blood biomarkers TNF-alpha, IL-6, IL-8 and IL-10 is described. Microfluidic chips and processing devices were designed, fabricated and evaluated by on-chip processing with the established IL-8 magnetic beads assay. To meet the criteria of point-of-care testing, solutions for on-chip reagents storage and a system for integrated magnetic beads handling were developed. A robust and automated platform was fabricated for an on-chip processing of magnetic beads assays. The system was validated by measuring IL-8 in serum samples from trauma patients at the intensive care unit.