Bedside Immune Monitoring: An Automated Immunoassay Platform for Quantification of Blood Biomarkers in Patient Serum within 20 Minutes.

This Article presents an automated, compact, and self-contained system for sensitive quantitative detection of blood biomarkers. A disposable microfluidic chip, prefilled with biomarker-specific reagents and magnetic beads, can be processed fully automatically by a readout platform, enabling an immunoassay-based analysis with a processing time from sample incubation to signal analysis of 20 min. Novel concepts for on-chip vortexing of the magnetic beads and on-chip reagent storage and actuation were developed. A lens-free photodiode readout system represents a cost-efficient approach for detecting the chemiluminescent signal. IL-8 spiked serum samples were measured with a high reproducibility and a limit of detection of 2.05 pg·mL-1. The system was validated with undiluted serum samples collected from trauma patients at the intensive care unit. The developed platform demonstrated good correlation with the clinical reference method, and the clinical trajectory course of IL-8 could be sufficiently followed. With an automated assay approach and an easily adaptable protocol, this portable platform has the potential to be utilized as a universal instrument for analyzing proteins in small sample volumes (<25 µL) in point-of-care settings.

A compact and integrated immunoassay with on-chip dispensing and magnetic particle handling.

We present a compact diagnostic platform for a rapid and sensitive detection of plasma biomarkers. The platform consists of a disposable microfluidic polymer chip, a processing device including a lens-free and cost efficient sensor system and a setup for dispersion of magnetic particles. The biomarkers of interest are quantified by magnetic bead based immunoassays with chemiluminescent readout technology. With a novel system for dispersion and manipulation of the magnetic particles in combination with chemiluminescence detection, the sensitivity of the immunoassay is improved and enables a rapid assay in a microfluidic format. In the disposable chip, extra chambers for storage and dispensing of biomarker specific reagents are integrated, which reduce the need of external dosing devices and thereby the cost of the platform is decreased. Plasma biomarkers for monitoring of sepsis could be quantified at 10 pg/mL concentrations within a total time of 30 min by the present system. This contribution is a fundamental step towards the development of an automatic and compact Point-of-Care testing device for monitoring of patients at the intensive care unit.