A fully integrated microfluidic platform for highly sensitive analysis of immunochemical parameters.

We present a novel fully integrated centrifugal microfluidic platform for highly sensitive immunoassays in point-of-care settings. The platform consists of a disposable cartridge containing structures for assay processing, a porous membrane and all dried reagents required for the analysis. Additionally, a blister containing a washing buffer is connected to a new aliquoting structure enabling the serial aliquoting of washing buffer for repetitive bound-free separation steps. The proof-of-concept for two immunoassays is shown in the cartridge with each requiring only 30 µL of whole blood or plasma as the sample material. The detection of the cardiac marker Troponin T with a functional sensitivity of 7.55 ng L-1 (cv = 10%) within 11 minutes is shown based on samples from ten donors which were measured with six breadboard instruments to prove the platform capability for highly sensitive measurements at diagnostic relevant concentrations. Furthermore an assay for the cardiac marker NT-proBNP (five donors, six instruments) with a time-to-result of 12 minutes demonstrates that high-titer analytes (43 to 16.566 ng L-1) can be measured as well. A method comparison of our platform with a state-of-the-art laboratory analyzer proves an excellent correlation of the measured analyte concentrations. All results are obtained from injection moulded cartridges and all components of the platform are compatible for mass production.

A new immunochemistry platform for a guideline-compliant cardiac troponin T assay at the point of care: proof of principle.

BACKGROUND: A multitude of troponin assays for the point-of-care (POC) have been developed showing a lack of analytical sensitivity and precision. We present a new platform solution for the high-sensitivity detection of cardiac troponin T (cTnT) in a 30 µL whole blood sample with a turnaround time of 11 min. METHODS: The immunoassay was completely run in a ready-to-use plastic disposable, a centrifugal microfluidic disc with fully integrated reagents. After the sample application, the assay was automatically processed by separating the cellular blood components via centrifugation, followed by incubation of a defined volume from the generated plasma with the immunoreagents. The fluorescence in the signal zone of a membrane was measured after its washing for the cTnT quantitation. RESULTS: A calibration curve, measured in whole blood samples spiked with native human cTnT, was generated covering a range up to a concentration of approximately 8300 ng/L. The lower detection limit was determined to be 3.0 ng/L. At a concentration of 14 ng/L, the 99th percentile value from the high-sensitivity cardiac troponin T (hs-cTnT) assay in the Elecsys® system, the imprecision (CV) was 3.8%. A CV profile indicated that the functional sensitivity for a CV <10% was 6.8 ng/L. The assay did not show any significant cross-reaction with human skeletal troponin T. We observed an excellent correlation with the hs-TnT Elecsys® assay for 49 clinical plasma samples (r=0.9744). CONCLUSIONS: The described technology shows that an analytical performance for a highly sensitive determination of cTnT can be achieved in a POC setting.