The use of nanobeads to increase the sensitivity of a nanofluidic biomarker detection device

Sensitivity of Point of care (POC) In Vitro Diagnostic (IVD) devices in the detection of biomarkers is crucial to determine the onset of certain medical conditions. In Acute Coronary Syndrome (ACS), the concentration of Cardiac Troponin (biomarker) plays an essential role in the assessment of patient's outcome. However, the concentration of Troponin that allows to diagnose a pathological condition is as low as 3 pg/mL, requiring the use of an extremely sensitive device. The development of a POC test that allows to precisely and readily determine the concentration of Cardiac Troponin in the blood stream of the patient would have a huge impact on global healthcare, as ACS and consequent hearth failure are the leading death cause worldwide. The aim of this work is to use fluorescent nanobeads to increase the sensitivity of Abionic's nanofluidic biomarker detection device, with the goal of developing an effective test for the concentration of Troponin. To achieve a proof of concept, the system was tailored to the Total IgE test currently in development at Abionic. The detection nanobeads were achieved through the conjugation of fluorescent anti human immunoglobulin E (IgE) antibodies to virus like particles (VLPs). This system allowed to greatly increase the signal of the test when using low/medium doses of recombinant human IgE. However, non-specifc interaction of the nanobeads with the surface of the biosensor lead to an increase in the Limit of Detection (LOD) of the system, reducing the advantage achieved through the increase in signal. Part of the non-specific interaction observed in the test seems to be due to the presence of VLP aggregates, which might have a greater non analyte mediated affinity for the detection surface compared to single beads. Addressing this aggregation could allow to benefit from the increase in signal and to reach the sensitivity needed for the development of the Troponin test.