Chemiluminescence Biosensor for the Determination of Cardiac Troponin I (cTnI)

Cardiac vascular diseases, especially acute myocardial infarction (AMI), are one of the leading causes of death worldwide. Therefore cardio-specific biomarkers such as cardiac Troponin I (cTnI) play an essential role in diagnostics. In order to enable rapid and accurate measurement of cTnI with the potential of online measurements, a proof of concept of a chemiluminescence-based biosensor is presented. A flow cell was designed and combined with a sensitive CMOS camera allowing an optical readout. In addition, a microfluidic setup was established, and cTnI was determined selectively. The biomarker cTnI was expressed in E. coli, and its characterization and correct folding were investigated by different analytical methods. This recombinant cTnI was used for enzyme-linked immunosorbent assays (ELISA), calibrated against commercially available recombinant cTnI, and applied for the biosensor measurements. Based on chemiluminescence detection, the biosensor was successfully tested, and the cTnI biomarker could be reproducibly determined in buffer, spiked blood serum, and plasma.