Electrochemical detection of cardiac biomarkers in point-of-care diagnostics

According to the International Agency for Research on Cancer (IARC), the worldwide number of cancer cases is rising. While 20 million new cancer diagnoses were made in 2022, this number is set to rise to 35 million per year by 2050. Alongside surgery and radiotherapy, chemotherapy is one of the central pillars of cancer therapy. It involves the treatment of malignant tumors with chemical substances known as chemotherapeutic agents or cytostatics, which intervene in the cancer cell reproduction cycle.

In recent decades, advances in oncological therapy have led to an improved survival rate for cancer patients, but this has also resulted in an increase in morbidity and mortality due to cardiovascular side effects. However, when manifesting cardiac dysfunction (e.g. cardiac arrhythmias, ECG changes and pericarditis-myocarditis syndrome) is detected early, preventive and supportive measures can be taken.

Specific cardiac biomarkers such as troponin (and its subtypes) are highly sensitive, which means that cardiotoxicity can be detected at an early stage. A disadvantage, however, is that the troponin value in the blood can vary greatly from patient to patient. This is why the times at which to examine cardiac biomarkers must be determined on an individual basis and carried out at close intervals, especially in high-risk patients. Monitoring the long-term cardiotoxic effects of chemotherapy is therefore very time-, material- and cost-intensive, while also requiring considerable human resources. Point-of-care tests (POCT) could provide a remedy here.

As part of the BMWi-funded “CARDIOTOX” project (funding code: KK5033910) a sensor demonstrator was developed at Fraunhofer IKTS. It is based on a polyethylene naphthalate (PEN) substrate with a printed gold coating and enables selective and sensitive detection of troponin I using differential pulse voltammetry. The researchers have thus succeeded in electro-chemically detecting cardiac troponin I on a laboratory scale with an accuracy of 0.3 ng/ml to 2.4 ng/ml. This range covers the troponin I levels during the onset of myocardial damage [1]. 

In the near future, a portable readout system will be developed and the sensitivity and reproducibility of this sensor will be improved further. Until now, the test solutions have been added manually. In the future, this is to be replaced by a microfluidic module.

The developed approach offers an additional diagnostic option to detect the risk of cardiac complications in oncology patients at an early stage and to initiate timely measures. In collaboration with clinical partners and stakeholders from industry, Fraunhofer IKTS is planning the validation and upscaling of the sensor technology as the next step.

• Development of electrochemical (bio)sensors (assay development, biochemical sensor functionalization, biocompatible assembly and connection technology)
• Sensor measurement
• Biocompatible sensor packaging
• Sensor testing and evaluation under the influence of different media

[1] S. Agewall, et al., »Troponin elevation in coronary vs. non-coronary disease«, European Heart Journal, vol. 32, no. 4, pp. 404–411, 2011.