Highly performing graphene-based field effect transistor for the differentiation between mild-moderate-severe myocardial injury

Cardiovascular diseases result in millions of deaths around the globe, many of which could have been avoided if identified at an early stage. Preventive cardiovascular disease diagnostics plays a vital role reducing the critical fatality rate by allowing to take timely necessary precautions. Here, we demonstrate the exceptional properties of aptamer modified graphene-based FET (GFET) for cardiac troponin I (cTnI) specific sensing in different bodily fluids. Concentration-dependent measurements made with cardiac troponin I (cTnI) on an aptamer/polyethylene glycol (PEG) modified GFET exhibited real-time detection of cTnI from 1 to 400 pg mL−1 in 0.01 × phosphate-buffered saline (PBS) solution. The sensor performance is within the clinical important window of 10 pg mL−1 to 500 pg mL−1, allowing the differentiation between healthy, and people with low and high risk for myocardial infraction (AMI). Even more important is the very reproducible shift and neglectable leakage current of the individual IDSVGS-curves upon contact with cTnI solutions. To further evaluate the applicability of the developed point of care device for troponin I sensing in serum, samples of 15 patients with different troponin levels were analysed for their troponin I levels. The 15 patients were grouped according to the magnitude of peri-operative myocardial injury as assessed by the clinical hs-cTnT assay into mild (cTnT<15 pg mL−1), moderate (15 pg mL−1>c-TnT<500 mL−1) and severe (cTnT>500 pg mL−1), cases. The GFET sensor allowed to categorise all the 15 samples correctly and corresponding to 3 troponin zones (respectively, low, medium and high). While indeed a larger patient sample collection is required for clinical assessments, these data seem highly promising.