Luminescence and Electroanalytical Properties of Carbon Quantum Dots in the Context of Immunosensor Design

Electroanalytical techniques are powerful tools in biological sensing because of their sensitivity and versatility. In recent decades, great attention has been given to the fabrication of electroactive nanomaterial-based biosensors. In this context, carbon quantum dots (CQDs) have received special attention and have been used to develop many sensors because of their remarkable advantages such as high photostability, high solubility and stability in water, biocompatibility, high photoluminescence emission intensities, and simple methods of synthesis. Since they are very small in size, they have high surface area to volume ratios which in turn can allow good catalytic activities of the working electrodes in electrochemical reactions. Being motivated by these advantages, in this work we prepared two types of carbon quantum dots (CQD-COOH and CQD-NH₂) and used them to modify screen printed carbon electrodes (SPCEs) for detection of Troponin I (cTnI). These carbon quantum dot – modified SPCE immunosensors have offered promising results for the determination of cTnI with a limit of detection 62 pg/mL and 171 pg/mL, respectively. This simple approach to sensor design further offers valuable insights into the construction of paper based printed electrodes modified with new carbon-based nanomaterials as immunosensors for detection of other biomarkers of various diseases.