High Sensitivity L‐Cysteine Indium Telluriselenide Quantum Dot‐Inspired Aptasensor for Interferon Gamma TB Biomarker

Tuberculosis (TB) continues to be a significant contributor to global death tolls among infectious diseases. It can be diagnosed using certain cytokines, such as interferon‐gamma (IFN‐γ). Interferon‐gamma is an essential component of the immune system's defense against pathogens which is known to be expressed in TB infection. This work involves the development of a quantum dot‐sensitized electrochemical aptasensor for IFN‐γ. The sensor system consists of gold disc electrode surface that was modified with novel L‐cysteine‐functionalized indium telluriselenide quantum dots (L‐cysteine‐InTeSe QD). Subsequently, the L‐cysteine‐InTeSe QDs are conjugated to an amine‐terminated IFN‐γ aptamer through a carbodiimide‐mediated amide bond formation. The electrochemical responses of the IFN‐γ aptasensor are studied by voltammetry. A linear calibration curve is generated for the concentration range studied (i.e., 10–21 pg mL −1 IFN‐γ), and a limit of detection of 0.312 pg mL −1 is obtained. The QD aptasensor is able to accurately detect IFN‐γ without interference from other substances. In a practical application using synthetic human serum, the QD aptasensor produced good detection recovery of 98–102%, highlighting its potential for diagnosing infectious diseases.