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

Abstract

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.