Design of a Novel Electrochemical Immunosensor for Toxoplasma gondii Detection Based on Gold Nanoparticle/Chitosan Decorated Screen Printed Electrode

Abstract

Toxoplasma gondii is an intracellular parasite that primarily utilizes cats as its definitive host. This parasite, which is spread through cat feces, can be transmitted to other animals and, from there, to humans through various routes. In healthy individuals, this parasite may not cause severe illness, but it can be fatal, especially in individuals with weakened immune systems due to factors like chemotherapy or organ transplantation, as well as in fetuses developing in the womb. Given its relatively common occurrence worldwide, controlling the spread of this parasite is imperative. In this study, an antibody-based electrochemical biosensor was developed to directly detect Toxoplasma, offering potential applications in disease surveillance and management. The biosensor was designed using screen-printed electrodes, and the electrode surface was modified with chitosan and gold nanoparticles. Anti-Toxoplasma gondii antibodies were immobilized onto the modified electrode surface using glutaraldehyde as a cross-linking agent. Changes in surface properties were investigated using various techniques, including differential pulse voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy. The surface morphology of the developed immunosensor was visualized using scanning electron microscopy. Subsequently, the biosensor's linear working range and detection limit were determined, followed by its application in the detection of Toxoplasma gondii in synthetic serum samples. This innovative approach holds promise for the development of sensitive and specific diagnostic tools for Toxoplasma gondii infection, which is crucial for effective disease management and prevention, particularly in vulnerable populations.