Development of highly sensitive electrochemical immunosensor using PPy-MoS₂-based nanocomposites modified with 90 MeV C⁶⁺ ion beams

The evaluation of electrochemical sensing activity of hydrothermally derived PPy-MoS₂-based nanocomposites subjected to 90 MeV C⁶⁺ ion beam with fluence ranging, 1.0 × 10¹⁰–1.0 × 10¹³ ions/cm², is reported. Cross-linking, chain scissioning, and ion track formation could occur in the irradiated systems, as revealed from Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FE-SEM) studies. Electrochemical studies, viz., cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were performed in 0.1 M phosphate buffer solution (PBS) containing 5 mM K₃[Fe(CN)₆] as redox probe. High redox activity, lower charge transfer resistance (R_ct = 490 Ω) and larger electroactive area (A = 0.4485 cm²) were obtained in case of the composite system irradiated with a fluence of 3.5 × 10¹¹ ions/cm². Immunosensor fabrication was executed via immobilization of mouse IgG over the pristine and post-irradiated electrodes. Afterwards, differential pulse voltammetry (DPV) was performed within the potential window − 0.2 to + 0.6 V (vs. Ag/AgCl) for the detection of specific analyte. Noticeably, the electrode system irradiated with a fluence of 3.5 × 10¹¹ ions/cm² is characterized by a lower limit of detection (LOD) of 0.203 nM and a higher sensitivity value of 10.0 µA mL ng⁻¹ cm⁻². The energetic particle irradiation at a modest fluence can offer beneficial effects to the PPy-MoS₂-based nanohybrid system providing immense scope as advanced electrochemical biosensor.