Nanoarchitectonics of aptamer-based electrochemical sensor using electrospun carbon nanofibers and Au nanoparticles for cd (II) analysis

Cadmium(II) is recognized as a hazardous heavy metal with severe implications for both the environment and human health. Traditional detection techniques, including atomic absorption spectroscopy and mass spectrometry, tend to be labor-intensive and require sophisticated instrumentation. In this study, we introduce a new electrochemical biosensor constructed from electrospun carbon nanofibers (CNFs) and gold nanoparticles (AuNPs) for the rapid and sensitive identification of Cd(II). The CNFs were synthesized from polyacrylonitrile (PAN) via a two-step thermal process involving stabilization and carbonization, and their structure was validated through X-ray diffraction and Raman spectroscopy. The synthesized nanofibers were utilized to modify the surface of a screen-printed carbon electrode (SPCE), followed by the electrodeposition of AuNPs to enhance its electrochemical performance. The surface morphology and elemental composition of the modified electrode were characterized using field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDS). A cadmium-selective aptamer was immobilized on the electrode and assessed using cyclic voltammetry (CV). The finalized aptasensor demonstrated a linear detection range from 0.5 to 10 ppb for Cd(II), achieving a detection limit of 0.05 ppb as measured by differential pulse voltammetry (DPV). The relative standard deviation (RSD) values for repeatability and reproducibility were about 3.2% and 3.5%, respectively. Therefore, this aptasensor can be considered as a promising tool for accurate environmental monitoring of Cd(II).