A Sensitive Electrochemical Immunosensor With Ppy/Rgo Composite for the Detection of Cd8+ T Cells in Blood Publisher



Amoo M ; Salimijazi H ; Labbaf S ; Karimzadeh F ; Baradaran A
Source: Microchemical Journal Published:2026

Abstract

Neurological disorders substantially diminish patients' quality of life. Present diagnostic techniques for neuron damage are often delayed and necessitate invasive procedures. This study introduces a development of an innovative electrochemical biosensor for the detection of CD8, a biomarker that is released into the blood and cerebrospinal fluid during the initial stages of axons damage. Here, a biosensor is fabricated using a composite of reduced graphene oxide and polypyrrole, synthesized via cyclic voltammetry with 20 cycles. The sensing performance of the developed electrode was evaluated through electrochemical impedance spectroscopy (EIS) measurements at varying concentrations of CD8. The electrical conductivity of the sensor was significantly improved compared to the conventionally printed electrodes. The synthesized sensor exhibited both faradaic and non-faradaic behavior. In concentration of 0–320 cells.mL−1 sensor showed faradaic behavior and above the concentration of 320 cells.mL−1, a non-faradaic behavior was detected. The charge transfer resistance was as low as 244 Ω·cm2 for the printed electrode and 35.39 Ω·cm2 for the optimized sensor. The biosensor achieved a detection limit of 14 cells.mL−1, with selectivity validated against CD19, CD4 and CD20 (p < 0.05). This highly sensitive and selective electrochemical biosensor for CD8 detection could present a significant advancement in the early diagnosis of axons damage. © 2026 Elsevier B.V.