An electrochemical biosensing platform based on α‑iron trioxide/ferriferrous oxide magnetic nanocomposites for early diagnosis of hepatocellular carcinoma.

The detection of biologically active proteins in complex biological matrices such as serum remains challenging. To enhance the sensitivity and accuracy of detecting the hepatocellular carcinoma biomarker stress-induced phosphoprotein 1 (STIP1), we proposed a label-free "Turn-off" electrochemical aptamer-based biosensing platform without requiring amplification steps. The biosensing platform integrated magnetic α-FeO/FeO (α‑iron trioxide/ferriferrous oxide, αITFO) nanocomposites synthesized via urea hydrolysis followed by calcination-reduction processes and further functionalized with Au nanoparticles (NPs), achieving significantly enhanced electrochemical activity. The moderate magnetism of the αITFO MNCs enabled efficient magnetic separation, while their compatibility with the magnetic glassy carbon electrode (MGCE) allowed rapid sensor fabrication and highly sensitive detection at a low cost. Another notable characteristic of the STIP1 biosensing platform lay in its exceptional detection capabilities, exhibiting excellent sensitivity and a broad detection range of 10 pg mL to 10 μg mL, with a remarkably low detection limit (LOD) of 3.29 pg mL. Furthermore, the STIP1 biosensing platform was successfully implemented for analyzing clinical spiked serum samples, demonstrating recovery rates ranging from 102.2 % to 114.2 %. This validated its accuracy and effectiveness for applications in early disease diagnosis and prognostic evaluation.