Aptamer-mediated portable SERS sensor based on bimetallic magnetic nanotubes for internal standard-calibrated...

Accurate early screening for hepatocellular carcinoma (HCC) requires multi-target detection methods with high sensitivity and strong anti-interference capability. In this study, we developed an aptamer-mediated SERS sensing method based on bimetallic magnetic nanotubes for the simultaneous detection of HCC markers alpha-fetoprotein (AFP) and Golgi protein 73 (GP73). Tubular Fe₃O₄ nanostructures were innovatively synthesized as magnetic carriers, onto which a gold-layer, an internal standard molecule (4-mercaptophenylboronic acid), and a silver-layer were sequentially deposited to construct a capture substrate integrating signal calibration and electromagnetic enhancement functions. Raman tags with non-overlapping spectra in the Raman-silent region (1800-2500 cm^-1) were screened to establish a sandwich detection system. Using a portable Raman spectrometer and intelligent software, this method achieved rapid quantification of AFP and GP73, with detection limits of 0.433 pg/mL and 0.370 pg/mL, respectively, and recovery rates in spiked serum samples ranging from 95.62% to 106.2%. By simply replacing the aptamers, this method can be readily extended to other targets, demonstrating excellent versatility. This work provides a reliable analytical tool for early HCC diagnosis and establishes a foundation for developing on-site multi-target detection systems for complex samples.