Ultrasensitive SERS platform for cisplatin detection using self-assembled gold nanooctahedra-silver nanocube core-shell nanoparticles.

This study addresses the critical need for rapid and sensitive detection of cisplatin, a widely used chemotherapeutic agent often limited by severe toxicities and drug resistance. Traditional detection methods are time-consuming and unsuitable for point-of-care applications. We developed an surface-enhanced Raman scattering (SERS) platform leveraging novel gold nanooctahedra‑silver nanocube core-shell (AuNO@AgNC) nanoparticles. Finite-difference time-domain (FDTD) simulations predicted a local field enhancement factor of 153.30 for the isolated nanostructure and further supported the use of 633 nm excitation by revealing a red-shifted coupled dimer plasmon mode near 644 nm in the film-relevant configuration. A facile oil-liquid interfacial self-assembly method enabled the fabrication of highly uniform SERS films. Evaluation with Rhodamine 6G (R6G) demonstrated a linear detection range from 0.5 nM to 500 nM, an impressive SERS enhancement factor of 1.57×108, and excellent signal reproducibility (relative standard deviation, RSD, of 14.85%). Applying this platform for cisplatin detection yielded a calibration range from 5 nM to 1000 nM, with an S/N-based limit of detection (LOD) of 1.9 nM and a limit of quantification (LOQ) of 6.5 nM. This research highlights the significant potential of our AuNO@AgNC SERS substrate for quantitative monitoring of low-concentration anticancer drugs.