Au@Pt@HP1-HP2@Fe3O4 Nanoenzymatic Complexes Based on CHA Signal Amplification Strategy for Ultrasensitive SERS Detection of ctDNA in Liver Cancer.

Early diagnosis of liver cancer requires highly sensitive detection of biomarkers. This study aims to develop a novel method for detecting circulating tumor DNA (ctDNA) in the serum of liver cancer patients, leveraging a catalytic hairpin self-assembly (CHA) signal amplification strategy combined with surface-enhanced Raman scattering (SERS) technology and nano-enzyme catalysis. We synthesized Au@Pt@HP1-HP2@Fe3O4 nano-enzyme complexes, utilizing the SERS-enhancing properties of Pt-coated Au nanoparticles (Au@Pt) and the separation-enrichment capability of Fe3O4 magnetic beads. The complexes catalyzed the oxidation of colorless TMB by H2O2 to produce blue ox-TMB, enabling quantitative detection of PIK3CA E542K mutant ctDNA. The assay's performance was validated using gold standard qRT-PCR. Under optimized conditions, the method achieved a detection limit for PIK3CA E542K as low as 4.12 aM. The assay demonstrated high sensitivity, specificity, and efficient magnetic separation, making it a robust tool for ctDNA detection. This study presents a highly sensitive and specific detection platform for liver cancer early diagnosis, characterized by magnetic separation and nano-enzyme catalysis. The method holds significant clinical potential for the accurate and early detection of liver cancer biomarkers.