Molecularly Engineered SERS Platform with Microturbulence-Enhanced Electrohydrodynamics for Multiplexed Profiling of Lung Cancer ctDNA

Precise profiling of multiple circulating tumor DNA (ctDNA) is hindered by the challenge of resolving single-nucleotide variants (SNVs) and their trace abundance. Herein, we present an integrated SERS platform that combines rationally molecularly engineered nanotags with a novel microturbulent electrofluidic interface for multiplexed SNV-level profiling of lung cancer ctDNAs. In particular, the SERS nanotags incorporate (1) a de novo isomeric Raman reporter library that systematically tailors vibrational signatures through molecular symmetry and electronic effects, (2) hollow hyperbranched Cu₂O/CuO@Ag heterostructures engineered to suppress carrier recombination for maximized electromagnetic-chemical signal enhancement, and (3) rationally designed dCas9-sgRNA units that confer single-nucleotide discrimination. To overcome diffusion-limited mass transport and further boost the signal, we fabricated nanopebble-structured asymmetric microelectrodes on aluminum foil. Unlike a conventional smooth interface, this unique topography induces powerful microturbulence-enhanced electrohydrodynamics (mt-EHD) that disrupts the interfacial depletion layer to accelerate target delivery while simultaneously offering high-density "hot spots" within interpebble gaps for secondary Raman signal amplification. This integrated system achieved the simultaneous quantification of six ctDNA mutations in 131 clinical samples. By leveraging machine learning algorithms, the platform enables accurate diagnosis, prognostic stratification, and dynamic treatment monitoring, establishing an integrated chemical-electrofluidic strategy for precision liquid biopsy.