A DNA framework-assembled SERS nanotag enables dual-mode lateral flow assays for rapid point-of-care screening and ultrasensitive quantification

Programmable DNA-assembled SERS nanotag enables simultaneous target capture and signal amplification. • Dual-mode LFA merges rapid visual screening with ultrasensitive SERS quantification on one platform. • Robust performance in complex clinical samples supports point-of-care infectious disease diagnostics. • Simultaneous dual-bacteria detection via LFIA achieved 20 min visual readout and 10 cfu/mL sensitivity under SERS system. The persistent threat of infectious diseases underscores the critical need for point-of-care diagnostic tools that are both rapid and ultrasensitive. This study addresses this challenge by developing a novel dual-mode lateral flow assay (LFA) platform powered by a programmable, DNA framework-assembled surface-enhanced Raman scattering (SERS) nanotag. The innovation lies in the rational integration of a high-load SERS signal core and a tailored plasmonic enhancer through DNA nanotechnology. First, a three-dimensional rolling circle amplification (RCA)-DNA nanoassembly scaffold was fabricated RCA reaction. Pre-synthesized Raman signal probes conjugated with gold nanoparticles were then immobilized onto this scaffold. Because the RCA template had been designed to include bacteria-specific primers, the assembled DNA-based SERS nanotag exhibits both the ability to specifically capture target microorganisms and the capacity for strong SERS signal output. When deployed on a standard LFA strip, this nanotag enables two distinct yet complementary detection modes: a rapid colorimetric readout for immediate, instrument-free screening and a quantitative SERS measurement for ultrasensitive confirmation. The platform enabled rapid visual detection via test strips within 20 min and achieved single-digit colony SERS quantification, demonstrating an ultrasensitive detection limit while retaining high specificity and robustness in complex sample matrices. This work establishes a versatile and powerful paradigm for next-generation point-of-care diagnostics, merging the convenience of rapid testing with the precision of laboratory-grade quantification, and highlights the transformative potential of synthetic biology in advanced biosensing. Download: Download high-res image (104KB) Download: Download full-size image