Dual-Function SERS Chip for High-Efficiency Single-Bacterium Isolation and In Situ Detection on a Superhydrophobic Nanostructured Platform

Rapid and precise detection of bacteria at the single-cell level remains a major challenge in clinical diagnostics and pathogen surveillance, where heterogeneity within bacterial populations can critically impact infection progression and therapeutic outcomes. Herein, we develop a dual-functional gold dot array chip that integrates single-bacterium capture with label-free surface-enhanced Raman spectroscopy (SERS) detection. By combining a three-dimensional superhydrophobic interface with patterned gold nanoparticle deposition, the chip enables single-bacterium array formation via precise droplet segmentation, while in situ SERS detection is facilitated by nanoscale gap hot spots formed between the nanofiber network and gold nanoparticles. Systematic characterization confirms excellent sensitivity, spatial uniformity, and long-term stability. The chip efficiently captures single Escherichia coli and Staphylococcus aureus cells even at high concentrations (up to 107 CFU/mL) with 78% efficiency, producing reproducible Raman fingerprints for reliable species differentiation. This design substantially streamlines the detection workflow, improves the analytical efficiency, and demonstrates broad applicability in clinical diagnostics, food safety, and environmental microbiology.