Self-driven microfluidic chip with integrated lateral and vertical flow assays for dual-readout point-of-care testing

Rapid and sensitive detection of biomarkers is pivotal for disease prevention and control in point-of-care testing (POCT). Traditional nitrocellulose (NC) membrane-based lateral flow assay (LFA) often cause suboptimal sensitivity and poor uniformity by disordered porous structure. Herein, we propose a self-driven microfluidic chip with integrated lateral and vertical flow assays (VFA), termed the SeDM-LV chip. By replacing the test line in LFA with an anodized aluminum oxide (AAO) membrane and incorporating surface-enhanced Raman scattering (SERS), the chip enables rapid, highly sensitive, and reproducible detection of target biomarkers. Taking Interleukin 6 (IL-6) as a proof of concept, the optimized chip demonstrates adequate detection performance, with naked-eye and SERS-based detection limits of 100 pg/mL and 0.95 pg/mL. The calibration curve exhibits a linear dynamic range spanning from 1 pg/mL to 1 μg/mL (R² = 0.972), while the one-step "sample-to-answer" protocol is completed only within 5 min. Chip evaluation revealed recoveries ranging from 92.1 % to 109 % in spiked healthy human serum for IL-6 quantification, alongside effective differentiate on between IL-6 abnormal (n = 8) and normal (n = 4) groups in clinical serum samples. Conceptually, this represents the first achievement of synergistic optimization of LFA and VFA, overcoming the long-standing trade-off between speed, sensitivity and user-friendliness in conventional POCT. The integrated chip features portability, simplicity, low cost and high expandability, rendering it highly significant for primary care screening and on-site detection during public health emergencies.