Vertically Stacked Paper‐Based Microarray Device for High‐Throughput SERS Detection of Two Cancer Biomarkers

Why It Matters

The device delivers ELISA‑level sensitivity with rapid, multiplexed, low‑cost testing, addressing a critical gap in point‑of‑care cancer diagnostics. Its scalability could accelerate early detection and large‑scale health monitoring worldwide.

Key Takeaways

• 16-layer wax‑patterned paper reduces signal variation to 6.7%.
• Detects CEA and AFP at sub‑nanogram per milliliter levels.
• Processes 14 samples simultaneously within 30 minutes.
• Achieves recoveries 80‑139% in spiked serum tests.
• Offers low‑cost, scalable platform for point‑of‑care diagnostics.

Pulse Analysis

The surge in point‑of‑care (POC) diagnostics has intensified the search for portable platforms that combine speed, sensitivity, and multiplexing. Surface‑enhanced Raman scattering (SERS) offers molecular‑level detection, yet controlling optical tags in fluidic environments remains problematic. Researchers have now introduced a vertically stacked paper‑based microarray device (µAPAD) that embeds the entire immunoassay workflow within a 16‑layer wax‑patterned architecture. By integrating sample migration, reaction, and capture zones on a single stack, the device eliminates the need for external instrumentation while preserving the high‑resolution spectral output characteristic of SERS.

Key engineering advances underpin µAPAD’s performance. Uniform microfluidic channels distribute nanotags consistently, slashing signal variation from 36.6 % to just 6.69 %. An agarose hydrogel layer acts as a flow regulator, boosting immunocapture efficiency and enabling simultaneous analysis of 14 samples in under 30 minutes. The platform achieves limits of detection of 0.34 ng/mL for carcinoembryonic antigen (CEA) and 0.69 ng/mL for alpha‑fetoprotein (AFP), surpassing conventional ELISA benchmarks. Validation with spiked serum yielded recoveries between 80 % and 139 % and relative standard deviations below 11 %.

The implications extend beyond laboratory proof‑of‑concept. Because the µAPAD is fabricated from inexpensive paper and wax, scaling production for mass deployment is feasible, positioning it as a cost‑effective tool for large‑scale health monitoring and early cancer screening. Its true multiplexing capability could streamline panels for multiple biomarkers, reducing patient visits and laboratory workload. As healthcare systems prioritize rapid, decentralized testing, technologies like µAPAD are poised to reshape diagnostic pathways, offering clinicians actionable data at the bedside while maintaining analytical rigor.