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

Area of Science:

• Analytical Chemistry
• Biomedical Engineering
• Materials Science

Background:

• Precise optical tag control is a critical challenge in point-of-care (POC) diagnostics, limiting accuracy.
• Portable analytical innovation is driven by the increasing demand for rapid diagnostic solutions.
• Surface-enhanced Raman scattering (SERS) offers high sensitivity but requires precise control for multiplexed detection.

Purpose of the Study:

• To develop a vertically stacked microarray paper-based device (µAPAD) for high-throughput SERS immunoassays.
• To improve optical tag control and reduce signal variation in multiplex biomarker detection.
• To create a low-cost, scalable platform for next-generation POC diagnostics.

Main Methods:

• Fabrication of a 16-layer wax-patterned architecture integrating sample migration, reaction, and capture.
• Optimization of microfluidic channels for uniform nanotag distribution and an agarose hydrogel layer for flow regulation.
• Simultaneous detection of carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP) using SERS immunoassays.

Main Results:

• Reduced signal variation from 36.6% to 6.69% through optimized microfluidics and flow control.
• Achieved low detection limits of 0.34 ng/mL for CEA and 0.69 ng/mL for AFP, outperforming ELISA.
• Demonstrated high analytical accuracy in spiked serum samples with recoveries of 80.3%-139% and RSDs of 6.30%-10.8%.

Conclusions:

• The µAPAD platform offers high sensitivity, flow precision, scalability, and true multiplexing capability.
• This low-cost device significantly enhances diagnostic accuracy and efficiency for POC applications.
• The developed technology holds substantial potential for advancing large-scale health monitoring and diagnostics.