This study introduces a novel, cost-effective method for fabricating microfluidic paper-based analytical devices (µPADs) using atom stamp printing (ASP). ASP offers advantages over other methods, including ease of operation, high production efficiency, and high resolution (328 µm hydrophilic channels and 312 µm hydrophobic barriers). The researchers demonstrated the µPADs' ability to detect Cu²⁺ via a colorimetric method, achieving a detection limit of 1 mg/L using a distance-based detection method. Furthermore, a new paper-based solid-liquid extraction device (PSED) with a 3D "3+2" structure and recyclable extraction mode was developed for efficient and cost-effective heavy metal ion extraction from soil samples. This PSED platform holds great potential for applications in food safety and environmental monitoring, especially in resource-limited settings.

Yanfang Guan, Baichuan Sun