A novel paper-based colorimetric sensor using parylene C for Al (III) detection on a smartphone platform.

[Display omitted] • A novel filter paper patterning method based on parylene C. • A paper-based colorimetric sensor for detection of Al (III) using a smartphone platform. • The detection range of the sensor for Al (III) detection is 0.05 to 10 mg/mL. The detection limit is 0.05 mg/mL. • The assembled paper-based smartphone sensor platform has the potential to detect other biochemical molecules. The paper-based analytical platforms have been applied in biochemical detection and environmental monitoring due to their low cost and easy operation. Despite their advantages, the complexity of fabrication has limited their further application. Here, a simple and innovative approach using parylene C, a material commonly used in semiconductors, is reported to fabricate paper-based chips and construct a point-of-care testing (POCT) platform through smartphones. Parylene C is deposited on the filter paper through a polydimethylsiloxane (PDMS) clamp and forms a hydrophobic barrier. A three-channel paper-based chip was utilized to detect aluminum (Al) ions on a smartphone platform by the chromogenic method. The color change after Al3+ detection is represented with △E which was photographed and calculated by app on smartphone. The detection limit is 0.05 mg/L and the detection range is from 0.05 mg/L to 10 mg/L which indicates the application potential in the field of biochemical detection. This new paper-based sensing method and smartphone-based portable detection platform are simple, low-cost, fast, and highly sensitive, and provides a potential application for on-site, visual detection of ions and even other substances. [ABSTRACT FROM AUTHOR]