Automated manufacturing of paper-based analytical devices through pen-plotting technique for depositing hydrophobic barriers and chromogenic reagents

Abstract

This report describes, for the first time, the use of the pen-plotting technique (PPT) for the fabrication of paper-based analytical devices (PADs) through two sequential steps. In brief, PPT was employed to delimiting microzones by dispensing hydrophobic barriers composed of manila copal resin (MCR) and depositing the chromogenic reagent chromeazurol S (CAS) within the detection zones for aluminum sensing. All experimental conditions including the bioink concentration, line spacing, drawing speed, applied force, and number of passes were successfully optimized to ensure reproducible fabricationt of PADs. The proposed device exhibited satisfactory selectivity and maintained analytical stability for 14 days under ambient conditions. As a proof of concept, the resulting device was applied for the colorimetric detection of Al3 + in tap water and pharmaceutical samples. The proposed method provided linear behavior versus the logarithmic function of the Al3 + concentration from 0.5 to 30 mg L−1, with a limit of detection of 1.2 mg L−1. The feasibility of the developed approach was further demonstrated through the analysis of aluminum hydroxide in antacid samples. The obtained results (59 ± 1 g L−1) revealed accuracy (97–109 %) and good agreement with the labelled concentration, showing no statistically significant difference compared to a reference technique (p < 0.05). The reported approach achieved a high analytical greenness score (0.9), thus highlighting its strong adherence to green chemistry principles. Lastly, the use of PPT emerges as a promising and scalable fabrication strategy for producing PADs at room temperature offering substantial potential for multipurpose applications.