The 96-Puddle Paper Plate as a Versatile Lab-on-Paper Platform.

Microfluidic paper-based analytical devices (µPADs) have facilitated the detection of a wide range of analytes, spanning human health indicators and environmental contaminants. However, their diverse designs necessitate specialized analytical equipment, which complicates standardization, limits productivity, impedes universal analysis, and hinders the acquisition of reliable data. To address these issues, a 96-Puddle Paper Plate (96-PPP) is presented, a versatile lab-on-paper platform that is fully compatible with microplate readers. The 96-PPP offers significant advantages in high-throughput analysis, enabling both qualitative assessments using visual inspection and smartphone cameras, as well as quantitative measurements of absorbance and fluorescence. The versatility of this platform is demonstrated by its ability to detect a wide range of key analytes, including acetone, magnesium ions (Mg²⁺), ascorbic acid, and ketone, which is pertinent to clinical diagnostics, metabolic research, and environmental monitoring. Additionally, 96-PPP enables the study of amyloid deposition (variation within 3.5% across 480 puddles) and proteolysis in cellulose networks that resemble extracellular matrix structures, a capability not achievable with conventional 96-well plates. Overall, 96-PPP replicates the functionality of 96-well plates and concurrently addresses the limitations of conventional µPADs, such as low productivity, versatility, and reliability. Furthermore, it provides unprecedented scalability via a stable, cellulose-based sheet.