Component optimization in optical and electrochemical paper-based analytical devices

Paper-based analytical devices (PADs) represent the diagnostic revolution in portable, low-cost, highly accessible tools for healthcare, environmental monitoring, and food safety. The current review describes the key role of buffers and reagents in the performance of optical and electrochemical PADs. Buffers maintain pH stability and optimize the reaction, while reagents provide selectivity, sensitivity, and signal amplification. The improvements in accuracy of detection, reduction in quantity of samples, and trace-level analyte detection have been effectively achieved by bettering nanomaterials, microfluidics, and multifunctional reagents. Challenges on reagent stability, environmental factors, and standardization are discussed alongside emerging trends such as environmentally friendly materials and real-time remote diagnostics. This comprehensive analysis underlines the transformative potential of PADs in modern diagnostics, especially in resource-limited settings, while it also underlines the need for interdisciplinary collaboration to drive future innovations.