Invited speaker at Pacifichem 2025, HI, USA, from Dec 15-20, 2025

Microfluidic paper-based analytical devices (µPADs) offer a globally accessible, low-cost, and portable platform for future diagnostics. Our research develops innovative µPADs for environmental, agricultural, and food analysis. Addressing the severe health impacts of air pollution, particularly in developing countries, we've focused on quantifying the critical link between copper (Cu) levels and particulate matter (PM) oxidative load, a key indicator of PM toxicity. Our dual colorimetric-electrochemical µPADs enable simultaneous detection of Cu and oxidative potential in PM, providing a crucial tool for environmental monitoring. For water quality assessment, we developed precipitation-based µPADs, overcoming the coffee ring effect with safe alcohol ink modifications. In agriculture, we introduced a non-destructive µPAD for durian maturity assessment, a valuable but challenging tropical fruit. This device automates peduncle fluid analysis for total sugar and amino acid content, streamlining sugar detection by reducing multiple enzymatic steps to a single step using invertase, followed by simplified gold nanoparticle (AuNP) detection. To tackle challenges with wide concentration ranges, we developed tunable working range µPADs, achieving six orders of magnitude detection for cysteine in processed food via strategic reagent spotting. These advancements expand µPAD applicability across diverse fields, fostering a sustainable bio-circular green economy.