The integrated oxygen sensor via luminescence quenching for monitoring oxygen variation in the microfluidic chip...

This study aimed to develop a low-cost and widely accessible integrated oxygen sensor for monitoring oxygen variations within microfluidic chips, which addressed the lack of universal sensing solutions in disposable biological applications. The sensor employed quenching technology, utilizing Ru(dpp)₃Cl₂ as an oxygen-sensitive indicator that was embedded in a PDMS matrix to form flexible oxygen-sensing films. A smartphone-based platform was used for luminescence detection, which ensured ease of use and broad compatibility. The fabricated sensor exhibited exceptional stability and a linear response to dissolved oxygen, with a correlation coefficient (R²) of 0.9998, which outperformed its response to gaseous oxygen (R² = 0.9936). Moreover, the sensor achieved a 1.9-fold increase in detection sensitivity compared to previously reported Ru(dpp)₃Cl₂-based film sensors, while the cost was reduced to approximately $12-significantly lower than that of commercial alternatives. This integrated system enhanced the functionality of microfluidic devices and provided a practical tool for studying oxygen-related biological processes with high precision.