Microenvironment regulation of ruthenium complexes based on PDMS microsphere carriers and highly sensitive detection of dissolved oxygen

Accurate monitoring of dissolved oxygen concentration in vivo is crucial for understanding cellular metabolism and pathological changes in the microenvironment. However, traditional oxygen sensing methods such as clark electrodes and magnetic resonance spectroscopy suffer from drawbacks including tissue damage, high cost, or insufficient spatial resolution. This study aims to develop a novel, cost-effective, biocompatible, and non-invasive oxygen sensor based on microfluidic technology for continuous, in situ monitoring of dissolved oxygen in the cellular microenvironment. We fabricated Polydimethylsiloxane flexible microspheres using microfluidic techniques, incorporating Ru (dpp) 3 Cl 2 nanoparticles (a derivative of tris(4,7-diphenyl-1,10-phenanthroline)ruthenium (II) dichloride) as an oxygen-sensitive indicator. By optimizing the flow rate ratio between the dispersed oil phase and continuous aqueous phase, as well as the concentration of Ru (dpp) 3 Cl 2 , we obtained microspheres with the highest fluorescence quenching constant and optimal dissolved oxygen responsiveness. These microspheres were subsequently co-cultured with three cancer cell lines (MDA-MB-231, HeLa, and A549) to dynamically monitor dissolved oxygen levels. To further evaluate their potential as a drug delivery platform, paclitaxel was loaded into the microspheres, demonstrating excellent biocompatibility. This study successfully achieves highly sensitive, in situ , and cost-effective visual monitoring of dynamic Dissolved oxygen fluctuations. The developed microspheres hold significant application prospects in the field of bio-oxygen sensors, providing new insights for biomedical research.