A platinum-porphine/poly(perfluoroether) film oxygen tension sensor for noninvasive local monitoring of cellular oxygen metabolism using phosphorescence lifetime imaging

We present a phosphorescence lifetime imaging (PLIM) based oxygen sensor to monitor the local O2 level in conventional petri dish-based or microfluidic in vitro cell culture. The sensor film is fabricated by dissolving Pt(II) meso-tetrakis(pentafluorophenyl) porphine (PtTFPP) into a thermal curable poly(perfluoroether) (PFPE). The lifetime response of the sensor to O2 follows a linear Stern-Volmer relationship. Compared with PDMS as polymer matrix, the use of PFPE as the polymer matrix for PtTFPP mitigates both the dye induced cytotoxicity and the biomolecule adsorption problems of polydimethylsiloxane (PDMS), while maintaining cell compatibility. By using the sensor film with PFPE as the polymer matrix, the O2 tension during cell proliferation can be monitored in real time, and the resulting value can be used to calculate the per-cell O2 consumption. We tested the application of the sensor for monitoring the O2 tension during long term cell culture of HeLa cells and MDA-MB-231 cells, and calculated the O2 consumption per cell for MDA-MB-231 cells. Our study demonstrates that the PtTFPP/PFPE sensor can be employed as a general noninvasive lifetime imaging platform for studying the di-oxygen in in vitro tissue models at the cellular level as a function of space and time.