Optical Oxygen Sensor Based on Luminescence Quenching for Dissolved Oxygen (DO) Detection: Metalloporphyrin Embedded in Fluorinated Acrylate Microspheres and Their Biological Application

• The Stern-Volmer equations kept high linearity. • The sensors exhibit high sensitivity, accuracy, fast response, and excellent photostability. • The Nanospheres were used as photosensitizers, efficiently destroyed human A431 cancer cells. • The Nanospheres has tremendous therapeutic potential for treating cancers. Optical oxygen sensor based on luminescence quenching mechanism by encapsulated platinum octaethylporphine (PtOEP) into fluoropolymer of Poly(methylmethacrylate-co-trifluoroethyl methacrylate) (Poly(MMA-co-TFEMA)) microspheres, and Poly(methylmethacrylate-co-trifluoroethyl methacrylate-co-butyl acrylate) Poly(MMA-co-TFEMA-co-BA) microspheres via a miniemulsion polymerization were developed for dissolved oxygen (DO) detection. The luminescence intensity of the oxygen sensing microspheres have an obvious decrease with the increase of the concentration of DO, the maximum quenching ratio (I 0 /I 100) is estimated to be 6.19 and 8.92 for Poly(MMA-co-TFEMA) and Poly(MMA-co-TFEMA-co-BA) microspheres, respectively. The response times are 28 s and 24 s to DO for Poly(MMA-co-TFEMA) and Poly(MMA-co-TFEMA-co-BA) microspheres. After 1 h continuous light irradiation, both the decay ratios of luminescence intensity are below 0.1%. The experimental results show that both microsphere-based oxygen sensors possess high sensitivity and accuracy, fast response time, and excellent photostability to the DO. Finally, the PtOEP@Poly (MMA-co-TFEMA-co-BA) was used as the photosensitizer, and their photodynamic therapy (PDT) in human A431cells was evaluated. The in vitro studies indicate that cancer cells are efficiently destroyed at a low dose of the PtOEP@Poly(MMA-co-TFEMA-co-BA) microspheres under the light irradiation, suggesting that the potential application of the oxygen sensing microspheres for photodynamic therapy.