Ratiometric fiber optic sensors for the detection of inter- and intra-cellular dissolved oxygen

A sensor platform was developed for the detection of inter- and intra-cellular dissolved oxygen, using a fiber optic probe. The design and fabrication of the oxygen fiber optic sensor are based on the excellent luminescence quenching properties of the near-infrared oxygen sensitive platinum(II) octaethylporphine ketone (PtOEPK) dye. Together with a reference dye, octaethyl porphyrin (OEP) or bodipy maleimide 577/618, the dye was entrapped, in an easily renewable liquid polymer matrix, made of polyvinyl chloride, including the plastisizing agent bis(2-ethylhexyl) sebacate (DOS). Multi-mode fibers were pulled down to submicron dimensions and a dip coating procedure was used to apply the sensing membrane film to the tip. This sensor was fully characterized and exhibits excellent reversibility, minimal photobleaching and leaching, and fast response times. The resulting oxygen sensor is one of the most sensitive optical oxygen sensors to date, with good linearity in the Stern–Volmer plot calibrations. This sensor is ultimately intended for biological inter- and intra-cellular measurements.