Re(I) complex doped nanofibers for oxygen optical sensing

Spatiotemporal oxygen sensing using dual emissive boron dye-polylactide nanofibers

Oxygenation in tissue scaffolds continues to be a limiting factor in regenerative medicine despite efforts to induce neovascularization or to use oxygen-generating materials. Unfortunately, many established methods to measure oxygen concentration, such as using electrodes, require mechanical disturbance of the tissue structure. To address the need for scaffold-based oxygen concentration monitoring, a single-component, self-referenced oxygen sensor was made into nanofibers. Electrospinning process parameters were tuned to produce a biomaterial scaffold with specific morphological features. The ratio of an oxygen sensitive phosphorescence signal to an oxygen insensitive fluorescence signal was calculated at each image pixel to determine an oxygenation value. A single component boron dye-polymer conjugate was chosen for additional investigation due to improved resistance to degradation in aqueous media compared to a boron dye polymer blend. Standardization curves show that in fully supplemented media, the fibers are responsive to dissolved oxygen concentrations less than 15 ppm. Spatial (millimeters) and temporal (minutes) ratiometric gradients were observed in vitro radiating outward from the center of a dense adherent cell grouping on scaffolds. Sensor activation in ischemia and cell transplant models in vivo show oxygenation decreases on the scale of minutes. The nanofiber construct offers a robust approach to biomaterial scaffold oxygen sensing.

Study on an oxygen sensing rhenium(I) complex with enlarged sensing/active area: fabrication, photophysical parameters and molecular oxygen sensing performance

In this paper, we synthesize a novel 1,10-phenanthroline-derived (Phen-derived) diamine ligand of benzo[f][1,10]phenanthroline-6,7-dicarbonitrile (Phen-CN) with enlarged conjugation planar and its corresponding Re(I) complex of Re(CO)3Cl(Phen-CN), hoping to achieve an optical sensor owing large sensing/active area. Its geometric and electronic structures are investigated, which suggests that the effective sensing/active area of Re(CO)3Cl(Phen-CN) is enlarged by the successful formation of conjugation planar. The promising photophysical parameters of Re(CO)3Cl(Phen-CN), including large sensing/active area and long excited state lifetime, make it a potential probe for oxygen detection. By doping Re(CO)3Cl(Phen-CN) into a polymer matrix of poly(vinylpyrrolidone), oxygen sensing performances of the resulted composite materials are investigated. Finally, a high sensitivity of 17.1 is realized, with short response/recovery time of 9s/32s.

Optical methods for sensing and imaging oxygen: materials, spectroscopies and applications

We review the current state of optical methods for sensing oxygen. These have become powerful alternatives to electrochemical detection and in the process of replacing the Clark electrode in many fields. The article (with 694 references) is divided into main sections on direct spectroscopic sensing of oxygen, on absorptiometric and luminescent probes, on polymeric matrices and supports, on additives and related materials, on spectroscopic schemes for read-out and imaging, and on sensing formats (such as waveguide sensing, sensor arrays, multiple sensors and nanosensors). We finally discuss future trends and applications and summarize the properties of the most often used indicator probes and polymers. The ESI† (with 385 references) gives a selection of specific applications of such sensors in medicine, biology, marine and geosciences, intracellular sensing, aerodynamics, industry and biotechnology, among others.