Bowman R D, Kneas K A, Demas J N, Periasamy A
Division of Natural Sciences, Maryville College, Maryville, TN 37804, USA.
J Microsc. 2003 Aug;211(Pt 2):112-20. doi: 10.1046/j.1365-2818.2003.01192.x.
Luminescence-based, polymer-supported oxygen sensors, particularly those based on platinum group complexes, continue to be of analytical importance. Commercial applications range from the macroscopic (e.g. aerodynamic investigations in wind tunnels, monitoring of oxygen concentration during fermentation, and measurement of biological oxygen demand) to the microscopic (e.g. imaging of oxygen in blood, tissue, cells and other biological samples). Problems hindering the design of improved oxygen sensors include non-linear Stern-Volmer calibration plots and the multi-exponentiality of measured lifetime decays, both of which are attributed primarily to heterogeneity of the sensor molecule in the polymer support matrix. Conventional, confocal and two-photon fluorescence microscopy have proven to be invaluable tools with which the microscale heterogeneity and response of luminescence-based oxygen sensors can be investigated and compared to the macroscopic response. Results obtained for three ruthenium(II) alpha-diimine complexes in polydimethylsiloxane polymer supports indicate the presence of unquenched microcrystals within the polymer matrix that probably degrade oxygen quenching sensitivity and linearity of the Stern-Volmer quenching plot. Two-photon fluorescence microscopy proved most useful for imaging microcrystals within sensor films, and conventional microscopy allowed direct comparison between microscopic and macroscopic sensor response. The implications of the results in the rational design and mass production of luminescence-based oxygen sensors are significant.
基于发光的聚合物负载氧传感器，特别是基于铂族配合物的传感器，在分析领域仍具有重要意义。其商业应用范围从宏观层面（如在风洞中进行空气动力学研究、发酵过程中氧气浓度监测以及生物需氧量测量）到微观层面（如对血液、组织、细胞和其他生物样品中的氧气进行成像）。阻碍改进型氧传感器设计的问题包括非线性的斯特恩-沃尔默校准曲线以及测量寿命衰减的多指数特性，这两者主要归因于传感器分子在聚合物支撑基质中的不均匀性。传统显微镜、共聚焦显微镜和双光子荧光显微镜已被证明是非常有价值的工具，利用它们可以研究基于发光的氧传感器的微观不均匀性和响应，并与宏观响应进行比较。在聚二甲基硅氧烷聚合物载体中对三种钌（II）α-二亚胺配合物的研究结果表明，聚合物基质中存在未被猝灭的微晶，这可能会降低氧猝灭灵敏度和斯特恩-沃尔默猝灭曲线的线性度。双光子荧光显微镜在对传感器薄膜中的微晶成像方面最为有用，而传统显微镜则可以直接比较微观和宏观传感器响应。这些结果对于基于发光的氧传感器的合理设计和大规模生产具有重要意义。
