Platinum(II) and palladium(II) complexes of porphyrins and related tetrapyrrolic pigments emit strong phosphorescence at room temperatures, which is characterized by long lifetimes falling into the sub-millisecond range and long-wave spectral characteristics. These features make the dyes useful as probes for a number of bioanalytical applications, particularly those employing time-resolved fluorescent detection. They can provide high sensitivity and selectivity, together with rather simple instrumental set-up. A number of analytical systems are now under development that are based on the use of phosphorescent porphyrin probes. Experimental results are presented on the following systems: (i) fibre-optic phosphorescence lifetime-based oxygen sensor on the basis of hydrophobic platinum-porphyrins and development of advanced sensing materials and prototype instrumentation; (ii) practical applications of the optical oxygen sensor, including a sensitive immunosensor that employs glucose oxidase labels, a rapid screening method for cell viability in microtitre-plate format, non-destructive measurement of oxygen in packaged foods and reagentless biosensors for metabolites (glucose, lactate); and (iii) the use of water-soluble platinum- and palladium-porphyrins as labels for ultra-sensitive time-resolved phosphorescence immunoassays.
Spectral characteristics of time resolved magnonic spin Seebeck effect