Oxygen Sensors Based on Luminescence Quenching: Interactions of Metal Complexes with the Polymer Supports

Abstract

Oxygen quenching of [Ru(Ph2phen)3]Cl2 (Ph2phen = 4,7-diphenyl-1,10-phenanthroline) has been studied in a diverse series of polymers, most with a common poly-(dimethylsiloxane) (PDMS) component. Systematic variations in the polymer properties have been made in order to delineate the structural features important for satisfactory use of supports for oxygen sensors. Most measurements were made using homo- or copolymers containing a PDMS region, although some measurements were made on small ring siloxane polymers. In particular, quenching behavior was examined as a function of polymer structure as well as the type of and amount of polar copolymer cross-linkers. Cross-linkers were added to enhance the solubility of oxygen probes in an otherwise nonpolar polymer. In addition, hydrophobic silica was added to alter quenching properties. Domain models are used to explain the variations in oxygen quenching properties as a function of additives and cross-linkers. These considerations have led to the most sensitive ruthenium-based sensor reported to date. The relative affinity of the different domains for the complex and the efficacy of the domains for oxygen quenching control the overall behavior of the sensing response. Guidelines for design of suitable polymer supports for oxygen sensors are proposed.

Enzymatic Fluorescent Microsphere Glucose Sensors:Evaluation of Response Under Dynamic Conditions

“…Matrices with high permeability to oxygen result in more sensitive responses, as do matrices that are more hydrophobic or polar in nature. 19 Separate experiments to determine the response of the sensors described here to changes in oxygen alone demonstrated that [Ru(dpp)3] 2+ immobilized in alginate microspheres results in a sensitivity (percent change in ratio from 0% to 100% dissolved O 2 ) of 42%, whereas the highest reported sensitivity for this molecule is 50-80% (immobilized in ormosil and silica matrices). 20 Thus, without altering any other sensor parameters, increasing the sensitivity of the immobilized oxygen indicator would increase the sensitivity and range of the glucose response.…”

Fluorescent Chemosensor for Quantitation of Multiple Atmospheric Gases

“…Their ability to sense and detect the chemicals and gas molecules result into the realization of new sensor strategies. Fluorescent organic nanoparticles have been employed to detect metal ions, anions, gases and biomolecules [46][47][48][49]. The aqueous suspension of organic nanoparticles prepared from simple reprecipitation method acts as excellent chemosensor [50,51].…”

Indicators for optical oxygen sensors

“…Examples are sol-gel [147,152,154,249], ethyl cellulose or PVC membranes [61], different types of ORMOSILs [39,94,106], polystyrene [91], polysulfones [11,18], poly (dimethylsiloxane) alone [251] or with different amounts of pendant acrylate groups [168], and a blended fluoropolymer matrix consisting of Nafion ® and Aflas ® [83]. In another approach, the [Ru(dpp) 3 ] 2+ complex was adsorbed onto silica and then dispersed in a silicone rubber support [38,93].…”