Abstract: A method of determining oxygen concentration, metabolic activity, and/or the effects of a test substance on the metabolic activity of a live cell sample by photoluminescence quenching technique employing a photoluminescent probe that self-loads sans any loading reagent into the cells of the cell sample. The probe comprises a plurality of polymeric particles each comprising an amphiphilic cationic polymer matrix having a hydrophobic core and a hydrophilic positively charged surface provided by quaternary amino groups, and a hydrophobic oxygen-sensitive photoluminescent dye embedded in the hydrophobic core.

Abstract: A method of determining oxygen concentration, metabolic activity, and/or the effects of a test substance on the metabolic activity of a live cell sample by photoluminescence quenching technique employing a photoluminescent probe that self-loads sans any loading reagent into the cells of the cell sample. The probe comprises a plurality of polymeric particles each comprising an amphiphilic cationic polymer matrix having a hydrophobic core and a hydrophilic positively charged surface provided by quaternary amino groups, and a hydrophobic oxygen-sensitive photoluminescent dye embedded in the hydrophobic core.

Abstract: The invention is based on the use of photoluminescent probes for intracellular sensing of oxygen, especially assaying intracellular oxygen concentration. The photoluminescent probe comprises a suspension of polymeric particles having an average diameter in the 20 nm to 100 nm range, formed from an amphiphilic cationic co-polymer which is oriented in the formed particle to provide a hydrophobic core and a hydrophilic shell. The probe includes a hydrophobic oxygen-sensitive photoluminescent dye such as Pt-tetrakis(pentafluorophenyl)porphine, PtPFPP embedded in the hydrophobic core of the particle, and the co-polymer includes quaternary ammonium groups which provide hydrophilic and cationic character to the particle shell. The photoluminescent probe, which in use is provided in the form of an aqueous suspension of probe, is incubated with live mammalian cells in a suitable growth medium for a period of time to allow the probe particles passively load into the cells.

Abstract: The invention is based on the use of photoluminescent probes for intracellular sensing of oxygen, especially assaying intracellular oxygen concentration. The photoluminescent probe comprises a suspension of polymeric particles having an average diameter in the 20 nm to 100 nm range, formed from an amphiphilic cationic co-polymer which is oriented in the formed particle to provide a hydrophobic core and a hydrophilic shell. The probe includes a hydrophobic oxygen-sensitive photoluminescent dye such as Pt-tetrakis(pentafluorophenyl)porphine, PtPFPP embedded in the hydrophobic core of the particle, and the co-polymer includes quaternary ammonium groups which provide hydrophilic and cationic character to the particle shell. The photoluminescent probe, which in use is provided in the form of an aqueous suspension of probe, is incubated with live mammalian cells in a suitable growth medium for a period of time to allow the probe particles passively load into the cells.