Patent ID: 7575890

Claim:
A method for rapidly detecting growth or metabolism of an immobilized cellular microorganism, the method comprising: placing a population of cells, comprising one or more microorganisms, into a sterile, liquid, aqueous, gelling culture medium, comprising a dissolved oxygen-quenchable phosphorescent compound that is non-toxic to the microorganism; evenly spacing and distributing the cells, without overlap, throughout the gelling medium; immobilizing the spaced and distributed cells by polymerizing the gelling medium, thereby forming a solid or semi-solid gel matrix ≦3 mm thick, immobilizing the cells therein; maintaining communicable contact between each cell and the oxygen-quenchable phosphorescent compound in the surrounding medium, such that the phosphorescent compound is responsive to oxygen pressure in the medium, while at the same time limiting exposure of the medium to only diffused external oxygen from the air into the gel, wherein non-uniform oxygen distributions form around each colony of growing cells; exciting the dissolved phosphorescent compound to phosphoresce; and detecting and measuring the phosphorescence in the gel matrix, wherein an increase in phosphorescence is indicative of growth or metabolism of the microorganism.