Patent ID: 8592217

Claim:
A method of conducting an assay comprising: (I) combining a sample droplet with a droplet comprising an umbelliferyl derivative to yield an assay droplet wherein: (a) the sample potentially comprises an enzyme capable of cleaving the umbelliferyl derivative; and (b) the umbelliferyl derivative is a modified version of an umbelliferyl parent compound comprising an umbelliferyl core modified with one or more modifying moieties, said one or more modifying moieties: (i) selected to increase hydrophilicity of the derivative relative to the parent compound without eliminating the fluorescence of the umbelliferyl core upon cleavage by the enzyme; and (ii) coupled to the umbelliferyl core at a site that remains with the umbelliferyl core following cleavage by the compound; and (II) detecting a signal from the assay droplet which is indicative of the presence of an enzyme capable of cleaving the umbelliferyl derivative.