A method of detecting a biological activity, comprising: providing, a sample that may comprise a first biological activity; a first indicator reagent that can be converted by the first biological activity to a first biological derivative, wherein the first indicator reagent comprises a fluorogenic enzyme substrate having a fluorophore selected from the group consisting of umbelliferone, 7-aminocoumarin, β-naphthylamine, β-naphthol, fluorescein, resorufin, 9 H -(1,3-dichloro-9,9-dimethyl acridin-2-one), rhodamine 110, a derivative of any of the foregoing fluorophores, and a combination of any of the foregoing fluorophores; a gelling agent; and a plurality of particles, each particle comprising an organic polymer that receives and retains the first biological derivative, wherein the particles have a mean particle diameter between 0.05 microns and 20 microns; forming an aqueous dispersion comprising the first indicator reagent and the plurality of particles; wherein forming the aqueous dispersion comprises forming a hydrogel; wherein the plurality of particles are substantially uniformly dispersed in the hydrogel and the hydrogel restricts the movement of the plurality of particles; bringing the sample into fluid communication with the aqueous dispersion; and detecting a presence or absence of the first biological derivative, wherein the first biological derivative is retained by a particle; wherein the presence of the first biological derivative is indicative of the presence of a first biological activity. providing, a sample that may comprise a first biological activity; a first indicator reagent that can be converted by the first biological activity to a first biological derivative, wherein the first indicator reagent comprises a fluorogenic enzyme substrate having a fluorophore selected from the group consisting of umbelliferone, 7-aminocoumarin, β-naphthylamine, β-naphthol, fluorescein, resorufin, 9 H -(1,3-dichloro-9,9-dimethyl acridin-2-one), rhodamine 110, a derivative of any of the foregoing fluorophores, and a combination of any of the foregoing fluorophores; a gelling agent; and a plurality of particles, each particle comprising an organic polymer that receives and retains the first biological derivative, wherein the particles have a mean particle diameter between 0.05 microns and 20 microns; a sample that may comprise a first biological activity; a first indicator reagent that can be converted by the first biological activity to a first biological derivative, wherein the first indicator reagent comprises a fluorogenic enzyme substrate having a fluorophore selected from the group consisting of umbelliferone, 7-aminocoumarin, β-naphthylamine, β-naphthol, fluorescein, resorufin, 9 H -(1,3-dichloro-9,9-dimethyl acridin-2-one), rhodamine 110, a derivative of any of the foregoing fluorophores, and a combination of any of the foregoing fluorophores; a gelling agent; and a plurality of particles, each particle comprising an organic polymer that receives and retains the first biological derivative, wherein the particles have a mean particle diameter between 0.05 microns and 20 microns; wherein the particles have a mean particle diameter between 0.05 microns and 20 microns; forming an aqueous dispersion comprising the first indicator reagent and the plurality of particles; wherein forming the aqueous dispersion comprises forming a hydrogel; wherein the plurality of particles are substantially uniformly dispersed in the hydrogel and the hydrogel restricts the movement of the plurality of particles; wherein forming the aqueous dispersion comprises forming a hydrogel; wherein the plurality of particles are substantially uniformly dispersed in the hydrogel and the hydrogel restricts the movement of the plurality of particles; bringing the sample into fluid communication with the aqueous dispersion; and detecting a presence or absence of the first biological derivative, wherein the first biological derivative is retained by a particle; wherein the presence of the first biological derivative is indicative of the presence of a first biological activity. wherein the presence of the first biological derivative is indicative of the presence of a first biological activity.