Abstract: The present invention generally relates to fluidic droplets, and techniques for screening or sorting such fluidic droplets. In some embodiments, the fluidic droplets may contain cells (e.g., hybridoma cells) that can secrete various species, such as antibodies, for example. In one aspect, a plurality of fluidic droplets containing cells is screened to determine proteins, antibodies, polypeptides, peptides, nucleic acids, or the like. For example, cells able to secrete species such as antibodies may be selected according to certain embodiments of the invention. Examples of such cells include, for instance, immortal cells such as hybridomas, or non-immortal cells such as B-cells. For instance, blood cells may be encapsulated within a plurality of fluidic droplets, and the cells able to produce antibodies may be determined. In some cases, expression or secretion levels may be determined using signaling entities, for example, determinable microparticles present within the fluidic droplet.

Abstract: In one aspect the invention relates to a method for identifying inhibitors or viral entry comprising providing an indicator cell wherein said cell expresses a reporter gene and wherein said cell is capable of supporting entry by an effector particle, providing a candidate inhibitor of viral entry, co-compartmentalizing said candidate inhibitor and said indicator cell, contacting said indicator cell with an effector particle, incubating to allow any effector particle entry to take place, and assaying said indicator cell for reporter gene activity, wherein detection of reporter gene activity identifies the candidate inhibitor as an inhibitor for viral entry. Preferably the effector particle is HIV, preferably the reporter gene is a CD4-?-lactamase fusion or a tPA fusion, preferably the reporter gene activity is assayed by cleavage of an inert substrate into a fluorescent product.