Abstract: Compositions and methods for the isolation of protein-nucleic acid complexes and microvesicles (collectively referred to as “bioparticles”) released by mammalian cells into body fluids or cell culture media are provided. Isolated bioparticles of the invention contain biological molecules that are useful as diagnostic/prognostic biomarkers or for identification of therapeutic targets (e.g., disease or disorder-associated miRNAs). The isolation of biological molecules as described herein results in purification and concentration of the molecules. Methods for producing bio fluids that are free of detectable bioparticles, that are largely depleted of bioparticles, or that possess a reduced concentration of bioparticles compared to a bio fluid starting material (collectively termed “bioparticle-depleted”) are also provided. Isolation of bioparticle-depleted biofluid is useful, e.g.

Abstract: The present invention provides novel microRNAs and their uses.