Abstract: Provided herein are nanoparticles that include a lipid layer and a compartment surrounded by the lipid layer. The lipid layer may include a lipid and a lipoprotein. The lipid may include a POPE lipid covalently attached to a hydrophilic polymer by a disulfide bond. The lipoprotein may include a trigger protein. The concentration of the first lipid may be between 1 mol % and 30 mol %. The disulfide bond of the first lipid is stable under conditions that include 10% human serum and is broken under conditions that include 50 micromolar glutathione. The hydrophilic polymer may include a PEG molecule. The trigger protein may include an amino acid repeat region, such as (GPX)n. The trigger protein may include a peptide bond that is cleaved by a gelatinase (e.g., gelatinase-B protease), or a member of the ADAM family of proteases (e.g., ADAM10 protease). Also provided are methods of using the nanoparticles.

Abstract: Provided herein are nanoparticles that include a lipid layer and a compartment surrounded by the lipid layer. The lipid layer may include a lipid and a lipoprotein. The lipid may include a POPE lipid covalently attached to a hydrophilic polymer by a disulfide bond. The lipoprotein may include a trigger protein. The concentration of the first lipid may be between 1 mol % and 30 mol %. The disulfide bond of the first lipid is stable under conditions that include 10% human serum and is broken under conditions that include 50 micromolar glutathione. The hydrophilic polymer may include a PEG molecule. The trigger protein may include an amino acid repeat region, such as (GPX)n. The trigger protein may include a peptide bond that is cleaved by a gelatinase (e.g., gelatinase-B protease), or a member of the ADAM family of proteases (e.g., ADAM10 protease). Also provided are methods of using the nanoparticles.

Abstract: Provided herein are methods for using lipid particles. In one embodiment, lipid particles are used for determining whether a composition includes a charged contaminant. The method includes combining a test composition that includes an analyte with lipid particles to form a mixture, and determining whether there is any change in zeta potential of the mixture and/or average aggregate diameter of liposome aggregates in the mixture. In one embodiment, lipid particles are used for enriching an analyte. The method includes combining a test composition that includes an analyte with lipid particles and multivalent cations to form a mixture, incubating the mixture under conditions suitable for forming a complex that includes the analyte bound to the lipid particle, and separating the complex from the contaminant present in the mixture.