title: Quantification of particle-conjugated or particle-encapsulated peptides on interfering reagent backgrounds.
abstract: Particle-based technologies are increasingly being used in diagnostics and therapeutics. The particles employed in these applications are usually composed of polymers such as poly(lactide-co-glycolide) (PLG) and functionalized with peptides or proteins. Peptide or protein conjugation to particles is frequently achieved using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), while dimethyl sulfoxide (DMSO) is used to retrieve surface-attached or encapsulated peptides or proteins by solubilizing the particles. We examined strategies based on bicinchoninic acid (BSA), Coomassie Plus, and 3-(4-carboxybenzoyl)quinoline-2-carboxaldehyde (CBQCA) assays for the quantification of surface-attached or encapsulated peptides or proteins. We determined that the CBQCA assay is a highly sensitive and accurate substitute for radioactivity-based assays that is suitable for measuring multiple particle-bound or particle-encapsulated peptides or proteins in the presence of EDC or PLG in DMSO, compounds that interfere with the more commonly used BSA and Coomassie Plus assays. Our strategy enables the accurate quantification of peptides or proteins loaded onto or into particles-an essential component of particle-based platform design for diagnostics and therapeutics.
authors.affiliation: Department of Biomedical Engineering, Northwestern University, Evanston, IL; Institute for BioNanotechnology in Medicine, Northwestern University, Chicago, IL.
authors.forename: Woon Teck
authors.initials: WT
authors.lastname: Yap
authors.affiliation: Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL; Institute for BioNanotechnology in Medicine, Northwestern University, Chicago, IL.
authors.forename: W Kelsey
authors.initials: WK
authors.lastname: Song
authors.affiliation: Department of Biomedical Engineering, Northwestern University, Evanston, IL; Institute for BioNanotechnology in Medicine, Northwestern University, Chicago, IL.
authors.forename: Niharika
authors.initials: N
authors.lastname: Chauhan
authors.affiliation: Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL; Institute for BioNanotechnology in Medicine, Northwestern University, Chicago, IL.
authors.forename: P Nina
authors.initials: PN
authors.lastname: Scalise
authors.affiliation: Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL; Institute for BioNanotechnology in Medicine, Northwestern University, Chicago, IL.
authors.forename: Radhika
authors.initials: R
authors.lastname: Agarwal
authors.affiliation: Departments of Microbiology-Immunology and Interdepartmental Immunobiology Center, Feinberg School of Medicine, Northwestern University, Evanston, IL.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Miller
authors.affiliation: Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL; Institute for BioNanotechnology in Medicine, Northwestern University, Chicago, IL; Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL; Chemistry of Life Processes Institute, Northwestern University, Evanston, IL.
authors.forename: Lonnie D
authors.initials: LD
authors.lastname: Shea
mesh_terms: D000595:Amino Acid Sequence; D001565:Benzoates / Q000737:chemistry; D001671:Biochemistry / Q000379:methods*; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D005022:Ethyldimethylaminopropyl Carbodiimide / Q000737:chemistry; D008969:Molecular Sequence Data; D010455:Peptides / Q000032:analysis* / Q000737:chemistry*; D011098:Polyglactin 910 / Q000737:chemistry; D011804:Quinolines / Q000737:chemistry
chemical_list: D001565:Benzoates; D010455:Peptides; D011804:Quinolines; C069617:3-(4-carboxybenzoyl)-2-quinolinecarboxaldehyde; D011098:Polyglactin 910; C047117:bicinchoninic acid; D005022:Ethyldimethylaminopropyl Carbodiimide; D004121:Dimethyl Sulfoxide
keywords: 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide; 3-(4-carboxybenzoyl)quinoline-2-carboxaldehyde; bicinchoninic acid; microparticles; nanoparticles; peptides; poly(lactide-co-glycolide); proteins