title: Harnessing immunomagnetic separation and quantum dot-based quantification capacities for the enumeration of absolute levels of biomarker.
abstract: The field of biomarker quantification has experienced a growth parallel to the discovery of new materials. In this paper, we propose an innovative system for the separation and quantification of biomarkers using a simple magnetic bead (MB)-quantum dot (QD) sandwich assay. The basis of the system lies in the interaction between histidine residues on protein G and Ni ions on QDs, and the use of imidazole to selectively detach QDs bound to target biomarkers, in effect enumerating the absolute number of biomarker units. We used C-reactive protein (CRP) as a proof-of-concept and demonstrated a detection sensitivity of 82.5 fmoles in 50 μl of sample volume, a commonly used analytical volume (e.g. ELISA). Although CRP was used as a model to conduct this study, the sensitivity and simplicity of this detachable system make it a viable approach in the quantification of other target analytes.
authors.affiliation: Center for Biomaterials Biomedical Research Institute, Korea Institute of Science and Technology-KIST, Seoul 136-791, Republic of Korea.
authors.forename: Hoyoung
authors.initials: H
authors.lastname: Park
authors.forename: Mintai P
authors.initials: MP
authors.lastname: Hwang
authors.forename: Jong-Wook
authors.initials: JW
authors.lastname: Lee
authors.forename: Jonghoon
authors.initials: J
authors.lastname: Choi
authors.forename: Kwan Hyi
authors.initials: KH
authors.lastname: Lee
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000378:metabolism; D015415:Biomarkers / Q000032:analysis*; D002097:C-Reactive Protein / Q000032:analysis; D002417:Cattle; D018189:Immunomagnetic Separation / Q000379:methods*; D057230:Limit of Detection; D059346:Magnets; D008956:Models, Chemical; D045663:Quantum Dots
chemical_list: D000911:Antibodies, Monoclonal; D015415:Biomarkers; D002097:C-Reactive Protein