title: Detection of proteins using a colorimetric bio-barcode assay.
abstract: The colorimetric bio-barcode assay is a red-to-blue color change-based protein detection method with ultrahigh sensitivity. This assay is based on both the bio-barcode amplification method that allows for detecting miniscule amount of targets with attomolar sensitivity and gold nanoparticle-based colorimetric DNA detection method that allows for a simple and straightforward detection of biomolecules of interest (here we detect interleukin-2, an important biomarker (cytokine) for many immunodeficiency-related diseases and cancers). The protocol is composed of the following steps: (i) conjugation of target capture molecules and barcode DNA strands onto silica microparticles, (ii) target capture with probes, (iii) separation and release of barcode DNA strands from the separated probes, (iv) detection of released barcode DNA using DNA-modified gold nanoparticle probes and (v) red-to-blue color change analysis with a graphic software. Actual target detection and quantification steps with premade probes take approximately 3 h (whole protocol including probe preparations takes approximately 3 days).
authors.affiliation: Department of Chemistry, Seoul National University, San 56-1, Sillim-dong, Gwanak-gu, Seoul 151-747, South Korea. jmnam@snu.ac.kr
authors.forename: Jwa-Min
authors.initials: JM
authors.lastname: Nam
authors.forename: Kyung-Jin
authors.initials: KJ
authors.lastname: Jang
authors.forename: Jay T
authors.initials: JT
authors.lastname: Groves
mesh_terms: D003124:Colorimetry / Q000379:methods*; D015342:DNA Probes; D001330:Electronic Data Processing / Q000379:methods*; D006046:Gold; D053768:Metal Nanoparticles / Q000737:chemistry; D015335:Molecular Probes; D053758:Nanoparticles; D011506:Proteins / Q000032:analysis* / Q000737:chemistry; D012680:Sensitivity and Specificity
chemical_list: D015342:DNA Probes; D015335:Molecular Probes; D011506:Proteins; D006046:Gold