title: Aptamer-based detection and quantitative analysis of ricin using affinity probe capillary electrophoresis.
abstract: The ability to detect sub-nanomolar concentrations of ricin using fluorescently tagged RNA aptamers is demonstrated. Aptamers rival the specificity of antibodies and have the power to simplify immunoassays using capillary electrophoresis. Under nonequilibrium conditions, a dissociation constant, Kd, of 134 nM has been monitored between the RNA aptamer and ricin A-chain. With use of this free-solution assay, the detection of 500 pM (approximately 14 ng/mL) or 7.1 amol of ricin is demonstrated. The presence of interfering proteins such as bovine serum albumin and casein do not inhibit this interaction at sub-nanomolar concentrations. When spiked with RNAse A, ricin can still be detected down to 1 nM concentrations despite severe aptamer degradation. This approach offers a promising method for the rapid, selective, and sensitive detection of biowarfare agents.
authors.affiliation: Naval Research Laboratory, 4555 Overlook Avenue, SW, Chemistry Division, Code 6112, Washington, DC 20375-5342, USA.
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Haes
authors.forename: Braden C
authors.initials: BC
authors.lastname: Giordano
authors.forename: Greg E
authors.initials: GE
authors.lastname: Collins
mesh_terms: D052157:Aptamers, Nucleotide / Q000032:analysis*; D019075:Electrophoresis, Capillary / Q000379:methods*; D012276:Ricin / Q000032:analysis* / Q000737:chemistry* / Q000378:metabolism; D012278:Ricinus / Q000737:chemistry / Q000378:metabolism
chemical_list: D052157:Aptamers, Nucleotide; D012276:Ricin