title: Sensitive detection of C-reactive protein in serum by immunoprecipitation-microchip capillary gel electrophoresis.
abstract: Sepsis represents a significant cause of mortality in intensive care units. Early diagnosis of sepsis is essential to increase the survival rate of patients. Among others, C-reactive protein (CRP) is commonly used as a sepsis marker. In this work we introduce immune precipitation combined with microchip capillary gel electrophoresis (IP-MCGE) for the detection and quantification of CRP in serum samples. First high-abundance proteins (HSA, IgG) are removed from serum samples using affinity spin cartridges, and then the remaining proteins are labeled with a fluorescence dye and incubated with an anti-CRP antibody, and the antigen/antibody complex is precipitated with protein G-coated magnetic beads. After precipitation the complex is eluted from the beads and loaded onto the MCGE system. CRP could be reliably detected and quantified, with a detection limit of 25 ng/μl in serum samples and 126 pg/μl in matrix-free samples. The overall sensitivity (LOQ = 75 ng/μl, R(2) = 0.9668) of the method is lower than that of some specially developed methods (e.g., immune radiometric assay) but is comparable to those of clinically accepted ELISA methods. The straightforward sample preparation (not prone to mistakes), reduced sample and reagent volumes (including the antibodies), and high throughput (10 samples/3 h) are advantages and therefore IP-MCGE bears potential for point-of-care diagnosis.
authors.affiliation: Institute of Chemical Technologies and Analytics, Vienna University of Technology, A-1060 Vienna, Austria.
authors.forename: Ela
authors.initials: E
authors.lastname: Herwig
authors.affiliation: Institute of Chemical Technologies and Analytics, Vienna University of Technology, A-1060 Vienna, Austria.
authors.forename: Martina
authors.initials: M
authors.lastname: Marchetti-Deschmann
authors.affiliation: Agilent Technologies R&D and Marketing GmbH & Co. KG, D-76337 Waldbronn, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Wenz
authors.affiliation: Agilent Technologies R&D and Marketing GmbH & Co. KG, D-76337 Waldbronn, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Rüfer
authors.affiliation: Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, A-1200 Vienna, Austria.
authors.forename: Heinz
authors.initials: H
authors.lastname: Redl
authors.affiliation: Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, A-1200 Vienna, Austria.
authors.forename: Soheyl
authors.initials: S
authors.lastname: Bahrami
authors.affiliation: Institute of Chemical Technologies and Analytics, Vienna University of Technology, A-1060 Vienna, Austria. Electronic address: guenter.allmaier@tuwien.ac.at.
authors.forename: Günter
authors.initials: G
authors.lastname: Allmaier
mesh_terms: D002097:C-Reactive Protein / Q000032:analysis*; D046209:Electrophoresis, Microchip / Q000379:methods*; D006801:Humans; D047468:Immunoprecipitation / Q000379:methods; D057230:Limit of Detection; D019095:Point-of-Care Systems; D018805:Sepsis / Q000097:blood; D044967:Serum / Q000737:chemistry
chemical_list: D002097:C-Reactive Protein
keywords: C-reactive protein; CGE-on-a-chip; Immunoprecipitation; Lab-on-a-chip; Microchip; Sepsis