title: Detection of Carcinoembryonic Antigens Using a Surface Plasmon Resonance Biosensor.
abstract: Carcinoembryonic antigen (CEA) is an oncofoetal cell-surface glycoprotein that serves as an important tumor marker for colorectal and some other carcinomas. In this work, a CEA immunoassay using a surface plasmon resonance (SPR) biosensor has been developed. SPR could provide label-free, real-time detection with high sensitivity, though its ability to detect CEA in human serum was highly dependent on the analytical conditions employed. We investigated the influences of various analytical conditions including immobilization methods for anti-CEA antibody and composition of sensor surface on the selective and sensitive detection of CEA. The results show that anti-CEA antibody immobilized via Protein A or Protein G caused a large increase in the resonance signal upon injection of human serum due to the interactions with IgGs in serum, while direct covalent immobilization of anti-CEA antibody could substantially reduce it. An optimized protocol based on further kinetic analysis and the use of 2ndand 3rdantibodies for the sandwich assay allowed detecting spiked CEA in human serum as low as 25 ng/mL. Furthermore, a self-assembled monolayer of mixed ethylene-glycol terminated alkanethiols on gold was found to have a comparable ability in detecting CEA as CM5 with thick dextran matrix and C1 with short flat layer on gold.
authors.affiliation: Center for Intelligent Materials and Systems, University of Washington, Box 352600, Seattle, WA98195, USA.
authors.forename: Fengyu
authors.initials: F
authors.lastname: Su
authors.affiliation: Center for Intelligent Materials and Systems, University of Washington, Box 352600, Seattle, WA98195, USA.
authors.forename: Chunye
authors.initials: C
authors.lastname: Xu
authors.affiliation: Center for Intelligent Materials and Systems, University of Washington, Box 352600, Seattle, WA98195, USA. tayam@u.washington.edu.
authors.forename: Minoru
authors.initials: M
authors.lastname: Taya
authors.affiliation: Division of Biomembrane Research, Pacific Northwest Research Institute, Seattle, WA98119, USA.
authors.forename: Kimie
authors.initials: K
authors.lastname: Murayama
authors.affiliation: Laboratory of Advanced Chemical Biology, Graduate School of Advanced Life Science, Hokkaido University, Sapporo 001-0021, Japan.
authors.forename: Yasuro
authors.initials: Y
authors.lastname: Shinohara
authors.affiliation: Laboratory of Advanced Chemical Biology, Graduate School of Advanced Life Science, Hokkaido University, Sapporo 001-0021, Japan.
authors.forename: Shin-Ichiro
authors.initials: SI
authors.lastname: Nishimura
keywords: Surface plasmon resonance (SPR); carcinoembryonic antigen (CEA).; early detection of cancer