title: Hydrogel-microsphere-enhanced surface plasmon resonance for the detection of a K-ras point mutation employing peptide nucleic acid.
abstract: Highly-sensitive detection of a K-ras point mutation in codon 12, frequently found in pancreatic cancer, based on DNA-carrying hydrogel microspheres as a response enhancer for surface plasmon resonance (SPR), is described. Acrylamide-based microspheres with carboxyl groups were conjugated with DNA probes. Use of the DNA-carrying microsphere in the sandwich method, that is, binding of the microspheres with target DNAs at the sensor surface, enhanced the SPR response as a combined result of increased dielectric constant by the DNA-carrying microspheres. Microspheres lead to response enhancement, as shown by a 100-fold increase in sensitivity compared to that of non-amplified DNA target hybridization. In addition, the advantage of peptide nucleic acid (PNA) in the detection of a K-ras point mutation at the sensor surface by increasing temperature and flow rate is discussed. Results illustrate that the sandwich method through DNA-carrying microspheres for a SPR sensor is a promising approach for ultrasensitive DNA detection.
authors.affiliation: Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Sato
authors.forename: Shinichi
authors.initials: S
authors.lastname: Ikegaki
authors.forename: Koji
authors.initials: K
authors.lastname: Suzuki
authors.forename: Haruma
authors.initials: H
authors.lastname: Kawaguchi
mesh_terms: D015342:DNA Probes / Q000235:genetics; D011905:Genes, ras / Q000235:genetics*; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D008863:Microspheres; D009693:Nucleic Acid Hybridization; D020135:Peptide Nucleic Acids / Q000235:genetics*; D017354:Point Mutation / Q000235:genetics*; D012680:Sensitivity and Specificity; D020349:Surface Plasmon Resonance / Q000295:instrumentation* / Q000379:methods*; D013696:Temperature
chemical_list: D015342:DNA Probes; D020135:Peptide Nucleic Acids; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate