Monoclonal antibody--gold biosensor chips for detection of depurinating carcinogen--DNA adducts by fluorescence line-narrowing spectroscopy

Anal Chem. 2000 Aug 15;72(16):3709-16. doi: 10.1021/ac000472w.

Abstract

A new direct readout methodology for detection and quantitation of fluorescent carcinogen-DNA adducts is described. It combines the binding specificity of an immobilized monoclonal antibody (MAb) with high-resolution, low-temperature fluorescence spectroscopy. The MAb, which is covalently bound to a gold surface via a chemisorbed disulfide coupling agent, binds the adduct of interest in an aqueous sample. Laser-induced fluorescence under nonline narrowing (FNLN) and line-narrowing (FLN) conditions was used to detect (benzo[a]pyren-6-yl)guanine (BP-6-N7Gua) bound to immobilized MAb. At room temperature, the BP-6-N7Gua fluorescence was not detected, most likely because of quenching by the gold surface and/or efficient dynamical quenching. However, fluorescence was observed at room temperature when the surface was covered with a thin layer of glycerol, and possible reasons for the fluorescence enhancement are considered. Lowering of the temperature to 77 K led to nearly an order of magnitude increase in fluorescence intensity. Highly structured FLN spectra obtained at 4.2 K allowed for definitive adduct identification. The potential of this methodology for risk assessments of individuals exposed to polycyclic aromatic hydrocarbons is discussed.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antibodies, Monoclonal / chemistry*
  • Antibodies, Monoclonal / immunology
  • Antibody Specificity
  • Biosensing Techniques*
  • Carcinogens / chemistry*
  • DNA Adducts / analysis*
  • DNA Adducts / immunology
  • Gold / chemistry*
  • Microscopy, Atomic Force / methods*
  • Spectrometry, Fluorescence / methods*

Substances

  • Antibodies, Monoclonal
  • Carcinogens
  • DNA Adducts
  • Gold