Numerical simulations of surface plasmon resonance system for monitoring DNA hybridization and detecting protein lipid film interactions

This paper presents a simple method to extract information about thin organ ic films from surface plasmon resonance (SPR) spectra. From numerical simul ations it was found that a shift (Delta theta(SPR)) of an absorption peak i n the SPR spectrum was directly proportional to the product of the thin org anic film thickness and the refractive index difference between the thin or ganic film and a buffer soaking the sample. It was also found that Delta th eta(SPR) was not sensitive to the thin organic film support of a gold film and a glass cover slip. Relationships between Delta theta(SPR) and distribu tions of macromolecule structures, in the thin organic films were theoretic ally established. Formulae were derived for a homemade SPR system to calcul ate length, transverse area, density and surface concentration of macromole cules in the thin organic film. The validity of these treatments was checke d by precisely measuring the size of a single distearoylphosphatidylcholine molecule on a gold-supported phospholipid film; by quantitatively monitori ng hybridization of synthesized oligonucleotides strands based on a biotin/ avidin system; and by quantitatively detecting the steric hindrance of rabb it C-reactive protein specifically bound to phospholipid monolayers compose d of synthesized lipids.