The effect of low pH on the glycitein-BSA conjugate interaction with specific antiserum: competitive inhibition study using surface plasmon resonance technique

Competitive inhibition serological assay for detection of the phytoestrogen glycitein (Glyc) was developed using surface plasmon resonance (SPR) technique with protein conjugates and polyclonal antibodies initially designed for the enzyme-linked immunosorbent assays (ELISA). The efficiency of the approach to the quantification of the soy isoflavone glycitein in water was investigated using the competitive reaction of analyte (free Glyc)and immobilized Glyc-BSA-conjugate with polyclonal antibodies. It was shown that the efficiency to detect Glyc drastically depends on the pH level of the probe solution. With the decrease in pH from 7.4 to 4.0, (i) the affinity of the specific reaction increases and (ii) the level of unspecific sorption becomes saturated. Non-specific adsorption to a SPR sensor surface obscures the specific component and shaded specific response at higher pH (6.0-7.4) when used serum for the quantification of specific analytes. The standard curves obtained in acidic solutions (pH 4-5) indicate that the linear part of the dependence completely covers the range between detection limit (0.1 μg/ml) and Glyc solubility in water (0.9 μg/ml). The difference in SPR- and ELISA-based analytical protocols as well as the requirements for increasing the efficiency in quantitative SPR analysis using purified antibodies is discussed.     

Monomolecular Langmuir-Blodgett layers and films based on an amphiphilic nickel(II) macrocyclic complex

A study has been made on the behavior of a complex formed by nickel(II) with the amphiphilic macrocyclic ligand 6-n-octadecyl-1,4,6,8,11-pentaazacyclotetradecane on the surface of water, and the Langmuir-Blodgett technology has been used to deposit films of that compound on glass substrates with and without electrically conducting coatings (SnO₂). Some optical characteristics of these sandwich structures have been examined.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 30, No. 1, pp. 45–49, January–February, 1994.     

Resonant Optical Phenomena in Heterogeneous Plasmon Nanostructures of Noble Metals: A Review

Theoretical and Experimental Chemistry - The interaction of electromagnetic radiation with ordered and disordered arrays of noble metal nanoparticles, leading to the excitation of various modes of...     

SPR Study of the Blocking Activity of Soybean Trypsin Inhibitor by Macrocyclic Complexes of Nickel Immobilized on a Gold Surface

A method is proposed for the modification of metallic gold surfaces by self-organization of a nickel(II) macrocyclic complex containing a thiol substituent. Effective blocking of biologically active soybean trypsin inhibitor by the immobilized complex was observed. The prospects of using the given surface to create sensitive elements for sensors capable of detecting both small molecules (thiocyanate ions) and some protein substrates is demonstrated.     

Contribution of charge-transfer complexes to the structure of electronic states of dibenzotetraazaannulene in the crystalline phase

Based on analysis of the electronic absorption spectra and study of thin films, we have established the characteristic features of electronic processes involving participation of intermolecular charge transfer processes in crystalline dibenzotetraazaannulene. We have shown that the specific spectral characteristics of this compound are connected with the presence of pre-dimer pairs of molecules in the solid state.L. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, 31 Nauki Prospekt, Kiev 252039, Ukraine. Translated from Teoreticheskaya i Éksperimertal'naya Khimiya, Vol. 32, No. 3, pp. 163–167, May–June, 1996. Original article submitted July 4, 1995.     

Effect of macrocyclic nickel(II) and copper(II) complexes on the reaction of trypsin with a soybean bioinhibitor

The blocking effect of nickel(II) azamacrocyclic complexes in the biospecific reaction between soybean trypsin inhibitor and trypsin and the absence of such a reaction for related copper(II) complexes were established. The efficiency for inhibition of the formation of the protein adduct was found to depend on the substituents in the macrocyclic ligands. In particular, electron-donor oxygen-containing groups lead not only to efficient blocking of this reaction but also possibly to a considerable change in the conformation of the soybean trypsin inhibitor molecule. __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 44, No. 4, pp. 248–253, July–August, 2008.