PubMed Health⌕ Search

Biomedical subjects

Vladimir M Mirsky

Publications and source records attributed to Vladimir M Mirsky.

5 recordsLinked to original sources
PubMed2006

Electrocatalytic activity of DNA on electrodes as an indication of hybridisation.

Electron transfer between metal electrodes and ferro/ferricyanide is completely suppressed at low ionic concentration. We describe here a new phenomenon related to this reaction: an immobilisation of thiolated single-stranded DNA on gold electrodes retains this activity at low ionic strength up to the level corresponding to the high ionic strength. In contrast, a hybridisation of the complementary DNA with the thiolated single-stranded DNA followed by a binding onto the electrodes, attenuated the electrocatalytic effect. These effects can be used for discrimination between single-stranded DNA and double-stranded DNA and for semi-quantitative measurement of complementary DNA in a sample.

Base Pairing↗
PubMed2005

Double-wavelength technique for surface plasmon resonance measurements: basic concept and applications for single sensors and two-dimensional sensor arrays.

A new technique for on-line monitoring of analyte binding to sensor surfaces by surface plasmon resonance (SPR) detection is described. It is based on differential measurements using two wavelengths provided by two diode lasers. The technique is as simple and robust as the conventional SPR detection measuring the reflected radiation at fixed incidence angle, but it has the advantage of being nonsensitive to variations of the resonance width and providing essentially higher signal/noise ratios. The paper presents the first four channel prototype system for parallel 2D-monitoring at four different spots. One channel is always used as a reference to compensate temperature fluctuations and nonspecific adsorptions. Calibration with sucrose solutions revealed an absolute sensitivity of Deltan approximately 5 x 10(-6). The new technique is tested with a biotin-streptavidin binding and with hybridization/denaturation of DNA. Biotin binding to a streptavidin monolayer is detected with a signal/noise ratio of about 5, which demonstrates the high potential of the new technique for applications in drug discovery. Applications to gene analysis are tested with short oligonucleotides of the sequences used for genotyping human hepatitis C viruses. A selective response to complementary oligonucleotides is observed. The high reproducibility in subsequent cycles of hybridization/denaturation (by formamide or by heating) points out potential applications of the technique in medical diagnostics, food industry, genomics, and proteomics too.

Biosensing Techniques↗
PubMed2002

A novel ultraviolet assay for testing side reactions of carbodiimides.

Carbodiimides possess considerable absorbance in the ultraviolet region; the extinction coefficient of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) in water is epsilon(214) = 6.3. 10(3) L x mol(-1) x cm(-1). It provides a very simple method for testing possible side reactions of carbodiimides. This technique was used to study effects of pH, different buffers, and other components typically present in biological samples on EDC stability. It was shown that the hydrolysis rate in pure water increased from 1.5. 10(-5) to 5. 10(-4) s(-1) by pH decreasing from 7 to 4. A strong increase of the rate of EDC loss was observed in the presence of different components. This effect can be described by the following row of hydrolysis rates: citrate >> acetate approximately phosphate >> SDS. The results can be used to optimize carbodiimide-mediated reactions of peptide bond formation in organic chemistry or peptide synthesis or during immobilization or cross-linking of biological molecules.

Buffers↗