Biomedical subjects

Michał Szumski

Publications and source records attributed to Michał Szumski.

4 recordsLinked to original sources

PubMed2006

Considerations on influence of charge distribution on determination of biomolecules and microorganisms and tailoring the monolithic (continuous bed) materials for bioseparations.

The importance of continuous beds (monoliths) as separation materials is connected with their better chromatographic properties and easier preparation in comparison to particulate-packed columns. Moreover the tuning of porosity as well as surface chemistry can lead to obtaining of highly selective materials, especially useful in separation of biologically important compounds or even microorganisms. To obtain high selectivity for such analytes as e.g. proteins, it is often important to have a knowledge about their shape, size, charge and finally charge distribution. This article presents our considerations on the charge distribution on the monolithic stationary phase and surface of such species as proteins or microorganisms as well as its eventual influence on the separation or sample preparation processes and tuning of their selectivity.

Animals↗

PubMed2005

Separation of microorganisms using electromigration techniques.

Like other colloidal particles bacteria have a surface charge that originates from the ionization of surface molecules and of the adsorption of ions from solution. Bacterial cell wall and membranes containing numerous proteins, lipid molecules, teichoic acids, lipopolisaccharides which give them characteristic charge. Therefore, bacterial cells undergo electrophoresis in a free solution with their own mobility depending on ionic strength and pH of buffer solution. Various electromigration techniques can be used to separate and determine the intact cells. Successful separation of five species of bacteria was obtained using a trimethylchlorosilane-modified capillary and a divinylbenzene-modified with suppressed EOF over a short distance (8.5 cm). The utilization of coated capillaries prevents adsorption of bacteria to the capillary wall. Another approach is utilization of a dilute dissolved polymer, polyethylene oxide (PEO) in the running buffer as a non-bonded coating for the purpose of altering the EOE These experiment have proved the possibility of diagnosing a variety of diseases and the ability to separate and identify viable cells.

Bacteria↗

PubMed2004

Study of electroosmotic flow in packed capillary columns.

The aim of the work was to find the relationship between the structure of the stationary phase and the velocity of the electroosmotic flow (EOF) that it can generate. The attention was paid to the dependence of the electroosmotic mobility (microEOF) on such parameters as: (i) coverage density of a series of specially synthesized C18 stationary phases with/without end-capping, with monomeric/polymeric architecture; (ii) the length of the alkyl chain in the alkylamide (AP) bonded phase (the phases studied were AP with: C1, C5, C6, C7, C8, C12 and C18 alkyl chains) and the effect of the presence of amide and residual amine groups; (iii) the effect of the mobile phase composition on the EOF; (iv) the effect of pH on the EOF. The obtained results have shown that there is no direct relationship between silanol activity (Galushko test) and electroosmotic mobility for C18 phases. The deterioration of the EOF has been observed for AP phases at high pH values. This effect has been attributed to the presence of hydrolytic pillow, which is connected with the sorption of water from hydro-organic mobile phases.

Chromatography, Micellar Electrokinetic Capillary↗

PubMed2004

Molecularly imprinted polymers: a new tool for separation of steroid isomers.

Molecularly imprinted polymers hold great promise for the separation of chiral compounds. A non-covalent approach to the synthesis of MIPs relies on the presence of specific and non-specific interactions, which lead to the formation of a molecular imprint. The structural differences between 17-alpha-estradiol and 17-beta-estradiol are too small to permit their efficient separation on a MIP prepared with beta-estradiol as a template. Molecular modeling revealed the presence of only one hydrogen bond that differentiates the two isomers.

Chromatography↗