Dalibor Matysek

Correlation Between Magnetic Susceptibility and Heavy Metal Concentrations in Forest Soils of the Eastern Czech Republic

Magnetic susceptibility measurements were performed on 2,000 samples of forest soils from the Ostrava-Karvina industrial region (Czech part of Upper Silesian Coal Basin) and the Moravian-Silesian Beskydy Mountains and their piedmont area, Podbeskydi. Concentrations of selected elements were determined in 1,200 samples from the same set. Industrial facilities (metallurgical industry and power plants) located in this region represent major sources of both magnetic particles and risk elements contaminating soils within the industrial region and neighboring mountainous areas. The magnetic susceptibility has a closely correlated relationship with Zn, Fe, As, Pb and Cu concentrations in soils. The magnetic susceptibilities vary inversely with distance from the sources. The behavior of individual chemical elements during transport and deposition was studied by means of ratios of concentrations of elements and values of magnetic susceptibility. Metals correlating very closely with magnetic susceptibility (Fe and Zn) were deposited together with dust particles, whereas Pb, As, and trace amounts of Zn can create independent particles which are components of long distance transport and deposition. The concentrations of Pb, As and, in part, Zn in soils are strongly dependent on the elevation of the sampling site; in the uppermost parts of mountains they are enriched. Other studied elements show neither relationship with sources of air pollution, nor with the geomorphology of the area. Concentrations of chemical elements V, Cr, Rb, Sr, U, Zr, Ca, Bi, Mn and Ti are related mostly to underlying sedimentary rocks.

Biodegradable, pH-responsive chitosan aerogels for biomedical applications

Novel pH-responsive biodegradable chitosan aerogels for biomedical applications were developed. Prepared from propylene glycol and bioactive acids under MW conditions hydrogels were transformed into aerogels by lyophilisation. Obtained materials were characterized with FT-IR spectroscopy and SEM imaging. Biodegradability, bioactivity and pH response were analysed. An anticancer drug release profile was investigated.

Microwave-assisted synthesis and characterization of antibacterial O-crosslinked chitosan hydrogels doped with TiO2 nanoparticles for skin regeneration

Abstract Tissue engineering provides alternative solutions to traditional transplantation. In this study a novel strategy of chitosan scaffolds obtainment based on selective O-crosslinking using Aspartic acid and the addition of TiO2 nanoparticles is presented. Prepared under microwave conditions biomaterials were of increased mechanical and thermal durability thanks to NPs presence comparing to pure chitosan. Moreover porous scaffolds maintained antimicrobial activity against S. Aureus and E. Coli. Biomaterials were susceptible to in vitro biodegradation and degradation. Hydrogels exhibited positive impact on proliferation activity of fibroblasts. Thus they may be applied as 3D scaffolds in tissue engineering focused on wound healing. GRAPHICAL ABSTRACT

Microwave-assisted synthesis and characterization of bioactive chitosan scaffolds doped with Au nanoparticles for mesenchymal stem cells culture

ABSTRACT In this work we present a novel strategy for chitosan-based scaffolds. Chitosan is a versatile biopolymer obtained from waste biomass known of its favorable biological properties. Thus it can replace other polymers in the preparation of bioactive scaffolds. To increase its durability chitosan can be crosslinked into form of the hydrogel yet application of toxic crosslinkers may lead to loss of biocompability. Mesenchymal stem cells can be used in cell therapy for advanced wound treatment. However their culture requires special biomaterials application. In this article a novel microwave-assisted synthesis method for bioactive chitosan scaffolds is presented. GRAPHICAL ABSTRACT

Magnetic sorbents biomineralization on the basis of iron sulphides

ABSTRACT Biomineralization means mineral formation under the influence of organisms. Sulphate-reducing bacteria (SRB) constitute an essential role of iron sulphide minerals precipitation. Their composition involves amorphous, non-stoichiometric or crystalline iron sulphides, weakly or strongly magnetic. Variation in environmental conditions can alter the reactive iron species within the mineral, potentially modifying their magnetic properties. Biogenic iron sulphide minerals can be used as heavy metals and toxic ions adsorbents in soil or water remediation. For these reasons, a series of laboratory-scale iron sulphide synthesis experiments with the aim to study the chemical composition, mineralogy and magnetic properties of iron sulphide precipitates were carried out using SRB under various cultivation mode and nutrient medium composition. Energy-dispersive X-ray analysis (EDX) showed formation of iron sulphides in all biogenic samples and iron phosphates in abiotic controls. Results of X-ray diffraction analysis (XRD) in biomineralized samples confirmed nanocrystalline greigite, mackinawite and sulphur alpha. Magnetic measurements showed that sample prepared by static cultivation without addition of fresh nutrient medium was the most magnetic, magnetic hysteresis of sample formed under semicontinuous mode without any nutrient supply was the lowest. Abiotic samples contained only vivianite and they did not prove any significant response to magnetic field.

Biodegradable, pH-sensitive chitosan beads obtained under microwave radiation for advanced cell culture

A new type of promising chitosan beads with advanced properties were obtained under microwave radiation according to Green Chemistry principles. Biomaterials were prepared using chitosan as raw material and glutamic acid/1,5-pentanodiol mixture as crosslinking agents. Additionally beads were modified with Tilia platyphyllos extract to enhance their antioxidant properties. Beads were investigated over their chemical structure by FT-IR analysis. Also their morphology has been investigated by SEM method. Additionally swelling capacity of the obtained hydrogels was determined. Lack of cytotoxicity has been confirmed by MTT assay. Proliferation studies were carried out on L929 mouse fibroblasts. Advanced properties of the obtained beads were investigated by studying pH sensitivity and antioxidant properties by DPPH method. Also susceptibility to degradation and biodegradation by Sturm Test method was evaluated. Results shows that proposed chitosan beads and their eco-friendly synthesis method can be applied in cell therapy and tissue engineering.

Problems with utilisation of engineering wood for energy purposes

Waste engineering wood in the form of chipboard and plywood is a potential source of renewable energy in boilers for biomass combustion. The conditions causing the silicate melt slagging during combustion were studied by proximate analysis, mineralogical analysis using X-ray diffraction, scanning electron microscope with energy dispersive analyser and thermogravimetry. Slags are formed by refractory mineralogical phases of Ca, Si, Ti and Al.