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Humic acids in medicine and cosmetics
Šmídová, Helena ; Sýkorová,, Ivana (referee) ; Pekař, Miloslav (advisor)
The main concern of this study was to form a web and literature search focused on the known theoretical knowledge, patent application and the actual realization, for the use of humic acids or material containing humic acids in human and veterinary medicine and cosmetics. The output is also a proposal to be promising directions in exploring these areas. The introduction deals with humic substances in general with emphasis on humic acids, history of humic chemistry and structure of humic substances. The second part deals with medical aspects, pharmacological effects and the use of humic substances in human medicine, veterinary medicine and cosmetics, also takes account of humic substances from the perspective of the environment. The task of third experimental part was to learn the basics of isolation and characterization of humic acids (measurement of IR and UV / VIS spectra and determination of moisture and ash in samples of humic acids).
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Methods for determination of hyaluronan
Černá, Lucie ; Venerová, Tereza (referee) ; Pekař, Miloslav (advisor)
This thesis deals with a summary of individual method for determining of hyaluronan concentration, especially in aqueous solutions. Selected methods were compared to their functionality in university workplace. Any functional methods may be used for many purposes in university workplace in research of materials based on hyaluronan. It has been studied usability to assess residual content of hyaluronan in supernatant of gel formed from hyaluronan and surfuctant, in this thesis. We choosed sptectrophotometric methods, especially with UV spectroscopy and IR spectroscopy. Two precipitation methods using alcian blue were also tested. As the most reliable, the least demanding and specific method seems to be the method using IR spectroscopy, thanks to it we are able to determine the concentration of HA from 0.01 %. With this method, it has been found, that if there will be located some amount of HA in supernatant, it will be below the detection limit of assay. The remanining methods were modified to help determine the concentrations of HA, but works only in aqueous solutions. A possible variation for determination of very low concentrations of HA may be the method using ELISA kits. However their cost is higher than the above-mentioned methods.
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Hyaluronan ion complexes
Cimalová, Jana ; Sedlařík, Vladimír (referee) ; Pekař, Miloslav (advisor)
This diploma thesis is focused on the study of physical and chemical properties of hyaluronan and cationic surfactant. As the cationic surfactant Septonex was used. The influence of the environment on the system, the effect of molecular weight of hyaluronan, and its concentration was studied. Then, the study of the influence and the effects of concentration of Septonex on the interaction of hyaluronan-surfactant followed. Different methods of measurement were chosen to characterize these ionokomplexes. The critical micelle concentration of the surfactant itself was measured, and then also with the addition of hyaluronan by spectrofluorimetry with fluorescent probe pyren. It was found, that hyaluronan forms gel with Septonex. On this basis, gels were prepared for three different molecular weights of hyaluronan – 300 kDa, 806 kDa and 1697 kDa. Gels were prepared in a ratio of hyaluronan – surfactant 1:1. In gels prepared in this way, the influence of environmental water and 0.15 M NaCl was studied and it was found that at 0.15 M NaCl clear gels are formed. Selected samples of the gels were then measured with oscillatory testing and the rheological behavior of gels of Septonex was studied. As the last method the turbidimetric measurement was chosen, which characterized the turbidity point in the gradual addition of Septonex to sodium hyaluronate solution. Again, the effect of the molecular weight of hyaluronan and its concentration in two environments - water and 0.15 M NaCl was evaluated. It was found that 0,15 M NaCl suppresses formation of turbidity and formation of precipitates.
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Optimalization of experimental method for study on penetration of humic acids into leaves.
Smilková, Marcela ; Pekař, Miloslav (referee) ; Sedláček, Petr (advisor)
This bachelor’s thesis is focused on the study of penetration of humic substances trough the plant cuticle. The main objective of the thesis aimed at a literature search on foliar fertilization and transport of substances in the plant leaves. According to the literature search, experimental technique was suggested and tested in order to study penetration of humic substances through the leaf cuticle. The method consists of observation of diffusion transport of humic acids between two inert agarose gels separated by the plant cuticle. Cuticles were prepared by the means of three different isolation procedures.
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Lignite hydrocolloids
Macháčková, Mirka ; Taraba, Boleslav (referee) ; Pekař, Miloslav (advisor)
This diploma thesis deals with the study of non-energy use of lignite. The main objective was to find an optimal recipe for the preparation of liquid and semi-solid (paste) hydrocolloids from the South Moravian lignite using the planetary mill and select the suitable dispersion medium with emphasis on possible use in agriculture. The used solutions were 10, 20 a 40 % w/w solutions of urea; 5, 10 a 15 % w/w solutions of citric acid; 1, 5 a 10 % w/w solutions of potassium chloride and deionized water. The best weight ratio for the preparation of lignite hydrocolloids is 1 part of lignite and 2 parts of the solution. The next part of this work is the isolation of humic acid from lignite hydrocolloids. The weight of isolated humic acids and amount of ash were compared to the used lignite hydrocolloids. Rheological behavior, particle size distribution, stability and thermal stablity of prepared lignite hydrocolloids were investigated. Correlation microscopy was used for determining elemental composition of selected location in the sample of lignite hydrocolloid.
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Development of non-energy use of lignite
Macháčková, Mirka ; Sedláček, Petr (referee) ; Pekař, Miloslav (advisor)
This bachelor thesis deals with the study of non-energetic use of lignite. The use as a sorbent is one of many possibilities. Sorption of chloride and sodium ions was carried out on natural lignite from the South Moravian, lignite washed with deionized water and lignite enriched with calcium ions. The experiments were realized monitoring pH, electrical conductivity, amounts of sodium and chloride ions in the prepared samples. Chemical oxygen demand was determined in the extract of lignite. This measurement was carried out in accordance with norm ČSN 83 0540-8 Chemical and physical analysis of waste water: Determination of dichromate oxidability. For use in agriculture were investigating the possibility of preparation of humic hydrocolloids by high speed dispergator and planetary mill. The ideal ratio of lignite and water was determined. The liquid and solid humic hydrocolloids were prepared by mechanochemical activation the lignite. These were characterized - particle size, UV-VIS spectroscopy of prepared extracts and sedimentation.
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Interactions of aminoclays with natural polyelectrolytes
Jančík Procházková, Anna ; Mravec, Filip (referee) ; Pekař, Miloslav (advisor)
This thesis deals with the preparation of products of interactions of aminoclay with natural polyelectrolytes. Sodium hyaluronate was chosen as the natural polyelectrolyte. The concentration and volume ratio of solutions of aminoclay and natural polyelectrolyte which led to the formation of any type of product were studied. The resulting coagulates were characterized by microscopy, FTIR spectroscopy and rheology. Furthermore the possibility of interactions with fluorescent probes was studied.
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Theranostic systems in sonography
Říkovská, Klára ; Pekař, Miloslav (referee) ; Mravec, Filip (advisor)
This work deals with preparation of microbubble suspension from a mixture of phospholipids, palmitic acid and polyethylene glycol. Properties of prepared systems were studied using bubble tensiometry and dynamic light scattering method and were compared with commercial contrast agent SonoVue®. Suspensions were prepared in various conditions including different atmosphere and increased temperature in some steps of preparation and different solution. Effect of polyethylene glycol addition on surface activity of the system was studied. Surface activity of phospholipids was insignificant. Surface tension decreased with increasing concentration and molecular weight of polyethylene glycol in the system. Effect of different atmosphere and increased temperature showed no substantial trend. It emerged that dynamic light scattering is not suitable for this type of samples because of high polydispersity and phase separation of the system.
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Modification of Biodegradable Polyurethanes by Biologically Active Substances
Kupka, Vojtěch ; Khunová, Viera (referee) ; Pekař, Miloslav (referee) ; Vojtová, Lucy (advisor)
Předkládaná dizertační práce se zabývá novým způsobem přípravy biodegradabilních polyuretanů (PU) a jejich modifikací biologicky aktivními celulózovými nanokrystaly. Literární rešerše se zaměřuje na bioresorbovatelné PU v tkáňovém inženýrství. Shrnuje příklady těchto PU elastomerů, skafoldů (nosičů buněk) i injektovatelných PU společně se způsoby biodegradace na netoxické produkty. Poslední část je zaměřena na nanocelulózu, která si získala pozornost díky svým pozoruhodným fyzikálním (velký specifický povrch, mechanické vlastnosti) a biologickým (biokompatibilita, biodegradabilita a nízká toxicita) vlastnostem jako materiál pro biomedicínu. V experimentální části byly charakterizovány amfifilní biodegradovatelné polyuretanové filmy (bio-PU) syntetizované bez použití rozpouštědla polyadiční reakcí z hydrofilního poly(ethylenglykolu) (PEG) a hydrofobního poly(e-kaprolaktonu) (PCL) jako makrodiolů společně s hexamethylen diizokyanátem. Připravené bio-PU filmy byly charakterizovány pro různé poměry jak mezi PEG/PCL, tak i mezi NCO/OH reagujícími skupinami (izokyanátový poměr). Bio-PU filmy projevily markantní nárůst mechanických vlastností při hmotnostním poměru PEG/PCL rovnému nebo menšímu než 20/80 díky vzniku krystalických domén PCL. Přítomnost PEGu zvyšovala schopnost bio-PU filmu absorbovat vodu i urychlila jeho hydrolytickou degradaci. Oproti tomu nižší absorpční schopnost a delší čas hydrolytické degradace materiálu způsobil vyšší izokyanátový poměr, a tedy i vyšší síťová hustota. Třetí část práce se zabývá přípravou polyuretanových nanokompozitů unikátní metodou bez použití rozpouštědla za využití bio-PU matrice a celulózových nanokrystalů buď nemodifikovaných, nebo povrchově roubovaných PEGem. Strukturní analýza prokázala, že přítomnost tyčinkovitých nanočástic způsobuje imobilizaci polymerních segmentů, v důsledku čehož se zvýšila tuhost a křehkost materiálu. Nastavením vhodného poměru mezi PEG/PCL, množstvím izokyanátu, či přídavkem modifikovaného nanoplniva může být bio-PU materiál "ušit na míru" s vhodnými mechanickými (houževnatost, tažnost) a fyzikálními (botnání, degradace) vlastnostmi. Díky přípravě bez použití rozpouštědla by mohly být připravené materiály využity v regenerativní medicíně např. jako cévní štěpy.
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Hyaluronane interactions with hydrophobic solutes
Slezáková, Dagmar ; Knotková,, Kateřina (referee) ; Pekař, Miloslav (advisor)
The diploma thesis is based on the study of hydrophobic interactions of the native hyaluronan with selected solutes. On the basis of a literature search were chosen fluorescent probes and fluorescing biologically active substances, which are useful for investigation of colloids as 6-(p-toluidino)-2-naphthalenesulfonic acid (polarity probe), lipophilic vitamin (±)-alpha-tocopherol, pyrene (polarity probe) and finally hydrophilic vitamin riboflavin. In the experimental part of this thesis was studied the influence of solvents with different polarities, or more precisely dielectric constant, on the emission spectra, as well. There were investigated interactions of native hyaluronan with TNS and then interactions, which were influenced by the ionic strength. Such influenced interactions were not observed, that was probably due to the strong solvation´s wrapping of the hyaluronan. Interactions were observed after the process of lyophilisation followed-up by the rehydratation of the samples. For the next study of interactions the riboflavin was chosen and was investigated the REES effect in the native hyaluronan in different concentrations of its different molecular weights. In this case were not observed any shifts in the emission maximum with the excitation wavelenght shift and that is why the interactions of hyaluronan with riboflavin were not demonstrated in the field of chosen concentrations. By using another probe alpha-tocopherol was investigated the associative behaviour of hyaluronan and moreover was observed anisotropy of alpha-tocopherol in different concentrations of different molecular weights of native hyaluronan. The anisotropy reached high values in contrast to the reference solute that was the mixture of glycerol and ethanol. The anisotropy depended more on the molecular weight than on the concentration of hyaluronan. Interactions of hyaluronan were also studied by using the polarity probe pyrene in different concentrations of different molecular weights of the hyaluronan. The pyrene 1:3 ratio did not show the concentration dependence within the chosen concentrations except for the molecular weight 253.9 kg mol–1. Both probes alpha-tocopherol and pyrene were performed by the process of lyophilisation followed-up by the rehydratation, which improved interactions of these probes with hyaluronan.
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