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Optimization of hydrogel carrier for assessment of antimicrobial activity of biocidal surfaces
Antálek, Adam ; Jančovičová, Viera (referee) ; Králová, Marcela (advisor)
This diploma thesis deals with the optimization of the composition and properties of hydrogels as carriers of microbial populations for the evaluation of the antimicrobial effects. There are standardized procedures for assessing antimicrobial surfaces, but they have shortcomings, such as the necessity of testing exclusively under laboratory conditions. In the presented work, a new evaluation methodology is proposed, which utilizes a modified resazurin test and hydrogels as platforms for bacterial seeding, enabling the assessment of the investigated antimicrobial surface. The composition and properties of hydrogel carriers were successfully optimized with respect to their swelling and mechanical properties, thereby improving recovery compared to standardized procedures. Tests on antimicrobial materials showed that the bacteria used on hydrogels continued to grow, rendering the use of composite hydrogels for this application impractical.
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Study of transport processes using microrheological techniques in hydrogels
Píšová, Denisa ; Kráčalík, Milan (referee) ; Smilek, Jiří (advisor)
This diploma thesis is focused on the determintaion of viscoelastic properties of agarose hydrogels containing different polyelectrolytes by microrheological and macrorheological techniques. From microrheological techniques the dynamic light scattering was used. Firstly, the influence of different polyelectrolyte volume was studied. Then the effect of variously charged polyelectrolyte and ionic strenght on microrheological properties of agarose hydrogels were determined. Classic rheology was used to compare the results obtained using the DLS microrheology method. Finally, the results from macro- and microrheology were correlated with each other.
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Preparation and properties of agarose hydrogel with micellar domains
Sapárová, Alica ; Krouská, Jitka (referee) ; Pekař, Miloslav (advisor)
This diploma thesis was focused on the system of agarose hydrogels with micellar domains. Polysaccharide agarose was used for the preparation of hydrogel matrices. Septonex was chosen as a surfactant. The release of solubilizate from the agarose hydrogel matrix was studied with a hydrophobic dye Sudan III in order to obtain a model system of hydrophobic solubilized drugs. Sudan III was solubilized via surfactant´s micels. Subsequently, this micellar aqueous solution with the dissolved dye was used to prepare the agarose hydrogel. The system was prepared in the environment of deionized water and physiologic solution. The gradual release of the dye into deionized water and physiologic solution was studied for 22 days using the UV-VIS spectrophotometry method. It was found that after 14 days the concentration of the releasing dyes into the deionized water was decreased. The cause is that after 14 and 22 days there was a slight degradation of gels, which was detected using the rheology method. Using the rheology method it was also found that Septonex does not affect the gel formation process.
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A microemulsion-based phase-separated hydrogel
Kacvinská, Katarína ; Sedláček, Petr (referee) ; Mravec, Filip (advisor)
The main aim of the bachelor thesis is to create a microemulsion based – phase – separated hydrogel. It describes the possible mechanism of preparation, which is based on microemulsion. Microemulsion was prepared by solubilization of oil in the hydrophobic parts of cationic surfactant CTAB. Followed by phase separation with hyaluronic acid has occurred the phase – separated hydrogel. Rheological measurements show that this hydrogel decreases mechanical properties as compared to phase – separated hydrogel from micellar solution. Overall, these hydrogels with the addition of oil, reduce the viscoelastic character, decrease elastic module and possibly increase the viscosity. The higher molecular weight of hyaluronan in these modified hydrogels forms stronger and more rigid gel structures, compared to low molecular weight. The measurements show that the hydrogel containing microemulsion of olive oil improve mechanical properties, unlike the microemulsion of sunflower oil. TSCPC analysis shows formation of spherical structure in the hydrophilic part of gel. Based on the lifetimes of Nile red this may be an emulsion w/o or more complicated structure like o/w/o.
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Effect of aggregate type on lime mortar rheology
Vozák, Rastislav ; Rovnaník, Pavel (referee) ; Vyšvařil, Martin (advisor)
The subject of this bachelor thesis is examining the effect of aggregate type on lime mortar rheology. In the theoretical part, the thesis describes types of liquids and basic rheological quantities. Afterwards there are described some of the rheological behaviour models of non-Newtonian fluids. Furthermore, the theoretical part characterizes measurement of the flow, devices used for the measurement including the oscillatory measurement and its individual modes. Scientific literature was used to describe the rheology of the lime mortars and it covers the effect of different additives on the rheological behaviour. There is also characterized the effect of aggregate on the properties of lime mortars. The experimental part talks about the effect of three various kinds of aggregate on rheological prop-erties of the fresh lime mortar. The chemical composition of aggregates and their granulometry was determined. Subsequently, flow measurements were carried out and evaluated into flow curves. The yield stress, coefficient of consistency and flow index were assayed. In the oscillatory measurement there were measured complex, elastic and viscous modulus and loss factor.
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The effect of polymer microfibers on rheological and mechanical properties of calcium phosphate bone cements
Dzurov, Matej ; Montufar Jimenez, Edgar Benjamin (referee) ; Vojtová, Lucy (advisor)
Táto diplomová práca sa zaoberá mechanickými a reologickými vlastnosťami resorbovateľného polymér-fosforečnanového kompozitu na báze kostného cementu vystuženého mikrovláknami z PCL (poly(-kaprolaktón)) a Pluronic-om modifikovanými PCL vláknami. Teoretická časť popisuje štruktúru kostí, vývoj kostných cementov a štrukturálne prídavky (aditíva). V experimentálnej časti je rozoberaná syntéza a charakterizácia PLGA-PEG-PLGA termosenzitívneho kopolyméru a - modifikácie fosforečnanu vápenatého ako aj technika prípravy mikrovláken. Roztok kopolyméru bol použitý pre zlepšenie obmedzenej injektovateľnosti pasty s pomerom kvapalnej k práškovej fáze (L/P) 0,5 ml/g pre všetky vzorky. Dve rôzne techniky zamiešania pasty boli použité pre možnosť kontrolovania porozity pripraveného cementu. PCL a PCL-Pluronic vlákna využité ako výstuž boli testované v troch rôznych prídavkoch, a to 1, 3 a 5 hmotnostných percent vláken na celkovú hmotnosť pripravenej pasty. Pripravené pasty boli testované pomocou dynamickej reologickéj analýzy na reometri pri laboratórnej teplote (23 °C) a fyzologických podmienkach (37 °C) so zámerom stanoviť spracovateľnosť a tuhnutie pasty. Vzorkám na ostatok analýz bolo umožnené vytvrdzovanie pri fyziologických podmienkach po dobu 10 dní. Po vytvrdení boli testované mechanické parametre ako sú pevnosť v tlaku, Youngov modul pružnosti a pevnosť v ťahu v priemere vysušených a v niektorých prípadoch aj hydratovaných vzoriek. Porozita vzoriek bola stanovená pomocou Roentgénovej počítačovej mikro-tomografie. Rastrovacia elektrónová mikroskopia bola využitá na študovanie mikroštruktúry a zabudovanie vláken do keramickej matrice. Prítomnosť vláken bola semi-kvantitatívne stanovená pomocou Fourier transformovanej infračervenej spektroskopie. Difrakcia Roentgénového žiarenia poskytla údaje o fázovom prechode prášku a jeho mineralogickom zložení. Jednotlivé hodnoty, obdržané z jednotlivých analýz, boli medzi sebou porovnané a adekvátne diskutované. Výsledkom práce je potvrdenie mierneho zlepšenia pevnosti v tlaku vzoriek vystužených hydrofóbnymi PCL alebo amfifilnými PCL-Pluronic vláknami pričom, PCL-Pluronic vlákna poskytli lepšie výsledky. Preto bolo usúdené, že polymér-fosforečnanový kostný cement vystužený vláknami je nádejným kandidátom na uplatnenie v chirurgickej praxi.
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The effect of polymer microfibers on rheological and mechanical properties of calcium phosphate bone cements
Dzurov, Matej ; Montufar Jimenez, Edgar Benjamin (referee) ; Vojtová, Lucy (advisor)
Táto diplomová práca sa zaoberá mechanickými a reologickými vlastnosťami resorbovateľného polymér-fosforečnanového kompozitu na báze kostného cementu vystuženého mikrovláknami z PCL (poly(-kaprolaktón)) a Pluronic-om modifikovanými PCL vláknami. Teoretická časť popisuje štruktúru kostí, vývoj kostných cementov a štrukturálne prídavky (aditíva). V experimentálnej časti je rozoberaná syntéza a charakterizácia PLGA-PEG-PLGA termosenzitívneho kopolyméru a - modifikácie fosforečnanu vápenatého ako aj technika prípravy mikrovláken. Roztok kopolyméru bol použitý pre zlepšenie obmedzenej injektovateľnosti pasty s pomerom kvapalnej k práškovej fáze (L/P) 0,5 ml/g pre všetky vzorky. Dve rôzne techniky zamiešania pasty boli použité pre možnosť kontrolovania porozity pripraveného cementu. PCL a PCL-Pluronic vlákna využité ako výstuž boli testované v troch rôznych prídavkoch, a to 1, 3 a 5 hmotnostných percent vláken na celkovú hmotnosť pripravenej pasty. Pripravené pasty boli testované pomocou dynamickej reologickéj analýzy na reometri pri laboratórnej teplote (23 °C) a fyzologických podmienkach (37 °C) so zámerom stanoviť spracovateľnosť a tuhnutie pasty. Vzorkám na ostatok analýz bolo umožnené vytvrdzovanie pri fyziologických podmienkach po dobu 10 dní. Po vytvrdení boli testované mechanické parametre ako sú pevnosť v tlaku, Youngov modul pružnosti a pevnosť v ťahu v priemere vysušených a v niektorých prípadoch aj hydratovaných vzoriek. Porozita vzoriek bola stanovená pomocou Roentgénovej počítačovej mikro-tomografie. Rastrovacia elektrónová mikroskopia bola využitá na študovanie mikroštruktúry a zabudovanie vláken do keramickej matrice. Prítomnosť vláken bola semi-kvantitatívne stanovená pomocou Fourier transformovanej infračervenej spektroskopie. Difrakcia Roentgénového žiarenia poskytla údaje o fázovom prechode prášku a jeho mineralogickom zložení. Jednotlivé hodnoty, obdržané z jednotlivých analýz, boli medzi sebou porovnané a adekvátne diskutované. Výsledkom práce je potvrdenie mierneho zlepšenia pevnosti v tlaku vzoriek vystužených hydrofóbnymi PCL alebo amfifilnými PCL-Pluronic vláknami pričom, PCL-Pluronic vlákna poskytli lepšie výsledky. Preto bolo usúdené, že polymér-fosforečnanový kostný cement vystužený vláknami je nádejným kandidátom na uplatnenie v chirurgickej praxi.
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Effect of aggregate type on lime mortar rheology
Vozák, Rastislav ; Rovnaník, Pavel (referee) ; Vyšvařil, Martin (advisor)
The subject of this bachelor thesis is examining the effect of aggregate type on lime mortar rheology. In the theoretical part, the thesis describes types of liquids and basic rheological quantities. Afterwards there are described some of the rheological behaviour models of non-Newtonian fluids. Furthermore, the theoretical part characterizes measurement of the flow, devices used for the measurement including the oscillatory measurement and its individual modes. Scientific literature was used to describe the rheology of the lime mortars and it covers the effect of different additives on the rheological behaviour. There is also characterized the effect of aggregate on the properties of lime mortars. The experimental part talks about the effect of three various kinds of aggregate on rheological prop-erties of the fresh lime mortar. The chemical composition of aggregates and their granulometry was determined. Subsequently, flow measurements were carried out and evaluated into flow curves. The yield stress, coefficient of consistency and flow index were assayed. In the oscillatory measurement there were measured complex, elastic and viscous modulus and loss factor.
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Preparation and properties of agarose hydrogel with micellar domains
Sapárová, Alica ; Krouská, Jitka (referee) ; Pekař, Miloslav (advisor)
This diploma thesis was focused on the system of agarose hydrogels with micellar domains. Polysaccharide agarose was used for the preparation of hydrogel matrices. Septonex was chosen as a surfactant. The release of solubilizate from the agarose hydrogel matrix was studied with a hydrophobic dye Sudan III in order to obtain a model system of hydrophobic solubilized drugs. Sudan III was solubilized via surfactant´s micels. Subsequently, this micellar aqueous solution with the dissolved dye was used to prepare the agarose hydrogel. The system was prepared in the environment of deionized water and physiologic solution. The gradual release of the dye into deionized water and physiologic solution was studied for 22 days using the UV-VIS spectrophotometry method. It was found that after 14 days the concentration of the releasing dyes into the deionized water was decreased. The cause is that after 14 and 22 days there was a slight degradation of gels, which was detected using the rheology method. Using the rheology method it was also found that Septonex does not affect the gel formation process.
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Study of transport processes using microrheological techniques in hydrogels
Píšová, Denisa ; Kráčalík, Milan (referee) ; Smilek, Jiří (advisor)
This diploma thesis is focused on the determintaion of viscoelastic properties of agarose hydrogels containing different polyelectrolytes by microrheological and macrorheological techniques. From microrheological techniques the dynamic light scattering was used. Firstly, the influence of different polyelectrolyte volume was studied. Then the effect of variously charged polyelectrolyte and ionic strenght on microrheological properties of agarose hydrogels were determined. Classic rheology was used to compare the results obtained using the DLS microrheology method. Finally, the results from macro- and microrheology were correlated with each other.
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