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Study of stability of antimicrobial nanomaterials in different environment by HPLC
Janderová, Šárka ; Trachtová, Štěpánka (referee) ; Márová, Ivana (advisor)
This thesis deals with the preparation of nanomaterials (nanoparticles, nanofibers) with encapsulated active substances and the stability of these nanomaterials in different environments using liquid chromatography. The development and optimization of methods for monitoring the kinetics of release of encapsulated substances from nanomaterials into various environments play a key role in research aimed at their utilization in the pharmaceutical, food, and cosmetic industries, and also contribute to the development of new antimicrobial nanomaterials limiting antibiotic resistance. The theoretical part focuses on the characterization of nanomaterials (nanoparticles, liposomes, nanofibers, and combined nanomaterials). Another section of the literature review deals with natural (eugenol, carvacrol, curcumin, thymol, vitamin E) and synthetic (ampicillin, streptomycin) antimicrobial substances. The final chapter discusses the instrumental methods used for the characterization of nanomaterials and the evaluation of their stability, released, and degradation products. In the practical part, the antioxidant activity of selected substances was first monitored. Liposomes were prepared, and their stability and encapsulation efficiency were examined. An HPLC method for determining active substances was optimized. Subsequently, the gradual release of the mentioned active substances from prepared liposomes was monitored. Nanofibers were prepared using forcespinning, and their release into selected model environments was also analyzed. Distilled water with minimal ion and impurity content served as a model environment, as well as a physiological solution at 25°C, simulating the temperature of the human body surface, and a physiological solution at 37°C, characteristic of human body temperature. This analysis provides a comprehensive view of the behavior of prepared materials and their potential practical applications. In the final section, combined nanomaterials (based on nanofibers and nanoparticles) with encapsulated active substances were prepared. The gradual release of active substances and any potential synergistic effects were examined for these nanomaterials.
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Characterization of cytotoxic effect of combined antimicrobial nanomaterials
Kozlíčková, Hana ; Fialová, Lenka (referee) ; Márová, Ivana (advisor)
This thesis deals with the study of the effects of combined nanomaterials on human skin cells. Pure antimicrobial substances, two types of liposomes enriched with antimicrobial substances, nanofibers with antimicrobial substances and, finally, four types of combined nanomaterials were analyzed from the point of view of cytotoxicity. The analysed active substances were eugenol, thymol, cavarcrol, curcumin, vitamin E and the antibiotics streptomycin and ampicillin. In the theoretical part of the work, the cell line of human keratinocytes, used in the experimental part of the work for cell tests, was characterized. Furthermore, individual active substances with an antimicrobial effect were described and the principles of biological effects were described, which include antimicrobial, antioxidant, cytotoxic and synergistic effects. Additionally, the theoretical part described individual nanomaterials, their preparation and usage in cosmetics and medicine. The experimental part was based on the characterization of prepared nanomaterials and on testing the influence of individual antimicrobial substances on the proliferation and viability of human HaCaT cells. Using the DLS method, the size of the prepared liposomes was measured and the effect of PHB and the type of active substance on their size was studied. MTT and LDH tests were chosen to test the cytotoxicity of individual substances. Furthermore, a scratch test was performed to monitor the effect of the investigated substances on proliferation and the rate of wound healing by cells. The last performed tests were immune response assays, in which were tested the samples for production of the human anti-inflammatory cytokines IL-6 and IL-8. In experimental part of this thesis, it was found that the prepared nanofibrous materials are safe for use in healthcare or cosmetics and, in the future, suitable to produce nanofibrous wound coverings enriched with antimicrobial substances, which can give them exceptional properties.
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Preparation of skin masks with the anti-acne effect
Geierová, Kateřina ; Bendová, Agáta (referee) ; Márová, Ivana (advisor)
This bachelor thesis was focused on the preparation and characterization of nanofibers containing active agents with the aim of using these materials in anti-acne facial masks. The nanofibers were prepared from polyhydroxybutyrate solution and gelatin solution by electrospinning method. Among the active ingredients, eugenol and piperine were used to functionalize the nanofibers. In the theoretical part, the types of face masks, the individual active ingredients, the materials for the preparation of nanofibers, their preparation methods and their characterization were characterized. In the practical part, the antioxidant and antimicrobial activity of the active ingredients themselves was investigated. Subsequently, the release rate of selected active ingredients from the prepared nanofibers was monitored in three model environments. The antimicrobial activity of the nanofibers was monitored on three microorganisms, namely Staphylococcus epidermidis, Cutibacterium acnes and Escherichia coli.
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Preparation of nanoparticles and nanofibers for application in anti-acne products
Tilšarová, Kamila ; Veselá, Mária (referee) ; Skoumalová, Petra (advisor)
The diploma thesis was focused on the preparation and characterization of nanoparticles and nanofibres with active substances from chosen herbs with the aim to apply this materials to the products against acne. Various types of extracts were tested on the content of polyphenols, flavonoids and antioxidation activity. These extracts were encapsulated to the liposomes and fibres of polyhydroxybutyrate. Prepared liposomes and fibres were tested mainly on antioxidation activity and antimicrobial activity against the strain Propionibacterium acnes. Then, liposomes were applied to cosmetic emulsions. These creams reported high antioxidation activity and excellent stability determined by analytical centrifugation. Prepared nanofibres also reported high antioxidation activity and antimicrobial effect as well. Finally, particles and fibres were tested in contact with human cells. In appropriate concentration, there was no cytotoxic effect and tested materials can be used in applications on problems with acne.
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Preparation of nanoparticles and nanofibers with antimicrobial components
Kubišová, Veronika ; Slaninová, Eva (referee) ; Skoumalová, Petra (advisor)
This thesis addresses the problem of inadequate current wound therapy and presents a solution in the form of nanomaterial-based wound dressings (coverings). Specifically, it focuses on the development and characterization of various nanofibrous materials with integrated liposome particles that could serve as a source of therapeutic agents and be useful specifically in the field of a wound therapy. The review in the introductory part of the thesis first focused on the mentioned problem, which describes the shortcomings of existing conventional dressing materials. A description of human skin from an anatomical and functional point of view was not omitted, nor was the wound healing process itself. Different types of covering materials were also presented. However, a large part was focused on nanomaterials and their use in the field of the skin wound therapy. The nanomaterials mentioned were mainly liposome particles and nanofibres, as the experimental part of the work was focused on these structures. The description dealt with the characterization of these structures as well as the biopolymers used for their preparation. However, the aim was to prepare nanofibers with liposome content, so the method of forming such systems was described. Various therapeutic agents are also an integral part of the covering materials, especially those that suppress the development of infection and reduce wound pain; therefore, the search focused on the antibiotic ampicillin and the analgesic ibuprofen. The experimental part was devoted to the actual production of nanofibers with liposomes and also to the qualitative demonstration of the presence of liposomes in electrostatically prepared nanofibers. The selected polymeric components of these systems were polyhydroxybutyrate (PHB) and gelatine. However, the nanofibers and liposome particles (as well as combined liposomes with PHB) were first prepared in their own form and characterized mainly in terms of the gradual release of the drug substances. The results obtained were then compared with those of therapeutic drug delivery via combined nanofibrous structures with liposomes. For these combined structures, the aim was to achieve synergy in drug delivery between these systems. The aim of this work was to create a biomaterial covering with the controlled drug release. The drugs contained in these materials were the aforementioned ampicillin and ibuprofen. An important part of the work was then to determine the safety of the prepared materials which were tested for cytotoxicity, where the tests performed were MTT test and LDH test. And the actual wound healing ability of the nanofibers was then monitored in a scratch test or a "wound healing" test. At the end of the paper, recommendations for future work on this topic are given.
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Towards highly-doped Ge and ZnO nanowires: Growth, characterization and doping level analysis
Pejchal, Tomáš ; Mikulík,, Petr (referee) ; Grym,, Jan (referee) ; Kolíbal, Miroslav (advisor)
Vysoce dopovaná polovodičová nanovlákna představují nadějnou třídu nanostruktur pro budoucí aplikace v elektronice, optoelektronice nebo bio-senzorice. Tato práce se zaměřuje na přípravu a charakterizaci nanovláken germania a oxidu zinečnatého s cílem dosáhnout vysoké úrovně dopování. Úvodní část dizertační práce se zabývá přípravou germaniových nanovláken metodou VLS (pára – kapalina – pevná látka). Nejprve jsou popsány faktory ovlivňující růst nanovláken a jejich morfologii – složení katalytické částice, vliv adsorbovaných atomů či molekul a potenciální inkorporace atomů katalyzátoru do objemu nanovláken. Nanovlákna připravená ze zlatých katalytických nanočástic v podmínkách ultravysokého vakua (tzv. MBE metodou) a za přítomnosti atomárního vodíku (proces napodobující podmínky CVD metod) vykazují odlišnou morfologii a směr růstu. Tyto rozdíly odhalují kombinovaný účinek adsorpce atomárního vodíku a šíření zlatého katalyzátoru na stěny nanovláken. Tento efekt je klíčový pro vysvětlení rozdílů ve výsledné morfologii nanovláken připravených MBE a CVD metodami. Další část práce se věnuje přípravě Ge nanovláken z katalyzátorů obsahujících prvky III. skupiny a studiu jejich případné inkorporace, která by mohla vést k dopování nanovláken. Bylo zjištěno, že in-situ připravené směsné Au–Ga nanočástice lze úspěšně využít pro růst germaniových nanovláken, přestože stabilita katalyzátoru je nižší než v případě čistého zlata. I přes vysokou koncentraci gallia v katalytické částici nebyla pozorována inkorporace gallia do objemu nanovlákna. Tato metoda dopování nanovláken se tedy pro uvedenou materiálovou kombinaci ukázala jako nevhodná. Ve třetí části práce jsou popsány výsledky charakterizace ZnO nanodrátů a vývoj metody jejich difuzního dopování galliem. Je prokázán vliv žíhání nanodrátů na koncentraci kyslíkových vakancí (VO) – ve srovnání s žíháním v podmínkách vysokého vakua se koncentrace VO snižuje žíháním v plynném peroxidu vodíku. Dále je zdokumentována inkorporace gallia do ZnO nanodrátů při teplotě nad 350 °C – pozorováno pomocí in-situ SEM. Při teplotě nad 450 °C dochází ke galliem indukované dekompozici ZnO nanodrátů. K určení koncentrace a prostorového rozložení Ga atomů v nanovláknech je využito teoretického difuzního modelu a STEM EDS měření nanovláken. Byla nalezena korelace mezi koncentrací kyslíkových vakancí a inkorporací gallia do objemu ZnO nanovláken. Koncentrace gallia dosahuje řádově 10^21 cm^-3, což dokazuje vhodnost použité metody pro dosažení vysokých úrovní dopování, které jsou potřebné pro budoucí bio-senzorické aplikace v infračervené oblasti.
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PREPARATION AND CHARACTERIZATION OF BIOPOLYMER-BASED NANOPARTICLES AND NANOFIBERS AND THEIR APPLICATION IN FOOD AND COSMETICS
Kundrát, Vojtěch ; Vilčáková, Jarmila (referee) ; Kráčmar, Stanislav (referee) ; Márová, Ivana (advisor)
The presented dissertation thesis deals with the polymer polyhydroxybutyrate and other biopolymers as a basic building block for the construction of micro- and nanoscopic structures and materials used in food and cosmetics. In the theoretical part, current literary review is prepared to introduce the basics of this application field. The practical part of the work is composed of three blocks developed during the doctoral study. In the first and most important part are summarized comments to the academic and patent outputs, where among the academic ones it is possible to find two peer-reviewed articles dealing with the electrostatic and wet spinning of PHB and properties of prepared materials. The patent outputs consist of several accepted and applied projects, which summarize results on both PHB spinning methods, but also on general approaches enabling the processing of PHB into forms enabling many applications in food and cosmetics. Second part was focused on the patented composition of the UV protection cream based on the prepared nanoscopic and micro- morphologies of PHB. The third block summarizes results focused predominantly on the electrostatic spinning of PHB and other biopolymers. Finally, a short chapter containing a brief description of projects that were in a way related to the dissertation topic, but rather practical development work in Central Tanzania and West Africa, which draw on knowledge and contacts gained during studies at FCH BUT Brno.
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Piezoelectric nanofiber materials for wearable electronics
Frolíková, Štěpánka ; Škarvada, Pavel (referee) ; Macků, Robert (advisor)
This thesis deals with the influence of production parameters on the morphology of PVDF nanofibers produced by electrospinning. Nanofibers are generally a widely used material, nanofibers are generally a widely used material, they can also have piezoelectric properties, which gives them a specific spectrum of use, eg in biosensors. The production of nanofibers was realized by electrospinning. A scanning electron microscope was used to examine the morphology and surface properties. The aim of this thesis is to compare the properties of PVDF nanofibers produced under different settings of production parameters.
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Characterization of PVDF material in nanoscale resolution
Pisarenko, Tatiana ; Dallaev, Rashid (referee) ; Sobola, Dinara (advisor)
Tato práce se zabývá charakterizací nanovláken na bázi polyvinylidenfluoridu. Zaměření práce je na piezoelektrické vlastnosti vlákna, které jsou studovány metodou piezoelektrické silové mikroskopie. Takto byly měřeny dva typy odlišných vzorků, které se lišily v parametrech výroby. Odlišnosti vláken v jejich fázovém složení byly také zkoumány za využití Ramanovy spektroskopie a infračervené spektroskopie s Fourierovou transformací. Chemická analýza povrchu a jeho stavu proběhla pomocí rentgenové fotoelektronové spektroskopie. Různé uspořádání nanovláken spolu s jejich průřezem bylo pozorováno rastrovacím elektronovým mikroskopem za využití fokusovaného iontového svazku. Rovněž byla zkoumána smáčivost a kontaktní úhel povrchu vzorků s demineralizovanou vodou. Bylo zjištěno, že vyšší rychlost otáček válce během procesu elektrostatického zvlákňování má velmi významný vliv na jejich uspořádání a tím i na parametry ovlivňující tvorbu piezoelektrického jevu a dalších materiálových vlastností.
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Preparation and characterization of nanofiber wound dressings
Jiroušková, Pavla ; Uhlířová, Renata (referee) ; Skoumalová, Petra (advisor)
The presented bachelor thesis deals with the preparation and characterization of nanofiber wound dressings. The materials used for the preparation of nanofibers were poly(3-hydroxybutyrate) and gelatin. Active substances, such as ampicillin and ibuprofen, were incorporated into the wound dressings. In the theoretical part of the work skin, wound healing, and nanofibers and their properties were described. This part also deals with the use of nanofibers as wound dressings. Additionally, it depicts materials suitable for the preparation of nanofiber wound dressings. Furthermore, this section contains a review focused on various methods of preparation of nanofibers, drugs that can be incorporated into the fibers and the subsequent determination of the safety of the prepared dressings. In the experimental part, nanofiber wound dressings containing ampicillin and ibuprofen were produced. The maximum possible amount of active substance feasible to be incorporated into the nanofibers has been determined. Subsequently, combined wound dressings were prepared to study the release rate of active substances into the model environments. The release in the time intervals was determined spectrophotometrically. Finally, antimicrobial activity assays were performed to test the effect of dressings containing ampicillin on selected strains of microbiirganism: S. Epidermidis, E. Coli and M. Luteus
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