Interaction in ionic surfactant/non-ionic surfactant/polyelectrolyte system

V této bakalářské práci byly zkoumány interakce v systému ionogenní tenzid/neionogenní tenzid/polyelektrolyt. Pomocí fluorescenční spektroskopie byla stanovena hodnota CMC kationaktivního didecyldimethylamonium chloridu (DDAC) ve třech různých prostředích s použitím fluorescenčních sond (pyren, perylen, nilská červeň). Dále byla stanovena hodnota CMC neionogenního oktylphenol ethoxylátu (Triton X-100) pomocí pyrenu a perylenu jako fluorescenčních sond. Bylo zkoumáno agregační chování neionogenního a ionogenního tenzidu s přídavkem polyelektrolytu poly(4-styrensulfonátu) sodného (PSS) a nativního hyaluronanu ve vodném prostředí s použitím pyrenu jako fluorescenční sondy. Pomocí zhášení fluorescence bylo stanoveno agregační číslo v systému ionogenní/neionogenní tenzid. Jako zhášeč byl použit cetylpyridium chlorid (CPC) a jako zhášená molekula pyren. Bylo zjištěno, že v systému ionogenní tenzid/neionogenní tenzid/polyelektrolyt docházelo k interakcím, což dokazuje i dvojzlomová sigmoidní křivka Boltzmannova typu. Přídavek nízkomolekulárního i vysokomolekulárního hyaluronanu nemělo na hodnotu CMC v systému ionogenní/neionogenní tenzid významný vliv.The interactions in an ionic surfactant/non-ionic surfactant/polyelectrolyte system have been studied in this bachelor thesis. The value of critical micelle concentration of cationic didecyldimethylammonium chloride (DDAC) has been determined in three different mediums by fluorescence spectroscopy using Pyrene, Perylene and Nile red as probes. The CMC value of non-ionic octylphenol ethoxylate (Triton X-100) has been determined using Pyrene and Perylene as probes. The aggregation behavior of non-ionic and ionic surfactant with addition of polyelectrolyte poly(sodium4-styrensulfonate) (PSS) and native hyaluronan in aqueous solution has been investigated using Pyrene as a probe. Aggregation number in system of ionic/non-ionic surfactant has been determined by a fluorescence quenching with cetylpyridium (CPC) as a quencher and Pyrene as a fluorescence probe. Interactions in ionic surfactant/non-ionic surfactant/polyelectrolyte system were observed. This result was proved by double sigmoid Boltzman´s type curve. The addition of low molecular as well as high molecular hyaluronan had no significant effect on CMC value of the system.

Colloidal particles marked with biopolymer

V této diplomové práci byl studován vliv hydrofobně modifikovaného hyaluronanu na agregaci tenzidů. Pomocí fluorescenční spektroskopie byla stanovena hodnota CMC aniontového tenzidu SDBS (dodecylbenzensulfonát sodný), kationtového tenzidu CTAB (cetyltrimetylamonium bromid) a neionogenního tenzidu Triton X-100 (oktylfenolethoxylát) pomocí pyrenu jako fluorescenční sondy. Dále bylo zkoumáno agregační chování jednotlivých tenzidů s přídavkem hydrofobizovaného hyaluronanu o dvou molekulových hmotnostech (17 kDa, 206 kDa) v prostředí vody. Největší vliv hydrofobizovaného hyaluronanu na agregační chování byl zaznamenán u kationaktivního CTAB. V systému obsahující kationtový tenzid a hydrofobizovaný hyaluronan byla pomocí zeta potenciálu zjištěna stabilita. V poslední části diplomové práce byly v tomto systému určeny velikosti částic metodou dynamického rozptylu světla.The effect of hydrophobically modified hyaluronan on surfactants aggregation has been studied in this master’s thesis. The value of critical micelle concentration of anionic surfactant SDBS (sodium dodecylbenzensulfonate), cationic surfactant CTAB (cetyltrimethylamonnium bromide) and nonionic surfactant Triton X-100 (octylphenol ethoxylate) was determined by fluorescence spectroscopy using pyrene probe. Aggregation behavior of surfactants was performed with addition of hydrophobically modified hyaluronan of two molecular weights (17 kDa, 206 kDa) in aqueous solution. The greatest influence of hydrophobized hyaluronan on aggregation behavior was observed in system with cationic surfactant CTAB. Stability of system containing cationic surfactant and hydrophobically modified hyaluronan was established through zeta potential. Last part of thesis deals with size determination using dynamic light scattering.

Glycoprofiling of cancer biomarkers: Label-free electrochemical lectin-based biosensors

Glycosylation of biomolecules is one of the most prevalent post- and co-translational modification in a human body, with more than half of all human proteins being glycosylated. Malignant transformation of cells influences glycosylation machinery resulting in subtle changes of the glycosylation pattern within the cell populations as a result of cancer. Thus, an altered terminal glycan motif on glycoproteins could provide a warning signal about disease development and progression and could be applied as a reliable biomarker in cancer diagnostics. Among all highly effective glycoprofiling tools, label-free electrochemical impedance spectroscopy (EIS)-based biosensors have emerged as especially suitable tool for point-of-care early-stage cancer detection. Herein, we highlight the current challenges in glycoprofiling of various cancer biomarkers by ultrasensitive impedimetric-based biosensors with low sample consumption, low cost fabrication and simple miniaturization. Additionally, this review provides a short introduction to the field of glycomics and lectinomics and gives a brief overview of glycan alterations in different types of cancer.Slovak research and development agency APVV 0282-11 and VEGA 2/0162/14 is acknowledged. The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Program (FP/2007-2013)/ERC Grant Agreement no 311532 and this work has received funding from the European Union’s Seventh Framework Program for research, technological development and demonstration under grant agreement no 317420.This publication was made possible by NPRP grant # 6-381-1-078 from the Qatar National Research Fund (a member of Qatar Foundation)