Title of thesis: Testing of adhesive properties of plasticized polyesters using rotational rheometer Author: Ogadah Chiazor Ugo Department: Pharmaceutical Technology Supervisor: PharmDr. Eva Šnejdrová, Ph.D. In this thesis, the rheological and adhesive properties of three polyesters intended for use as drug carriers in polymeric drug delivery systems were studied. The theoretical section summarizes the polymers used as drug carriers. Plasticizers, mechanism of action, types and uses and finally bioadhesion mechanism, application of the bioadhesive preparations, and methods of testing bioadhesion are reviewed. In the experimental section, ethyl salicylate, ethyl pyruvate and triethyl citrate were selected as the plasticizers to decrease the viscosity of the polyesters for easy processability, and setting of the optimal adhesive properties. Flow properties of the plasticized systems was measured with a rotational rheometer at temperature 37o C and a shear rate range from 0.10 to 100 s-1 . The analysis of the viscosity curves revealed that the resulting plasticized systems are mostly Newtonian. All tested plasticizers decrease the viscosity of the systems. The most effective is ethyl pyruvate. The adhesive properties were determined by the "pull away test" on the rotational rheometer, and evaluated as...

No description available.

No description available.

No description available.

No description available.

No description available.

The state of adhesion of bacteria to nanofiber-textured model surfaces is analyzed at single-cell level. The results reveal similarities between the effect of topography on bacteria-surface interactions and vesicle-surface interactions. The results are discussed in the context of controlling bacterial adhesion to surfaces using nanofibrous topographical features. / Master of Science

Lung cancer has the highest mortality rate relative to all types of cancers, and unfortunately there still exist numerous challenges towards decreasing this rate. One of these challenges is gaining a clear understanding of why metastatic lung cancer cells attach and detach to colonize other areas of the body. Reports suggest that the attachment of cells to secondary tumor sites does not occur randomly. It is theorized that both the physical and chemical properties of the tissue are able to create a suitable environment for their adhesion. Therefore, the motivation for the work presented herein is to use dynamic thermoresponsive polymer surfaces as a tool towards unraveling this seemingly mysterious behavior of metastatic cancer cells. This type of polymer is able to swell and deswell as a function of temperature. As such, spin-cast thin films of this polymer provide for topographies that have been used to investigate how highly metastatic lung cancer cells are able to rearrange their structure, specifically the cytoskeleton. Changes in cell to surface anchorage as a function of thin film structure can also monitored. One of the most studied reversibly binding surfaces is poly(Nisopropylacrylamide) (PNIPAAm), which has been considered for the past two decades as a non-destructive method for the harvest of confluent cell sheets. As a result of this property, a series of photocrosslinkable copolymers based on PNIPAAm and methacroyloxybenzophenone (MaBP) have been developed. Coatings are created by spin-casting the polymer followed by ultraviolet (UV) radiation, which triggers the transition in the benzophenone groups. This leads to the formation of a biradicaloid triplet that abstracts a hydrogen from a neighboring aliphatic C-H group, leading to a stable C-C bond. The characteristics of the polymer film, i.e. thickness, pattern, and topography, can be tuned during the spin casting and subsequent exposure/ developing process.The ease of tunability of this polymer allows for the investigation of the aforementioned parameters and their possible effects on bioadhesion.

No description available.

Les huîtres présentent un cycle de vie en deux phases : les larves pélagiques s’adhérent avant de se métamorphoser pour une vie benthique.L’adhésion larvaire se fait au stade pédivéligère par sécrétion d’un bioadhésif produit par un organe spécialisé : le pied. Bien que l’huître Crassostrea gigas soit un organisme d’importance économique et écologique, et un modèle d’étude en biologie marine, le phénomène d’adhésion chez la larve pédivéligère est peu documenté. Une étude morphologique des larves pédivéligères par histologie et microscopie électronique a été réalisée, afin de décrire les glandes responsables de la sécrétion de l’adhésif. Une composition majoritairement protéique de l’adhésif a été révélée par histochimie et spectroscopie FTIR.Une analyse in silico des données transcriptomiques disponibles chez C. gigas a permis d’identifier des gènes probablement impliqués dans l’adhésion.Deux analyses protéomiques, menées sur les larves entières et l’adhésif sécrété ont permis de caractériser des protéines en lien avec la biosynthèse et la structure de l’adhésif. Une protéine de type collagène apparaît impliquée dans la structure de l’adhésif de C. gigas. Cette première approche de l’étude de l’adhésion de C. gigas, permet d’envisager la valorisation biotechnologique des molécules identifiées. Le développement d’adhésifs biomimétiques, élaborés sur le principe des bioadhésifs marins, autoriserait le collage en milieu humide, et serait une alternative aux adhésifs synthétiques qui malgré leur toxicité, dominent le marché mondial. / Oysters show a two-phase life cycle: pelagic larvae adhere before metamorphosis into benthic life. Larval adhesion occurs at the pediveliger stage by secretion of a bioadhesive produced by a specialized organ: the foot. The oyster Crassostrea gigas is an organism of economic and ecological importance, and a model for study in marine biology, but the phenomenon of adhesion in the pediveliger larvae is poorly documented. A morphological description of the pediveliger larvae by histology and electron microscopy was performed to describe the glands responsible for the secretion of the adhesive.A predominantly proteinaceous composition of the adhesive was revealed by histochemistry and FTIR spectroscopy. An in silico analysis of available transcriptomic data from C. gigas was made to identify genes probably involved in adhesion. Two proteomic analyses, performed on whole larvae and on the secreted adhesive, characterizing proteins related to biosynthesis and adhesive structure. A collagen-like protein appears to be involved in the adhesive structure of C. gigas. This first approach to the study of the adhesion of C. gigas makes it possible to consider the biotechnological enhancement of the identified molecules. Despite their toxicity, synthetic adhesives dominate the world market. The development of biomimetic adhesives, based on marine bioadhesive strategies could be an alternative, and allowing furthermore bonding in wet condition.