Organo-anorganické hybridní materiály s antibakteriálními vlastnostmi

Abstract

This thesis is dealing with the preparation and characterization of organo-inorganic hybrid materials which display antibacterial activity. The clay mineral vermiculite is the main inorganic component of these materials. The organic part is represented by an organic antibacterial agent chlorhexidine diacetate. Samples of hybrid materials were prepared by intercalation of chlorhexidine into vermiculite’s structure. This work summarizes the results of four main studies during which the antibacterial activity of monoionic forms of vermiculite and their subsequently prepared organovermiculites were tested, further the influence of surface treatment of the original vermiculite on antibacterial effect of organovermiculites was studied and efficiency of ion exchange reaction of vermiculite or stability investigation of the active antibacterial component (chlorhexidine) under various conditions were also determined. The last study was focused on the preparation of samples applicable in practice. The organo-inorganic powder hybrid samples were used for the preparation of nanocomposites in the polyethylene matrix. Samples from the individual studies were characterized by various methods, such as X-ray powder diffraction, infrared spectrometry with Fourier transformation, scanning electron microscopy, or the determination of total organic carbon when the stability of chlorhexidine in the samples was monitored. All samples were tested for their antibacterial activity. The theoretical part of the PhD thesis is addressing to the basic description of the clay materials structure, their classification and description of modifications along with antibacterial testing and description of clinically significant bacterial stems. The theoretical part also includes background research dealing with antibacterial organoclays and nanocomposite materials. The entire series of experiments resulted in very important insights for the future preparation of samples with antibacterial effect. The antibacterial tests confirmed antibacterial activity of all prepared organovermiculite samples, nevertheless, regarding the very specific behavior of individual bacteria the conditions inhibiting the bacterial growth substantially varies for each sample toward each bacteria stem. Therefore, the result is varying effect of the sample towards individual bacterial stems. The very important finding was the chlorhexidine outflow is negligible and has minimal effect on the resulting antibacterial effect which indicates large stability of the composites. Also the polyethylene nanocomposite samples showed longterm antibacterial activity which confirmed the idea of utilizing these materials at the production of substances with antibacterial effect.