Sagrario Muñoz

A preliminary exploration of the physiology and morphology of the zebrafish embryo (ZFE) during the late-blastula and early-gastrula stages through its electrical properties was performed, applying the electrorotation (ROT) technique. This method, based on induced polarizability at the interfaces, was combined with an analytical spherical shell model to obtain the best fit of empirical data and the desired information, providing a means of understanding the role of different membranes. Suspended in two solutions of low conductivity, the major compartments of the ZFE were electrically characterized, considering morphological data from both observed records and data from the literature. Membrane integrity was also analyzed for dead embryos. The low permeability and relatively high permittivity obtained for the chorion probably reflected both its structural characteristics and external conditions. Reasonable values were derived for perivitelline fluid according to the influx of water that occurs after the fertilization of the oocyte. The so-called yolk membrane, which comprises three different and contiguous layers at the epiboly stage, showed atypical electrical values of the membrane, as did the yolk core with a relatively low permittivity. The internal morphological complexity of the embryo itself could be addressed in future studies by developing an accurate geometric model.

The possible effects of ionizing radiation on four commercial membranes, which are typically used as electrolytes in fuel cells supplying energy to a huge variety of medical implantable devices, were studied. These devices could obtain energy from the biological environment through a glucose fuel cell, which could be a good candidate to replace conventional batteries as a power source. In these applications, materials with high radiation stability for the fuel cell elements would be disabled. The polymeric membrane is one of the key elements in fuel cells. Membrane swelling properties are very important because they affect the fuel cell’s performance. For this reason, the swelling behaviors of various samples of each membrane irradiated with different doses were analyzed. Each sample was irradiated with a typical dose of a conventional radiotherapy treatment, and the regular conditions of the biological working environment were simulated. The target was to examine the possible effect of the received radiation on the membranes. The results show that the ionizing radiation influenced their swelling properties, as well as that dimensional changes were dependent on the existence of reinforcement, be it internal or external, in the membrane structure.