Interaction between Conjugated Polyelectrolytes and Biological Systems: Characterization and Biotechnological Applications
Fluorescent conjugated polyelectrolytes (CPEs) display very interesting and useful properties. They are polymers with π-conjugated backbones which show strong absorption and high efficiencies in both photoluminescence and electroluminescence; further they contain ionic side groups to facilitate thei...
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| Tipo de recurso: | tesis doctoral |
| Fecha de publicación: | 2016 |
| País: | España |
| Institución: | Universidad Miguel Hernández de Elche |
| Repositorio: | REDIUMH. Depósito Digital de la UMH |
| OAI Identifier: | oai:dspace.umh.es:11000/5149 |
| Acceso en línea: | http://hdl.handle.net/11000/5149 |
| Access Level: | acceso abierto |
| Palabra clave: | Proteinas Lípidos Polielectrolitos CDU:5 - Ciencias puras y naturales:57 - Biología |
| Sumario: | Fluorescent conjugated polyelectrolytes (CPEs) display very interesting and useful properties. They are polymers with π-conjugated backbones which show strong absorption and high efficiencies in both photoluminescence and electroluminescence; further they contain ionic side groups to facilitate their water solubilization. These properties have been used to study interactions with biomolecules such as proteins and DNA, allowing to develop sensing platforms and bioimaging tools. In the present Thesis, we characterized two cationic CPEs, with different emission wavelength: blue-emitting HTMA-PFP and red-emitting HTMAPFNT, and we explored their potential use in biotechnological applications. For biomedical applications such as bioimaging, the preliminary condition is the dispersibility of CPEs in aqueous media. Therefore, in the first part of this Thesis, the behaviour of HTMA-PFP and HTMA-PFNT in aqueous solutions was explored. Afterwards, we investigated the interaction of these CPEs with anionic and zwitterionic model membranes in order to use them as fluorescent markers. This study showed that both types of CPEs have higher affinity and selectivity towards anionic lipids, which are the dominant lipid component in bacterial membranes. Taking into account these results, a study by mimicking the mammalian and bacterial membranes with different lipid mixtures was performed and the interaction of these CPEs with both model systems was explored. This study confirmed the selectivity of CPEs, especially HTMA-PFNT, towards bacterial model membranes. Preliminary experiments with living bacteria and mammalian cells supported these results, showing that in samples containing both types of cells, HTMA-PFNT only images the bacterial cells. These results were a proof-of-concept of its use for selective recognition and imaging of bacteria. Moreover, we studied the ability of HTMA-PFP and HTMA-PFNT to form stable fluorescent nanostructures, and we explored their potential applications. Firstly, we investigated the interaction of HTMA-PFNT with two biological systems which are known to be used as nanocarriers: human serum albumin and lipid vesicles. Results showed the formation of red-emitting nanoparticles, preserving the biological functionality. The ability of these nanoparticles to carry hydrophobic and polar compounds was also checked, as well as, the capacity to be used as fluorescent probes for bioimaging. Results supported the potential use of these novel structures as multifunctional platforms for therapeutic and diagnostic purposes. Secondly, the complexation of blue-emitting HTMA-PFP with lipid vesicles was explored. The obtained nanoparticles were characterized and coupled to the enzyme Alkaline Phosphatase to develop a fluorescent biosensor for enzyme inhibitor determination. The components of the biosensor (nanoparticles and enzyme) were immobilized in a sol-gel matrix to facilitate its handling, allowing its reutilization. The biosensor was optimized for the determination of phosphate ion, a competitive inhibitor of the enzyme. |
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