Novel Hybrid Polymeric and Inorganic Structures for Applications in Nanobiotechnology

This cumulative doctoral dissertation deals with the use of diverse polymers in different applications within nanoscience. The synthesis and characterization of several nano and microstructures is also explained, focusing on the later surface modification via the use of...

Ausführliche Beschreibung

Gespeichert in:
1. Verfasser: Valdeperez Toledo, Daniel
Beteiligte: Parak, Wolfgang J. (Prof. Dr.) (BetreuerIn (Doktorarbeit))
Format: Dissertation
Sprache:Englisch
Veröffentlicht: Philipps-Universität Marburg 2017
Physik
Ausgabe:http://dx.doi.org/10.17192/z2017.0227
Schlagworte:
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Zusammenfassung:This cumulative doctoral dissertation deals with the use of diverse polymers in different applications within nanoscience. The synthesis and characterization of several nano and microstructures is also explained, focusing on the later surface modification via the use of different polymers. Polymers are chemical compounds formed by the combination of several repeating structural units (monomers) in a process called polymerization. These structures are assembled following a specific pattern and their subsequent properties are given by the monomers added in the polymerization process. Several uses of polymers have been reported, being their use in the process of engineering novel composite materials for applications within fields like aerospace industry, biotechnology or medicine. The work shown in this thesis aimed to implement novel applications for some of the general polymer uses found in literature and the employment of amphiphilic zwitterionic polymers to test their stability for different biological applications. The dissertation is first focused on the study of three different applications of polymers inside nanotechnology. One of the most common applications of the use of amphiphilic polymers is the coating of inorganic NPs initially synthesized in organic solutions, transferring them into aqueous solutions. The resulting polymer coated NPs count on functional groups on their surface allowing further modifications for new functionalities. This procedure is applied to NPs with different size (ranging from 4 to 29 nm core size) and material (gold and iron oxide). A second application of the polymers is the protection of highly unstable, water and oxygen-sensitive clusters from degradation in aqueous environments. For that purpose gold NPs (Au NPs) of 4 nm were used as template and the clusters were collected between the surface of the NP and the amphiphilic polymer shell. The kinetic activity of the clusters was studied in aqueous environment, obtaining signal in at least the first 24 hours after the coating. As a complementary study inside this dissertation, different amphiphilic zwitterionic polymers were synthesized and optimized for a correct stabilization of NPs in water. The influence of parameters like pH, protein concentration and ionic strength was studied to obtain a complete description of the stability of the different zwitterionic polymer-coated NPs, comparing them to the single charge polymer coated NPs (e.g. fully positive or fully negative). A third application involves the self-assembly of alternating-charge polyelectrolyte layers deposited via adsorption on sacrificial calcium carbonate cores, yielding polymeric hollow microstructures able to be provided with physical and biological properties. Both properties are obtained via the accumulation of iron oxide nanoparticles between the polymer layers and the attachment of specific antibodies vion the outermost polymer layer, giving physical (magnetic) and biological (specific recognition) properties to the whole structure. These microcapsules were utilized to obtain a magnetic immunosensor able to specifically recognize and extract horseradish peroxidase (used as protein model) from a solution.
Beschreibung:282 pages.
DOI:http://dx.doi.org/10.17192/z2017.0227