In der vorliegenden Arbeit wurde eine neue Klasse von implantierbaren biochemischen Sensoren bezüglich ihrer Sensitivität im physiologisch relevanten pH- (pH 7,4) sowie Glukose-Konzentrationsbereich (2 - 20 mM) entwickelt und untersucht. Die Glukose-sensitiven Hydrogele basieren auf der Bindung von 5-fach-Zuckern an Boronsäuregruppen, die in einem Acrylamid-basierten Hydrogel mit N,N′-Methylenbisacrylamid (BIS) als Vernetzter (AAm/APB/BIS, 80/20/0,75 mol%) verankert sind. Weiterhin konnten pH-sensitive Hydrogele auf Basis von 2-(Dimethylamino)ethyl Methacrylate (DMAEMA), Hydroxypropyl-methacrylat (HPMA) sowie Tetraethyleneglycol dimethacrylate (TEGDMA) als Vernetzter in unterschiedlichen Zusammensetzungen und Geometrien untersucht werden. Die verwendeten Hydrogele wurden hinsichtlich der Diffusionsprozesse sowie ihrer Quellkinetik charakterisiert, um deren Sensitivität, Selektivität, Reproduzierbarkeit und Ansprechzeit gegenüber den physiologischen Parametern (pH, pCO2, Glukose) zu verbessern. Die aufgebauten pCO2-Sensoren zeigten vielversprechende Ansprechzeiten von wenigen Minuten. Die Glukose und pH-Sensoren wiesen im physiologischen Medium (PBS) deutlich höhere Ansprechzeiten von mehreren Stunden auf. Die Kombination von piezoresistiven Drucksensoren mit Stimuli-sensitiven Hydrogelen bietet nicht nur eine große Vielfalt bezüglich der zu detektierenden Analyten, sondern ermöglicht auch miniaturisierte und implantierbare Sensoren für die kontinuierliche Erfassung von physiologischen Parametern. So war die Verkapselung zum Schutz und zugleich zur Gewährleistung der Biokompatibilität und ohne Beeinträchtigung der Funktionalität und Flexibilität der elektronischen Bauteile das Ziel. Dazu wurden die Sensoren mit dem Polymer Parylene C eingehaust, dass zusätzlich eine Polyethylenglykolschicht enthielt. Hierfür wurden Blockcopolymere mittels Ringöffnungspolymerisation synthetisiert, die Polyaminosäuren als Linkermoleküle und PEG zur gezielten Funktionalisierung enthalten. Nach kovalenter Anbindung an die inerte Parylene C-Oberfläche zeigten sich deutlich veränderte Oberflächeneigenschaften und eine verbesserte Zellkompatibilität und Hämokompatibilität. Zudem wurde der sogenannte Tarnkappeneffekt von PEG-Ketten, die sich in der Schicht nach außen ausrichten, festgestellt. Damit wurde Adsorption von Proteinen (Fibronektin, Fibrinogen), die in Entzündungsreaktionen, der Zelladhäsion sowie der Blutgerinnung maßgebend sind, deutlich verringert. / In this work a new class of implantable biochemical sensors with a high sensitivity at physiological pH (pH 7,4) and glucose (2 – 20 mM) ranges were developed and tested. The glucose sensitive hydrogel was made of acrylamide and N,N′-methylene-bis(acrylamide) as a crosslinker (AAm/APB/BIS, 80/20/0,75 mol%). The swelling mechanism was based on the reversible interaction of sugar molecules and the boronic acid groups in the hydrogel. Also a pH sensitive hydrogel made of 2-(dimethylamino) ethyl methacrylate (DMAEMA), hydroxypropyl-methacrylat (HPMA) and the crosslinker tetraethylene glycol dimethacrylate (TEGDMA) with different molar ratios and geometries was characterized. The swelling kinetics as well as the diffusion processes of different hydrogels were studied to advance sensitivity, selectivity, reproducibility and response time with respect to physiological parameters (pH, pCO2, glucose). pCO2 sensors showed promising short response times of about 4 min whereas glucose and pH sensors displayed longer response times of several hours in phosphate-buffered saline solution. The combination of piezoresistive pressure sensors and stimuli-sensitive hydrogels enables a great diversity of detecting analytes as well as miniaturized and implantable sensors for continuous measuring of physiological parameters. However, to implant the sensors an encapsulation strategy is needed that secures the electronics as well as ensures the biocompatibility without loss of functionality and flexibility. For this, the devices were coated with the polymer parylene C and an additional layer of blockcopolymers composed of polyaminoacid (PAA) and polyethyleneglycol (PEG) blocks synthesized via ring-opening polymerization. The functionalization units are carried out by the PEG blocks whereas the PAA blocks perform as linker molecules onto the activated parylene C surface. After covalent coupling of blockcopolymers to the inert polymer the surface characteristics changed and hence the cell and blood compatibility was improved. Furthermore the stealth effect of the outwards PEG chains was utilized to reduce the adsorption of proteins like fibronectin or fibrinogen. These proteins play a major role in inflammatory processes, cell adhesion and blood coagulation. The results gave proof that the encapsulation leads to decisively reduced physiological reactions.

Content: Nowadays, protein-based nanoparticle as a biodegradable, biocompatible product attracts considerable interest for new uses in specialized technical areas. Gelatin is a denatured, biodegradable, and nonimmunogenic protein obtained by controlled hydrolysis of the triple-helix structure of collagen into single-strain molecules. As an amphiphilic biopolymer, gelatin can easily assemble into different kinds of aggregates under the defined pH and temperature and the resulting gelatin nanoparticles have been developed to be applied in the food industry and biomedical fields. Herein we report a novel macromolecular microsphere composites (MMC) hydrogels with the use of prepared methacrylated gelatin nanoparticles (MA-GNP) as the cross-linker. MA-GNP have the ability of chemical crosslinking by the polymerization of C=C bonds, such that the composite hydrogels can be formed by radical polymerization of acrylamide (AAm) on the surface of MA-GNP. The smooth spherical particles with an average size of ~100 nm have been synthesized through a modified two-step desolvation method as proved by atomic force microscopy (AFM). The results of nuclear magnetic resonance and dynamic light scattering further confirm the presence of reactive groups (C=C bonds) in the particles and its narrow sizes distribution. The resulting composite hydrogels (MA-GNP/PAAm) are porous materials with tunable pore sizes and exhibit enhanced compressive resistance and elasticity as well. Increasing appropriately the dosage of MA-GNP reduces the equilibrium swelling ratio and improves thermal stability of the gels. Moreover, all the hydrogels exhibit prolonged blood-clotting time, nonhemolytic nature and strong suitability for cell proliferation, indicating the improved antithrombogenicity and excellent cyto-compatibility. It suggests that the novel MA-GNP/PAAm hydrogels have potential application as tissue engineer scaffold materials, and the MA-GNP can be a promising macromolecular microsphere cross-linker for application in biomedical materials. The present work not only exploits new strategies to fabricate MMC hydrogels but also advance the potential application of biodegradable gelatin-based nanoparticles in biomedical fields. Take-Away: 1. A well-dispersed methacrylated gelatin nanoparticle (MA-GNP) with an average size of ~100 nm is presented by a modified two-step desolvation method. 2. MA-GNP is readily introduced into the polyacrylamide (PAAm) system as a cross-linker to prepare macromolecular microsphere composites (MMC) hydrogels via a free radical polymerization reaction. 3. MA-GNP is an effective cross-linker, improving both the compressive resistance and elasticity of MMC hydrogels as well as the biocompatibility.

The content of this diploma thesis was testing the applicability of available structural analysis techniques on a appropriate model hydrogel system. The main aim was to evaluate the advantages and disadvantages of selected structural analysis techniques and the influence of the composition change of the hydrogel system on its internal structure. Semi-interpenetrated hydrogels based on agarose of different concentration were chosen as model system, this type of material was chosen for simple and repeatable preparation and also for its application potential. Electron microscopy (SEM, cryoSEM), mercury porosimetry and turbidimetry were chosen as structural analysis techniques. Experimental results could be used to improve knowledge about the influence of hydrogel composition on its structure and the comparison of chosen techniques will be used for the choice of appropriate structural analysis in the future, which will be applicable to other hydrogel systems as well.

The thesis deals with molecular dynamic simulation of the influence of water on the deformation of hydrogels. Hydrogels are model materials formed from macromolecular networks solvated with water. It was found that water can form bridges between macromolecules that take the form of temporary ionic crosslinks. These bridges affect the behavior of the network during deformation. Water bridges are water molecules that have a limited radius of motion in the space between two macromolecules. The concentration of the water bridges was regulated by a partial charge on the macromolecular chain in the organic network. Bridges are a type of interaction that is relatively strong but significantly delocalized. It is not possible to dissociate the water bridge, after dissociation it will be re-created in another place in a short time. The influence of water bridges was compared with other types of network crosslinks, especially covalent and physical bonds. Covalent crosslinks are modeled as a simple binding interaction between two macromolecules. They are undissociable and are local throughout the simulation. Physical bonds are modeled as micelles, where hydrophobic groups form the core and hydrophilic groups form the micelle shell. Physical bonds have the nature of dissociable bonds that are local. Different types of crosslinks have different effects on deformation properties. The deformation of a network containing a combination of two types of crosslinks was simulated: (i) physically-covalent, (ii) ionically-covalent, and (iii) physically-ionic networks and (iv) ternary physically-covalent-ion networks. For individual and combined networks, the behavior depending on simple networks was verified. The number of water bridges was fundamentally affected by the primary structure of the chains. When the PEG chain was replaced with hydrophobic polyoxymethylene (POM) or polyoxytrimethylene (POTM), their solvation and mechanical behavior deteriorated.

This doctoral thesis studies the properties and behaviour of phase-separated hydrogels. These can be prepared by interaction of polyelectrolytes with oppositely charged surfactants. Negatively charged polysaccharide hyaluronan and cationic surfactant carbethopendecinium bromide (Septonex), whose properties, behaviour and utilization are described in the first two chapters of theoretical part, were selected for this role. Hyaluronan is naturally-occuring in living organisms and is known for his specific targeting to the tumour cells. Septonex is used as antiseptic and disinfectant. Experimental part of this work is focused on examination of the structure and behaviour of these types of hydrogels especially from rheological point of view. The crucial part of this study was to establish mechanical properties and their dependence on environment. This led to design further studies. Structural analysis was held using the methods of ATR-FTIR, ionic chromatography and ICP-OES helping to measure the inner content of entry materials in the gels and supernatants respectively. The last chapter deals with antimicrobial activity. The results of this study indicate a potential usage of these substances in the field of medical applications.

This master´s thesis deals with the study on mechanical and transport properties of hybrid hydrogel systems. Considering applications of hydrogels, especially in chemical industry, pharmacy, or eventually medical applications, for the study gellan and alginate-based hydrogels were selected. In order to compare individual characteristics physical and hybrid hydrogels were prepared. Gellan hydrogels were prepared in deionization aqua solution, calcium chloride dihydrate and tween 80 solution. Alginate hydrogels were prepared in calcium chloride dihydrate solution as well, and polyacrylamide with N,N´–methylenbisacrylamide. For the study of mechanical properties moisture analyser and rheology measurements were selected. Transport properties were studied using the diffusion experiments combined with UV-VIS spectroscopic detection. Concluding of this thesis is summarization of measured values, which provides comprehensive review of the problematics. It was discovered that the conveniently selected concentrations of structural components of hydrogel matrix and the additives can influence both the mechanical as well as the transport properties of studied hydrogels.

The content of this diploma thesis is study of interactions between humic acids and model probes (such as organic dyes and ions of heavy metals) by the simple diffusion experiments in diffusion cell. The main aim was to desctibe the influence of charge of different diffusion sonds (solved substances) on interactions with humic acids imobilized in model gel phase. As a appropriete model probe was chosen copper ions (as a representation of heavy metals) and organic dyes (methylene blue, rhodamine, fluorescein and chicago blue). Experimental results could be used to improve knowledge based on natural barier properties of humic acids and to inovate simple diffusion laboratory techniques for characterization of reaktivity of biopolymers in general.

Diploma thesis main goal is to obtain new pieces of knowledge about relationship between hydrogel structures and its flow and transport properties. Thesis is mainly focusing on combining pertinent biopolymers into model hydrogels based on agarose. Then perform correlation of results obtained by diffusion methods, and by rheologic measurements on macroscopic and microscopic level. Properties of hydrogels were measured by selected rheologic measurements, dynamic light scattering method, and correlative fluorescence spectroscopy. From these methods various parameters (MSD modules, values of complex viscosity) were obtained. Afterwards transport properties of prepared hydrogels were studied by observing Rhodamine 6G diffusion. Here two different approaches were used. From macroscopic perspective, simple principles of mass diffusion from dye solution to cuvettes filled with hydrogels containing individual biopolymers were used. From microscopic perspective, dye was added during the sample preparation and then the mass diffusion was investigated using FCS. Based on evaluated results it was discovered that added biopolymers don’t influence properties of carrier medium, in this case agarose hydrogels. During the study of prepared hydrogels’ reactivity and barrier properties some differences were observed. Charge of biopolymer and its charge density were discovered as main factors influencing transport of charged solutes into prepared hydrogels.

In der vorliegenden Arbeit wurde eine neue Klasse von implantierbaren biochemischen Sensoren bezüglich ihrer Sensitivität im physiologisch relevanten pH- (pH 7,4) sowie Glukose-Konzentrationsbereich (2 - 20 mM) entwickelt und untersucht. Die Glukose-sensitiven Hydrogele basieren auf der Bindung von 5-fach-Zuckern an Boronsäuregruppen, die in einem Acrylamid-basierten Hydrogel mit N,N′-Methylenbisacrylamid (BIS) als Vernetzter (AAm/APB/BIS, 80/20/0,75 mol%) verankert sind. Weiterhin konnten pH-sensitive Hydrogele auf Basis von 2-(Dimethylamino)ethyl Methacrylate (DMAEMA), Hydroxypropyl-methacrylat (HPMA) sowie Tetraethyleneglycol dimethacrylate (TEGDMA) als Vernetzter in unterschiedlichen Zusammensetzungen und Geometrien untersucht werden. Die verwendeten Hydrogele wurden hinsichtlich der Diffusionsprozesse sowie ihrer Quellkinetik charakterisiert, um deren Sensitivität, Selektivität, Reproduzierbarkeit und Ansprechzeit gegenüber den physiologischen Parametern (pH, pCO2, Glukose) zu verbessern. Die aufgebauten pCO2-Sensoren zeigten vielversprechende Ansprechzeiten von wenigen Minuten. Die Glukose und pH-Sensoren wiesen im physiologischen Medium (PBS) deutlich höhere Ansprechzeiten von mehreren Stunden auf. Die Kombination von piezoresistiven Drucksensoren mit Stimuli-sensitiven Hydrogelen bietet nicht nur eine große Vielfalt bezüglich der zu detektierenden Analyten, sondern ermöglicht auch miniaturisierte und implantierbare Sensoren für die kontinuierliche Erfassung von physiologischen Parametern. So war die Verkapselung zum Schutz und zugleich zur Gewährleistung der Biokompatibilität und ohne Beeinträchtigung der Funktionalität und Flexibilität der elektronischen Bauteile das Ziel. Dazu wurden die Sensoren mit dem Polymer Parylene C eingehaust, dass zusätzlich eine Polyethylenglykolschicht enthielt. Hierfür wurden Blockcopolymere mittels Ringöffnungspolymerisation synthetisiert, die Polyaminosäuren als Linkermoleküle und PEG zur gezielten Funktionalisierung enthalten. Nach kovalenter Anbindung an die inerte Parylene C-Oberfläche zeigten sich deutlich veränderte Oberflächeneigenschaften und eine verbesserte Zellkompatibilität und Hämokompatibilität. Zudem wurde der sogenannte Tarnkappeneffekt von PEG-Ketten, die sich in der Schicht nach außen ausrichten, festgestellt. Damit wurde Adsorption von Proteinen (Fibronektin, Fibrinogen), die in Entzündungsreaktionen, der Zelladhäsion sowie der Blutgerinnung maßgebend sind, deutlich verringert. / In this work a new class of implantable biochemical sensors with a high sensitivity at physiological pH (pH 7,4) and glucose (2 – 20 mM) ranges were developed and tested. The glucose sensitive hydrogel was made of acrylamide and N,N′-methylene-bis(acrylamide) as a crosslinker (AAm/APB/BIS, 80/20/0,75 mol%). The swelling mechanism was based on the reversible interaction of sugar molecules and the boronic acid groups in the hydrogel. Also a pH sensitive hydrogel made of 2-(dimethylamino) ethyl methacrylate (DMAEMA), hydroxypropyl-methacrylat (HPMA) and the crosslinker tetraethylene glycol dimethacrylate (TEGDMA) with different molar ratios and geometries was characterized. The swelling kinetics as well as the diffusion processes of different hydrogels were studied to advance sensitivity, selectivity, reproducibility and response time with respect to physiological parameters (pH, pCO2, glucose). pCO2 sensors showed promising short response times of about 4 min whereas glucose and pH sensors displayed longer response times of several hours in phosphate-buffered saline solution. The combination of piezoresistive pressure sensors and stimuli-sensitive hydrogels enables a great diversity of detecting analytes as well as miniaturized and implantable sensors for continuous measuring of physiological parameters. However, to implant the sensors an encapsulation strategy is needed that secures the electronics as well as ensures the biocompatibility without loss of functionality and flexibility. For this, the devices were coated with the polymer parylene C and an additional layer of blockcopolymers composed of polyaminoacid (PAA) and polyethyleneglycol (PEG) blocks synthesized via ring-opening polymerization. The functionalization units are carried out by the PEG blocks whereas the PAA blocks perform as linker molecules onto the activated parylene C surface. After covalent coupling of blockcopolymers to the inert polymer the surface characteristics changed and hence the cell and blood compatibility was improved. Furthermore the stealth effect of the outwards PEG chains was utilized to reduce the adsorption of proteins like fibronectin or fibrinogen. These proteins play a major role in inflammatory processes, cell adhesion and blood coagulation. The results gave proof that the encapsulation leads to decisively reduced physiological reactions.

Tesis por compendio / [ES] El objetivo de esta tesis doctoral ha sido el diseño y caracterización estructural de estructuras tipo gel basadas de polisacáridos extraídos de biomasa acuática con interés para aplicaciones relacionadas con la alimentación. Las propiedades de los polisacáridos extraídos de algas y plantas acuáticas son adecuadas para producir diferentes estructuras tipo gel basadas en la formación de redes reticuladas, como hidrogeles, aerogeles y emulsion-gels. En la primera parte de esta tesis se investigaron los diferentes mecanismos de gelificación de polisacáridos sulfatados, así como los parámetros que afectan a la estructura y las propiedades funcionales de los hidrogeles obtenidos. En base a los resultados, se evaluó la potencial aplicación de los hidrogeles y aerogeles de agar y k-carragenato para encapsular una proteína alimentaria modelo como la caseína, explorando así el efecto protector contra la hidrólisis enzimática tras digestiones gastrointestinales simuladas. En la segunda parte de esta tesis, se desarrollaron estructuras de aerogeles mediante la valorización de una fuente de biomasa residual infrautilizada, como es el Arundo donax. Con esta biomasa se generaron fracciones celulósicas con diferentes grados de purificación y extractos bioactivos solubles en agua, que posteriormente se utilizaron para producir aerogeles bioactivos híbridos. La estructura altamente porosa y la elevada capacidad de sorción de los aerogeles los convierten en excelentes candidatos para la sustitución de las almohadillas absorbentes para mantener la calidad de los productos cárnicos envasados. Los emulsion-gels son reconocidos por su gran potencial como ingredientes funcionales en la industria alimentaria como modificadores de textura y como sustitutos de grasas sólidas. Además, pueden utilizarse como vehículo para la liberación controlada de compuestos bioactivos liposolubles. Así, en la última parte de esta tesis, se investigó la naturaleza de las interacciones entre los componentes en las formulaciones de emulsion-gels basadas en polisacáridos y se relacionó con su estructura y comportamiento mecánico y reológico. Después de estudiar el mecanismo de gelificación de los emulsion-gels de carragenato, estos sistemas se adaptaron y utilizaron para dos diferentes aplicaciones relevantes para los sectores de alimentación y biomedicina. En primer lugar, se produjeron y evaluaron estructuras gelificadas a partir de emulsion-gels de agar y k-carragenato y aerogeles cargados de aceite como encapsulantes de un bioactivo lipofílico como la curcumina. Los resultados mostraron que el tipo de polisacárido y el estado físico de las redes del gel tenían un impacto en la estructura de los productos de la digestión. Por otro lado, se evaluó el potencial de los emulsion-gels basados en polisacáridos sulfatados (k-carragenato y agar) para la producción de un material capaz de simular tejido graso. Los resultados evidencian que los emulsions-gels de agar son adecuadas para producir materiales que simulan las propiedades dieléctricas para imitar tejidos de bajo y alto contenido en agua. / [CA] L'objectiu d'aquesta tesi doctoral ha sigut, el disseny i caracterització estructural d'estructures tipus gel, basades en polisacàrids extrets de biomassa aquàtica amb interès per a aplicacions relacionades amb l'alimentació. Les propietats dels polisacàrids extrets d'algues i plantes aquàtiques, són adequades per a produir diferents estructures tipus gel basades en la formació de xarxes reticulades, com a hidrogels, aerogels i emulsió-gels. En la primera part d'aquesta tesi es van investigar els diferents mecanismes de gelificació de polisacàrids sulfatats, així com els paràmetres que afecten l'estructura i les propietats funcionals dels hidrogels obtinguts. Sobre la base dels resultats, es va avaluar la potencial aplicació dels hidrogels i aerogels d'agar i k-carraguenina per a encapsular una proteïna alimentària model com la caseïna, explorant així l'efecte protector contra la hidròlisi enzimàtica després de digestions gastrointestinals simulades. A la segona part d'aquesta tesi, es van desenvolupar estructures d' aerogels mitjançant la valorització d'una font de biomassa residual infrautilitzada, com és el Arundo donax. Amb aquesta biomassa es van generar fraccions cel·lulòsiques amb diferents graus de purificació i extractes bioactius solubles en aigua, que posteriorment es van utilitzar per a produir aerogels bioactius híbrids. L'estructura altament porosa i l'elevada capacitat de sorció dels aerogels els converteixen en excel·lents candidats per a la substitució dels coixinets absorbents per a mantenir la qualitat dels productes carnis envasats. Els emulsió-gels són reconeguts pel seu gran potencial com a ingredients funcionals en la indústria alimentària com a modificadors de textura i com a substituts de greixos sòlids. A més, poden utilitzar-se com a vehicle per a l'alliberament controlat de compostos bioactius liposolubles. Així, a l'última part d'aquesta tesi, es va investigar la naturalesa de les interaccions entre els components dins les formulacions d' emulsió-gels basades en polisacàrids i es va relacionar amb la seua estructura i comportament mecànic i reològic. Després d'estudiar el mecanisme de gelificació dels emulsió-gels de carraguenina, aquests sistemes es van adaptar i es van utilitzar per a dues aplicacions diferents, rellevants per als sectors de l' alimentació i la biomedicina. En primer lloc, es van produir i van avaluar estructures gelificades a partir de emulsió-gels d'agar i k-carraguenina i aerogels carregats d'oli com a encapsulants d'un bioactiu lipofílic com la curcumina. Els resultats van mostrar que el tipus de polisacàrid i l'estat físic de les xarxes del gel tenien un impacte en l'estructura dels productes de la digestió. D'altra banda, es va avaluar el potencial dels emulsió-gels basats en polisacàrids sulfatats (k-carraguenina i agar) per a la producció d'un material capaç de simular teixit gras. Els resultats evidencien que els emulsió-gels d'agar són adequats per a produir materials que simulen les propietats dielèctriques podentimitar teixits de baix i alt contingut en aigua. / [EN] The aim of this doctoral thesis was to design and characterize the structure of gel-like structures based on polysaccharides extracted from aquatic biomass, with interest for food-related applications. The properties of polysaccharides extracted from seaweeds and aquatic plants make them suitable to produce a range of gel-like structures based on the formation of interconnected networks, such as hydrogels, aerogels and emulsion-gels. In the first part of this thesis, the different gelation mechanism of sulphated polysaccharides and the parameters affecting the structure and functional properties of the obtained hydrogels were investigated. Based on the results, the potential application of agar and k-carrageenan hydrogels and aerogels to encapsulate a model food protein such as casein was evaluated, thus exploring the protective effect against the enzymatic hydrolysis upon simulated gastrointestinal digestions. In the second part of this thesis, aerogel structures were developed by valorising an underutilized waste biomass source such as Arundo donax. This biomass was used to generate cellulosic fractions with different purification degrees and water-soluble bioactive extracts, which were subsequently used to produce hybrid bioactive aerogels. The highly porous structure and high sorption capacity of aerogels make them excellent candidates for the replacement of absorbent pads to maintain the quality of packaged meat products. Emulsion-gels are recognized for their great potential as functional ingredients in the food industry to modify texture and for solid fat replacement. Moreover, they can be used as a delivery vehicle for the controlled release of fat-soluble bioactive compounds. Thus, in the last part, the nature of interactions between the components in polysaccharide-based emulsion-gel formulations was investigated and related to their structure and mechanical and rheological behavior. After studying the gelation mechanism of carrageenan emulsion-gels, these systems were adapted and used for two different applications relevant to the food and biomedicine sectors. Firstly, oil-filled gel-like structures from agar and k-carrageenan emulsion-gels and oil-filled aerogels were produced and evaluated as carriers of a lipophilic bioactive such as curcumin. The results showed that the polysaccharide type and the physical state of the gel network had an impact on the structure of the digestion products. On the other hand, the potential of emulsion-gels based on sulphated polysaccharides (k-carrageenan and agar) for the production of tissue mimicking phantoms was evaluated. The results evidence that the agar emulsion-gels are suitable to produce materials simulating the dielectric properties to mimic low- and high-water content tissues. / Synchrotron experiments were performed at NCD beamline at ALBA Synchrotron with the collaboration of ALBA staff (2018022638 project). This work was financially supported by the grant RTI2018-094268-B-C22 (MCIU/AEI/FEDER, UE). Part of this work was supported by the COST Action ES1408 European network for algal-bioproducts (EUALGAE). Cynthia Fontes-Candia is recipient of a pre-doctoral grant from CONACYT (MEX/Ref. 306680). The projects RTI2018-094268-B-C22 and RTI2018-094408-J-I00 were funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”. This work has also received financial support from project PID2019-107663RB-I00 from the Spanish Ministry of Science and Innovation (MICINN). Cynthia Fontes-Candia is recipient of a pre-doctoral grant from CONACYT (MEX/Ref. 306680). Marta Martinez-Sanz is recipient of a Juan de la Cierva (IJCI-2015-23389) contract from the Spanish Ministry of Economy, Industry and Competitiveness. / Fontes Candia, C. (2022). Development and Characterization of Gel-Like Structures from Aquatic Biomass for Food Applications [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/181564 / TESIS / Compendio