Degradable polymers have gained an increased attention in the field of biomedical applications over the past decades, for example in tissue engineering. One way of improving the biocompatibility of these polymers is by chemical surface modification, however the risk of degradation during the modification procedure is a limiting factor. In some biomedical applications, for example in nerve guides, a patterned surface is desired to improve the cell attachment and proliferation. In this thesis a new non-destructive, single-step, and solvent free method for surface modification of degradable polymers is described. Poly(L-lactide) (PLLA) substrates have been functionalized with one of the following vinyl monomers; N-vinylpyrrolidone (VP), acrylamide (AAm), or maleic anhydride (MAH) grafts. The substrates were subjected to a vapor phase atmosphere constituted of a mixture of a vinyl monomer and a photoinitiator (benzophenone) in a closed chamber at very low pressure and under UV irradiation. Poly(ε-caprolactone) (PCL), poly(lactide-co-glycolide) (PLGA), and poly(trimethylene carbonate) (PTMC) have been surface modified with VP using the same procedure to show the versatility of the method. The wettability of all of the four substrates increased after grafting. The surface compositions were confirmed by ATR-FTIR and XPS. The VP grafted PLLA, PTMC and PLGA substrates have been shown to be good substrates for the normal human cells i.e. keratinocytes and fibroblasts, to adhere and proliferate on. The topography of substrates with well defined nano patterns was preserved during grafting, since the grafted layer is very thin. We have also shown that the method is useful for a simultaneous chemical and topographical modification of substrates by masked vapor phase grafting. The surface topography was determined with SEM and AFM. / Intresset för användningen av nedbrytbara polymerer till biomedicinska applikationer som till exempel vävnads rekonstruktion har ökat avsevärt de senaste decennierna. Ett sätt att öka biokompatibiliteten hos dessa polymerer är genom kemisk ytmodifiering, men risken för nedbrytning under själva modifieringen är en begränsande faktor. I vissa biomedicinska applikationer, till exempel nervguider, är det önskvärt att ha en väldefinierad ytstruktur för att öka vidhäftningen och tillväxten av celler. I den här avhandlingen presenteras en ny ickeförstörande, lösningsmedelsfri enstegsprocess för ytmodifiering av nedbrytbara polymerer. Substrat av poly(L-laktid) (PLLA) har ytfunktionaliserats med var och en av följande vinylmonomerer, N-vinylpyrrolidon (VP), akrylamid (AAm) eller maleinsyraanhydrid (MAH). Substraten har exponerats för en gasfasatmosfär av en blandning av en vinylmonomer och en fotoinitiator (bensofenon) i en tillsluten reaktor vid mycket lågt tryck och under UV-strålning. Metodens mångsidighet har även påvisats genom att ytmodifiera substrat av poly(ε-kaprolakton) (PCL), poly(laktid-co-glykolid) (PLGA) och poly(trimetylen karbonat) (PTMC) med VP. Vätbarheten ökade för alla fyra materialen efter ympning med en vinylmonomer. Ytsammansättningen fastställdes med ATR-FTIR och XPS. De VP ympade filmerna av PLLA, PLGA och PTMC visade sig vara bra substrat för mänskliga celler, i detta fall keratinocyter och fibroblaster, att vidhäfta och växa på. Yttopografin hos filmer med väldefinierade nanomönstrade ytor kunde bevaras efter ympning, tack vare att det ympade lagret är så tunt. Gasfas metoden har också visat sig användbar för att simultant ytmodifiera både kemiskt och topografiskt genom maskad gasfasympning. Yttopografin bestämdes med SEM och AFM. / QC 20101014

Medical devices, such as catheters and heart valves, are an important part of patient care. However, blood-contacting devices can activate the blood coagulation cascade to produce factor (f) Xa, the clotting enzyme that induces thrombin generation. By activating platelets and converting soluble fibrinogen to fibrin, thrombin leads to blood clot formation. Blood clots that form on medical devices create problems because they may foul the device and/or serve as a nidus for infection. In addition, clots can break off from the device, travel through the circulation and lodge in distant organs; a process known as embolization. This is particularly problematic with central venous catheters because clots that form on them can break off and lodge in pulmonary arteries, thereby producing a pulmonary embolism. Similarly, clots that form on heart valves can break off and lodge in cerebral arteries, thereby producing a stroke. Therefore, anticoagulants, blood thinning drugs, are frequently used to prevent clotting on medical devices. Conventional anticoagulants, such as heparin and warfarin, target multiple clotting factors. Heparin binds to antithrombin in plasma and accelerates the rate at which it inhibits fXa, thrombin and many other clotting enzymes. Warfarin, which is a vitamin K antagonist, attenuates thrombin generation by interfering with the synthesis of the vitamin K-dependent clotting factors, which include fX and prothrombin, the precursor of thrombin. In contrast to heparin and warfarin, more recent anticoagulants inhibit only a single clotting enzyme. For example, fondaparinux, a synthetic heparin fragment, only inhibits fXa and dabigatran, an oral thrombin inhibitor, only targets thrombin. Although effective for many indications, fondaparinux was less effective than heparin for preventing clotting on catheters in patients undergoing heart interventions and dabigatran was less effective than warfarin for preventing strokes in patients with mechanical heart valves. The failure of these new anticoagulants highlights the need for a better understanding into the drivers of clotting on medical devices. Therefore, the overall purpose of this thesis is to gain this understanding so that more rational approaches to its prevention can be identified. In the classical model of blood coagulation, clotting is triggered via two distinct pathways; the tissue factor (TF) pathway or extrinsic pathway and the contact pathway or intrinsic pathway; pathways which are initiated by fVIIa and fXIIa, respectively. The mechanism by which medical devices initiate clotting is uncertain. Platelet and complement activation and microparticle formation have been implicated, which would drive clotting via the TF pathway. Alternatively, medical devices can bind and activate fXII, thereby initiating the contact pathway. We hypothesized that medical devices trigger clotting via the contact pathway and induce the local generation of fXa and thrombin in concentrations that exceed the capacity of fondaparinux and dabigatran to inhibit them. To test this hypothesis, we used catheters as a prototypical medical device and we used a combination of in vitro and rabbit models. Several lines of evidence indicate that catheters initiate clotting via the contact pathway. First, catheter segments shortened the clotting time of human plasma, and this activity was attenuated in fXII- or fXI-deficient plasma, which are key components of the contact pathway, but not in fVII-deficient plasma, which is the critical component of the extrinsic pathway. Second, corn trypsin inhibitor (CTI), a potent and specific inhibitor of fXIIa, attenuates catheter thrombosis. Third, selective knockdown of fXII or fXI with antisense oligonucleotides attenuated catheter-induced thrombosis in rabbits, whereas knockdown of fVII had no effect. Therefore, these results revealed the importance of the contact pathway in device-associated thrombosis, and identified CTI or fXII or fXI knockdown as novel strategies for preventing this problem. Focusing on fXIIa as the root cause of medical device associated clotting, we coated catheters with CTI using a polyethylene glycol (PEG) spacer. In addition to unmodified catheters, other controls included catheters coated with albumin via a PEG spacer or catheters coated with PEG alone. Compared with unmodified catheters or with the other controls, CTI-coated catheters attenuated clotting in buffer or plasma systems and were resistant to occlusion in rabbits. These findings support the concept that catheter-induced clotting is driven via the contact pathway and identify CTI coating as a viable strategy for its prevention. We next set out to test the hypothesis that fondaparinux and dabigatran, which inhibit fXa and thrombin, respectively, are less effective than heparin, which inhibits multiple clotting enzymes. Fondaparinux and dabigatran were less effective than heparin at preventing catheter induced clotting and thrombin generation, respectively. Likewise, in a rabbit model of catheter thrombosis, fondaparinux was less effective than heparin and dabigatran was only effective when administered at doses that yielded plasma dabigatran levels similar to those found at peak in human given the drug; at trough levels, dabigatran was no better than placebo. Finally, we also showed synergy between heparin and either fondaparinux or dabigatran. Thus, when co-administered to rabbits in doses that on their own had no effect, the combination of fondaparinux or dabigatran plus heparin extended the time to catheter thrombosis. These findings support the hypothesis that when catheters trigger clotting via the contact pathway, fXa and thrombin are generated in concentrations that overwhelm the capacity of fondaparinux or dabigatran to inhibit them. Furthermore, the synergy between heparin and fondaparinux or dabigatran has clinical implications because it explains why supplemental heparin attenuated the risk of catheter thrombosis in patients treated with fondaparinux who underwent cardiac procedures and it identifies the potential role of supplemental heparin in dabigatran-treated patients who require such interventions. In summary, we have shown that catheters trigger clotting via the contact pathway and have identified CTI coating or fXII or fXI knockdown as viable strategies for prevention of this problem. In addition, for prevention of catheter thrombosis, we also have shown that heparin, which inhibits multiple coagulation enzymes, is more effective than fondaparinux or dabigatran, which only inhibit fXa or thrombin, respectively; findings consistent with the clinical observations. Moreover, the synergy that we observed between fondaparinux or dabigatran and heparin identifies supplemental heparin as strategy for preventing catheter thrombosis in patients receiving these drugs. Taken together, these studies provide insight into the mechanisms of catheter thrombosis and potential strategies for its prevention. / Thesis / Doctor of Philosophy (PhD)

Master‘s thesis focuses on concrete combined with polypropylen fibres produced commercially, fibres without surface modifications and fibres modificated by plasma. Most important topic of the thesis is experimental verification of influence of plasma modificated fibres on attributes of fresh concrete and physical-mechanical attributes of solidified concrete. Based on the results of the tests perfomed on examin units compares results and anylyses applicability of different fibre surface modifications.

GaAs-based nanowires are attractive building blocks for the development of future (opto)electronic devices owing to their excellent intrinsic material properties, such as the direct band gap and high electron mobility. A pre-requisite for the implementation of novel functionalities on a single Si chip is the monolithic integration of the nanowires on the well-established Si complementary-metal-oxide-semiconductor (CMOS) platform with precise control of the nanowire growth process. The self-catalyzed (Ga-assisted) growth of GaAs nanowires on Si(111) substrates using molecular beam epitaxy has offered the possibility to obtain vertical nanowires with predominant zinc blende structure, while potential contamination by external catalysts like Au is eliminated. Although the growth mechanism is fairly well understood, control of the nucleation stage, the nanowire number density and the crystal structure has been proven rather challenging. Moreover, conventional growth processes are typically performed at relatively high substrate temperatures in the range of 560-630 °C, which limit their application to the industrial Si platform. This thesis provides two original methods in order to tackle the aforementioned challenges in the conventional growth processes. In the first part of this thesis, a simple surface modification procedure (SMP) for the in situ preparation of native-SiOx/Si(111) substrates has been developed. Using a pre-growth treatment of the substrates with Ga droplets and two annealing cycles, the SMP enables highly synchronized nucleation of all nanowires on their substrate and thus, the growth of exceptionally uniform GaAs nanowire ensembles with sub-Poissonian length distributions. Moreover, the nanowire number density can be tuned within three orders of magnitude and independent of the nanowire dimensions without prior ex situ patterning of the substrate. This work delivers a fundamental understanding of the nucleation kinetics of Ga droplets on native-SiOx and their interaction with SiOx, and confirms theoretical predictions about the so-called nucleation antibunching, the temporal anti-correlation of consecutive nucleation events. In the second part of this thesis, an alternative method called droplet-confined alternate-pulsed epitaxy (DCAPE) for the self-catalyzed growth of GaAs nanowires and GaAs/AlxGa1-xAs axial nanowire heterostructures has been developed. DCAPE enables nanowire growth at unconventional, low temperatures in the range of 450-550 °C and is compatible with the standard Si-CMOS platform. The novel growth approach allows one to precisely control the crystal structure of the nanowires and, thus, to produce defect-free pure zinc blende GaAs-based nanowires. The strength of DCAPE is further highlighted by the controlled growth of GaAs/AlxGa1-xAs axial quantum well nanowires with abrupt interfaces and tunable thickness and Al-content of the AlxGa1-xAs sections. The GaAs/AlxGa1-xAs axial nanowire heterostructures are interesting for applications as single photon emitters with tunable emission wavelength, when they are overgrown with thick lattice-mismatched InxAl1-xAs layers in a core-shell fashion. All results presented in this thesis contribute to paving the way for a successful monolithic integration of highly uniform GaAs-based nanowires with controlled number density, dimensions and crystal structure on the mature Si platform. / GaAs-basierte Nanodrähte sind attraktive Bausteine für die Entwicklung von zukünftigen (opto)elektronischen Bauelementen dank ihrer exzellenten intrinsischen Materialeigenschaften wie zum Beispiel die direkte Bandlücke und die hohe Elektronenbeweglichkeit. Eine Voraussetzung für die Realisierung neuer Funktionalitäten auf einem einzelnen Si Chip ist die monolithische Integration der Nanodrähte auf der etablierten Si-Metall-Oxid-Halbleiter-Plattform (CMOS) mit präziser Kontrolle des Wachstumsprozesses der Nanodrähte. Das selbstkatalytische (Ga-unterstützte) Wachstum von GaAs Nanodrähten auf Si(111)-Substrat mittels Molekularstrahlepitaxie bietet die Möglichkeit vertikale Nanodrähte mit vorwiegend Zinkblende-Struktur herzustellen, während die potentielle Verunreinigung der Nanodrähte und des Substrats durch externe Katalysatoren wie Au vermieden wird. Obwohl der Wachstumsmechanismus gut verstanden ist, erweist sich die Kontrolle der Nukleationsphase, Anzahldichte und Kristallstruktur der Nanodrähte als sehr schwierig. Darüber hinaus sind relativ hohe Temperaturen im Bereich von 560-630 °C in konventionellen Wachstumsprozessen notwendig, die deren Anwendung auf der industriellen Si Plattform begrenzen. Die vorliegende Arbeit liefert zwei originelle Methoden um die bestehenden Herausforderungen in konventionellen Wachstumsprozessen zu bewältigen. Im ersten Teil dieser Arbeit wurde eine einfache Prozedur, bezeichnet als surface modification procedure (SMP), für die in situ Vorbehandlung von nativem-SiOx/Si(111)-Substrat entwickelt. Die Substratvorbehandlung mit Ga-Tröpfchen und zwei Hochtemperaturschritten vor dem Wachstumsprozess ermöglicht eine synchronisierte Nukleation aller Nanodrähte auf ihrem Substrat und folglich das Wachstum von sehr gleichförmigen GaAs Nanodraht-Ensembles mit einer sub-Poisson Verteilung der Nanodrahtlängen. Des Weiteren kann die Anzahldichte der Nanodrähte unabhängig von deren Abmessungen und ohne ex situ Vorstrukturierung des Substrats über drei Größenordnungen eingestellt werden. Diese Arbeit liefert außerdem ein grundlegendes Verständnis zur Nukleationskinetik von Ga-Tröpfchen auf nativem-SiOx und deren Wechselwirkung mit SiOx und bestätigt theoretische Voraussagen zum sogenannten Nukleations-Antibunching, dem Auftreten einer zeitlichen Anti-Korrelation aufeinanderfolgender Nukleationsereignisse. Im zweiten Teil dieser Arbeit wurde eine alternative Methode, bezeichnet als droplet-confined alternate-pulsed epitaxy (DCAPE), für das selbstkatalytische Wachstum von GaAs Nanodrähten und GaAs/AlxGa1-xAs axialen Nanodraht-Heterostrukturen entwickelt. DCAPE ermöglicht das Nanodrahtwachstum bei unkonventionell geringeren Temperaturen im Bereich von 450-550 °C und ist vollständig kompatibel mit der Standard-Si-CMOS-Plattform. Der neue Wachstumsansatz erlaubt eine präzise Kontrolle der Kristallstruktur der Nanodrähte und folglich das Wachstum von defektfreien Nanodrähten mit phasenreiner Zinkblende-Struktur. Die Stärke der DCAPE Methode wird des Weiteren durch das kontrollierte Wachstum von GaAs/AlxGa1-xAs axialen Quantentopf-Nanodrähten mit abrupten Grenzflächen und einstellbarer Dicke und Al-Anteil der AlxGa1-xAs-Segmente aufgezeigt. Die GaAs/AlxGa1-xAs axialen Nanodraht-Heterostrukturen sind interessant für den Einsatz als Einzelphotonen-Emitter mit einstellbarer Emissionswellenlänge, wenn diese mit gitterfehlangepassten InxAl1-xAs-Schichten in einer Kern-Hülle-Konfiguration überwachsen werden. Alle Ergebnisse dieser Arbeit tragen dazu bei, den Weg für eine erfolgreiche monolithische Integration von sehr gleichförmigen GaAs-basierten Nanodrähten mit kontrollierbarer Anzahldichte, Abmessungen und Kristallstruktur auf der industriell etablierten Si-Plattform zu ebnen.

<p>The development of low-cost, and reliable platforms for on-site detection of pathogenic agents, and toxic environmental traces is still a critical need for real-time monitoring of potential environmental pollution and imminent outbreaks. The biosensors market is projected to attain 31.5 billion by 2024. In this landscape, colorimetric and electrochemical devices continue to have significant relevance, with paper-based platforms leading the point-of-care (POC) segment for pathogen detection and environmental monitoring.</p> <p>Despite the true potential of biosensors in general, they have witnessed a slow rate in commercialization, mainly due to cost restrictions, and concerns related to their reliability and repeatability once scaled-up. This research evaluates the implementation of printing techniques as a strong approach for the fabrication of paper-based and flexible electrochemical biosensors. The results obtained demonstrated the ability to control and predict the variables affecting the sensing performance, achieving high precision of the printing parameters, and allowing optimization, and iterations since very early stages of prototype development.</p> <p>Besides the novel fabrication approach, this work introduces the use of truncated aptameric DNA sequences for whole cell detection of E. coli O157:H7 and heavy metals (Hg2+ and As3+), providing evidence of high stability and robustness under harsh conditions. Results obtained demonstrate their equal or even superior performance when compared to antibodies.</p> <p>We established the use of aptamer-functionalized multilayered label particles (PEI-grafted gold decorated polystyrene) with high stability as label particles. These particles address the well known drawback of non-selective aggregation typical of traditional naked Gold nanoparticles. The outstanding stability of these multilayered labels was demonstrated when used in an enhanced version of the lateral flow assay for detection of E. coli O157:H7 (state of the art for paper-based colorimetric detection of whole cell bacteria), and in a multiplexed paper-based microfluidic device for dual detection of Mercury and Arsenic. This work sets the foundation of the development of a next generation of health care and environmental monitoring devices that are portable, sensitive, quantitative, and can reliably detect multiple targets with one single test.</p>

Proteins and their intricate network of interactions are fundamental to many molecular processes that govern life. Mass spectrometry-based structural proteomics represents a powerful set of techniques for characterizing protein structures and interactions. The last decade has witnessed a large-scale adoption in the application of these techniques toward solving a variety of biological questions. Addressing these questions has often been coincident with the further development of these techniques. Insight into the structures of individual proteins and their interactions with other proteins in a proteome-wide context has been made possible by recent developments in the relatively new field of chemical crosslinking combined with mass spectrometry. In these experiments crosslinking reagents are used to capture protein-protein interactions by forming covalent linkages between proximal amino acid residues. The crosslinked proteins are then enzymatically digested into peptides, and the covalently-coupled crosslinked peptides are identified by mass spectrometry. These identified crosslinked peptides thus provide evidence of interacting regions within or between proteins. In this dissertation the development of tools and methods that facilitate this powerful technique are described. The primary arc of this work follows the development and application of mass spectrometry-based approaches for the identification of protein crosslinks ranging from those which exist endogenously to those which are introduced synthetically. Firstly, the development of a novel strategy for comprehensive determination of naturally occurring protein crosslinks in the form of disulfide bonds is described. Secondly, the application of crosslinking reagents to create synthetic crosslinks in proteins coupled with molecular dynamics simulations is explored in order to structurally characterize the intrinsically disordered tau protein. Thirdly, improvements to a crosslinking-mass spectrometry method for defining a protein-protein interactome in a complex sample is developed. Altogether, these described approaches represent a toolset to allow researchers to access information about protein structure and interactions. / Graduate

Das Fügen mehrerer Komponenten während des Spritzgießprozesses wird bei vielen Spritzgießsonderverfahren angewandt. Diese Arbeit beschäftigt sich mit der Verbundbildung zwischen einem kalten Einlegeteil und der einströmenden Kunststoffschmelze beim Spritzgießen, im Folgenden Stoffübertragung genannt. Ein Großteil der Untersuchungen findet an Zweikomponenten-Zugstäben statt, wobei erste und zweite Komponente aus dem gleichen Thermoplast gefertigt werden. Mögliche Einflussfaktoren auf die Verbundfestigkeit werden zunächst im Theorieteil vorgestellt und diskutiert. Eine Auswahl relevanter Prozess- und Materialparameter wird dann in praktischen Versuchen detailliert analysiert. Es wird nach korrelierenden Tendenzen sowohl zwischen unterschiedlichen Verfahren als auch zwischen verschiedenen Kunststoffen gesucht. Mittels statistischer Versuchsplanung werden die Spritzgießparameterkombinationen nach Größe des Einflusses auf die Verbundfestigkeit sortiert. Dies trägt zum Verständnis der bei der Stoffübertragung ablaufenden Grundmechanismen bei. Weiterhin werden die Einflüsse der Prozessparameter auf das neue Verfahren der In-Mold Oberflächenmodifizierung, bei dem ein funktionaler Modifikator während des Spritzgießprozesses übertragen wird, mit den Ergebnissen der Zweikomponenten-Verbundfestigkeit verglichen. Abschließend wird auf die Besonderheiten bei der selektiven Stoffübertragung eingegangen und das neue Verfahren des In-Mold Printing vorgestellt. / The joining of two components by the process of injection molding is state of the art, although adhesion phenomena are not fully understood yet. The formation of bonds between a cold material, which was inserted or applied onto the surface of the cavity before injection molding, and an injected polymer melt is studied in this work. Providing sufficient bond strength, the material is transferred from the surface of the mold to the injection molded part. Possibly influencing factors on the bond strength are first identified, theoretically discussed, later in experiments varied and finally analyzed. Thereby correlating tendencies between different polymers and different in-mold technologies are observed. The relevant material and processing parameters are put in order by their influence on the bond strength using design of experiments. This helps to understand the mechanisms of the formation of bonds. The majority of the experiments is concerned with two component injection molding by measuring the bond strength of two component tensile bars, produced under varying processing conditions. In each case, first and second components are made of the same thermoplastic polymer. The thermal energy of the melt can be used also to initiate chemical reactions. This permits bonding of a thin layer of a functional polymer, which is applied onto the surface of the mold before injecting the melt, to the surface of the molded part. In this way, process-integrated surface modification during injection molding becomes possible. In a further attempt, patterns of paint are printed onto the surface of the mold by pad printing. During injection molding the paint is transferred completely to the surface of the polymeric part. Using this new technology of In-Mold Printing, fully finished surface decorated parts can be produced by injection molding.

Das Fügen mehrerer Komponenten während des Spritzgießprozesses wird bei vielen Spritzgießsonderverfahren angewandt. Diese Arbeit beschäftigt sich mit der Verbundbildung zwischen einem kalten Einlegeteil und der einströmenden Kunststoffschmelze beim Spritzgießen, im Folgenden Stoffübertragung genannt. Ein Großteil der Untersuchungen findet an Zweikomponenten-Zugstäben statt, wobei erste und zweite Komponente aus dem gleichen Thermoplast gefertigt werden. Mögliche Einflussfaktoren auf die Verbundfestigkeit werden zunächst im Theorieteil vorgestellt und diskutiert. Eine Auswahl relevanter Prozess- und Materialparameter wird dann in praktischen Versuchen detailliert analysiert. Es wird nach korrelierenden Tendenzen sowohl zwischen unterschiedlichen Verfahren als auch zwischen verschiedenen Kunststoffen gesucht. Mittels statistischer Versuchsplanung werden die Spritzgießparameterkombinationen nach Größe des Einflusses auf die Verbundfestigkeit sortiert. Dies trägt zum Verständnis der bei der Stoffübertragung ablaufenden Grundmechanismen bei. Weiterhin werden die Einflüsse der Prozessparameter auf das neue Verfahren der In-Mold Oberflächenmodifizierung, bei dem ein funktionaler Modifikator während des Spritzgießprozesses übertragen wird, mit den Ergebnissen der Zweikomponenten-Verbundfestigkeit verglichen. Abschließend wird auf die Besonderheiten bei der selektiven Stoffübertragung eingegangen und das neue Verfahren des In-Mold Printing vorgestellt. / The joining of two components by the process of injection molding is state of the art, although adhesion phenomena are not fully understood yet. The formation of bonds between a cold material, which was inserted or applied onto the surface of the cavity before injection molding, and an injected polymer melt is studied in this work. Providing sufficient bond strength, the material is transferred from the surface of the mold to the injection molded part. Possibly influencing factors on the bond strength are first identified, theoretically discussed, later in experiments varied and finally analyzed. Thereby correlating tendencies between different polymers and different in-mold technologies are observed. The relevant material and processing parameters are put in order by their influence on the bond strength using design of experiments. This helps to understand the mechanisms of the formation of bonds. The majority of the experiments is concerned with two component injection molding by measuring the bond strength of two component tensile bars, produced under varying processing conditions. In each case, first and second components are made of the same thermoplastic polymer. The thermal energy of the melt can be used also to initiate chemical reactions. This permits bonding of a thin layer of a functional polymer, which is applied onto the surface of the mold before injecting the melt, to the surface of the molded part. In this way, process-integrated surface modification during injection molding becomes possible. In a further attempt, patterns of paint are printed onto the surface of the mold by pad printing. During injection molding the paint is transferred completely to the surface of the polymeric part. Using this new technology of In-Mold Printing, fully finished surface decorated parts can be produced by injection molding.

Membrane filtration processes are widely utilized across different industrial sectors for biological and environmental separations. Examples of the former are sterile filtration and protein fractionation via microfiltration (MF) and ultrafiltration (UF) while drinking water treatment, tertiary treatment of wastewater, water reuse and desalination via MF, UF, nanofiltration (NF) and reverse-osmosis (RO) are examples of the latter. A common misconception is that the performance of membrane separation is solely dependent on the membrane pore size, whereas a multitude of parameters including solution conditions, solute concentration, presence of specific ions, hydrodynamic conditions, membrane structure and surface properties can significantly influence the separation performance and the membrane’s fouling propensity. The conventional approach for studying filtration performance is to use a single lab- or pilot-scale module and perform numerous experiments in a sequential manner which is both time-consuming and requires large amounts of material. Alternatively, high-throughput (HT) techniques, defined as the miniaturized version of conventional unit operations which allow for multiple experiments to be run in parallel and require a small amount of sample, can be employed. There is a growing interest in the use of HT techniques to speed up the testing and optimization of membrane-based separations. In this work, different HT screening approaches are developed and utilized for the evaluation and optimization of filtration performance using flat-sheet and hollow-fiber (HF) membranes used in biological and environmental separations. The effects of various process factors were evaluated on the separation of different biomolecules by combining a HT filtration method using flat-sheet UF membranes and design-of-experiments methods. Additionally, a novel HT platform was introduced for multi-modal (constant transmembrane pressure vs. constant flux) testing of flat-sheet membranes used in bio-separations. Furthermore, the first-ever HT modules for parallel testing of HF membranes were developed for rapid fouling tests as well as extended filtration evaluation experiments. The usefulness of the modules was demonstrated by evaluating the filtration performance of different foulants under various operating conditions as well as running surface modification experiments. The techniques described herein can be employed for rapid determination of the optimal combination of conditions that result in the best filtration performance for different membrane separation applications and thus eliminate the need to perform numerous conventional lab-scale tests. Overall, more than 250 filtration tests and 350 hydraulic permeability measurements were performed and analyzed using the HT platforms developed in this thesis. / Thesis / Doctor of Philosophy (PhD) / Membrane filtration is widely used as a key separation process in different industries. For example, microfiltration (MF) and ultrafiltration (UF) are used for sterilization and purification of bio-products. Furthermore, MF, UF and reverse-osmosis (RO) are used for drinking water and wastewater treatment. A common misconception is that membrane filtration is a process solely based on the pore size of the membrane whereas numerous factors can significantly affect the performance. Conventionally, a large number of lab- or full-scale experiments are performed to find the optimum operating conditions for each filtration process. High-throughput (HT) techniques are powerful methods to accelerate the pace of process optimization—they allow for multiple experiments to be run in parallel and require smaller amounts of sample. This thesis focuses on the development of different HT techniques that require a minimal amount of sample for parallel testing and optimization of membrane filtration processes with applications in environmental and biological separations. The introduced techniques can reduce the amount of sample used in each test between 10-50 times and accelerate process development and optimization by running parallel tests.