@phdthesis{Jones2018,
  author    = {Jones, Gabriel},
  title     = {Bioinspired FGF-2 delivery for pharmaceutical application},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-153179},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2018},
  abstract  = {In resent years the rate of biologics (proteins, cytokines and growth-factors) as newly registered drugs has steadily risen. The greatest challenge for pharmaceutical biologics poses its arrival at the desired target location due to e.g. proteolytic and pH dependent degradation, plasma protein binding, insolubility etc. Therefore, advanced drug delivery systems, where biologics are site directed immobilized to carriers mimicking endogenous storage sites such as the extra cellular matrix can enormously assist the application and consequently the release of exogenous administered pharmaceutical biologics. We have resorted to the fibroblast growth factor 2/ heparansulfate/ fibroblast growth factor bindingprotein 1 system as a model. Phase I deals with the selection and subcloning of a wild type murine FGF-2 construct into the bacterial pHis-Trx vector system for high yields of expression and fast, feasible purification measurements. This first step enables the provision of mFGF-2, which plays a pivotal part as a growth factor in the wound healing process as well as the vascularization of tumors, for future investigations. Therefore, the correct expression of mFGF-2 was monitored via MALDI-MS and SDS-PAGE, whereas the proper folding of the tertiary beta-trefoil structure was assessed by fluorescence spectroscopy. The MTT assay allowed us to ensure that the bioactivity was comparable to sourced FGF-2. In the last step, the purity; a requirement for future binding- and protein-protein interaction assays was monitored chromatographically (RP-HPLC). In addition, a formulation for freeze-drying was developed to ensure protein stability and integrity over a period of 60 days. Altogether, the bacterial expression and purification proved to be suitable, leading to bioactive and stable production of mFGF-2. In Phase II the expression, purification and characterization of FGFBP1, as the other key partner in the FGF-2/ HS/ FGFBP1 system is detailed. As FGFBP1 exhibits a complex tertiary structure, comprised of five highly conserved disulfide bonds and presumably multiple glycosylation sites, a eukaryotic expression was used. Human embryonic kidney cells (HEK 293F) as suspension cells were transiently transfected with DNA-PEI complexes, leading to expression of Fc-tagged murine FGFBP1. Different PEI to DNA ratios and expression durations were investigated for optimal expression yields, which were confirmed by western blot analysis and SDS-PAGE. LC-MS/MS analysis of trypsin and elastase digested FGFBP1 gave first insights of the three O-glycosylation sites. Furthermore, the binding protein was modified by inserting a His6-tag between the Fc-tag (for purification) and the binding protein itself to enable later complexation with radioactive 99mTc as radio ligand to track bio distribution of administered FGFBP1 in mice. Overall, expression, purification and characterization of mFGFBP1 variants were successful with a minor draw back of instability of the tag free binding protein. Combining the insights and results of expressed FGF-2 as well as FGFBP1 directed us to the investigation of the interaction of each partner in the FGF-2/ HS/ FGFBP1 system as Phase III. Thermodynamic behavior of FGF-2 and low molecular weight heparin (enoxaparin), as a surrogate for HS, under physiological conditions (pH 7.4) and pathophysiological conditions, similar to hypoxic, tumorous conditions (acidic pH) were monitored by means of isothermal titration calorimetry. Buffer types, as well as the pH influences binding parameters such as stoichiometry (n), enthalpy (ΔH) and to some extent the dissociation constant (KD). These findings paved the way for kinetic binding investigations, which were performed by surface plasmon resonance assays. For the first time the KD of full length FGFBP1 and FGF-2 was measured. Furthermore the binding behavior of FGF-2 to FGFBP1 in the presence of various heparin concentrations suggest a kinetic driven release of bound FGF-2 by its chaperone FGFBP1. Having gathered multiple data on the FGF-2 /HS /FGFBP1 system mainly in solution, our next step in Phase IV was the development of a test system for immobilized proteins. With the necessity to better understand and monitor the cellular effects of immobilized growth factors, we decorated glass slides in a site-specific manner with an RGD-peptide for adhesion of cells and via the copper(I)-catalyzed-azide-alkyne cycloaddition (CuAAC) a fluorescent dye (a precursor for modified proteins for click chemistry). Human osteosarcoma cells were able to grow an the slides and the fluorescence dye was immobilized in a biocompatible way allowing future thorough bioactivity assay such as MTT-assays and phospho-ERK-assays of immobilized growth factors.},
  subject      = {Fibroblastenwachstumsfaktor},
  language  = {en}
}
@phdthesis{Wistlich2019,
  author    = {Wistlich, Laura},
  title     = {NCO-sP(EO-stat-PO) as functional additive for biomaterials' development},
  doi       = {10.25972/OPUS-17836},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178365},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2019},
  abstract  = {The aim of this thesis was the application of the functional prepolymer NCO-sP(EO-stat-PO) for the development of new biomaterials. First, the influence of the star-shaped polymers on the mechanical properties of biocements and bone adhesives was investigated. 3-armed star-shaped macromers were used as an additive for a mineral bone cement, and the influence on the mechanical properties was studied. Additionally, a previously developed bone adhesive was examined regarding cytocompatibility. The second topic was the examination of novel functionalization steps which were performed on the surface of electrospun fibers modified with NCO-sP(EO-stat-PO). This established method of functionalizing electrospun meshes was advanced regarding the modification with proteins which was then demonstrated in a biological application. Two different kinds of antibodies were immobilized on the fiber surface in a consecutive manner and the influence of these proteins on the cell behavior was investigated. The final topic involved the quantification of surface-bound peptide sequences. By functionalization of the peptides with the UV-reactive molecule 2-mercaptopyridine it was possible to quantify this compound via UV measurements by cleavage of disulfide bridges and indirectly draw conclusions about the number of immobilized peptides. In the field of mineral biocements and bone adhesives, NCO-sP(EO-stat-PO) was able to influence the setting behavior and mechanical performance of mineral bone cements based on calcium phosphate chemistry. The addition of NCO-sP(EO-stat-PO) resulted in a pseudo-ductile fracture behavior due to the formation of a hydrogel network in the cement, which was then mineralized by nanosized hydroxyapatite crystals following cement setting. Accordingly, a commercially available aluminum silicate cement from civil engineering could be modified. In addition, it could be shown that the use of NCO-sP(EO-stat-PO) is beneficial for adjusting specific material properties of bone adhesives. Here, the crosslinking behavior of the prepolymer in an aqueous medium was exploited to form an interpenetrating network (IPN) together with a photochemically curing poly(ethylene glycol) dimethacrylate (PEGDMA) matrix. This could be used for the development of a bone adhesive with an improved adhesion to bone in a wet environment. The developed bone adhesive was further investigated in terms of possible influences of the initiator systems. In addition, the material system was tested for cytocompatibility by using different cell lines. Moreover, the preparation of electrospun fiber meshes via solution electrospinning consisting of poly(lactide-co-glycolide) (PLGA) as a backbone polymer and NCO-sP(EO-stat-PO) as functional additive is an established method for the application of the meshes as a replacement of the native extracellular matrix (ECM). In general, these fibers reveal diameters in the nanometer range, are protein and cell repellent due to the hydrophilic properties of the prepolymer and show a specific biofunctionalization by immobilization of peptide sequences. Here, the isocyanate groups presented on the fiber surface after electrospinning were used to carry out various functionalization steps, while retaining the properties of protein and cell repellency. The modification of the electrospun fibers involved the immobilization of analogs or antagonists of tumor necrosis factor (TNF) and the indirect detection of these by interaction with a light-producing enzyme. Here, a multimodal modification of the fiber surface with RGD to mediate cell adhesion and two different antibodies could be achieved. After culturing the cell line HT1080, the pro- or anti-inflammatory response of cells could be detected by IL-8 specific ELISA measurements. Furthermore, the quantification of molecules on the surface of electrospun fibers was investigated. It was tested whether the detection by means of super-resolution microscopy would be possible. Therefore, experiments were performed with short amino acid sequences such as RGD for quantification by fluorescence microscopy. Based on earlier results, in which a UV-spectrometrically active molecule was used to detect the quantification of RGD, it was shown that short peptides can also be quantified in a small scale on flat functional substrates (2D) such as NCO-sP(EO-stat-PO) hydrogel coatings, and modified electrospun fibers produced from PLGA and NCO-sP(EO-stat-PO) (3D). In addition, a collagen sequence was used to prove that a successful quantification can be carried out as well for longer peptide chains. These studies have revealed that NCO-sP(EO-stat-PO) can serve as a functional additive for many applications and should be considered for further studies on the development of novel biomaterials. The rapid crosslinking reaction, the resulting hydrogel formation and the biocompatibility are to be mentioned as positive properties, which makes the prepolymer interesting for future applications.},
  subject      = {Sternpolymere},
  language  = {en}
}
@phdthesis{Gutmann2019,
  author    = {Gutmann, Marcus},
  title     = {Functionalization of cells, extracellular matrix components and proteins for therapeutic application},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170602},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2019},
  abstract  = {Glycosylation is a biochemical process leading to the formation of glycoconjugates by linking glycans (carbohydrates) to proteins, lipids and various small molecules. The glycans are formed by one or more monosaccharides that are covalently attached, thus offering a broad variety depending on their composition, site of glycan linkage, length and ramification. This special nature provides an exceptional and fine tunable possibility in fields of information transfer, recognition, stability and pharmacokinetic. Due to their intra- and extracellular omnipresence, glycans fulfill an essential role in the regulation of different endogenous processes (e.g. hormone action, immune surveillance, inflammatory response) and act as a key element for maintenance of homeostasis. The strategy of metabolic glycoengineering enables the integration of structural similar but chemically modified monosaccharide building blocks into the natural given glycosylation pathways, thereby anchoring them in the carbohydrate architecture of de novo synthesized glycoconjugates. The available unnatural sugar molecules which are similar to endogenous sugar molecules show minimal perturbation in cell function and - based on their multitude functional groups - offer the potential of side directed coupling with a target substance/structure as well as the development of new biological properties. The chemical-enzymatic strategy of glycoengineering provides a valuable complement to genetic approaches. This thesis primarily focuses on potential fields of application for glycoengineering and its further use in clinic and research. The last section of this work outlines a genetic approach, using special Escherichia coli systems, to integrate chemically tunable amino acids into the biosynthetic pathway of proteins, enabling specific and site-directed coupling with target substances. With the genetic information of the methanogen archaea, Methanosarcina barkeri, the E. coli. system is able to insert a further amino acid, the pyrrolysine, at the ribosomal site during translation of the protein. The natural stop-codon UAG (amber codon) is used for this newly obtained proteinogenic amino acid. Chapter I describes two systems for the integration of chemically tunable monosaccharides and presents methods for characterizing these systems. Moreover, it gives a general overview of the structure as well as intended use of glycans and illustrates different glycosylation pathways. Furthermore, the strategy of metabolic glycoengineering is demonstrated. In this context, the structure of basic building blocks and the epimerization of monosaccharides during their metabolic fate are discussed. Chapter II translates the concept of metabolic glycoengineering to the extracellular network produced by fibroblasts. The incorporation of chemically modified sugar components in the matrix provides an innovative, elegant and biocompatible method for site-directed coupling of target substances. Resident cells, which are involved in the de novo synthesis of matrices, as well as isolated matrices were characterized and compared to unmodified resident cells and matrices. The natural capacity of the matrix can be extended by metabolic glycoengineering and enables the selective immobilization of a variety of therapeutic substances by combining enzymatic and bioorthogonal reaction strategies. This approach expands the natural ability of extracellular matrix (ECM), like the storage of specific growth factors and the recruitment of surface receptors along with synergistic effects of bound substances. By the selection of the cell type, the production of a wide range of different matrices is possible. Chapter III focuses on the target-oriented modification of cell surface membranes of living fibroblast and human embryonic kidney cells. Chemically modified monosaccharides are inserted by means of metabolic glycoengineering and are then presented on the cell surface. These monosaccharides can later be covalently coupled, by "strain promoted azide-alkyne cycloaddition" (SPAAC) and/or "copper(I)-catalyzed azide-alkyne cycloaddition" (CuAAC), to the target substance. Due to the toxicity of the copper catalysator in the CuAAC, cytotoxicity analyses were conducted to determine the in vivo tolerable range for the use of CuAAC on living cell systems. Finally, the efficacy of both bioorthogonal reactions was compared. Chapter IV outlines two versatile carrier - spacer - payload delivery systems based on an enzymatic cleavable linker, triggered by disease associated protease. In the selection of carrier systems (i) polyethylene glycol (PEG), a well-studied, Food and Drug Administration approved substance and very common tool to increase the pharmacokinetic properties of therapeutic agents, was chosen as a carrier for non-targeting systems and (ii) Revacept, a human glycoprotein VI antibody, was chosen as a carrier for targeting systems. The protease sensitive cleavable linker was genetically inserted into the N-terminal region of fibroblast growth factor 2 (FGF-2) without jeopardizing protein activity. By exchanging the protease sensitive sequence or the therapeutic payload, both systems represent a promising and adaptable approach for establishing therapeutic systems with bioresponsive release, tailored to pre-existing conditions. In summary, by site-specific functionalization of various delivery platforms, this thesis establishes an essential cornerstone for promising strategies advancing clinical application. The outlined platforms ensure high flexibility due to exchanging single or multiple elements of the system, individually tailoring them to the respective disease or target site.},
  subject      = {Glykosylierung},
  language  = {en}
}
@phdthesis{Bertlein2019,
  author    = {Bertlein, Sarah},
  title     = {Hydrogels as Biofunctional Coatings and Thiol-Ene Clickable Bioinks for Biofabrication},
  doi       = {10.25972/OPUS-17422},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-174225},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2019},
  abstract  = {Ziel dieser Arbeit war die Entwicklung von funktionalisierbaren Hydrogel Beschichtungen f{\"u}r Schmelz-elektrogeschriebene PCL Ger{\"u}ste und von Bio-druckbaren Hydrogelen f{\"u}r die Biofabrikation. Hydrogel Beschichtungen von Schmelz-elektrogeschriebenen Konstrukten erm{\"o}glichten die Kontrolle der Oberfl{\"a}chen-Hydrophilie und damit Zell-Material Interaktionsstudien in minimal Protein-adh{\"a}siven Umgebungen. Zu diesem Zweck wurde ein hydrophiles sternf{\"o}rmiges vernetzbares Polymer verwendet und eine Optimierung der Beschichtungsbedingungen durchgef{\"u}hrt. Außerdem boten neu entwickelte photosensitive Konstrukte eine Zeit- und pH-unabh{\"a}ngige Biofunktionalisierung. Bio-druckbare Hydrogele f{\"u}r die Biofabrikation basierten auf der Allyl-Funktionalisierung von Gelatine (GelAGE) und modifizierten Hyalurons{\"a}ure-Produkten, die das Hydrogel-Vernetzen mittels Thiol-En Click Chemie erm{\"o}glichen. Die Optimierung der GelAGE Hydrogel-Eigenschaften wurde durch eine detaillierte Analyse der Syntheseparameter, variierender En:SH Verh{\"a}ltnisse, unterschiedlicher Vernetzungsmolek{\"u}le und Photoinitiatoren erreicht. Die Homogenit{\"a}t der Thiol-En Netzwerke wurde mit denen der freien radikalischen Polymerisation verglichen und die Verwendbarkeit von GelAGE als Bio-Tinte f{\"u}r den Extrusions-basierten Bio-Druck wurde untersucht. Es wurde angenommen, dass reine Hyalurons{\"a}ure-basierte Bio-Tinten eine Beibehaltung der mechanischen und rheologischen Eigenschaften, der Zellviabilit{\"a}t und der Prozessierbarkeit erm{\"o}glichen trotz geringerem Polymer- und Thiol-Anteil der Hydrogele. Hydrogel-Beschichtungen: Hoch definierte PCL Ger{\"u}ste wurden mittels MEW hergestellt und anschließend mit sechs armigen sternf{\"o}rmigen vernetzbaren Polymeren (sP(EO-stat-PO)) beschichtet. Die Vernetzung wird durch die w{\"a}ssrig-induzierte Hydrolyse reaktiver Isocyanatgruppen (NCO) von sP(EO-stat-PO) bedingt. Diese Beschichtung erh{\"o}hte die Oberfl{\"a}chen-Hydrophilie und stellte eine Plattform f{\"u}r weitere Biofunktionalisierungen, in minimal Protein-adh{\"a}siven Umgebungen, dar. Nicht nur das Beschichtungsprotokoll wurde hinsichtlich der sP(EO-stat-PO) Konzentrationen und der Beschichtungsdauern optimiert, sondern auch Vorbehandlungen der Ger{\"u}ste wurden entwickelt. Diese waren essentiell um die finale Hydrophilie von sP(EO-stat-PO) beschichteten Ger{\"u}ste so zu erh{\"o}hen, dass unspezifische Protein-Adh{\"a}sionen vollst{\"a}ndig unterbunden wurden. Die sP(EO-stat-PO) Schichtdicke, von ungef{\"a}hr 100 nm, erm{\"o}glicht generell in vitro Studien nicht nur in Abh{\"a}ngigkeit der Ger{\"u}st-Biofunktionalisierung, sondern auch in Abh{\"a}ngigkeit der Ger{\"u}st-Architektur durchzuf{\"u}hren. Das Ausmaß der Hydrogel-Beschichtung wurde mittels einer indirekten Quantifizierung der NCO-Hydrolyse-Produkte ermittelt. Kenntnis {\"u}ber die NCO-Hydrolyse-Kinetik erm{\"o}glichte ein Gleichgewicht zwischen ausreichend beschichteten Ger{\"u}sten und der Pr{\"a}senz der NCO-Gruppen herzustellen, welche f{\"u}r die anschließenden Biofunktionalisierungen genutzt wurden. Diese Zeit- und pH-abh{\"a}ngige Biofunktionalisierung war jedoch nur f{\"u}r kleine Biomolek{\"u}le m{\"o}glich. Um diese Beschr{\"a}nkung zu umgehen und auch hochmolekulare Biomolek{\"u}le kovalent anzubinden, wurde ein anderer Reaktionsweg entwickelt. Dieser basierte auf der Photolyse von Diazirin-Gruppen und erm{\"o}glichte eine Zeit- und pH-unabh{\"a}ngige Biofunktionalisierung der Ger{\"u}ste mit Streptavidin und Kollagen Typ I. Die Fibrillen bildende Eigenschaft von Kollagen wurde genutzt um auf den Ger{\"u}sten verschiedene Kollagen-Konformationen zu erhalten und eine erste in vitro Studie best{\"a}tigte die Anwendbarkeit f{\"u}r Zell-Material Interaktionsstudien. Die hier entwickelten Ger{\"u}ste k{\"o}nnten verwendet werden um tiefere Einblicke in die Grundlagen der zellul{\"a}ren Wahrnehmung zu erhalten. Insbesondere die Komplexit{\"a}t mit der Zellen z.B. Kollagen wahrnehmen bleibt weiterhin kl{\"a}rungsbed{\"u}rftig. Hierf{\"u}r k{\"o}nnten diverse Hierarchien von Kollagen-{\"a}hnlichen Konformationen an die Ger{\"u}ste gebunden werden, z.B. Gelatine oder Kollagen-abgeleitete Peptidsequenzen. Dann k{\"o}nnte die Aktivierung der DDR-Rezeptoren in Abh{\"a}ngigkeit der Komplexit{\"a}t der angebundenen Substanzen bestimmt werden. Aufgrund der starken Streptavidin-Biotin Bindung k{\"o}nnten Streptavidin funktionalisierte Ger{\"u}ste eine vielseitige Plattform f{\"u}r die Immobilisierung von jeglichen biotinylierten Molek{\"u}len darstellen. Gelatine-basierte Bio-Tinten: Zuerst wurden die GelAGE-Produkte hinsichtlich der Molekulargewichts-Verteilung und der Integrit{\"a}t der Aminos{\"a}uren-Zusammensetzung synthetisiert. Eine detailliert Studie, mit variierenden molaren Edukt-Verh{\"a}ltnissen und Synthese-Zeitspannen, wurde durchgef{\"u}hrt und implizierte, dass der Gelatine Abbau am deutlichsten f{\"u}r stark alkalische Synthesebedingungen mit langen Reaktionszeiten war. Gelatine beinhaltet mehrere funktionalisierbare Gruppen und anhand diverser Model-Substanzen und Analysen wurde die vorrangige Amingruppen-Funktionalisierung ermittelt. Die Homogenit{\"a}t des GelAGE-Polymernetzwerkes, im Vergleich zu frei radikalisch polymerisierten GelMA-Hydrogelen, wurde best{\"a}tigt. Eine ausf{\"u}hrliche Analyse der Hydrogel-Zusammensetzungen mit variierenden funktionellen Gruppen Verh{\"a}ltnissen und UV- oder Vis-Licht induzierbaren Photoinitiatoren wurde durchgef{\"u}hrt. Die UV-Initiator Konzentration ist aufgrund der Zell-Toxizit{\"a}t und der potenziellen zellul{\"a}ren DNA-Besch{\"a}digung durch UV-Bestrahlung eingeschr{\"a}nkt. Das Zell-kompatiblere Vis-Initiator System hingegen erm{\"o}glichte, durch die kontrollierte Photoinitiator-Konzentration bei konstanten En:SH Verh{\"a}ltnissen und Polymeranteilen, die Einstellung der mechanischen Eigenschaften {\"u}ber eine große Spanne hinweg. Die Flexibilit{\"a}t der GelAGE Bio-Tinte f{\"u}r unterschiedliche additive Fertigungstechniken konnte, durch Ausnutzung des temperaturabh{\"a}ngigen Gelierungsverhaltens unterschiedlich stark degradierter GelAGE Produkte, f{\"u}r Stereolithographie und Extrusions-basiertem Druck bewiesen werden. Außerdem wurde die Viabilit{\"a}t zellbeladener GelAGE Konstrukte bewiesen, die mittels Extrusions-basiertem Bio-Druck erhalten wurden. Die Verwendung diverser multifunktioneller und makromolekularer Thiol-Vernetzungsmolek{\"u}le erm{\"o}glichte eine Verbesserung der mechanischen und rheologischen Eigenschaften und ebenso der Prozessierbarkeit. Verglichen mit dem kleinen bis-Thiol-funktionellen Vernetzungsmolek{\"u}l waren geringere Thiol-Vernetzer-Konzentrationen notwendig um bessere mechanische Festigkeiten und physikochemische Eigenschaften der Hydrogele zu erhalten. Der Extrusions-basierte Bio-Druck unterschiedlicher eingekapselter Zellen verdeutlichte die Notwendigkeit der individuellen Optimierung von Zell-beladenen Hydrogel-Formulierungen. Nicht nur die Zellviabilit{\"a}t von eingekapselten Zellen in Extrusions-basierten biogedruckten Konstrukten sollte bewertet werden, sondern auch andere Parameter wie die Zellmorphologie oder die Kollagen- oder Glykosaminoglykan-Produktion, da diese einige der essentiellen Voraussetzungen f{\"u}r die Verwendung in Knorpel Tissue Engineering Konzepten darstellen. Außerdem sollten diese Studien auf die stereolithographischen Ans{\"a}tze erweitert werden und letztlich w{\"a}re die Flexibilit{\"a}t und Zellkompatibilit{\"a}t der Formulierungen mit makromolekularen Vernetzern von Interesse. Makromolekulare Vernetzer erm{\"o}glichten die Reduktion des Polymeranteils und des Thiol-Gehalts und k{\"o}nnen, insbesondere in Kombination mit dem Zell-kompatibleren Vis-Initiator-System, voraussichtlich zu einer gesteigerten Zellkompatibilit{\"a}t beitragen, was zu kl{\"a}ren bleibt. Hyalurons{\"a}ure-basierte Bio-Tinten: Unterschiedliche Hyalurons{\"a}ure-Produkte (HA) wurden synthetisiert, sodass diese En- (HAPA) oder Thiol-Funktionalit{\"a}ten (LHASH) beinhalteten, um reine HA Thiol-En vernetzte Hydrogele zu erhalten. In Abh{\"a}ngigkeit des Molekulargewichts der HA-Produkte, der Polymeranteile und des En:SH Verh{\"a}ltnisses, konnte eine große Spanne an mechanischen Festigkeiten abgedeckt werden. Aufgrund der hohen Viskosit{\"a}t war allerdings im Falle von hochmolekularen HA (HHAPA) Produkt-L{\"o}sungen (HHAPA + LHASH) die Handhabbarkeit auf 5.0 wt.-\% beschr{\"a}nkt. Die Verwendung der gleichen HA Thiol-Komponenten (LHASH) erm{\"o}glichte Hybrid-Hydrogele, mit HA und GelAGE, mit reinen HA-Hydrogelen zu vergleichen. Obwohl der Polymeranteil von HHAPA + LHASH Hydrogelen signifikant geringer war, als im Vergleich zu Hybrid-Hydrogelen (GelAGE + LHASH), wurden f{\"u}r gleiche En:SH Verh{\"a}ltnisse {\"a}hnliche mechanische und physikochemische Eigenschaften reiner HA-Hydrogele bestimmt. Aufgrund der geringen Viskosit{\"a}t niedermolekularer HA L{\"o}sungen (LHAPA + LHASH) konnten diese nicht f{\"u}r den Extrusions-basierten Druck verwendet werden. Das nicht temperaturabh{\"a}ngige HHAPA + LHASH System hingegen konnte mit nur einem Viertel des Polymeranteils der Hybrid Formulierungen gedruckt werden. Im Vergleich zu der Hybrid Bio-Tinte wurde angenommen, dass das hoch viskose Verhalten von HHAPA + LHASH L{\"o}sungen, der geringere Polymeranteil, der geringere Druck f{\"u}r das Drucken und eine demzufolge geringere Scherspannung, maßgeblich zu der hohen Zellviabilit{\"a}t in Extrusions-basiert-biogedruckten Konstrukten beisteuerten. Die niedrigmolekulare HA Formulierung (LHAPA + LHASH) konnte zwar nicht f{\"u}r den Extrusions-basierten Druck verwendet werden, allerdings besitzt dieses System Potential f{\"u}r andere additive Fertigungstechniken wie z.B. der Stereolithographie. Um dieses System weiterzuentwickeln w{\"a}re, analog zu dem GelAGE System, eine detailliertere Studie zu den Funktionen eingekapselter Zellen hilfreich. Außerdem sollte die Initiierung dieses Systems mit dem Vis-Initiator untersucht werden.},
  subject      = {Biomaterial},
  language  = {en}
}
@phdthesis{Blum2021,
  author    = {Blum, Carina},
  title     = {A first step to an integral biointerface design for the early phase of regeneration},
  doi       = {10.25972/OPUS-21211},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-212117},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2021},
  abstract  = {The implantation of any foreign material into the body automatically starts an immune reaction that serves as the first, mandatory step to regenerate tissue. The course of this initial immune reaction decides on the fate of the implant: either the biomaterial will be integrated into the host tissue to subsequently fulfill its intended function (e.g., tissue regeneration), or it will be repelled by fibrous encapsulation that determines the implant failure. Especially neutrophils and macrophages play major roles during this inflammatory response and hence mainly decide on the biomaterial's fate. For clinically relevant tissue engineering approaches, biomaterials may be designed in shape and morphology as well as in their surface functionality to improve the healing outcome, but also to trigger stem cell responses during the subsequent tissue regeneration phase. The main focus of this thesis was to unravel the influence of scaffold characteristics, including scaffold morphology and surface functionality, on primary human innate immune cells (neutrophils and macrophages) and human mesenchymal stromal cells (hMSCs) to assess their in vitro immune response and tissue regeneration capacity, respectively. The fiber-based constructs were produced either via melt electrowriting (MEW), when the precise control over scaffold morphology was required, or via solution electrospinning (ES), when the scaffold design could be neglected. All the fiber-based scaffolds used throughout this thesis were composed of the polymer poly(ε caprolactone) (PCL). A novel strategy to model and alleviate the first direct cell contact of the immune system with a peptide-bioactived fibrous material was presented in chapter 3 by treating the material with human neutrophil elastase (HNE) to imitate the neutrophil attack. The main focus of this study was put on the effect of HNE towards an RGDS-based peptide that was immobilized on the surface of a fibrous material to improve subsequent L929 cell adhesion. The elastase efficiently degraded the peptide-functionality, as evidenced by a decreased L929 cell adhesion, since the peptide integrated a specific HNE-cleavage site (AAPV-motif). A sacrificial hydrogel coating based on primary oxidized hyaluronic acid (proxHA), which dissolved within a few days after the neutrophil attack, provided an optimal protection of the peptide-bioactivated fibrous mesh, i.e, the hydrogel alleviated the neutrophil attack and largely ensured the biomaterial's integrity. Thus, according to these results, a means to protect the biomaterial is required to overcome the neutrophil attack. Chapter 4 was based on the advancement of melt electrowriting (MEW) to improve the printing resolution of MEW scaffolds in terms of minimal inter-fiber distances and a concomitant high stacking precision. Initially, to gain a better MEW understanding, the influence of several parameters, including spinneret diameter, applied pressure, and collector velocity on mechanical properties, crystallinity, fiber diameter and fiber surface morphology was analyzed. Afterward, innovative MEW designs (e.g., box-, triangle-, round , and wall-shaped scaffolds) have been established by pushing the printing parameters to their physical limits. Further, the inter-fiber distance within a standardized box-structured scaffold was successfully reduced to 40 µm, while simultaneously a high stacking precision was maintained. In collaboration with a co-worker of my department (Tina Tylek, who performed all cell-based experiments in this study), these novel MEW scaffolds have been proven to facilitate human monocyte-derived macrophage polarization towards the regenerative M2 type in an elongation-driven manner with a more pronounced effect with decreasing pore sizes. Finally, a pro-adipogenic platform for hMSCs was developed in chapter 5 using MEW scaffolds with immobilized, complex ECM proteins (e.g., human decellularized adipose tissue (DAT), laminin (LN), and fibronectin (FN)) to test for the adipogenic differentiation potential in vitro. Within this thesis, a special short-term adipogenic induction regime enabled to more thoroughly assess the intrinsic pro-adipogenic capacity of the composite biomaterials and prevented any possible masking by the commonly used long-term application of adipogenic differentiation reagents. The scaffolds with incorporated DAT consistently showed the highest adipogenic outcome and hence provided an adipo-inductive microenvironment for hMSCs, which holds great promise for applications in soft tissue regeneration. Future studies should combine all three addressed projects in a more in vivo-related manner, comprising a co-cultivation setup of neutrophils, macrophages, and MSCs. The MEW-scaffold, particularly due to its ability to combine surface functionality and adjustable morphology, has been proven to be a successful approach for wound healing and paves the way for subsequent tissue regeneration.},
  subject      = {Scaffold <Tissue Engineering>},
  language  = {en}
}
@phdthesis{Hahn2022,
  author    = {Hahn, Lukas},
  title     = {Novel Thermoresponsive Hydrogels Based on Poly(2-oxazoline)s and Poly(2-oxazine)s and their Application in Biofabrication},
  doi       = {10.25972/OPUS-27129},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-271299},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2022},
  abstract  = {In this work, the influence of aromatic structures on drug encapsulation, self-assembly and hydrogel formation was investigated. The physically crosslinked gelling systems were characterized and optimized for the use in biofabrication and applied in initial (bio)printing experiments. Chapter I: The cytocompatible (first in vitro and in vivo studies) amphiphile PMeOx-b-PBzOx-b- PMeOx (A-PBzOx-A) was used for the solubilization of PTX, schizandrin A (SchA), curcumin (CUR), niraparib and HS-173. Chapter II: Compared to the polymers A-PPheOx-A, A-PBzOx-A and A-PBzOzi-A, only the polymer A-PPheOzi-A showed a reversible temperature- and concentration-dependent inverse thermogelation, which is accompanied by a morphology change from long wormlike micelles in the gel to small spherical micelles in solution. The worm formation results from novel interactions between the hydrophilic and hydrophobic aromatic polymer blocks. Changes in the hydrophilic block significantly alter the gel system. Rheological properties can be optimized by concentration and temperature, which is why the hydrogel was used to significantly improve the printability and stability of Alg in a blend system. Chapter III: By extending the side chain of the aromatic hydrophobic block, the inverse thermogelling polymer A-poly(2-phenethyl-2-oxazoline)-A (A-PPhenEtOx-A) is obtained. Rapid gelation upon cooling is achieved by inter-correlating spherical micelles. Based on ideal rheological properties, first cytocompatible bioprinting experiments were performed in combination with Alg. The polymers A- poly(2-benzhydryl-2-oxazoline)-A (A-PBhOx-A) and A-poly(2-benzhydryl-2-oxazine) (A-PBhOzi-A) are characterized by two aromatic benzyl units per hydrophobic repeating unit. Only the polymer A- PBhOzi-A exhibited inverse thermogelling behavior. Merging micelles could be observed by electron microscopy. The system was rheologically characterized and discussed with respect to an application in 3D printing. Chapter IV: The thermogelling POx/POzi system, in particular the block copolymer PMeOx-b- PnPrOzi, was used in different applications in the field of biofabrication. The introduction of maleimide and furan units along the hydrophilic polymer part ensured additional stabilization by Diels-Alder crosslinking after the printing process.},
  subject      = {Polymer Science},
  language  = {en}
}
@phdthesis{Siverino2020,
  author    = {Siverino, Claudia},
  title     = {Induction of ectopic bone formation by site directed immobilized BMP2 variants \(in\) \(vivo\)},
  doi       = {10.25972/OPUS-16935},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-169359},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2020},
  abstract  = {In contrast to common bone fractures, critical size bone defects are unable to self-regenerate and therefore external sources for bone replacement are needed. Currently, the gold standard to treat critical size bone fractures, resulting from diseases, trauma or surgical interventions, is the use of autologous bone transplantation that is associated with several drawbacks such as postoperative pain, increased loss of blood during surgery and extended operative time. The field of bone tissue engineering focuses on the combination of biomaterials and growth factors to circumvent these adverse events and thereby to improve critical size bone defects treatment. To this aim, a promising approach is represented by using a collagen sponge soaked with one of the most powerful osteoinductive proteins, the bone morphogenetic protein 2 (BMP2). After the approval by the Food and Drug Administration (FDA), BMP2 was used to successfully treat several severe bone defects. However, the use of BMP2 delivery systems is associated with severe side effects such as inflammation, swelling, ectopic bone formation outside of the site of implantation and breathing problems if implanted in the area of the cervical spine. The occurrence of severe side effects is related to the supraphysiological amounts of the applied protein at the implantation site. The BMP2 is typically adsorbed into the scaffold and diffuses rapidly after implantation. Therefore, intensive research has been conducted to improve the protein's retention ability, since a prolonged entrapment of the BMP2 at the implantation site would induce superior bone formation in vivo due to a minimized protein release. By controlling the release from newly designed materials or changing the protein immobilization methods, it seems possible to improve the osteoinductive properties of the resulting BMP2-functionalized scaffolds. The combination of biocompatible and biodegradable scaffolds functionalized with a covalently immobilized protein such as BMP2 would constitute a new alternative in bone tissue engineering by eliminating the aforementioned severe side effects. One of the most common immobilization techniques is represented by the so-called EDC/NHS chemistry. This coupling technique allows covalent biding of the growth factor but in a non-site direct manner, thus producing an implant with uncontrollable and unpredictable osteogenic activities. Therefore, the generation of BMP2 variants harboring functional groups that allow a site-directed immobilization to the scaffold, would enable the production of implants with reproducible osteogenic activity. The new BMP2 variants harbor an artificial amino acid at a specific position of the mature polypeptide sequence. The presence of the unnatural amino acid allows to use particular covalent immobilization techniques in a highly specific and site directed manner. The two selected BMP2 variants, BMP2 E83Plk and BMP2 E83Azide, were expressed in E. coli, renatured and purified by cation exchange chromatography. The final products were intensively analyzed in terms of purity and biological activity in vitro. The two BMP2 variants enabled the application of different coupling techniques and verify the possible options for site directed immobilization to the scaffold. Intensive analyses on the possible side effects caused by the coupling reactions and on the quantification of the coupled protein were performed. Both click chemistry reactions showed high reaction efficacies when the BMP2 variants were coupled to functionalized fluorophores. Quantification by ELISA and scintillation counting of radioactively labeled protein revealed different outcomes. Moreover, the amounts of protein detected for the BMP2 variants coupled to microspheres were similar to that of the wild type protein. Therefore, it was not possible to conclude whether the BMP2 variants were covalently coupled or just adsorbed. BMP2 variants being immobilized to various microspheres induced osteogenic differentiation of C2C12 cells in vitro, but only in those cells that were located in close proximity to the functionalized beads. This selectivity strongly indicates that the protein is for a great portion covalently coupled and not just adsorbed. Moreover, the difference between the covalently coupled BMP2 variants and the adsorbed BMP2 WT was confirmed in vivo. Injection of the BMP2-functionalized microspheres in a rat model induced subcutaneous bone formation. The main aim of the animal experiment was to prove whether covalently coupled BMP2 induces bone formation at significant lower doses if compared to the amount being required if the protein is simply adsorbed. To this aim, several BMP2 concentrations were tested in this animal experiment. The BMP2 variants, being covalently immobilized, were hypothesized to be retained and therefore bio-available at the site of implantation for a prolonged time. However, in the animal experiments, lower doses of either coupled or adsorbed protein were unable to induce any bone formation within the 12 weeks. In contrast, the highest doses induced bone formation that was first detected at week 4. During the 12 weeks of the experiment, an increase in bone density and a steady state bone volume was observed. These results were obtained only for the covalently coupled BMP2 E83Azide but not for BMP2 E83Plk that did not induce bone formation in any condition. The negative outcome after application of BMP2 E83Plk suggested that the coupling reaction might have provoked changes in the protein structure that extremely influenced its osteogenic capabilities in vivo. However, the histological examination of the different ossicles induced either by BMP2 WT or BMP2 E83Azide, revealed clear morphological differences. BMP2 WT induced a bone shell-like structure, while the covalently coupled protein induced uniform bone formation also throughout the inner part. The differences between the two newly formed bones can be clearly associated with the different protein delivery mechanisms. Thus, the developed functionalized microspheres constitute a new interesting strategy that needs further investigations in order to be able to be used as replacement of the currently used BMP2 WT loaded medical devices.},
  language  = {en}
}
@phdthesis{Gador2018,
  author    = {Gador, Eva},
  title     = {Strategies to improve the biological performance of protein therapeutics},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-161798},
  school      = {Universit{\"a}t W{\"u}rzburg},
  pages     = {199},
  year      = {2018},
  abstract  = {During the last decades the number of biologics increased dramatically and several biopharmaceutical drugs such as peptides, therapeutic proteins, hormones, enzymes, vaccines, monoclonal antibodies and antibody-drug conjugates conquered the market. Moreover, administration and local delivery of growth factors has gained substantial importance in the field of tissue engineering. Despite progress that has been made over the last decades formulation and delivery of therapeutic proteins is still a challenge. Thus, we worked on formulation and delivery strategies of therapeutic proteins to improve their biological performance. Phase I of this work deals with protein stability with the main focus on a liquid protein formulation of the dimeric fusion protein PR-15, a lesion specific platelet adhesion inhibitor. In order to develop an adequate formulation ensuring the stability and bioactivity of PR-15 during storage at 4 °C, a pH screening, a forced degradation and a Design of Experiments (DoE) was performed. First the stability and bioactivity of PR-15 in 50 mM histidine buffer in relation to pH was evaluated in a short-term storage stability study at 25 °C and 40 °C for 4 and 8 weeks using different analytical methods. Additionally, potential degradation pathways of PR-15 were investigated under stressed conditions such as heat treatment, acidic or basic pH, freeze-thaw cycles, light exposure, induced oxidation and induced deamidation during the forced degradation study. Moreover, we were able to identify the main degradation product of PR-15 by performing LC/ESI-MS analysis. Further optimization of the injectable PR 15 formulation concerning pH, the choice of buffer and the addition of excipients was studied in the following DoE and finally an optimal PR-15 formulation was found. The growth factors BMP-2, IGF-I and TGF-β3 were selected for the differentiation of stem cells for tissue engineering of cartilage and bone in order to prepare multifunctionalized osteochondral implants for the regeneration of cartilage defects. Silk fibroin (SF) was chosen as biomaterial because of its biocompatibility, mechanical properties and its opportunity for biofunctionalization. Ideal geometry of SF scaffolds with optimal porosity was found in order to generate both tissues on one scaffold. The growth factors BMP-2 and IGF-I were modified to allow spatially restricted covalent immobilization on the generated porous SF scaffolds. In order to perform site-directed covalent coupling by the usage of click chemistry on two opposite sides of the scaffold, we genetically engineered BMP-2 (not shown in this work; performed by Barbara Tabisz) and IGF-I for the introduction of alkyne or azide bearing artificial amino acids. TGF β3 was immobilized to beads through common EDC/NHS chemistry requiring no modification and distributed in the pores of the entire scaffold. For this reason protein modification, protein engineering, protein immobilization and bioconjugation are investigated in phase II. Beside the synthesis the focus was on the characterization of such modified proteins and its conjugates. The field of protein engineering offers a wide range of possibilities to modify existing proteins or to design new proteins with prolonged serum half-life, increased conformational stability or improved release rates according to their clinical use. Site-directed click chemistry and non-site-directed EDC/NHS chemistry were used for bioconjugation and protein immobilization with the aim to underline the preferences of site-directed coupling. We chose three strategies for the incorporation of alkyne or azide functionality for the performance of click reaction into the protein of interest: diazonium coupling reaction, PEGylation and genetic engineering. Azido groups were successfully introduced into SF by implementation of diazonium coupling and alkyne, amino or acid functionality was incorporated into FGF-2 as model protein by means of thiol PEGylation. The proper folding of FGF-2 after PEGylation was assessed by fluorescence spectroscopy, WST-1 proliferation assay ensured moderate bioactivity and the purity of PEGylated FGF-2 samples was monitored with RP-HPLC. Moreover, the modification of native FGF-2 with 10 kDa PEG chains resulted in enhanced thermal stability. Additionally, we genetically engineered one IGF-I mutant by incorporating the unnatural amino acid propargyl-L-lysine (plk) at position 65 into the IGF-I amino acid sequence and were able to express hardly verifiable amounts of plk-IGF-I. Consequently, plk-IGF-I expression has to be further optimized in future studies in order to generate plk-IGF-I with higher yields. Bioconjugation of PEGylated FGF-2 with functionalized silk was performed in solution and was successful for click as well as EDC/NHS chemistry. However, substantial amounts of unreacted PEG-FGF-2 were adsorbed to SF and could not be removed from the reaction mixture making it impossible to expose the advantages of click chemistry in relation to EDC/NHS chemistry. The immobilization of PEG-FGF-2 to microspheres was a trial to increase product yield and to remove unreacted PEG-FGF-2 from reaction mixture. Bound PEG-FGF-2 was visualized by fluorescence imaging or flow cytometry and bioactivity was assessed by analysis of the proliferation of NIH 3T3 cells. However, immobilization on beads raised the same issue as in solution: adsorption caused by electrostatic interactions of positively charged FGF-2 and negatively charged SF or beads. Finally, we were not able to prove superiority of site-directed click chemistry over non-site-directed EDC/NHS. The skills and knowledge in protein immobilization as well as protein characterization acquired during phase II helped us in phase III to engineer cartilage tissue in biofunctionalized SF scaffolds. The approach of covalent immobilization of the required growth factors is relevant because of their short in vivo half-lives and aimed at controlling their bioavailability. So TGF-β3 was covalently coupled by means of EDC/NHS chemistry to biocompatible and biostable PMMA beads. Herein, we directly compared bioactivity of covalently coupled and adsorbed TGF-β3. During the so-called luciferase assay bioactivity of covalent coupled as well as adsorbed TGF-β3 on PMMA beads was ensured. In order to investigate the real influence of EDC/NHS chemistry on TGF-β3's bioactivity, the amount of immobilized TGF-β3 on PMMA beads was determined. Therefore, an ELISA method was established. The assessment of total amount of TGF-β3 immobilized on the PMMA beads allowed as to calculate coupling efficiency. A significantly higher coupling efficiency was determined for the coupling of TGF-β3 via EDC/NHS chemistry compared to the reaction without coupling reagents indicating a small amount of adsorbed TGF-β3. These results provide opportunity to determine the consequence of coupling by means of EDC/NHS chemistry for TGF β3 bioactivity. At first sight, no statistically significant difference between covalent immobilized and adsorbed TGF-β3 was observed regarding relative luciferase activities. But during comparison of total and active amount of TGF-β3 on PMMA beads detected by ELISA or luciferase assay, respectively, a decrease of TGF-β3's bioactivity became apparent. Nevertheless, immobilized TGF β3 was further investigated in combination with SF scaffolds in order to drive BMSCs to the chondrogenic lineage. According to the results obtained through histological and immunohistochemical studies, biochemical assays as well as qRT-PCR of gene expression from BMSCs after 21 days in culture immobilized TGF-β3 was able to engineer cartilage tissue. These findings support the thesis that local presentation of TGF β3 is superior towards exogenous TGF β3 for the development of hyaline cartilage. Furthermore, we conclude that covalent immobilized TGF β3 is not only superior towards exogenously supplemented TGF-β3 but also superior towards adsorbed TGF-β3 for articular hyaline cartilage tissue engineering. Diffusion processes were inhibited through covalent immobilization of TGF-β3 to PMMA beads and thereby a stable and consistent TGF-β3 concentration was maintained in the target area. With the knowledge acquired during phase II and III as well as during the studies of Barbara Tabisz concerning the expression and purification of plk-BMP-2 we made considerable progress towards the formation of multifunctionalized osteochondral implants for the regeneration of cartilage defects. However, further studies are required for the translation of these insights into the development of multifunctionalized osteochondral SF scaffolds.},
  subject      = {biologics},
  language  = {en}
}
@phdthesis{Haider2022,
  author    = {Haider, Malik Salman},
  title     = {Structure Property Relationship and Therapeutic Potential of Poly(2-oxazoline)s and Poly(2-oxazines)s based Amphiphiles},
  doi       = {10.25972/OPUS-28903},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-289036},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2022},
  abstract  = {In the past decade, poly(2-oxazoline)s (POx) and very recently poly(2-oxazine)s (POzi) based amphiphiles have shown great potential for medical applications. Therefore, the major aim of this thesis was to further explore the pharmaceutical and biomedical applications of POx/POzi based ABA triblock and AB diblock copolymers, respectively with the special emphasis on structure property relationship (SPR). ABA triblock copolymers (with shorter side chain length in the hydrophobic block) have shown high solubilizing capacity for hydrophobic drugs. The issue of poor aqueous solubility was initially addressed by developing a (micellar) formulation library of 21 highly diverse, hydrophobic drugs with POx/POzi based ABA triblock copolymers. Theoretically, the extent of compatibility between polymers and drug was determined by calculating solubility parameters (SPs). The SPs were thoroughly investigated to check their applicability in present systems. The selected formulations were further characterized by various physico-chemical techniques. For the biomedical applications, a novel thermoresposive diblock copolymer was synthesized which has shown promising properties to be used as hydrogel bioink or can potentially be used as fugitive support material. The most important aspect i.e. SPR, was studied with respect to hydrophilic block in either tri- or di-block copolymers. In triblock copolymer, the hydrophilic block played an important role for ultra high drug loading, while in case of diblock, it has improved the printability of the hydrogels. Apart from the basic research, the therapeutic applications of two formulations i.e. mitotane (commercially available as tablet dosage form for adrenocortical carcinoma) and BT-44 (lead compound for nerve regeneration) were studied in more detail.},
  language  = {en}
}
@phdthesis{He2024,
  author    = {He, Feng},
  title     = {Drug Discovery based on Oxidative Stress and HDAC6 for Treatment of Neurodegenerative Diseases},
  doi       = {10.25972/OPUS-25349},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-253497},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2024},
  abstract  = {Most antioxidants reported so far only achieved limited success in AD clinical trials. Growing evidences suggest that merely targeting oxidative stress will not be sufficient to fight AD. While multi-target directed ligands could synergistically modulate different steps in the neurodegenerative process, offering a promising potential for treatment of this complex disease. Fifteen target compounds have been designed by merging melatonin and ferulic acid into the cap group of a tertiary amide HDAC6 inhibitor. Compound 10b was screened as the best hybrid molecule exhibit potent HDAC6 inhibition and potent antioxidant capacity. Compound 10b also alleviated LPS-induced microglia inflammation and led to a switch from neurotoxic M1 to the neuroprotective M2 microglial phenotype. Moreover, compound 10b show pronounced attenuation of spatial working memory and long-term memory damage in an in vivo AD mouse model. Compound 10b can be a potentially effective drug candidate for treatment of AD and its druggability worth to be further studied. We have designed ten novel neuroprotectants by hybridizing with several common antioxidants, including ferulic acid, melatonin, lipoic acid, and trolox. The trolox hybrid compound exhibited the most potent neuroprotective effects in multiple neuroprotection assays. Besides, we identified the synergistic effects between trolox and vitamin K derivative, and our trolox hybrid compound showed comparable neuroprotection with the mixture of trolox and vitamin K derivative. We have designed and synthesized 24 quinone derivatives based on five kinds of different quinones including ubiquinone, 2,3,5-trimethyl-1,4-benzoquinone, memoquin, thymoquinone, and anthraquinone. Trimethylbenzoquinone and thymoquinone derivatives showed more potent neuroprotection than other quinones in oxytosis assay. Therefore, trimethylbenzoquinone and thymoquinone derivatives can be used as lead compounds for further mechanism study and drug discovery for treatment of neurodegenerative disease. We designed a series of photoswitchable HDAC inhibitors, which could be effective molecular tools due to the high spatial and temporal resolution. In total 23 target compounds were synthesized and photophysicochemically characterized. Azoquinoline-based compounds possess more thermally stable cis-isomers in buffer solution, which were further tested in enzyme-based HDAC inhibition assay. However, none of those tested compounds show significant differences in activities between trans-isomers and corresponding cis-isomers.},
  subject      = {Alzheimerkrankheit},
  language  = {en}
}