Cells are covered by a dense layer consisting of different carbohydrates. These carbohydrates mediate various interactions, such as the attachment of pathogens to the host cell. One class of these carbohydrates are the sulfated glycosaminoglycans (GAGs), which occur as linear, sulfated polysaccharides with high versatility. In addition to their anticoagulant properties, they have attracted lots of interests for example as antiviral compounds. One problem in exploring the potential of these GAGs is the limited access to structurally defined GAGs, e.g. those isolated from biological sources. Our aim is to synthesis new oligomeric and polymeric GAG mimetics with high structural control and diversity in positioning, chain length, sulfation pattern, etc. These will then be incorporated into synthetic membranes to obtain „glycocalyx mimetics“ and study effects such as their spatiotemporal and dynamic organisation. In this way, we hope to better understand their role and mechanism in pathogen attachment.
Imagine materials that can change and adapt just like living organisms, responding to light and chemical changes in their environment. The project aims to combine light- and redox-responsive polymers made from renewable resources to form dynamic polymer networks. By leveraging the unique properties of these responsive polymers, we will develop adaptive materials and devices for diverse applications, including 3D printing and surface coatings.
Complex systems in nature are often based on the precise assembly of smaller, often rather simple building blocks. The sequence and type of building blocks defines the function and role of these systems. Similar to nature, we seek to build sequence-defined poly- and oligomers by iterative selective couplings of custom-tailored building blocks. In this project, we target amphiphilic glycomacromolecules that respond to both, redox-fuels such as H2O2 and the presence of carbohydrate-recognizing lectins. We will study the adaptive assembly and disassembly of these molecules both, as biomimetic materials as well as for their potential applications e.g., in biomedicine.
Eukaryotic cells are surrounded by a dense carbohydrate layer that facilitates interactions such as pathogen attachment to host cells. A key class of these carbohydrates is sulfated glycosaminoglycans (GAGs) like heparan sulfate, which are linear, sulfated polysaccharides with significant complexity. While known for their anticoagulant properties, sGAGs are gaining attention as antiviral agents. However, their study is limited by the scarce availability of structurally defined GAGs from biological sources.
In collaboration with partners from inorganic chemistry and biotechnology, copolymers based on PLA are developed to optimize the morphology and degradation profiles of PLA. In addition, the biobased alpha-ketoglutarate-based polymer is systematically characterized focusing on its degradation profile and adhesive properties.
Glycoproteins play a critical role in various biological processes, from cell signaling and immune response to protein stability and trafficking. However, due to the complexity and diversity of glycan structures, studying glycoproteins can be challenging. My research focuses on developing and applying innovative chemical tools to probe the structure, function, and interaction partners of glycoproteins. By designing selective chemical probes and employing advanced analytical techniques, I aim to uncover the functional impact of these biomolecules on the biological system. This research not only contributes to a deeper understanding of glycobiology but will also open new therapeutic avenues in the fields of immunology and oncology.
Endoperoxides are cyclic structures containing a bridged O-O bond and have already been successfully investigated for various biomedical applications, e.g. to provide oxygen in cell cultures or to kill bacteria by releasing singlet oxygen. Their incorporation into materials has so far been limited. In this project, we aim to systematically incorporate endoperoxides into polymer networks containing saccharide moieties and explore the ability to reversibly store and release oxygen. To this end, my project deals with the synthesis of new functional saccharides that can be used as monomers in polymer synthesis. With an efficient and easy way to synthesize saccharide monomers that are functionalized in 6 position with either sulfate or phosphate groups, the resulting polymers can gain specific biological activity.
Interfering peptides (iPs) selectively modulate protein-protein interactions and are widely used in biochemistry and pharmacology. Over 200 peptide-based therapeutics are already approved. However, their potential for controlling growth processes in crops has barely been explored. Analyses of pyruvate phosphate dikinase (PPDK), a key enzyme in C4 photosynthesis, identified peptides that can inhibit PPDK activity. PPDK catalyzes the conversion of pyruvate to phosphoenolpyruvate (PEP) and is crucial for C4 photosynthesis. In this project and in collaboration with the group of Prof. Georg Groth at HHU Düsseldorf, these peptides are synthesized and evaluated for their inhibitory effect. Promising candidates are fluorescently labeled and made crosslinkable to characterize the peptide-enzyme interaction. The goal is to develop biological herbicides for sustainable plant protection.
In this project I am investigating the dynamic behavior of materials driven by fuel-induced aggregation. We utilize a modified AIE (Aggregation-Induced Emission) fluorophore that remains soluble in water at pH 7 but aggregates under acidic conditions or upon the addition of a so-called fuel. This aggregation process, facilitated by the formation of active esters with the fuel molecule EDC, is reversible over time. What sets my research apart is the visualizability of this phenomenon. The AIE fluorophore exhibits fluorescence upon aggregation, offering real-time insight into material behavior. Through this experimentation, I aim to unravel the mechanisms underlying fuel-induced aggregation and explore potential applications in responsive materials and environmental sensing.
Catechol units are known for their adhesive properties and reversible oxidation into quinones, which can undergo irreversible crosslinking when in close proximity. This property has been utilized for electrochemically induced reduction in adhesion and reversible crosslinking in the presence of boronates for adhesive applications. The aim is to incorporate these functional groups into polymer networks and surfaces to tune properties such as crosslinking degree and surface polarity, potentially leading to self-regulating materials and enhanced device performance.
Sulfated glycosaminoglycans (sGAGs) are a class of diverse polysaccharides at the outer cell membrane that bind proteins, pathogens and other entities. As viral cell infection is often associated with virus adhesion to sGAGs, my research focuses on the investigation into the interactions of sGAGs with proteins and pathogens. The aim is to build up a repertoire of different polymeric sGAG mimetics to evaluate the respective binding properties with pathogens. In this context, the glycocalyx shall be modeled for a deeper understanding of viral cell infection mechanisms.
The LipoBiocat project, funded by the Federal Ministry of Education and Research, aims to provide solutions for biocatalytic challenges encountered in chemical industries: synthesis and hydrolysis of polymers. By developing and/or improving enzymatic degradation of polymers, this project should deliver important contributions to making biocatalysts more attractive and profitable and will help to enable the biocatalytic recycling of synthetic plastics for the industrial uses.
In LipoBioCat phase II, new enzymes will be identified and new methods developed to degrade polyesters and/or polyamides plastic polymers. AK Hartmann would develop new strategies for plastic pre-treatment in an integrated approach, in order to make it easier for the enzymes to access the polymer backbone.
