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Author: Krömmelbein, Catharina × Type: Text ×

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    Design of biomimetic collagen matrices by reagent-free electron beam induced crosslinking: Structure-property relationships and cellular response
    (Amsterdam [u.a.] : Elsevier Science, 2019) Riedel, Stefanie; Hietschold, Philine; Krömmelbein, Catharina; Kunschmann, Tom; Konieczny, Robert; Knolle, Wolfgang; Mierke, Claudia T.; Zink, Mareike; Mayr, Stefan G.
    Novel strategies to mimic mammalian extracellular matrix (ECM) in vitro are desirable to study cell behavior, diseases and new agents in drug delivery. Even though collagen represents the major constituent of mammalian ECM, artificial collagen hydrogels with characteristic tissue properties such as network size and stiffness are difficult to design without application of chemicals which might be even cytotoxic. In our study we investigate how high energy electron induced crosslinking can be utilized to precisely tune collagen properties for ECM model systems. Constituting a minimally invasive approach, collagen residues remain intact in the course of high energy electron treatment. Quantification of the 3D pore size of the collagen network as a function of irradiation dose shows an increase in density leading to decreased pore size. Rheological measurements indicate elevated storage and loss moduli correlating with an increase in crosslinking density. In addition, cell tests show well maintained viability of NIH 3T3 cells for irradiated collagen gels indicating excellent cellular acceptance. With this, our investigations demonstrate that electron beam crosslinked collagen matrices have a high potential as precisely tunable ECM-mimetic systems with excellent cytocompatibility.
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    A study on the material properties of novel PEGDA/gelatin hybrid hydrogels polymerized by electron beam irradiation
    (Lausanne : Frontiers Media, 2023) Şener Raman, Tuğçe; Kuehnert, Mathias; Daikos, Olesya; Scherzer, Tom; Krömmelbein, Catharina; Mayr, Stefan G.; Abel, Bernd; Schulze, Agnes
    Gelatin-based hydrogels are highly desirable biomaterials for use in wound dressing, drug delivery, and extracellular matrix components due to their biocompatibility and biodegradability. However, insufficient and uncontrollable mechanical properties and degradation are the major obstacles to their application in medical materials. Herein, we present a simple but efficient strategy for a novel hydrogel by incorporating the synthetic hydrogel monomer polyethylene glycol diacrylate (PEGDA, offering high mechanical stability) into a biological hydrogel compound (gelatin) to provide stable mechanical properties and biocompatibility at the resulting hybrid hydrogel. In the present work, PEGDA/gelatin hybrid hydrogels were prepared by electron irradiation as a reagent-free crosslinking technology and without using chemical crosslinkers, which carry the risk of releasing toxic byproducts into the material. The viscoelasticity, swelling behavior, thermal stability, and molecular structure of synthesized hybrid hydrogels of different compound ratios and irradiation doses were investigated. Compared with the pure gelatin hydrogel, 21/9 wt./wt. % PEGDA/gelatin hydrogels at 6 kGy exhibited approximately up to 1078% higher storage modulus than a pure gelatin hydrogel, and furthermore, it turned out that the mechanical stability increased with increasing irradiation dose. The chemical structure of the hybrid hydrogels was analyzed by Fourier-transform infrared (FTIR) spectroscopy, and it was confirmed that both compounds, PEGDA and gelatin, were equally present. Scanning electron microscopy images of the samples showed fracture patterns that confirmed the findings of viscoelasticity increasing with gelatin concentration. Infrared microspectroscopy images showed that gelatin and PEGDA polymer fractions were homogeneously mixed and a uniform hybrid material was obtained after electron beam synthesis. In short, this study demonstrates that both the presence of PEGDA improved the material properties of PEGDA/gelatin hybrid hydrogels and the resulting properties are fine-tuned by varying the irradiation dose and PEGDA/gelatin concentration.