TY - JOUR A1 - Weigl, Franziska A1 - Blum, Carina A1 - Sancho, Ana A1 - Groll, Jürgen T1 - Correlative Analysis of Intra– Versus Extracellular Cell Detachment Events via the Alignment of Optical Imaging and Detachment Force Quantification JF - Advanced Materials Technologies N2 - In recent decades, hybrid characterization systems have become pillars in the study of cellular biomechanics. Especially, Atomic Force Microscopy (AFM) is combined with a variety of optical microscopy techniques to discover new aspects of cell adhesion. AFM, however, is limited to the early-stage of cell adhesion, so that the forces of mature cell contacts cannot be addressed. Even though the invention of Fluidic Force Microscopy (FluidFM) overcomes these limitations by combining the precise force-control of AFM with microfluidics, the correlative investigation of detachment forces arising from spread mammalian cells has been barely achieved. Here, a novel multifunctional device integrating Fluorescence Microscopy (FL) into FluidFM technology (FL-FluidFM) is introduced, enabling real-time optical tracking of entire cell detachment processes in parallel to the undisturbed acquisition of force-distance curves. This setup, thus, allows for entailing two pieces of information at once. As proof-of-principle experiment, this method is applied to fluorescently labeled rat embryonic fibroblast (REF52) cells, demonstrating a precise matching between identified force-jumps and visualized cellular unbinding steps. This study, thus, presents a novel characterization tool for the correlated evaluation of mature cell adhesion, which has great relevance, for instance, in the development of biomaterials or the fight against diseases such as cancer. KW - Fluorescence Microscopy KW - FluidFM technology KW - detachment force quantification Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318544 SN - 2365-709X VL - 7 IS - 11 ER - TY - JOUR A1 - Ryma, Matthias A1 - Tylek, Tina A1 - Liebscher, Julia A1 - Blum, Carina A1 - Fernandez, Robin A1 - Böhm, Christoph A1 - Kastenmüller, Wolfgang A1 - Gasteiger, Georg A1 - Groll, Jürgen T1 - Translation of collagen ultrastructure to biomaterial fabrication for material-independent but highly efficient topographic immunomodulation JF - Advanced materials N2 - Supplement-free induction of cellular differentiation and polarization solely through the topography of materials is an auspicious strategy but has so far significantly lagged behind the efficiency and intensity of media-supplementation-based protocols. Consistent with the idea that 3D structural motifs in the extracellular matrix possess immunomodulatory capacity as part of the natural healing process, it is found in this study that human-monocyte-derived macrophages show a strong M2a-like prohealing polarization when cultured on type I rat-tail collagen fibers but not on collagen I films. Therefore, it is hypothesized that highly aligned nanofibrils also of synthetic polymers, if packed into larger bundles in 3D topographical biomimetic similarity to native collagen I, would induce a localized macrophage polarization. For the automated fabrication of such bundles in a 3D printing manner, the strategy of “melt electrofibrillation” is pioneered by the integration of flow-directed polymer phase separation into melt electrowriting and subsequent selective dissolution of the matrix polymer postprocessing. This process yields nanofiber bundles with a remarkable structural similarity to native collagen I fibers, particularly for medical-grade poly(ε-caprolactone). These biomimetic fibrillar structures indeed induce a pronounced elongation of human-monocyte-derived macrophages and unprecedentedly trigger their M2-like polarization similar in efficacy as interleukin-4 treatment. KW - biofabrication KW - extracellular matrix KW - immunomodulation KW - macrophages KW - melt electrofibrillation KW - melt electrowriting Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256381 VL - 33 IS - 33 ER - TY - JOUR A1 - Blum, Carina A1 - Taskin, Mehmet Berat A1 - Shan, Junwen A1 - Schilling, Tatjana A1 - Schlegelmilch, Katrin A1 - Teßmar, Jörg A1 - Groll, Jürgen T1 - Appreciating the First Line of the Human Innate Immune Defense: A Strategy to Model and Alleviate the Neutrophil Elastase-Mediated Attack toward Bioactivated Biomaterials JF - Small N2 - Biointerface engineering is a wide-spread strategy to improve the healing process and subsequent tissue integration of biomaterials. Especially the integration of specific peptides is one promising strategy to promote the regenerative capacity of implants and 3D scaffolds. In vivo, these tailored interfaces are, however, first confronted with the innate immune response. Neutrophils are cells with pronounced proteolytic potential and the first recruited immune cells at the implant site; nonetheless, they have so far been underappreciated in the design of biomaterial interfaces. Herein, an in vitro approach is introduced to model and analyze the neutrophil interaction with bioactivated materials at the example of nano-bioinspired electrospun surfaces that reveals the vulnerability of a given biointerface design to the contact with neutrophils. A sacrificial, transient hydrogel coating that demonstrates optimal protection for peptide-modified surfaces and thus alleviates the immediate cleavage by neutrophil elastase is further introduced. KW - solution electrospinning KW - human neutrophil elastase (HNE) KW - peptide immobilization KW - polymeric matrix Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-257691 VL - 17 IS - 13 ER - TY - JOUR A1 - Tylek, Tina A1 - Blum, Carina A1 - Hrynevich, Andrei A1 - Schlegelmilch, Katrin A1 - Schilling, Tatjana A1 - Dalton, Paul D A1 - Groll, Jürgen T1 - Precisely defined fiber scaffolds with 40 μm porosity induce elongation driven M2-like polarization of human macrophages JF - Biofabrication N2 - Macrophages are key players of the innate immune system that can roughly be divided into the pro-inflammatory M1 type and the anti-inflammatory, pro-healing M2 type. While a transient initial pro-inflammatory state is helpful, a prolonged inflammation deteriorates a proper healing and subsequent regeneration. One promising strategy to drive macrophage polarization by biomaterials is precise control over biomaterial geometry. For regenerative approaches, it is of particular interest to identify geometrical parameters that direct human macrophage polarization. For this purpose, we advanced melt electrowriting (MEW) towards the fabrication of fibrous scaffolds with box-shaped pores and precise inter-fiber spacing from 100 μm down to only 40 μm. These scaffolds facilitate primary human macrophage elongation accompanied by differentiation towards the M2 type, which was most pronounced for the smallest pore size of 40 μm. These new findings can be important in helping to design new biomaterials with an enhanced positive impact on tissue regeneration. KW - cell elongation KW - human macrophages KW - melt electrowriting (MEW) KW - macrophage polarization KW - 3D scaffolds Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-254012 VL - 12 IS - 2 ER - TY - JOUR A1 - Meininger, Susanne A1 - Blum, Carina A1 - Schamel, Martha A1 - Barralet, Jake E. A1 - Ignatius, Anita A1 - Gbureck, Uwe T1 - Phytic acid as alternative setting retarder enhanced biological performance of dicalcium phosphate cement in vitro JF - Scientific Reports N2 - Dicalcium phosphate cement preparation requires the addition of setting retarders to meet clinical requirements regarding handling time and processability. Previous studies have focused on the influence of different setting modifiers on material properties such as mechanical performance or injectability, while ignoring their influence on biological cement properties as they are used in low concentrations in the cement pastes and the occurrence of most compounds in human tissues. Here, analyses of both material and biological behavior were carried out on samples with common setting retardants (citric acid, sodium pyrophosphate, sulfuric acid) and novel (phytic acid). Cytocompatibility was evaluated by in vitro tests with osteoblastic (hFOB 1.19) and osteoclastic (RAW 264.7) cells. We found cytocompatibility was better for sodium pyrophosphate and phytic acid with a three-fold cell metabolic activity by WST-1 test, whereas samples set with citric acid showed reduced cell number as well as cell activity. The compressive strength (CS) of cements formed with phytic acid (CS = 13 MPa) were nearly equal to those formed with citric acid (CS = 15 MPa) and approximately threefold higher than for other setting retardants. Due to a proven cytocompatibility and high mechanical strength, phytic acid seems to be a candidate replacement setting retardant for dicalcium phosphate cements. KW - implants KW - biomedical materials KW - dicalcium phosphate cement KW - phytic acid Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-171047 VL - 7 IS - 558 ER -