Biology subjects

Ruetten, S.

Publications and source records attributed to Ruetten, S..

3 recordsLinked to original sources

bioRxiv2026

The impact of crystallographic plane orientation as an unexplored terrain in hemocompatible material design

Thrombogenicity causes significant complications in the application of blood-contacting implants, requiring strategies to prevent adverse coagulation reactions. The thrombotic responses to the foreign surfaces are mainly driven by surficial factors such as surface energy, topography, and electrochemical interactions. Although anticoagulation therapies reduce the risks of clotting, patients might still encounter bleeding complications. Therefore, rather than high-risk anticoagulation therapies to counteract coagulation, it is essential to ensure hemocompatibility through the materials intrinsic properties. Endothelialization is crucial in preventing thrombotic complications, with various strategies explored for facilitating endothelial cell adhesion and proliferation. We investigated the impact of crystallographic anisotropy on endothelial and blood cell interactions on four main planes (A-, C-, M-, and R-planes) of single crystalline alumina (-Al2O3, sapphire). Employing advanced surface characterization techniques, including SIMS, KPFM and Zeta potential measurements, our study sheds light on the hemocompatibility of biomaterials considering anisotropic effects. We elucidated that the A-plane of alumina promotes endothelialization and suppresses platelet activation in contrast to other crystallographic planes. Our investigation into cell-surface interactions provides valuable insights and contributes to the advanced biomaterial design, ultimately leading to enhanced clinical outcomes.

bioengineering↗

bioRxiv2023

Towards Biohybrid Lung Development? Inflammatory Conditions Disrupt Endothelial Layer Integrity on Gas Exchange Membranes

Systemic inflammation presents a significant challenge to the long-term function of biohybrid implants. While endothelialisation of biohybrid implants has been shown to improve device hemocompatibility, its feasibility under the influence of patients inflammatory status remains largely unexplored. To investigate this, we developed a controlled in vitro model which allows to study endothelial dysfunction under inflammatory stress. Endothelial cells were cultured on polydimethylsiloxane under physiological shear stress and exposed to lipopolysaccharide (LPS)-activated peripheral blood mononuclear cells (PBMCs), simulating inflammatory conditions. Endothelial morphology and confluence was assessed using immunohistochemistry and scanning electron microscopy. Leukocyte adhesion was evaluated directly as well as indirectly, using flow cytometry to analyse cell adhesion molecules. Quantitative PCR was used for gene expression analysis of inflammatory mediators. Notably, neither LPS nor PBMCs alone induced endothelial disruption, whereas their combination significantly impaired endothelial confluence: Inflammatory activation led to substantial loss of endothelial confluence, increased leukocyte adhesion, and elevated expression of adhesion molecules ICAM-1, VCAM-1, and E-selectin. Gene expression analysis highlights the upregulation of inflammatory mediators, such as IL-6, IL-8, IL-10, and MCP-1. This study underscores the challenges of implementing endothelialisation in biohybrid devices, particularly in patients with systemic inflammation. By considering translational hurdles, this work contributes to the development of clinically viable biohybrid constructs and highlights the importance of considering inflammatory dynamics when designing next-generation implants.

bioengineering↗

bioRxiv2020

LSP1-myosin1e bi-molecular complex regulates focal adhesion dynamics and cell migration

Several cytoskeleton-associated proteins and signalling pathways work in concert to regulate actin cytoskeleton remodelling, cell adhesion and migration. We have recently demonstrated that the bi-molecular complex between the leukocyte-specific protein 1 (LSP1) and myosin1e controls actin cytoskeleton remodelling during phagocytosis. In this study, we show that LSP1 down regulation severely impairs cell migration, lamellipodia formation and focal adhesion dynamics in macrophages. Inhibition of the interaction between LSP1 and myosin1e also impairs these processes resulting in poorly motile cells, which are characterised by few and small lamellipodia. Furthermore, cells in which LSP1-myosin1e interaction is inhibited are typically associated with inefficient focal adhesion turnover. Collectively, our findings show that the LSP1-myosin1e bimolecular complex plays a pivotal role in the regulation of actin cytoskeleton remodelling and focal adhesion dynamics required for cell migration.

cell biology↗