29. Jahrestagung der Deutschen Gesellschaft für Biomaterialien

Chair

Prof. Dr.

Within a compact presentation and short training sessions you will learn best-practice techniques regarding topics like connection of word and illustration and reduction of complex content. More about Dr. Gordian can be found here https://lebensklug.com/.

Keynote Lecture: How to visualize your scientific results

Speaker

Young Scientist Talk

Break

Effect of microenvironment on human dental pulp stem cells

Abstract text (incl. figure legends and references) Introduction Human dental pulp stem cells (hDPSCs) are attracting significant attention in dentistry due to their ability to differentiate into odontoblasts and osteoblasts. The physiology of hDPSCs is modulated by environmental factors, including interactions with human and microbial cells. However, these processes have not been extensively studied. Objectives The aim of the study was to investigate exosome-based interactions between hDPSCs and other eukaryotic cells as well as metabolic interactions between hDPSCs and oral microorganisms. Material and Methods The effect of conditioned cell culture medium (CM) or exosomes from diverse eukaryotic cells on mineralization and osteo-/odontogenic differentiation was evaluated using Alizarin Red S staining, immunoblotting, ELISA and alkaline phosphatase activity assay. The effects of culture supernatant or short-chain fatty acids (SCFAs) from Fusobacterium nucleatum, on hDPSCs were characterized using same methods but also CellTiter-Blue assay, CLSM and SEM. Gene expression profiling at a whole-genome level was assessed using microarrays. Results The differentiation and mineralization abilities of hDPSCs were significantly improved only by treatment with exosomes from HUVECs, while CM from NHOst and M2-polarised macrophages enhanced calcium deposition alone. High concentrations of SCFAs decreased cell viability and increased cell size. Treatment of hDPSCs with F. nucleatum culture supernatant or butyrate reduced mineralization. Gene expression profiling revealed an inhibition potential of butyrate regarding differentiation of hDPSCs through TGF-β/BMP signalling pathway. Conclusion This study demonstrated various effects of conditions modulated by both eukaryotic and bacterial cells on the physiology of hDPSCs and highlighted the importance of a specific stem cell microenvironment in the successful implementation of tissue regeneration approaches in dentistry.

Clinical applications and translation

Tissue regeneration/regenerated medicine

Interaction of plasma and ECM proteins with self-assembled fibrinogen nanofibers

Abstract text (incl. figure legends and references) Introduction: We recently showed that self-assembled fibrinogen nanofibers support the growth of fibroblasts and keratinocytes1,2 and enhance adhesion and spreading of blood platelets3. Since platelet interaction with fibrinogen nanofibers is dependent on the presence of plasma proteins3, we now want to understand how self-assembled fibrinogen nanofibers interact with various proteins involved in tissue repair. Objectives: Hence, we studied the ability of various plasma and ECM proteins to bind to self-assembled fibrinogen nanofibers. Methods: Fibrinogen nanofibers were assembled as previously described using planar and physisorbed fibrinogen samples2 as controls. Collagen, laminin, fibronectin, and fibrinogen were dissolved in HEPES buffer and incubated on the different samples for 4 h at 37 °C. Subsequently, the amount of bound protein was measured by UV-Vis spectroscopy of the supernatant at 280 nm and with a colorimetric bicinchoninic acid (BCA) assay. Results: UV-Vis spectroscopy and BCA assay showed that all proteins bound to fibrinogen nanofibers to a greater extent than to planar and physisorbed fibrinogen. We attributed these differences to the 15-fold difference in surface roughness2. When the time of scaffold cross-linking in formaldehyde vapor was increased from 1 to 2 h we also found an increase in binding of all proteins independent of the surface topography. When the pH of fibrinogen solutions was raised above its IEP and below its IEP for collagen solutions, we observed increased binding to all fibrinogen substrates, which might be correlated with changes in the electrostatic interaction forces. Conclusion: Self-assembled fibrinogen nanofibers support the binding of selected ECM and plasma proteins. Further studies are needed to characterize fully the molecular bioactivity of nanofibrous fibrinogen scaffolds. References: 1 Suter, N. et al. Mater. Sci. Eng. C 2021 2 Joshi, A. et al. ACS Omega 2023 3 Kenny, M. et al. Adv. Healthc. Mater. 2022

Surface modification technologies

Fabrication of oxidized alginate (ADA)/ gelatin (GEL) microcapsules incorporating Cu doped mesoporous bioactive glass nanoparticles (MBGNs) for soft tissue engineering applications

Abstract text (incl. figure legends and references) Microcapsules (&lt; 500 μm) encapsulated with cells using biodegradable and biocompatible hydrogels based on crosslinked alginate dialdehyde (ADA) and gelatin (GEL) are interesting candidates to fabricate tissue-engineered organs as well as for the regeneration of damaged tissues [1], due to their high porosity facilitating oxygen and nutrition supply [2]. The aim of this research is to fabricate ADA by periodate oxidation of alginate which facilitates crosslinking with gelatin through Schiff's base formation between the free amino groups of gelatin and the available aldehyde groups of ADA in 1:1 proportion [2]. The fabricated microcapsules were incorporated with Cu-doped mesoporous bioactive glass nanoparticles (Cu-MBGNs) prepared by the sol-gel method to promote angiogenesis. The swelling ratio and degradability of ADA–GEL microcapsules were significantly decreased with the increase of Cu-MBGN concentration due to the presence of the ceramic material. ADA-GEL microcapsules showed spherical morphology and successful incorporation of Cu-MBGNs, as evaluated by SEM. The cellular viability of fabricated ADA-GEL microcapsules increased with the addition of Cu-MBGNs, which was characterized using the NIH3T3 fibroblast cell line. In conclusion, ADA-GEL microcapsules incorporating Cu-MBGNs are biocompatible and biodegradable and exhibit intrinsic vascularization potential which makes them ideal candidates for soft tissue engineering applications. References: [1] F. F. Cai, S. Heid, and A. R. Boccaccini, &quot;Potential of Laponite® incorporated oxidized alginate–gelatin (ADA-GEL) composite hydrogels for extrusion-based 3D printing,&quot; J. Biomed. Mater. Res. - Part B Appl. Biomater., vol. 109, no. 8, pp. 1090–1104, 2021. [2] B. Sarker et al., &quot;Fabrication of alginate-gelatin crosslinked hydrogel microcapsules and evaluation of the microstructure and physico-chemical properties,&quot; J. Mater. Chem. B, vol. 2, no. 11, pp. 1470–1482, 2014.

Biofabrication

Establishment of a 3D bio printed diabetes chondrocyte model

High-throughput characterization of interspecies interactions in oral implant-associated biofilms

Abstract text (incl. figure legends and references) Introduction During polymicrobial biofilm formation on implant surfaces, the involved species of oral microorganisms interact on different levels. In this regard, exploitation of metabolites released by other species can be an important survival strategy that contributes to biofilm fitness and leads to disease development and progression. Identification and characterization of these hallmark interactions are therefore imperative to detect early pathology and prevent implant-associated diseases. Objectives Characterization of synergistic metabolic interactions in implant-associated biofilms and tracing of chemical compounds that are actively involved in these inter-species metabolite flows are the primary goals of this study. The knowledge gained should contribute to the decoding of these interaction networks in complex clinical biofilms. Materials &amp; methods Interspecies metabolic interactions were characterized using diverse agar diffusion assays. Clinical oral biofilm samples, more than one hundred reference strains of diverse species, various metabolites and their corresponding combinations were studied. Liquid biofilm cultures were used to verify selected interactions. Results Porphyromonas gingivalis showed satellite growth exclusively around colonies of other species from classes such as Actinobacteria, Bacteroidia, Negativicutes and Gammaproteobacteria, thereby indicating metabolite exploitation under experimental conditions. Chemical complementation experiments identified menaquinones and their related precursors as major drivers of these interactions. Conclusion We were able to characterize exploitation interactions involving the key oral pathogen Porphyromonas gingivalis. Targeting these interactions may support the development of innovative preventive and therapeutic strategies for implant-associated infections. References Fenn et al. Quinones are the growth factors of human gut microbiota. Microbiome 2017; Vol. 5(1): 1-11

Biofilm formation

Infections

YSF award ceremony after plenary vote for best presentation and best presentation design. The winners will additionally be mentioned at the award ceremony of the main conference.

Young Scientist Session

Termin

Chair

Programm