Despite medical achievements, the number of patients with end-stage kidney disease keeps steadily raising, thereby entailing a high number of surgical and interventional procedures to establish and maintain arteriovenous vascular access for hemodialysis. Due to vascular disease, aneurysms or infection, the preferred access—an autogenous arteriovenous fistula—is not always available and appropriate. Moreover, when replacing small diameter blood vessels, synthetic vascular grafts possess well-known disadvantages. A continuous multilayered gradient electrospinning was used to produce vascular grafts made of collagen type I nanofibers on luminal and adventitial graft side, and poly-ɛ-caprolactone as medial layer. Therefore, a custom-made electrospinner with robust environmental control was developed. The morphology of electrospun grafts was characterized by scanning electron microscopy and measurement of mechanical properties. Human microvascular endothelial cells were cultured in the graft under static culture conditions and compared to cultures obtained from dynamic continuous flow bioreactors. Immunofluorescent analysis showed that endothelial cells form a continuous luminal layer and functional characteristics were confirmed by uptake of acetylated low-density-lipoprotein. Incorporation of vancomycin and gentamicin to the medial graft layer allowed antimicrobial inhibition without exhibiting an adverse impact on cell viability. Most striking a physiological hemocompatibility was achieved for the multilayered grafts.

A case study on the effect of the employment of two different NHC ligands in complexes [Ni(NHC) 2 ] (NHC = i Pr 2 Im Me 1 Me , Mes 2 Im 2) and their behavior towards alkynes is reported. The reaction of a mixture of [Ni 2 ( i Pr 2 Im Me ) 4 (μ-(η 2 : η 2 )-COD)] B/ [Ni( i Pr 2 Im Me ) 2 (η 4 -COD)] B' or [Ni(Mes 2 Im) 2 ] 2, respectively, with alkynes afforded complexes [Ni(NHC) 2 (η 2 -alkyne)] (NHC = i Pr 2 Im Me : alkyne = MeC�CMe 3, H 7 C 3 C�CC 3 H 7 4,

A major challenge in tissue engineering and artificial scaffolding is to combine easily tunable scaffolds biomimicking the extracellular matrix of native organs with delivery-controlled cell culturing to create fully cellularized, large artificial 3D scaffolds. Aiming at bioartificial liver construction, we present our research using galactose-functionalized, ultraporous polylactide 3D nanofiber sponges fabricated out of electrospun fibers. Sponge biomodification by blend galactosylation and in-solution coating is performed, respectively, using a polylactide-galactose carriercopolymer that promotes cell delivery and features a pronounced autofluorescence. It allows us to verify the galactosylation success, evaluate its quality, and record dye-free, high-resolution images of the sponge network using confocal laser scanning microscopy. The galactose carrier and its impact on scaffold cellularization is validated in benchmark to several reference systems. Verification of the human hepatic cell asialoglycoprotein receptor presence and galactose interaction in culture is performed by Cu 2+ receptor-blocking experiments. The culture results are extensively investigated in and ex situ to trace and quantify the cell culture progress, cell activity, and viability at different culture stages. Bioreactor cultivation of sponges reveals that the galactose carrier does not only facilitate cell adhesion but also enhances cellular distribution throughout the scaffold. The promising 3D culture results allow us to move forward to create mature in vitro liver model research systems. The elaboration into ex vivo testing platforms could help judging native cell material interactions with drugs or therapeutics, without the need of direct human or animal testing.

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After multiple trauma, development of systemic inflammatory response and innate immune dysfunction have been described, reflected by disturbances of the cellular defense and uncontrolled activation of the complement system. However, little is known about the complement function during the early posttraumatic period (< 90 min after accident). Therefore, we investigated the complement status and function in sera from trauma victims (n=40 with an injury severity score of ISS=35.2 „b 3.1), obtained at the scene, immediately after admission in the emergency room (ER), 4h, 12h, 24h and 120h and 240h after trauma. There was a robust complement activation at the scene with significantly enhanced levels of the complement activation products C3a, C5a and MAC. While the serum levels of C3a were consistently elevated over the 10 day observation period, C5a and MAC concentrations dropped over time after the initial peak. There was also a significant loss of chemotactic activity up to 4h after injury. Complement function was assessed by the hemolytic activity of serum (CH50). At the scene, CH50 activity was impaired and virtually abolished in the ER, indicating consumption of complement within the first hours after trauma. Furthermore, a positive correlation between the loss of hemolytic activity at the scene and the 10 day outcome was found. In conclusion, the complement‐associated defence seems to be compromised rapidly after severe trauma, which may lead to the enhanced susceptibility and impairment of the innate immune response after trauma. This work was supported by NIH Grants No. GM‐61656, GM‐29507 and HL‐31963.