@article{KruegerGengeSchulzKratzetal.2018,
  author    = {Kr{\"u}ger-Genge, Anne and Schulz, Christian and Kratz, Karl and Lendlein, Andreas and Jung, Friedrich},
  title     = {Comparison of two substrate materials used as negative control in endothelialization studies},
  series = {Clinical hemorheology and microcirculation : blood flow and vessels},
  volume    = {69},
  journal   = {Clinical hemorheology and microcirculation : blood flow and vessels},
  number    = {3},
  publisher = {IOS Press},
  address   = {Amsterdam},
  issn      = {1386-0291},
  doi       = {10.3233/CH-189904},
  pages     = {437 -- 445},
  year      = {2018},
  abstract  = {The endothelialization of synthetic surfaces applied as cardiovascular implant materials is an important issue to ensure the anti-thrombotic quality of a biomaterial. However, the rapid and constant development of a functionallycon-fluent endothelial cell monolayer is challenging. In order to investigate the compatibility of potential implant materials with endothelial cells several in vitro studies are performed. Here, glass and tissue culture plates (TCP) are often used as reference materials for in vitro pre-testing. However, a direct comparison of both substrates is lacking. Therefore, a comparison of study results is difficult, since results are often related to various reference materials. In this study, the endothelialization of glass and TCP was investigated in terms of adherence, morphology, integrity, viability and function using human umbilical vein endothelial cells (HUVEC). On both substrates an almost functionally confluent HUVEC monolayer was developed after nine days of cell seeding with clearly visible cell rims, decreased stress fiber formation and a pronounced marginal filament band. The viability of HUVEC was comparable for both substrates nine days after cell seeding with only a few dead cells. According to that, the cell membrane integrity as well as the metabolic activity showed no differences between TCP and glass. However, a significant difference was observed for the secretion of IL-6 and IL-8. The concentration of both cytokines, which are associated with migratory activity, was increased in the supernatant of HUVEC seeded on TCP. This result matches well with the slightly increased number of adherent HUVEC on TCP. In conclusion, these findings indicate that both reference materials are almost comparable and can be used equivalently as control materials in in vitro endothelialization studies.},
  language  = {en}
}
@article{KruegerGengeDietzeYanetal.2018,
  author    = {Kr{\"u}ger-Genge, Anne and Dietze, Stefanie and Yan, Wan and Liu, Yue and Fang, Liang and Kratz, Karl and Lendlein, Andreas and Jung, Friedrich},
  title     = {Endothelial cell migration, adhesion and proliferation on different polymeric substrates},
  series = {Clinical hemorheology and microcirculation : blood flow and vessels},
  volume    = {70},
  journal   = {Clinical hemorheology and microcirculation : blood flow and vessels},
  number    = {4},
  publisher = {IOS Press},
  address   = {Amsterdam},
  issn      = {1386-0291},
  doi       = {10.3233/CH-189317},
  pages     = {511 -- 529},
  year      = {2018},
  abstract  = {BACKGROUND: The formation of a functionally-confluent endothelial cell (EC) monolayer affords proliferation of EC, which only happens in case of appropriate migratory activity. AIM OF THE STUDY: The migratory pathway of human umbilical endothelial cells (HUVEC) was investigated on different polymeric substrates. MATERIAL AND METHODS: Surface characterization of the polymers was performed by contact angle measurements and atomic force microscopy under wet conditions. 30,000 HUVEC per well were seeded on polytetrafluoroethylene (PTFE) (theta(adv) = 119 degrees +/- 2 degrees), on low-attachment plate LAP (theta(adv) = 28 degrees +/- 2 degrees) and on polystyrene based tissue culture plates (TCP, theta(adv) = 22 degrees +/- 1 degrees). HUVEC tracks (trajectories) were recorded by time lapse microscopy and the euclidean distance (straight line between starting and end point), the total distance and the velocities of HUVEC not leaving the vision field were determined. RESULTS: On PTFE, 42 HUVEC were in the vision field directly after seeding. The mean length of single migration steps (SML) was 6.1 +/- 5.2 mu m, the mean velocity (MV) 0.40 +/- 0.3 mu m.min(-1) and the complete length of the trajectory (LT) was 710 +/- 440 mu m. On TCP 82 HUVEC were in the vision field subsequent to seeding. The LT was 840 +/- 550 mu m, the SML 6.1 +/- 5.2 mu m and the MV 0.44 +/- 0.3 mu m.min(-1). The trajectories on LAP differed significantly in respect to SML (2.4 +/- 3.9 mu m, p <0.05), the MV (0.16 +/- 0.3 mu m.min(-1), p <0.05) and the LT (410 +/- 300 mu m, p <0.05), compared to PTFE and TCP. Solely on TCP a nearly confluent EC monolayer developed after three days. While on TCP diffuse signals of vinculin were found over the whole basal cell surface organizing the binding of the cells by focal adhesions, on PTFE vinculin was merely arranged at the cell rims, and on the hydrophilic material (LAP) no focal adhesions were found. CONCLUSION: The study revealed that the wettability of polymers affected not only the initial adherence but also the migration of EC, which is of importance for the proliferation and ultimately the endothelialization of polymer-based biomaterials.},
  language  = {en}
}