Heparin culture surfaces

Moreover, heparin-functionalized thermoresponsive cell culture surfaces have an affinity interaction with heparin-binding EGF-like growth factor (HB-EGF), which is a potent mitogen for hepatocytes [41]. An HB-EGF-bound heparin-functionalized thermoresponsive surface was utilized for creating hepatocyte sheets with maintaining hepatic functions during cultivation [42]. The addition of HB-EGF in the cell culture media was es-sentialfor the survival of hepatocytes. When the medium contained less than 10 ng/cm of soluble HB-EGF, the hepatocytes were not able to adhere and form their cell sheets. Hepatocytes adhered well and formed their sheets on the HB-EGF-bound heparin-functionalized... 

The functional importance of such integrins has been demonstrated by perturbation using antibodies (Bronner-Fraser, 1985) and anti-sense oligonucleotides (Lallier and Bronner-Fraser, 1992) in tissue culture. The responses to the heparinbinding site is presumably mediated by heparin-sulfate (HS)-PG at the cell surface. 

Fig. 1. Induction of MHC class II antigens on PMN in culture. PMN were cultivated with AIM-V, 2.5% heat-inactivated autologous serum with or without IFN-y (100 U/ml) plus GM-CSF (50 U/ml). a Surface expression of MHC class II was measured after 24 and 48 h. An antibody to CD66b (former CD67) was used to identify the PMN population isotype controls are on the left the middle panel shows PMN without cytokines, b RT-PCR products generated using MHC class Il-specific primers and PMN-derived RNA are shown. PMN had been cultured for 24 h with AIM-V/NHS (1), +IFN-7 (100 U/ml) (2), and GM-CSF (50 U/ml) (3). The left panel shows the respective RT-PCR products for P-actin. c By coirfocal laser microscopy and cytofluorometry it was seen that only a subpopulation of PMN acquired MHC class II antigens, d Induction of MHC class II antigens on PMN in whole blood. Whole blood (heparinized peripheral blood of healthy donors) was cultivated with IFN-7 (100 U/1 ml blood) for 48h then upregulation of MHC class II on PMN was measured by cytofluorometry and compared to that obtained with PMN isolated from the same donor. D1-D5 designate five individual donors.

PPy is a conductive polymer with several biomedical applications owing to its good biocompatibility and the ability of cells to attach, differentiate and proliferate on its surface [148,149]. In one study, the attachment, proliferation and differentiation of rat MSCs on PPy surfaces was shown to be comparable to those of regular tissue culture plastic surfaces [150]. The synthesis of PPy involves either electrochemical or chemical polymerization, with the admicellar polymerization technique enabling the uniform deposition of thin PPy films from a few to 100 nm thick [151]. Moreover, the attachment of cells to the PPy surface can be improved, for example, via the adsorption of fibronectin or the incorporation of Arg-Gly-Asp (RGD)-containing peptides [152]. Immobilization of the glycosaminoglycans heparin and hyaluronic acid on PPy surfaces was also shown to maintain bone marrow-derived MSC cultures and to induce differentiation successfully into mature osteoblasts [153]. 

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