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ABSTRACT: This study used human bone-derived cells (HBDC) grown on two defined polymeric substrata to examine the effect of substrata chemistry on the expression of mRNAs and proteins characteristic of the osteoblastic phenotype. The growth profile of cells grown on tissue culture polystyrene (TCP) was exponential whereas for those seeded on polyethyleneterephthalate (PET) there was a pronounced lag period before cellular multiplication. The temporal expression pattern of mRNAs in HBDC cultured on TCP was similar to that of cells on PET. On TCP, the levels of several mRNAs peaked at day 4, as cellular proliferation slowed. In contrast, the induction in mRNA levels in cells grown on PET corresponded to maximum mitotic activity. There appears to be sequential cascade in protein expression in cells grown on TCP with overlapping peaks of thrombospondin (Tsp), osteocalcin (OC) and osteopontin (OP) expression. In contrast, peak intracellular protein expression levels for Tsp, OC and OP did not overlap when cells were grown on PET.
Journal of Biomaterials Science Polymer Edition 02/1999; 10(2):199-216. · 1.69 Impact Factor
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ABSTRACT: Our group is investigating the potential of modifying the surface atomic layers of biomaterials by ion beam implantation in order to stimulate adhesion of bone cells to these treated biomaterials. In this study alumina that had been implanted with magnesium ions (Mg)–(Al2O3), was compared to unmodified alumina (Al2O3) for the adhesion of cells cultured from explanted human bone. The attachment and spreading of cultured human bone derived cells onto (Mg)–(Al2O3) was significantly enhanced as compared to Al2O3. The role of adsorption of serum adhesive glycoproteins fibronectin (Fn) and vitronectin (Vn) in the adhesion of human bone derived cells to (Mg)–(Al2O3) was determined. The requirement for Fn or Vn for the attachment and spreading of bone-derived cells onto the Al2O3 and (Mg)–(Al2O3) surfaces was directly tested by selective removal of Fn or Vn from the serum prior to addition to the culture medium. The cell adhesion to both the alumina and the (Mg)–(Al2O3) surfaces in the presence of FBS was dependent upon serum Vn.
Journal of Materials Science Materials in Medicine 08/1994; 5(9):715-722. · 2.32 Impact Factor
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ABSTRACT: Fluoropolymers modified by plasma modification were studied for their suitability as surfaces for the adhesion of cells. We compared films made by plasma modification of fluoroethylenepropylene (FEP) using nitrogen-containing gases (ammonia or dimethyl acetamide) with films deposited using oxygen-containing monomers (methanol, methyl methacrylate or sequential treatment with toluene then water). The surfaces were compared for the attachment and spreading of human vein endothelial cells and human dermal fibroblasts. The initial attachment and spreading of cultured fibroblasts and endothelial cells onto films deposited using nitrogen-containing gases were equivalent to that onto films deposited using oxygen-containing monomers, but there were some differences in the mechanism of attachment. With films deposited using oxygen-containing monomers, the initial attachment and spreading of endothelial cells failed when the medium contained 15% (v/v) serum from which both fibronectin (Fn) and vitronectin (Vn) had been removed. Similarly, initial attachment and spreading of endothelial cells onto films deposited using oxygen-containing monomers were reduced by 62-86% when the cells were seeded in medium containing Vn-depleted serum (which contained Fn). Endothelial cells attached and spread onto films made using oxygen-containing monomers, when seeded in medium containing Fn-depleted serum (which contained Vn). On films deposited using nitrogen-containing gases, the adhesion of endothelial cells was only slightly reduced in Vn-depleted medium (as compared to attachment in medium containing unmodified serum). Furthermore, surfaces which had incorporated nitrogen were more effective than were oxygen-containing films in adsorbing sufficient serum Fn as to promote endothelial cell attachment. Similar results were seen for the attachment and spreading of fibroblasts as for the endothelial cells. For fibroblasts, attachment and spreading onto oxygen-containing films and onto nitrogen-containing films were not simply dependent upon either the Vn content or the Fn content of the medium. Maximal attachment and spreading of fibroblasts were, however, dependent upon adsorption of both serum Vn and Fn.
Journal of Biomaterials Science Polymer Edition 02/1994; 6(6):511-32. · 1.69 Impact Factor
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ABSTRACT: Cell culture studies have often been used in the determination of the suitability of biomaterials as surfaces for the attachment and growth of cells. For such studies of surfaces for potential use in bone implants, cells derived from bone may be maintained in culture on tissue culture polystyrene (TCPS). We have determined the contribution that serum fibronectin (FN) or vitronectin (VN) make to the attachment and spreading of cells cultured from explanted human bone (bone-derived cells) during the first 90 min following seeding on culture surfaces. The attachment of bone-derived cells to TCPS was simulated two-fold by the addition of 10% (v/v) fetal bovine serum (FBS) to the seeding culture medium. The roles of FN and VN were determined by selective removal of the FN or VN from the FBS prior to addition to the culture medium. FBS from which the VN had been removed did not have this stimulatory activity. In contrast, the attachment of bone-derived cells onto TCPS from medium containing FN-depleted serum (which contained VN) was the same as when intact FBS was used. There was incomplete attachment of bone-derived cells (27% of cells) when seeded in medium containing FBS depleted of both VN and FN. Our results show that for human bone-derived cells, the attachment onto TCPS of cells planted in medium containing FBS during the first 90 min of culture is principally as a result of adsorption onto the surface of serum VN. As unmodified polystyrene (PS) has also been used previously as a model biomaterial surface, PS was compared to TCPS for attachment of the bone-derived cells. Attachment of bone-derived cells to TCPS was twice that onto PS, both when the medium was serum-free and when it contained FBS. Bone-derived cells attached to TCPS or PS onto which purified VN or FN had been precoated, with VN adsorbed onto PS being as effective as was VN adsorbed onto TCPS. With FN, there was an effect of the polystyrene surface chemistry which was evident in that suboptimal concentrations of FN had a slightly higher potency when adsorbed onto TCPS than did the same concentrations of FN coated onto PS. When preadsorbed onto TCPS, the potency of FN for attachment of bone-derived cells was at least equal to that of VN.
Journal of Biomaterials Science Polymer Edition 02/1993; 5(3):245-57. · 1.69 Impact Factor
