Attachment of cultured human bone cells to novel polymers

Abstract

The initial attachment of human bone-derived cells (HBDC) to several polymer systems has been studied in vitro. A novel polymer system based on poly(ethyl methacrylate) polymer and tetrahydrofurfuryl methacrylate monomer (PEMA/THFMA) was compared with a variant in which THFMA was replaced by 2-hydroxyethyl methacrylate (PEMA/HEMA). Tissue culture polystyrene (TCPS) and polystyrene (PS) were used as reference materials. The ability of the substrates to adsorb the attachment glycoproteins fibronectin (Fn) and vitronectin (Vn) from serum and the subsequent effect on radiolabeled HBDC attachment were examined. Initial cell attachment from the medium containing 10% (v/v) serum was highest on TCPS; on PEMA/THFMA and PEMA/HEMA substrates it was about 25% of this level, and on PS it was only 10% of that on TCPS. Attachment of HBDC to all substrates was dependent on the presence of Vn, which, unlike Fn, was able to adsorb in the face of competition from other serum components. Both Vn and Fn were able to support cell attachment when precoated onto all substrates. In comparison to TCPS, PEMA/THFMA did not show enhanced adsorption of either Fn or Vn from serum, and this was reflected in the level of cell attachment. Interestingly, the potency of preadsorbed Fn for cell attachment was much higher on this substrate than on any other: 45 ng/cm2 Fn when adsorbed to PEMA/THFMA gave a level of cell attachment 1.6-fold higher than the same density of Fn on PS or TCPS. The maximum Fn surface density achieved on HEMA/PEMA was 16 ng/cm2. Cells on PEMA/THFMA showed typical clustering of the alpha5 beta1 Fn receptor, but this was not evident in cells attached to PEMA/HEMA even when precoated with Fn. This study indicates that the initial attachment of HBDC to all substrates was Vn dependent. It also indicates that on PEMA/THFMA the favorable presentation of subsequently adsorbed Fn may assist matrix assembly.

Cell adhesion and response to synthetic nanopatterned environments by steering receptor clustering and spatial location

“…Rezania and Healy (1999) showed that the response of cells on RGD-grafted surfaces is dependent on the specific peptide sequence. RGD peptides enhance the rate of cell spreading and adhesion strength (McFarland et al, 1999;Rezania et al, 1997). Cell binding to covalently linked RGD peptides causes increase in expression of integrins and FA molecules and promotes resistance to apoptotic stimuli (Cavalcanti-Adam et al, 2002;Grigoriou et al, 2005).…”

Removal of surface by‐products from sintered hydroxyapatite: Effect of a chelation treatment on fibronectin adsorption and cell adhesion

“…20 Among those, fibronectin, a 550-kDa extracellular matrix glycoprotein, is well known to increase cell adhesion on abiotic surfaces. 18,21 Fibronectin would also be involved in the early stages of osteogenesis [22][23][24] and in mineralization processes 25,26 The present work focuses on optimizing cell adhesion onto calcium-phosphate ceramics with the use of a fibronectin interface. Preliminary studies performed in the laboratory indicated that a labile layer on hydroxyapatite materials gives rise to fibronectin precipitation and prevents its adsorption.…”

RGD Peptides Immobilized on a Mechanically Deformable Surface Promote Osteoblast Differentiation

“…(1)(2)(3)(4) Alteration in any of these physical characteristics can profoundly influence short-term activities (adhesion) and long-term functional events (gene expression and protein synthesis). (5)(6)(7)(8)(9)(10)(11)(12) How bone cell-material interaction mediates complex functions such as those linked to the synthesis of the extracellular matrix (ECM) and the osseointegration process remains to be established.…”

“…One motif that is present in a number of matrix proteins is the arginine-glycine-aspartic acid (RGD) sequence. (13) RGD is an integrin-binding motif that enhances osteoblast attachment and spreading, (8,14) induces mineralization of the ECM, and influences downstream maturation events. (7) Im-mobilization of RGD peptides on titanium implants by physiosorption has been reported to significantly increase bone formation, (15,16) although free RGD-containing peptides induce skeletal cell death.…”