Adsorption of Fibrinogen on Silica Surfaces—The Effect of Attached Nanoparticles

Abstract

When a biomaterial is inserted into the body, proteins rapidly adsorb onto its surface, creating a conditioning protein film that functions as a link between the implant and adhering cells. Depending on the nano-roughness of the surface, proteins will adsorb in different amounts, with different conformations and orientations, possibly affecting the subsequent attachment of cells to the surface. Thus, modifications of the surface nanotopography of an implant may prevent biomaterial-associated infections. Fibrinogen is of particular importance since it contains adhesion epitopes that are recognized by both eukaryotic and prokaryotic cells, and can therefore influence the adhesion of bacteria. The aim of this study was to model adsorption of fibrinogen to smooth or nanostructured silica surfaces in an attempt to further understand how surface nanotopography may affect the orientation of the adsorbed fibrinogen molecule. We used a coarse-grained model, where the main body of fibrinogen (visible in the crystal structure) was modeled as rigid and the flexible α C-chains (not visible in the crystal structure) were modeled as completely disordered. We found that the elongated fibrinogen molecule preferably adsorbs in such a way that it protrudes further into solution on a nanostructured surface compared to a flat one. This implicates that the orientation on the flat surface increases its bio-availability.

A multistep in vitro hemocompatibility testing protocol recapitulating the foreign body reaction to nanocarriers

“…Fibrinogen binding to NP with different physicochemical properties has been widely documented and related to both the NP surface electrostatic charges and size [ 21 , 22 ]. In the present protocol, the assay adopted assessed the binding of fibrinogen to platelets by spiking freshly isolated PRP with labeled fibrinogen.…”

Improving Fibrin Hydrogels’ Mechanical Properties, through Addition of Silica or Chitosan-Silica Materials, for Potential Application as Wound Dressings

“…This is because the fibrinogen can be adsorbed on the siliceous surface by electrostatic interaction between the positively charged amino acids (i.e., Lys and Arg) and deprotonated silanol groups at near-neutral pH of the human plasma [ 39 ]. This adsorption occurred mainly by the disordered α C-chains and fibrinogen strands on the surface [ 40 ], which could be beneficial for their polymerization and crosslinking because the presence of particles did not interfere with the fibrin network formation [ 23 ]. Electrostatic colloidal stabilization of S materials allowed reaching concentrations up to 20 mg/mL S suspension ( Figure 1 ).…”

Principles of Fibrinogen Fiber Assembly In Vitro

“…[ 59 ] When a coarse grain model of fibrinogen was used, which was based on its crystal structure, [ 40 ] the far distal ends of the molecule were found to exhibit a more hydrophobic character than the rest of the protein and an overall net charge of −8 at pH 7.4 and a low ionic strength of 0.025 m was found. [ 60 ] By including the αC regions in the same study a total negative charge of −12 at the same pH and low ionic strength was reported for the whole molecule. [ 60 ] This implies an overall negative net charge of the αC region [ 60 ] contrary to the work of Adamczyk et al., for which a positive net charge of +3e is reported at pH 7.4 [ 42 ] for the αC‐terminal domain.…”

“…[ 60 ] By including the αC regions in the same study a total negative charge of −12 at the same pH and low ionic strength was reported for the whole molecule. [ 60 ] This implies an overall negative net charge of the αC region [ 60 ] contrary to the work of Adamczyk et al., for which a positive net charge of +3e is reported at pH 7.4 [ 42 ] for the αC‐terminal domain.…”