The antithrombotic and antimicrobial properties of PEG-protected silver nanoparticle coated surfaces

Cardiovascular implant-associated complications such as infection and thrombosis may be reduced by modification of device surfaces using antimicrobial and antithrombotic agents. Silver nanoparticles (SNPs) are well accepted for its broad-spectrum antimicrobial effect. A recent report suggested its antiplatelet effect also. So the hypothesis of this study is that polyethylene glycol (PEG) protected SNPs can be incorporated with biomaterials to attain dual properties; and by adjusting an optimum concentration, its cytotoxicity to tissues and cells can be prevented. To prove this, detailed study of PEG–SNP was done at three levels: (i) direct inhibitory effect on platelet activation, aggregation and biochemical pathways when PEG–SNP is added into platelet suspension; (ii) inhibition of platelet adhesion to PEG–SNP incorporated biological matrix and polymer scaffold and (iii) non-cytotoxic behavior of immobilized PEG–SNP in fibrin matrix. Inhibitory effects demonstrated are on: platelet function by aggregometry, exposure of activation and apoptosis markers by flow cytometry, biochemical pathway by malondealdehyde (MDA) estimation and protein phosphorylation by Western blot. Reduced platelet adhesion onto PEG–SNP incorporated scaffold is shown using scanning electron microscopy (SEM). Non-toxic behavior of endothelial cells (EC) and smooth muscle cells (SMC) grown on PEG–SNP-fibrin disc is shown by fluorescence microscopy and cell phenotype stability by real-time polymerase chain reaction (PCR).