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).