Vitamin E blended UHMWPE has the potential to reduce bacterial adhesive ability [*G.Banche and P. Bracco contributed equally to this work; ** AM Cuffini is the corresponding author]

Biomaterial-associated infection (BAI), a clinical significant problem often resulting in the implant septic failure, is initiated by the bacterial adhesion, mainly by Staphylococcus epidermidis. Ultra High Molecular Weight Polyethylene (UHMWPE) has been the material of choice in total joint replacement for many years; reducing the adhesion of S. epidermidis to the polymer could be a means to decrease infection. This interdisciplinary study examined the adhesion of 2 ATCC and one clinical strain of S. epidermidis to standard Polyethylene (PE), Vitamin E blended UHMWPE (VE-PE) and oxidised UHMWPE (OX-PE) after different incubation times: a significant (p<0.01) decrease in the adhered staphylococci on VE-PE and a significantly highest incidence of the dislodged biofilm bacteria on OX-PE was observed compared with that registered on PE. At ATR-FTIR spectroscopy before and after suspension in bacterial medium for 48 h, new absorptions were observed mainly in OX-PE, indicating adsorption of protein-like substances on the polymer surface. We hypothesized that the different hydrophilicity of surfaces with different chemical characteristics can influence protein adsorption and bacterial adhesion. These results may have clinical implications concerning the prevention of septic loosening: the VE-PE could have the potential to reduce S. epidermidis adhesive ability if the preliminary data observed in these selected strains is further confirmed, as diversity among clinical strains is well known.