Incorporation of antibiofilm compounds in a sulphonated poly-ether-ether-ketone (SPEEK).

Objectives: PEEK is currently presented as an alternative for orthopedic implants due to its biocompatibility and low modulus compared to titanium. PEEK has been shown to be very attractive for incorporating compounds thanks to the sulfonation process, which promotes a balance between the mechanical properties and thermo-oxidative stability. The objective of this work was to functionalize a poly-ether-ether-ketone (PEEK) film in order to incorporate novel lactam-based anti-biofilms compounds.
Methods: PEEK samples (OPTIMA 450P, Victrex; England) were functionalized by sulphuric acid treatment for 1h and then dissolved in dimethylsulfoxide where lactam-based antibiofilm compounds were added to be incorporated into the polymer. A dip coating technique (oven at 50ºC for 24h) was used to synthesize a thin film on a glass-based substrate. The sulfonation degree (DS) and the incorporation of anti-biofilm compounds (lactams) into SPEEK were analysed by Thermogravimetric Analysis (TGA), Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (HNMR), and Scanning Electron Microscopy (SEM-EDS).
Results: The characterization indicated a degree of sulfonation (DS) of 65% and TGA curves confirmed the presence of SO₃H and lactams in the SPEEK structure. Biofilm formation over the functionalized materials was determined using Streptococcus mutans as tester strain. Effects of the incorporated lactams on the surrounding media were also assessed, by measuring bacterial planktonic growth on SPEEK were statistically analysed by one-way analysis of variance test (ANOVA), at significance level (p < 0.05) and biofilm densities over SPEEK surface containing lactams were lower than those observed over SPEEK free of lactams,
Conclusions: Results presented here indicate that inclusion of lactams into SPEEK represents a good alternative for the production of biomaterials resistant to bacterial contamination.