Modification of methacrylate bone cement with eugenol – A new material with antibacterial properties

Nowadays, the search for unconventional antibacterial agents is very common. One of them may be eugenol (EU) (4-allyl-2-methoxyphenol), which exhibits antimicrobial properties against pathogenic bacteria and is used in the pharmaceutical industry. Owing to its structure, EU decreases the exotherm of polymerization without a negative impact on the degree of conversion. The properties of EU-modified bone cement, such as doughing time, maximum temperature, and setting time, will be characterized, as well as mechanical properties, EU release, and antibacterial properties. Bone cements were synthesized by mixing a powder phase composed of two commercially available methacrylate copolymers (Evonic) and a liquid phase containing 2-hydroxyethyl methacrylate, methyl methacrylate, triethylene glycol dimethacrylate, and EU with an amount of 0.5 wt% of bone cement sample. As an initiating system, benzoyl peroxide and N,N-dimethylaniline were used. Samples were prepared with various amounts of the initiating system. The doughing time, maximum temperature (T max), setting temperature (T set), setting time (t set), and compressive strength tests were determined according to the ISO 5833:2002 standard requirements. The doughing time for bone cement depends on the amount of the initiating system. The maximum temperature during curing of bone cement is very low; however, the setting time is closer to the upper limit set by the standard. The compressive strength of the tested materials is good and significantly exceeds the requirements of the standard. EU release was very high and ranged from around 43–62% after 168 h. Moreover, antibacterial studies show that the tested bone cements are bacteriostatic for Staphylococcus aureus or and Escherichia coil strains. In summary, modified bone cements meet the ISO 5833:2002 standard requirements in all parameters and are characterized by good mechanical properties (similar to or higher than commercial bone cement), high EU release, and bacteriostatic properties.