Nanofilms of adsorbed thymol formed on Ti surfaces for biomedical applications. Antimicrobial activity and biocompatibility

GONZALEZ, ARIEL; MIÑAN, ALEJANDRO; GRILLO, CLAUDIA; SCHILARDI, PATRICIA; FERNÁNDEZ LORENZO, MÓNICA

Mar del Plata

Congreso; Reunión Anual de Sociedades de Biociencia 2019; 2019

Titanium (Ti) and its alloys are widely used in the construction of permanent orthopedic and cardiovascular implants. However, one of the most frequent causes of failures are bacterial infections by Staphylococcus aureus. This is aggravated by the abusive use of antibiotics that generate microbial resistance to conventional therapies. As a consequence, new antimicrobial nanotechnologies emerge as promising alternatives to prevent prosthetic infections.The objective of this work was to evaluate the antimicrobial effect of an innovative nanotechnology: thymol (phenolic phytocompound) nanofilms adsorbed on Ti (NPTOH-Ti) against Staphylococcus aureus. The biocompatibility was determined using preosteoblast cells (MC3T3-E1). To that end, 1cm diameter grade 2 Ti discs were used and thymol was adsorbed onto their surface by 2h immersion in 0.1M thymol acid solution. NPTOH-Ti was detected by infrared spectroscopy (FTIR-ATR). The antibiofilm activity of NPTOH-Ti and Ti (control) was determined by immersing the metal discs in a suspension of S. aureus (108 bacteria/ml) for 3h. Subsequently, the number of bacteria adhered on the discs was evaluated after sonication by colony forming unit (CFU) counting. In addition, Live/Dead (Invitrogen) staining was used to determine if the adhered bacteria were alive or dead. Finally, biocompatibility was assessment through cells attachment on NPTOH-Ti and Ti by staining with acridine orange. The results showed that NPTOH-Ti had effective anti-biofilm properties. On the one hand, viable bacteria were not observed by the plating count method and live/dead staining assay exhibited only dead (red) bacteria on the surface. On the other hand, control Ti revealed 4±0.5x105 adhered bacteria that were mostly (95%) alive (green). In addition, NPTOH-Ti showed similar growth and adherent cells respect to Ti (107±12% and 100±16% respectively; p>0.05).It was concluded that NPTOH-Ti are biocompatible and have antibiofilm properties which make them promising to prevent prosthetic infections.