Effects of hexagonal boron nitride nanoparticles on antimicrobial and antibiofilm activities, cell viability

The objective of this work was to investigate the antimicrobial and antibiofilm activities of hBN nanoparticles against Streptococcus mutans 3.3, Staphylococcus pasteuri M3, Candida sp. M25 and S. mutans ATTC 25175. Minimum Inhibitory Concentration (MIC) of hBN nanoparticles were determined against Streptococcus mutans 3.3, Staphylococcus pasteuri M3, Candida sp. M25 growth. In addition, we aimed to evaluate the cytotoxic effects of hBN nanoparticles on human normal skin fibroblast (CCD-1094Sk, ATCC® CRL 2120 ™) and Madin Darby Canine Kidney (MDCK) cells by using various toxicological endpoints. Cell viability was assessed by MTT, SRB and PicoGreen assays. After experimental analyses, it was revealed that hBN nanoparticles show better MIC results. The MIC values were higher for Streptococcus mutans ATTC 25175 and Staphylococcus pasteuri M3 and lower against Streptococcus mutans 3.3, Candida sp. M25. Surprisingly, hBN nanoparticles showed a high antibiofilm activity on preformed biofilm, which inhibited biofilm growth of S. mutans 3.3, S. mutans ATTC 25175 and Candida sp.M25. These results show that hBN nanoparticles may be an option to control oral biofilms. In cell viability tests, the cells were exposed to 0.025-0.4 mg/mL concentrations of hBN nano particle suspension. The exposure time to the hBN nanoparticle suspensions were 24 h and 48 h. The results indicate that there is no cytotoxic effect on CRL 2120 and MDCK cells at the concentration range of 0.025-0.1 mg/mL. However, on both first and second day, hBN caused mild cytotoxicity on CRL-2120 cells at high hBN concentration (0.2-0.4 mg/mL). Considering all the results of this study, in appropriate concentration (0.1 mg/mL) hBN nanoparticles can be considered a potential safe oral care product.