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.

Biocompatibility of designed MicNo-ZnO particles: Cytotoxicity, genotoxicity and phototoxicity in human skin keratinocyte cells.

Recently, designed platelet shaped micron particles that are composed of nano primary particles, called MicNo (=Micron+naNo) particles, have been developed to exploit the benefits of nano size, while removing the adverse effects of nanoparticles. It has been shown that MicNo-ZnO particles exhibit both micron and nanosized particle characteristics. Although physical and chemical properties of MicNo-ZnO particles have been studied, their biocompatibility has not yet been evaluated. Accordingly, the research objective of this study was to evaluate in vitro cytotoxicity, genotoxicity and phototoxicity behaviors of designed MicNo-ZnO particles over human epidermal keratinocyte (HaCaT) cells. MicNo-ZnO particles exhibit much less cytotoxicity with IC50 concentrations between 40 and 50µg/ml, genotoxicity above 40µg/ml and lower photo genotoxicity under UVA on HaCaT than the ZnO nanoparticles. Although their chemistries are the same, the source of this difference in toxicity values may be attributed to size differences between the particles that are probably due to their ability to penetrate into the cells. In the present study, the expansive and detailed in vitro toxicity tests show that the biocompatibility of MicNo-ZnO particles is much better than that of the ZnO nanoparticles. Consequently, MicNo-ZnO particles can be considered an important active ingredient alternative for sunscreen applications due to their safer characteristics with respect to ZnO nanoparticles.