26 × 107 4.00 × 107 – 4.30 × 106 4.20 × 106 – 1.43 × 108 1.42 × 108 5.94 × 108 2.78 × 108 2.74 × 108 2.60 × 108
4.00 × 107 3.87 × 107 – 2.02 × 107 1.98 × 107 – 1.20 × 108 1.17 × 108 3.37 × 108 2.27 × 108 2.21 × 108 2.08 × 108 3.62 × 107 3.53 × 107 – 2.52 × 107 2.48 × 107 – 1.16 × 108 1.13 × 108 2.86 × 108 E. coli 6.04 × 108 5.57 × 108 6.04 × 108 8.96 × 107 7.17 × 107 2.94 × 108 1.69 × 107 1.50 × 107 – 2.17 × 108 2.04 × 108 5.51 × 108 2.98 × 108 2.76 × 108 3.21 × 108 6.04 × 107 4.17 × 107 9.85 × 107 4.89 × 107 4.39 × 107 – 2.07 × 108 1.93 × 108 3.38 × 108 1.51 × 108 1.41 × 108 1.52 × 108 4.80 × 107 3.42 × 107 – 5.99 × 107 5.11 × 107 – 1.38 × 108 1.23 × 108 1.87 × 108 6.55 × 107 6.02 × 107 6.34 × 107 3.75 × 107 2.51 × 107 – 5.12 × 107 4.20 × 107 – 6.31 × 107 5.55 × 107 8.11 × 107 5.47 × 107 5.20 × 107 3.68 × 107 3.28 × 107 1.87 × 107 – 4.47 × 107 4.07 × 107 – 5.10 × 107 4.44 × 107 8.11 × 107 Lenvatinib clinical trial aBacterial cell number was measured by flow cytometry (FCM) and spectrophotometer method of optical density (OD) Selleck NVP-BGJ398 measurement after 1 hr exposure to ZnO, TiO2 and SiO2 nanoparticles; inoculum used for each experiment was indicated in the control samples, i.e. no nanoparticles. bPresented data were converted from each sample cells concentration according to the each species standard curve of cell/ml vs OD660 and as mean of triplicate with standard deviations (SD) of < 5%. cValue was negative. Conclusions In summary, this study compared
three most commonly used bacterial quantification methods including colony counts, spectrophotometer method of optical density measurement, and flow cytometry in the presence of
metal oxide nanoparticles. Our results demonstrated that flow cytometry is the best method with no apparent interference by the nanoparticles, indicating that it is suitable for rapid, accurate and automatic detection of bacteria. Flow cytometry is also able to detect both live and dead bacterial cells and allows detection of all bacteria including those that are uncultured. Although the bacterial quantification determined by plate counts was not affected by the nanoparticles, it was time consuming, less accurate and not suitable for automation. The spectrophotometer method using optical density measurement was the most unreliable method to quantify and detect bacteria in the presence of oxide nanoparticles. The data presented in this study indicated that flow G protein-coupled receptor kinase cytometry method for bacterial quantification is superior to the other two methods. This study provides data examining the potential interference of oxide nanoparticles on bacterial quantification. The information provided here will be useful in the assessment of bacterial contamination in food, drug and cosmetic products containing nanoparticles. Future studies on other nanoparticles and limit of the bacterial detection by FMC are warranted. Methods Materials and preparation of nanoparticle suspensions ZnO (purity >97%), TiO2 (purity ≥99.5%), and SiO2 (purity 99.