ŠKODOVÁ Petra Technical University of Liberec

Comparison of the Influence of Nanoparticles on Escherichia Coli and Pseudomonas Aeruginasa Bacterial Populations


As use of nanoparticles continues to increase in various fields of human activity, it becomes increasingly important to understand all interactions that occur between nanoparticles and cells. In this experiment, we explore the influence of several types of nanoparticle on populations of facultative anaerobic bacteria (Escherichia coli) and aerobic bacteria (Pseudomonas aeruginosa). Nanoparticle toxicity (nanoparticle concentration 1 g/l) was evaluated through respirometry and microscopic fluorescence analysis, which allows for observation and comparison of both living and dead cells in a sample. These two methods were supplemented by determination of colony forming units. Basal salt medium (BSM) with differing concentration of glucose and a soya broth medium were used for both bacterial populations as a culture medium. Nanodiamond proved to be the least toxic of the nanoparticles tested (though these contained impurities that may have affected the results), while nanoparticles of praseodymium had the most toxic effect on bacterial populations. A scanning electron microscope (SEM) was used to assess both the appearance and the approximate sizes of the nanoparticles and bacteria. The bacteria clearly differed in size, with E. coli averaging 3-4 µm and P. aeruginosa averaging 1.5 µm. The various nanoparticles ranged between 50 and 200 nm. SEM confirmed colonization of nanoparticle aggregate surfaces by bacteria in almost all samples.