Cytotoxicity Study of Textile Fabrics Impregnated With CuO Nanoparticles in Mammalian Cells.

Copper and copper compounds have multifunctional properties (antibacterial, antiviral, and antifungal) with promising applications. Copper in its nanoparticle (Cu NPs) forms has been widely used in various industrial and commercial applications. In the current research, the cytotoxic effects of textile fabrics impregnated with copper oxide nanoparticles (CuO NPs) were studied in mammalian cell lines. CuO NPs were impregnated onto textile substrates using 2 different techniques: the sonochemical generation and impregnation of NPs from metal complexes ( insitu) and a "throwing the stones" technology using commercially prepared CuO NPs. The cytotoxicity of these 2 textile fabric types was assayed on human dermal fibroblast (HDF) cells and human hepatocellular carcinoma cells (HepG2) and was evaluated by indirect contact using an MTT assay. The impregnated fabrics were not exposed to the cells, rather their leachates were used to test cytotoxicity. The fabrics were soaked into the growth media for up to 7 days, and the leachates from day 1 and day 7 were incubated with the cell lines for 24 hours prior to the testing. The discharge or leaching from antimicrobial nanomaterials into the surroundings and surface waters is posing a serious environmental threat, which needs to be addressed. Hence, with regard to product safety, it is a good approach to study the fabric leachates rather than the intact material. The results showed that CuO NPs are not toxic to HDF cells. However, cytotoxicity was seen in HepG2 cells with cell viability decreasing by 20% to 25% for all the fabrics after 24 hours.

Effect of sonication frequency on the disruption of algae.

In this study, the efficiency of ultrasonic disruption of Chaetoceros gracilis, Chaetoceros calcitrans, and Nannochloropsis sp. was investigated by applying ultrasonic waves of 0.02, 0.4, 1.0, 2.2, 3.3, and 4.3 MHz to algal suspensions. The results showed that reduction in the number of algae was frequency dependent and that the highest efficiency was achieved at 2.2, 3.3, and 4.3MHz for C. gracilis, C. calcitrans, and Nannochloropsis sp., respectively. A review of the literature suggested that cavitation, rather than direct effects of ultrasonication, are required for ultrasonic algae disruption, and that chemical effects are likely not the main mechanism for algal cell disruption. The mechanical resonance frequencies estimated by a shell model, taking into account elastic properties, demonstrated that suitable disruption frequencies for each alga were associated with the cell's mechanical properties. Taken together, we consider here that physical effects of ultrasonication were responsible for algae disruption.

Combined Effect of Ultrasound and Ozone on Bacteria in Water.

The aim of this study is to assess the synergetic effect of combined ultrasound and ozone treatment on the biological disinfection of water on a large-scale application using viable plate counts and flow cytometry. Escherichia coli B bacteria in saline suspension was treated using a commercially available combined ultrasound and ozone system (USO3 (Ultrasonic Systems Gmbh)) for 16 min. Two analytical methods were used to assess the results in terms of live and dead cells in the bulk liquid: standard viable plate counting recorded in terms of colony forming units per milliliter and flow cytometry. In the latter case 1 mL of bacterial suspension was stained simultaneously with the fluorescent stains SYTO9 and propidium iodide (PI). Transmission electron microscopy was used to generate images identifying the biological effects of different treatments using ultrasound and ozone on bacterial cell walls. Results demonstrated that treatment with ozone alone (1 mg/L) resulted in a significant reduction (93%) in the number of live cells after 16 min treatment whereas ultrasound alone showed only a small reduction (24%). However, a combination of ozone and ultrasound showed a synergistic effect and enhanced the inactivation to 99% after 4 min. A combined ultrasound and ozone treatment of bacterial suspensions using a commercial system affords a promising method for water disinfection that is better than treatment using either method alone. Standard viable plate count analysis is normally used to assess the effectiveness of disinfection treatments; however flow cytometry proved to be a more sensitive method to determine the actual effects in terms of not only live and dead cells but also damaged cells. This type of analysis (cell damage) is difficult if not impossible to achieve using traditional plate counting methodology.

Effect of ultrasonic frequency and power on the disruption of algal cells.

In this work the effect of ultrasonic waves on suspensions of Chlamydomonas concordia and Dunaliella salina have been investigated at frequencies of 20, 585, 864 and 1146 kHz and at different acoustic powers. Results showed that the reduction in algal numbers was dependent on both frequency and acoustic power. The order of efficiency of the ultrasonic disruption of C. concordia at different frequencies was 20 < 580 < 864 < 1146 kHz, and for D. salina was 20< 580 ≅ 864 ⩽ 1146 kHz. It is clear that high-frequency sonication is more effective than conventional low-frequency sonication for the disruption of cells for both species. Results showed that suitable disruption frequencies for each algae were associated with the mechanical properties of the cell. The frequency dependence of the efficiency of algae disruption on the mechanical resonances of both the algae cell is discussed in terms of bubble oscillation in an ultrasonic field.

Evaluation of the mechanisms of the effect of ultrasound on Microcystis aeruginosa at different ultrasonic frequencies.

Blooms of cyanobacteria are now considered to be a common environmental issue. They are hazardous to both domestic and wild animals and humans. Current treatments are unable to effectively control such blooms as they become tolerant to biocides and it is difficult to degrade cyanobacterial toxins in water. Alternative methods for control are currently under investigation. One potential effective method is ultrasonic irradiation. Ultrasound inactivates algal and cyanobacteria cells through cavitation by generating extreme conditions, resulting in a number of physical, mechanical and chemical effects. The aim of this study was to investigate the effect of ultrasound at different frequencies on Microcystis aeruginosa. Flow cytometry was used to measure cyanobacterial metabolic cell viability in addition to the more commonly used haemocytometry, optical density and fluorimetry. Results indicate low frequency 20 kHz ultrasound with high intensity (0.0403 W cm(-3)) is effective for the inactivation of cyanobacterial cells. Higher frequencies of 580 kHz (0.0041 W cm(-3)) also resulted in an inactivation effect, but 1146 kHz (0.0018 W cm(-3)) showed a declumping effect as evidenced by flow cytometry. Ultrasonic treatment over time under different sonication conditions demonstrates the following: 1. Acoustic cavitation via mechanical effects can induce sufficient shear forces to directly rupture cyanobacteria cells. 2. At higher ultrasonic frequencies the mechanical energy of cavitation is less but a larger proportion of free radicals are produced from the ultrasonic degradation of water, which chemically attacks and weakens the cyanobacteria cell walls. 3. At higher frequencies free radicals also damage chlorophyll a leading to a loss in photosynthetic cell viability. 4. At low powers ultrasonic energy results in declumping of cyanobacteria.

Effect of ultrasonic frequency and power on algae suspensions.

Cyanobacteria are photosynthetic bacteria with some characteristics of algae. Some cyanobacteria produce toxins that have been shown to be hazardous to both animals and humans. Previous research has demonstrated power ultrasound can provide a suitable method to control algae blooms although the optimum ultrasonic parameter settings have not been determined to ensure an effective and energy efficient treatment. In this work the effect of ultrasound on suspensions of Microcystis aeruginosa has been investigated at the following frequencies 20, 40, 580, 864 and 1146 kHz. Results showed that the reduction in algal numbers is dependent on both frequency and intensity. In order to quantify the effect we have defined the efficiency of the ultrasonic control of algae at a specific frequency as: (% inactivation of the algae) / (ultrasonic intensity applied). When this is applied to the results at different frequencies the order of efficiency for algae reduction is 20 < 1146 < 864 < 580 kHz. This suggests that ultrasound can offer a suitable method for algae inactivation or control but the sonication conditions must be taken into account.