Concentrations Of CuO Nanoparticles Research Articles

Synthesis of Copper Oxide Nanoparticles Using Plant Leaf Extract of Catha edulis and Its Antibacterial Activity

Development of green technology is generating interest of researchers towards ecofriendly and low-cost methods for biosynthesis of nanoparticles (NPs). In this study, copper oxide (CuO) NPs were synthesized using a copper nitrate trihydrate precursor and Catha edulis leaves extract as a reducing and capping agent during the synthesis. The biosynthesized CuO NPs were characterized using an X-ray diffractometer (XRD), scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS), transmission electron microscope (TEM), Ultraviolet visible spectroscopy (UV-Vis), and Fourier transform infrared (FTIR) spectroscopy. XRD characterization confirmed that the biosynthesized CuO NPs possessed a good crystalline nature which perfectly matched the monoclinic structure of bulk CuO. Furthermore, the results obtained from SEM and TEM showed that the biosynthesized CuO NPs were spherical in shape. EDS characterization of the biosynthesized NPs also indicated that the reaction product was composed of highly pure CuO NPs. Moreover, the antimicrobial activities of different concentrations of CuO NPs synthesized using Catha edulis extract were also tested. Accordingly, the result showed that the highest zone of inhibitions measured were for CuO NPs synthesized using 1 : 2 ratios at 40 mg/ml solution concentration and observed to be 22 ± 0.01 mm, 24 ± 0.02 mm, 32 ± 0.02 mm, and 29 ± 0.03 mm for S. aureus, S. pyogenes, E. coli, and K. pneumonia, respectively.

Effect of CuO nanoparticles concentration on the performance and emission characteristics of the diesel engine running on jojoba (Simmondsia Chinensis) biodiesel

The utilization of the petroleum products in engines is harmful to the humans as they pollute the environment. Nowadays, extensive research is in process to find an alternative fuel and improve its quality. The nanoparticles are one of the recent technologies that is useful for upgrading the fuel properties. This work aims to find the influence of CuO nanoparticles on performance of diesel engine, emission and combustion characteristics which runs on jojoba biodiesel blend (JB20) as a fuel. Different proportions of CuO nanoparticles (25, 50, and 75 ppm) were dispersed into the JB20 fuel. It is experimentally seen that BTE for the JB20CN50 fuel was higher than that of other Jojoba biodiesel fuel samples. The combustion characteristics such as ignition delay, HRR and cylinder pressure were also determined for analysing the effect of CuO nanoparticles. Engine emission hydrocarbons, CO and smoke emissions were also found lesser when the CuO nanoparticles added to JB20.

Enhancement of Low-Temperature Gas-Sensing Performance Using Substoichiometric WO3-x Modified with CuO.

To verify the effect of oxygen vacancy on gas sensitivity, we have systematically investigated the gas-sensing performance of copper oxide/substoichiometric tungsten oxide (CuO/WO3-x) nanocomposite sensors. Oxygen deficiency in WO3-x facilitates the reaction of hydrogen sulfide (H2S) gas with chemisorbed oxygen species (i.e., O2-, O-, and O2-) at low temperature. The oxygen/sulphur exchange reaction between CuO and H2S in the sensing process can achieve room temperature operation of gas sensors. After the WO3-x nanorods were modified by a low content of CuO nanoparticles (Cu:W = 1:20), the sensors present an n-type sensing behavior. Their best working temperatures drop from 289 °C (or 386 °C) to 99 °C (or 70 °C) at which the responses are improved by 14 to 163 times for different x values. Among them, CuO(L)/W5O14 shows the highest sensitivity of 1575.7 to 10 ppm H2S at 99 °C and 171.5 to 10 ppm H2S at room temperature. Once WO3-x were loaded with a high concentration of CuO nanoparticles (Cu:W = 1:2), they exhibit a p-type behavior, and the optimal working temperatures reduce suddenly to room temperature at which CuO(H)/W18O49 displays the most sensitive response of 7.2 even toward trace amounts of H2S as low as 100 ppb. In addition, p-type CuO weakens the metal-like characteristics of W18O49 and such weakening effect enhances with an increase in the CuO content. Therefore, the sensing performance of the CuO/W18O49 composite is the best among the four CuO/WO3-x sensors. The two designs for low and high Cu/W molar ratios all achieve enhanced room-temperature H2S gas response, with a fast recovery time of ∼60 s under heating pulse, as well as an excellent selectivity, which makes the sensors a promising candidate for practical applications. Moreover, the micro-Raman spectra confirmed CuS formation and the thermal effect on the decomposition of CuS in the sensing process was studied.

Molecular ecotoxicological effect of CuO nanoparticles stress on Bellamya aeruginosa

In this research, responsive sensitivities of hepatopancreatic Na+, K+-ATPase, malondialdehyde (MDA) and heat shock protein 70 family (HSP70) in Bellamya aeruginosa to CuO nanoparticles (CuO-NPs) were investigated through sediment bioassay, potential molecular ecotoxicological mechanism of CuO-NPs stress on Bellamya aeruginosa was explored, and feasibility of Na+, K+-ATPase, MDA and HSP70 as biomarkers for CuO-NPs contaminated sediment was evaluated. The results showed that under the stress of CuO-NPs, three molecular biomarkers displayed significant concentration- and time-effect relationships. After exposure to contaminated sediment with different concentrations of CuO-NPs, the Na+, K+-ATPase activity initially increased and then deceased; the content of low MDA initially increased and then deceased as well, while the content of high MDA showed a fluctuated trend. For HSP70, short exposure time (3 d) induced a sharp increase in HSP70 expression, but long exposure time had little effect on HSP70 expression. It demonstrated that the hepatopancreatic Na+, K+-ATPase activity and MDA content showed good sensitivity to CuO-NPs stress, whereas HSP70 only responded to CuO-NPs stress within short exposure time. HSP70 may be not a suitable long-term biomarker for CuO-NPs stress.

Numerical investigation of turbulent flow and heat transfer of nanofluid inside a wavy microchannel with different wavelengths

In the present study, turbulent flow and heat transfer inside a three-dimensional wavy microchannel with different wavelengths have been numerically simulated. The main purpose of this study is to investigate the effects of changing the wavelength of the sinusoidal microchannel and CuO nanoparticle concentration on flow and heat transfer properties. For this reason, flow is simulated at Reynolds numbers of 3000, 4500, 6000, and 7500 with volume fractions of 0, 1.5, and 3% in three different geometries and the effects of each parameter have been investigated. Validation of the results showed there is an excellent agreement between the presented results with the previous studies. The average Nusselt number, pressure loss ratio, performance evaluation criterion, and local Nusselt number have been presented. Moreover, the distribution of the static temperature contour has been presented. In the flow with lower Reynolds numbers, the Nusselt number is not changed significantly; however, in flow with Reynolds number of 7500, the Nusselt number is increased. The performance evaluation criterion has the highest value in nanofluid flow with the volume fraction of 3%, indicating the effects of heat transfer with pressure drop caused by nanoparticles, and from engineering and economic perspectives, using nanoparticles in the wavy microchannel is recommended.

Mechanism of CuO nano-particles on stimulating production of actinorhodin in Streptomyces coelicolor by transcriptional analysis

In this research, antibiotic-producing bacteria, Streptomyces coelicolor (S. coelicolor) M145, was exposed to copper oxide (CuO) particles to investigate the effects of nano-particles (NPs) on antibiotic production. Results showed that a higher yield of antibiotics was obtained with smaller particle sizes of CuO NPs. When exposed to 10 mg/L of 40 nm CuO NPs, the maximum amount of actinorhodin (ACT) obtained was 2.6 mg/L after 144 h, which was 2.0-fold greater than that of control. However, the process was inhibited when the concentration of CuO NPs was increased to higher than 20 mg/L. Transcriptome analysis showed that all the genes involved in the ACT cluster were significantly up-regulated after exposure to 10 mg/L NPs, which could be the direct cause of the increase of ACT production. Additionally, some genes related to the generation of acetyl-coA were up-regulated. In this way, CuO NPs led to an increase of secondary metabolites. The mechanism related to these changes indicated that nano-particle‒induced ROS and Cu2+ played synergetic roles in promoting ACT biosynthesis. This is a first report suggesting that CuO NPs had a significant effect on antibiotic production, which will be helpful in understanding the mechanism of antibiotic production in nature.

Effect of CuO Nanoparticles on Rheological Behavior of ISO VG46, Jatropha Oil, and Their Blend

Abstract This article presents experimental results on the mixing of CuO nanoparticles in ISO VG 46 oil, Jatropha oil, and a blend of the two oils. Initially, blend oil was prepared by mixing ISO VG46 and Jatropha oil in a fixed proportion. This blending caused a reduction in the viscosity of the oil mix as compared to the ISO VG46 oil. Therefore, to bring the viscosity of the blend oil to the level of the ISO VG46 oil, various concentrations of CuO nanoparticles were added to the blend to prepare stable nano-blend oils. The stability of the blend oil, ISO VG46, and Jatropha oil-based nano-lubricants was checked by measuring viscosity at regular intervals of time, and it is observed that stability decreases with the increase of CuO loading in base fluid. Viscosity values of nano-blend oils for various concentrations of CuO ranging from 0 to 3 wt. % were measured. These values were compared to the viscosity values of ISO VG46 and Jatropha oil-based nano-lubricants with the same CuO concentrations. About 19, 17, and 20 % enhancement in viscosity was observed in the blend oil, ISO VG46 oil, and Jatropha oil-based nano-lubricants, respectively, for 3 wt. % concentrations of CuO at 30°C. The nano-blend oil showed inferior performance up to 2 wt. % concentration of CuO in the entire temperature range (30 to 60°C). The viscosity of the nano-blend oil dispersing with 3 wt. % concentration matched well with the viscosity of ISO VG46 mineral oil. Furthermore, the experimental viscosity data of all the types of nano-lubricants are compared to the different viscosity models, and it is observed that the viscosity of the nano-lubricants closely matched with a viscosity model available in the literature. It is observed from viscosity sensitivity analysis that viscosity is more sensitive to greater concentration. The studies on the effects of nanoparticles’ concentration on density and friction coefficients revealed that the addition of nanoparticles in base oils had a small impact on pumping power.

Intensified Thermal Conductivity and Convective Heat Transfer of Ultrasonically Prepared CuO–Polyaniline Nanocomposite Based Nanofluids in Helical Coil Heat Exchanger

In this study, investigation of convective heat transfer enhancement with the use of CuO–Polyaniline (CuO–PANI) nanocomposite basednanofluid inside vertical helically coiled tube heat exchanger was carried out experimentally. In these experiments, the effects of different parameters such as Reynolds number and volume % of CuO–PANI nanocomposite in nanofluid on the heat transfer coefficient of base fluid have been studied. In order to study the effect of CuO–PANI nanocomposite based nanofluid on heat transfer, CuO nanoparticles loaded in PANI were synthesized in the presence of ultrasound assisted environment at different loading concentration of CuO nanoparticles (1, 3 and 5 wt.%). Then the nanofluids were prepared at different concentrations of CuO–PANI nanocomposite using water as a base fluid. The 1 wt.% CuO–PANI nanocomposite was selected for the heat transfer study for nanofluid concentration in the range of 0.05 to 0.3 volume % and Reynolds number range of was 1080 to 2160 (±5). Around 37 % enhancement in the heat transfer coefficient was observed for 0.2 volume % of 1 wt.% CuO–PANI nanocomposite in the base fluid. In addition, significant enhancement in the heat transfer coefficient was observed with an increase in the Reynolds number and percentage loading of CuO nanoparticle in Polyaniline (PANI).

Impact of Copper Oxide Nanoparticles on Enhancement of Bioactive Compounds Using Cell Suspension Cultures of Gymnema sylvestre (Retz.) R. Br

Gymnema sylvestre is a plant that is enriched in bioactive compounds. In particular, gymnemic acids (GA) and phenolic compounds (PC) are pharmaceutically important. There is a commercial demand for naturally occurring bioactive compounds, but their availability is limited due to geographical and seasonal variations. The elicitation approach can enhance the biosynthesis of phytochemicals during in vitro culture of G. sylvestre. Here, to further improve gymnemic acid II (GA II) and phenolic compounds (PC) production by G. sylvestre, cell suspension cultures (CSC), which has attracted attention for the production of essential phytochemicals, was explored using copper oxide nanoparticles (CuO NPs). Callus was obtained on MS medium containing 2,4-dichlorophenoxyacetic acid, kinetin, phytoagar, and sucrose. Agar-free MS medium was used to initiate CSC, which was treated with three concentrations of CuO NPs (1, 3 or 5 mg/L). Treatment for 48 h with 3 mg/L CuO NPs resulted in the greatest yields of GA II, total phenolics, and flavonoids. The cultures also displayed pronounced antioxidant, antidiabetic, anti-inflammatory, antibacterial, antifungal, and anticancer activities. The use of CuO NPs (3 mg/L) significantly increased the production of GA II (nine-fold) and PC compared to unamended CSC. We propose that CSC and use of nanoparticles (NPs) as a new generation of elicitors, offer a suitable prospect for the production of bioactive compounds.

Copper oxide nanoparticle doped bulk-heterojunction photovoltaic devices

Organic and metal oxide-based hybrid solar cells have drawn attention for their improved device performance along with mechanical stability and cost-effectiveness. We investigated the incorporation of various concentrations of copper oxide (CuO) nanoparticles (NPs) blended with poly 3-hexylthiophene: [6,6]-phenyl-C61-butyric methyl ester (P3HT:PCBM) bulk-heterojunction devices. With an optimum concentration of CuO NPs in P3HT: PCBM the devices power conversion efficiency is about 35% larger than without CuO NPs. The overall improvement in the photovoltaic properties of the device is attributed to the improved optical absorption, crystallinity and roughness of the photoactive layer confirmed by the AFM and XRD characteristics of the blended films. Beyond optimum nanoparticle concentration deteriorates the device performance from high trapped charge density as evidenced by steady-state current-voltage characteristics and charge-extraction-by-linearly-increasing-voltage (CELIV).

The Polarizability and Optical Characteristics of Zinc Phosphate Glasses Doped Terbium Embedded with Copper Oxide Nanoparticles

Tuning the concentration of nanoparticles (NPs) to accommodate wider application demanded a better understanding of the physicals and structural properties of the glass. A series of zinc phosphate glasses with the composition of (57-x) P2O5- 40ZnO-3Tb2O3 –xCuO, (0 ≤ x ≤ 2 mol %) has been prepared by melt quenching technique and their physical and optical characterization have been studied. The X-Ray Diffraction technique and UV-Vis Spectroscopy have been used to characterize the glass sample. The XRD confirms the amorphous nature of the prepared glasses. The physical properties of glasses with different CuO NPs such as density, molar volume, refractive index and electronic polarizability are determined. It is found that both density and molar volume decreases with increasing CuO NPs concentration. The optical band gap (4.54 eV-2.96 eV) and the Urbach energy (0.19 eV-0.54 eV) are showing a decreasing trend with the increasing amount of CuO NPs.This is due to the formation of non-bridging oxygen, (NBO) in the glass network. The glass exhibits high refractive index ~2.40 and polarizability ~1.12 ×10-23 cm3 and is useful for solid-state laser and optoelectronic devices.

Experimental investigation of tribological effect on vegetable oil with CuO nanoparticles and ZDDP additives

PurposeThis paper aims to report the friction and wear characteristics of refined soybean oil (RSBO) blended with copper oxide (CuO) nanoparticles and zinc dialkyldithiophosphate (ZDDP) as additives.Design/methodology/approachFour different concentrations 0.04, 0.05, 0.1 and 0.2 Wt.% of CuO nanoparticles were added with ZDDP in RSBO. The friction and wear characteristics of lubricants have been investigated on a pin-on-disc tribotester under loads of 120 and 180 N, with rotating speeds of 1,200 and 1,500 rpm in half hour of operating time. The dispersion stability of CuO nanoparticles has been analyzed using ultraviolet visible (UV-Vis) spectroscopy. The wearout surface of pins has been examined by using a scanning electron microscope.FindingsThe results revealed that there is a reduction in the friction and wear by the addition of CuO nanoparticles and ZDDP in RSBO. Coefficient of friction increases at a high sliding speed for RSBO with ZDDP. From UV-Vis spectroscopy, it is observed that 100 ml of oleic acid surfactant per gram of CuO nanoparticles has stable dispersion in RSBO.Originality/valueThe addition of ZDDP and CuO nanoparticles in RSBO is more efficient to reduce the friction and wear in comparison to base oil. The optimum concentration of CuO nanoparticles in RSBO is 0.05 Wt.%.

Heat transfer simulation during charging of nanoparticle enhanced PCM within a channel

Current research contains numerical modeling of the melting process acceleration with nanoparticles. The upper layer filled with paraffin contains CuO nanoparticles. Air hot flow inside the lower layer makes the NEPCM to change its phase from solid to liquid. Such model can be employed in a building to control the temperature of air in the room. The mathematical model has been provided considering single phase model and has been solved via finite volume method. Outputs demonstrate that melt fraction enhances with increasing in concentration of CuO nanoparticles. By dispersing nanoparticles, the air outlet temperature augments and heat conduction become stronger in upper layer

Optical, thermal, mechanical properties, and non‐isothermal degradation kinetic studies on PVA/CuO nanocomposites

The CuO nanoparticle doped poly(vinyl alcohol) (PVA) nanocomposite films were prepared by the solution casting method. The structure of the prepared CuO nanoparticles and PVA nanocomposite films were confirmed by FTIR spectroscopy and XRD. The (101) crystal plane of PVA was observed at 19.8° in XRD. The size of the CuO nanoparticles was determined as 20 nm using Scherrer's formula. It was further confirmed with HRTEM. The surface morphology of the nanocomposite films was investigated using SEM. The optical properties of the prepared CuO nanoparticles and PVA nanocomposite films were analyzed by UV–Visible spectroscopy. The band gap of PVA was decreased after the incorporation of CuO in PVA. The thermal stability of the pure PVA and its nanocomposites was examined using TGA to assess their thermal degradation temperature at five different heating rates. The thermal stability of PVA nanocomposites was increased as compared with pure PVA. The non‐isothermal degradation kinetic studies were also carried out to determine the energy of activation (Ea) for the degradation process using four different kinetic models. The tensile strength and Young's modulus of PVA nanocomposite films were notably increased with the increasing concentration of CuO nanoparticles. POLYM. COMPOS., 40:3737–3748, 2019. © 2019 Society of Plastics Engineers

Lattice Boltzmann simulation of free convection’s hydrothermal aspects in a finned/multi-pipe cavity filled with CuO-water nanofluid

PurposeThis paper aims to investigate the natural convection fluid flow and heat transfer in a finned/multi-pipe cavity.Design/methodology/approachThe cavity is filled with the CuO-water nanofluid. The Koo–Kleinstreuer–Li model is used to estimate the dynamic viscosity and consider Brownian motion. On the other hand, the effect of the shapes of nanoparticles on the thermal conductivity and related heat transfer rate is presented.FindingsIn the present investigation, the governing parameters are Rayleigh number, CuO nanoparticle concentration in pure water and the thermal arrangements of internal active fins and solid bodies. Impacts of these parameters on the nanofluid flow, heat transfer rate, total/local entropy generation and heatlines are presented. It is concluded that adding nanoparticles to the pure fluid has a significant positive influence on the heat transfer performance. In addition, the average Nusselt number and total entropy generation have direct a relationship with the Rayleigh number. The thermal arrangement of the internal bodies and fins is a good controlling tool to determine the desired magnitude of heat transfer rate.Originality/valueThe originality of this paper is to use the lattice Boltzmann method in simulating the nanofluid flow and heat transfer within a cavity included with internal active bodies and fins.

Antimicrobial activity of chitosan composites against bacterial strains isolated from goat meat and cheese

Chitosan composites based on residual biomass (shrimp shell) and polyvinyl alcohol (PVA) with different concentrations of CuO nanoparticles (NPs) were prepared and tested against bacteria isolated from goat meat and cheese. A casting method was used to prepare composites with 0, 0.05, 0.10, 0.15 and 0.20% CuO in the mixed solution (chitosan + PVA). The CuO NPs were characterized using FTIR spectroscopy and XRD. Additionally, these composites were analyzed by thermogravimetric analysis (TGA). NPs were detected by XRD mainly in the composite with the highest concentration (0.2%). Isolated bacteria from goat meat and milk (15 strains) were used to test the antibacterial properties of the composites, evaluating the effect of CuO NP concentration. All synthesized composites presented antibacterial inhibition against bacteria. However, for some strains of gram-positive and gram-negative bacteria, inhibition was 50% of that observed for the combination of antibiotics, amoxicillin/clavulanic acid (AMC) or trimethoprim/sulfamethoxazole (SXT). Gram-negative bacteria isolated from goat meat were sensitive to PVA composites with CuO NPs. In most of the tested strains, the zone of inhibition increased as the NP concentration in the composite increased.

Effects of Copper Oxide Nanoparticles on Tissue Accumulation and Antioxidant Enzymes of Galleria mellonella L.

Effects of copper oxide nanoparticles (CuO NPs) were investigated in the midgut and fat body of Galleria mellonella. Fourth instar larvae were exposed to 10µg Cu/L of CuO until becoming last instar larvae, and catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione-s-transferase (GST) and acetylcholinesterase (AChE) and metal accumulation were evaluated. Copper accumulation was observed in midgut and fat body tissues of G. mellonella larvae exposed to CuO NPs. CuO NPs increased CAT activities in midgut and fat body, while SOD activities were decreased. CuO NPs exhibited significant increases in GST activity in fat body, while no significant differences were observed in the midgut of G. mellonella larvae. AChE activity significantly decreased in the midgut of G. mellonella whereas there is no significant effect on fat body in CuO NPs exposed larvae. In overall, these findings demonstrate that tissue accumulation and oxidative stress that is countered by antioxidant enzymes occur when G. mellonella larvae exposed to environmental concentration of CuO nanoparticles.

Nanolubrication Mechanisms: Influence of Size and Concentration of CuO Nanoparticles

Abstract In nanolubrication, friction-reduction and anti-wear behaviors are dependent on the characteristics of nanoparticles, such as size, shape, and concentration. Some mechanisms of friction-reduction and anti-wear of NNP in lubricant have been reported as protective film, rolling effect, polishing or smoothing effect, mending effect, and the third body. Thus, this work studied differences in nanolubrication mechanism as functions of size and concentration of CuO NNP added in synthetic oil. Three levels of concentration and size were evaluated: 0.1, 0.25, and 0.5 % wt., and 2.5, 4.4, and 8.7 nm, respectively. The methodology was divided into three steps: first, the preparation of CuO NNP from an alcohol-thermal method. These were characterized by XRD (X-ray diffraction) and TEM (Transmission electron microscopy). The second part was constituted by evaluation of lubricant with NNP by a tribological test, which was carried out under boundary lubrication conditions in high frequency reciprocating rig (HFRR) equipment. The last step was the characterization of the wear mechanism; scanning electron microscopy (SEM) and Raman spectroscopy aided to identify tribochemistry interactions between nanolubricant and steel surface. The results showed that the concentration of NNP influenced wear: low concentration decreased the wear and promoted a smooth surface, while more plastic deformation was observed in high concentration. For the NNP size, the smallest size corresponded to the lowest friction coefficient. The best results were obtained for nanolubricant with a concentration of 0.1 % wt. and a NNP size of 2.5 nm.

Copper Oxide Nanoparticles Toxicity on Eisenia fetida Earthworms and Bacterial Species

The extensive use of nanoparticles (NPs) in a variety of applications has raised great concerns about their environmental fate and biological effects. To investigate the role of CuO NPs in soil on microbes and earthworms, we exposed microorganisms and earthworms (<i>Eisenia fetida</i>) to different concentrations of CuO NPs <100 nm. The results obtained showed that the CuO NPs exhibited good anti-microbial activity. A dose-related increase in mortality was not observed in earthworms exposed to CuO- NPs by soil contact method. In direct contact method the average death time of <i>E. fetida</i> to CuO NPs is not dose related. Dose related weight loss of earthworms was noticed after 15 days of exposure. This study will be very useful in regulation of nanomaterials that are entering into the environment.<div><br></div>

Mechanisms of oxidative stress caused by CuO nanoparticles to membranes of the bacterium Streptomyces coelicolor M145

Toxic effects of widely used CuO nanoparticles (NPs) on the genus Streptomyces has been seldom studied. This work investigated toxicities of several sizes of CuO nanoparticles (NPs) to Streptomyces coelicolor M145 (S. coelicolor M145). Compared with NPs, toxicity of micrometer-sized CuO on M145 was trivial. In 0.9% NaCl, when the concentration of CuO NPs was 100 mg/L, survival of bacteria increased from 18.3% in 20 nm particles to 31.1% in 100 nm particles. With increasing concentrations of CuO, the level of ROS gradually increased and there were significant differences (p ＜ 0.05) in ROS exposed to 20, 40 and 100 nm (80 nm) CuO NPs. In TSBY medium, toxicity of CuO NPs was less and mainly attributed to release of Cu2+, analysis by confocal laser scanning microscope (CLSM) showed that size of the mycelium did not change although some individual bacteria died. This was likely due to Cu2+ released from NPs entering cells through the membrane, while in 0.9% NaCl, lesions on membranes was caused by NPs outside the bacteria. This research indicated that toxicity of CuO NPs to S. coelicolor, is related to both size of NPs and is dependent on characteristics of the medium. CapsuleThis is the first time to measure the toxicity of nano materials to Streptomyces, and toxic CuO NPs to Streptomyces have been shown to differ depending on medium.