In vitro and in vivo antibiofilm effect of copper nanoparticles against aquaculture pathogens

Exploring In Vitro Antibiofilm Potential and In Vivo Toxicity Assessment of Gold Nanoparticles

In this study, biogenically synthesized AuNPs were first characterized via UV visible spectroscopy, SEM, XRD, and FTIR followed by toxicity evaluation using mice model. UV-visible spectroscopy of biogenic AuNPs showed peaks at 540-549 nm, while FTIR spectrum showed various functional groups involving O-H, Amide I, Amide II, O-H, C-H groups, and so on. SEM showed the size variation from 30 to 60 nm. Antibacterial potential against pathogenic isolates showed bigger ZOI (31.0 mm) against Pseudomonas aeruginosa AuNPs. Antibiofilm activity showing up to 100% inhibition at 90 µg mL-1 concentration of AuNPs. Toxicity evaluation showed LD50 as 70 mg kg-1. Exposure to AuNPs caused significant changes in the levels of serum AST (p < 0.05) at 100-150 mg kg-1 of AuNPs exposure. Histopathology of male albino mice kidney and liver revealed that mice exposed to maximum concentration of AuNPs showed necrosis, cell distortion, and hepatocytes detachment. Present study showed that biologically synthesized AuNPs possess effective antimicrobial and biofilm inhibitory potential. AuNPs strong bactericidal effect even at lower concentration suggest that NPs could have excellent potential for combating pathogens. In conclusion, nanotechnology may revolutionize human life and medical industry by developing innovative drugs with the potential to treat diseases in shorter and noninvasive time period. Hence, in vitro biosafety and experimental observations followed by in vivo outcomes are crucial in shifting the novel therapeutics into medical practice thus leading further into their future development.

Biofabrication of copper oxide nanoparticles using Dalbergia sisso leaf extract for antibacterial, antibiofilm and antioxidant activities

One of the biggest challenges encountered by the current generation is the evolution of antibiotic resistant bacteria as a result of excessive and inappropriate use of antibiotics. This problem has led to the development of alternative approaches to treat the diseases caused by these multidrug resistant bacteria (MDR). One of the most promising and novel approaches to combat these pathogens is utilization of nanomaterials as antimicrobial agents. In the current investigation, copper oxide nanoparticles (CuO NPs) were fabricated by green method using Dalbergia sissoo leaf extract. The fabricated nanoparticles were characterized through various techniques like UV-visible spectroscopy, scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The UV-visible spectroscopy revealed an absorption peak at 290 nm. SEM micrograph revealed only few spherical nanoparticles (with average diameter of < 100 nm), whereas most of the CuO NPs were agglomerated and formed large clusters. FTIR indicated presence of different functional groups that were used as reducing and capping agents while XRD analysis showed crystalline phase structure for the nanoparticles. These nanoparticles exhibited significant growth inhibition in terms of maximum inhibitory zones of 24 mm with minimum inhibitory concentrations (MIC) ranging from 62.5 to 125 µg/ml against MDR bacteria such as Acinetobacter baumannii, Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae. The effect of different concentrations of nanoparticles on cell membrane disruption was also investigated and a significant increase (p < 0.05) in the leakage of cellular content such as DNA, proteins and reducing sugar was measured. These nanoparticles also showed antibiofilm potential and a significant increase (p < 0.05) in biofilm inhibition was observed by increasing the concentration of nanoparticles. It was noted that percentage of inhibition of biofilm was found to be 68.4-75.8% at the highest tested concentration. The combined effects of antibiotics and nanoparticles revealed a synergistic interaction between them against tested bacteria. In vitro antioxidant activity of fabricated nanoparticles revealed significant antioxidant potential (p < 0.05) by quenching free radicals such as DPPH (73.6%), ABTS (68%) and H2O2 (63%) in a dose-dependent manner.

Antimicrobial and anthelmintic effects of copper nanoparticles against Koi carp parasites and their toxicity

This study investigated the in vitro antimicrobial and anthelmintic effect of copper nanoparticles (CuNPs) against the bacterium Aeromonas hydrophila, the monogeneans Dactylogyrus minutus, Dactylogyrus extensus, Gyrodactylus cyprini, and the cestode Schyzocotyle acheilognathi, as well as their toxicity to Cyprinus carpio Koi. In the antimicrobial in vitro test, the inhibition zone method and minimum inhibitory concentration (MIC) were performed. In order to determine the time and efficacy of monogenean parasite mortality, the parasites were exposed to CuNP concentrations of 20, 50, 100, 150, 200, and 300 mg L-1, and a control group with tank water and one with copper sulphate pentahydrate (CuSO4.5H2O) at a concentration of 0.3 mg L-1, performed in triplicate. The parasites were observed every 10 min for 300 min, and mortality was recorded. For the cestodes, parasites were immersed in CuNP concentrations of 50, 100, 150, and 300 mg L-1. At the end of the in vitro tests, the anthelmintic efficacy of each treatment was calculated. To assess the tolerance and toxicity in fish, they were exposed to CuNP concentrations of 0.6, 1.25, 2.5, 5, 10, 20, and 50 mg L-1 for 12 h. The MIC demonstrated that CuNPs effectively inhibited the growth of A. hydrophila up to a dilution of 12,500 mg L-1 and showed an inhibition zone of 14.0 ± 1.6 mm for CuNPs. The results of anthelmintic activity showed a dose-dependent effect of concentration for both groups of parasites, with the most effective concentration being 300 mg L-1 in 120 min. In the toxicity test, the carps showed tolerance to lower concentrations. The study indicated that CuNPs were effective against the studied pathogens. However, it proved to be toxic to fish at high concentrations. The use of low concentrations is recommended still requires further investigation.

Carica Papaya leaf-infused metal oxide nanocomposite: a green approach towards water treatment and antibacterial applications

This study successfully synthesized ZnO-CuO nanocomposite using the hydrothermal method with Carica papaya leaf extract. The incorporation of the leaf extract significantly enhanced the nanocomposite properties, a novel approach in scientific research. Characterization techniques, including X-ray diffraction, Fourier Transmission Infrared spectroscopy, and Scanning Electron Microscopy with Energy Dispersive X-Ray Analysis, confirmed a cubic crystal structure with an average size of 22.37 nm. The Fourier Transmission Infrared spectrum revealed distinctive vibrations at 627, 661, and 751 cm-1 corresponding to ZnO-CuO nanocomposite corresponding to stretching and vibration modes. SEM images confirmed a cubic-like and irregular structure. The nanocomposite exhibited outstanding photocatalytic activity, degrading methylene blue dye by 96.73% within 120 min under visible light. Additionally, they showed significant antimicrobial activity, inhibiting Staphylococcus aureus (20 mm) and Klebsiella pneumonia (17 mm). The results highlight the efficiency of Carica papaya leaf-derived ZnO-CuO nanocomposite for environmental and health challenges.

Synthesis and characterization of Pyrus communis fruit extract synthesized ZnO NPs and assessed their anti-diabetic and anti-microbial potential

The fruit Pyrus communis, owing to its presence of phenolics and flavonoids, was chosen for its nanoparticle's reducing and stabilizing properties. Furthermore, the zinc metal may be nano-absorbed by the human body. As a result, the study involves synthesizing zinc oxide nanoparticles (ZnO NPs) from P. communis fruit extract using the green method. The synthesized nanoparticle was examined with a UV-visible spectrophotometer, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Dynamic Light Scattering (DLS). When absorption studies were performed with a UV-visible spectrophotometer, the nanoparticle exhibited a blue shift. The FTIR spectrum revealed the molecular groups present in both the fruit extract and metal. In the SEM analysis, the ZnO NPs appeared as spherical particles, agglomerated together, and of nano-size. The larger size of the ZnO NPs in DLS can be attributed to their ability to absorb water. After characterization, nanoparticles were tested for anti-diabetic (α-amylase and yeast glucose uptake activity) and anti-microbial properties. The α-amylase inhibition percentage was 46.46 ± 0.15% for 100 μg/mL, which was comparable to the acarbose inhibition percentage of 50.58 ± 0.67% at the same concentration. The yeast glucose uptake activity was 64.24 ± 0.80% at 20 mM glucose concentration, which was comparable to the standard of 78.03 ± 0.80. The nanoparticle was more effective against Gram-negative bacteria Shigella sp. and Salmonella typhi than against Gram-positive bacteria Bacillus cereus and Streptococcus pneumoniae.

Bio-fabrication of calcium oxide nanoparticles from Coccinia grandis as a potential photocatalyst for dye degradation with antimicrobial activity

In the current study, Coccinia grandis fruit extract was used to synthesize calcium oxide nanoparticles (CaO NPs) in an economical and environmentally friendly manner. UV-Vis spectroscopy and Fourier transform infrared spectroscopy revealed that the phytoconstituents found in Coccinia grandis fruit extract facilitated the production of CaO NPs by acting as better stabilizing, biodegradable, and reducing agents. The synthesized CG-CaO NPs were also tested for photocatalytic activity in the breakdown of selective dyes such as methyl red, methyl orange, and methylene blue in the presence of sunlight. The degradation percentage was determined by analyzing the color removal rates for all dye components. After 6 h of reaction, the IC50 values for methyl red, methyl orange, as well as methylene blue dyes were 73, 107, and 133, respectively. The CG-CaO NPs were further evaluated for their antimicrobial activity against specific bacteria and fungi using the agar-well diffusion method. 200 μg/mL CG-CaO NPs inhibited Aspergillus niger, Escherichia coli, Salmonella typhi, Streptococcus mutans, and Staphylococcus aureus at zones of 13, 14, 16, 14, and 15 mM, respectively. Further checkerboard assay confirmed the antagonism effect with gentamicin. Also, Artemia salina toxicity assay showed that the LD50 value of CaO NPs was 400 μg/mL of CaO NPs. The findings confirm that Coccinia grandis-mediated CG-CaO NPs can be used effectively in antimicrobial and environmental settings.

Assessing cardiovascular toxicity in zebrafish embryos exposed to copper nanoparticles

The toxicity of copper nanoparticles (CuNPs) to aquatic animals, particularly their effects on the cardiovascular system, has not been thoroughly investigated. In the present study, zebrafish embryos were used as a model to address this issue. After exposure to different concentrations (0.01, 0.1, 1, and 3 mg/L) of CuNPs for 96 h (4 to 100 h post-fertilization), cardiac parameters of the heart rate (HR), end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), and cardiac output (CO), and vascular parameters of the aortic blood flow velocity (ABFV) and aortic diameter (AD) were examined by a video-microscopic method. Morphologically, CuNPs induced concentration-dependent pericardial edema. Although CuNPs did not alter the HR, they significantly reduced the EDV, SV, and CO at ≥0.1 mg/L, the ESV and EF at 3 mg/L, the ABFV at ≥0.1 mg/L, and the AD at ≥1 mg/L. Transcript levels of several cardiac genes, nppa, nppb, vmhc, and gata4, were also examined. CuNPs significantly suppressed nppa and nppb at ≥0.1 mg/L, gata4 at ≥0.01 mg/L, and vmhc at 1 mg/L. This study demonstrated that CuNPs can induce cardiovascular toxicity at environmentally relevant concentrations during fish embryonic development and highlight the potential ecotoxicity of CuNPs to aquatic animals.

Carbon Nanomaterials for Biomedical Applications: Progress and Outlook

Recent developments in nanoscale materials have found extensive use in various fields, especially in the biomedical industry. Several substantial obstacles must be overcome, particularly those related to nanostructured materials in biomedicine, before they can be used in therapeutic applications. Significant concerns in biomedicine include biological processes, adaptability, toxic effects, and nano-biointerfacial properties. Biomedical researchers have difficulty choosing suitable materials for drug carriers, cancer treatment, and antiviral uses. Carbon nanomaterials are among the various nanoparticle forms that are continually receiving interest for biomedical applications. They are suitable materials owing to their distinctive physical and chemical properties, such as electrical, high-temperature, mechanical, and optical diversification. An individualized, controlled, dependable, low-carcinogenic, target-specific drug delivery system can diagnose and treat infections in biomedical applications. The variety of carbon materials at the nanoscale is remarkable. Allotropes and other forms of the same element, carbon, are represented in nanoscale dimensions. These show promise for a wide range of applications. Carbon nanostructured materials with exceptional mechanical, electrical, and thermal properties include graphene and carbon nanotubes. They can potentially revolutionize industries, including electronics, energy, and medicine. Ongoing investigation and expansion efforts continue to unlock possibilities for these materials, making them a key player in shaping the future of advanced technology. Carbon nanostructured materials explore the potential positive effects of reducing the greenhouse effect. The current state of nanostructured materials in the biomedical sector is covered in this review, along with their synthesis techniques and potential uses.

Poly-Gamma-Glutamic Acid Nanopolymer Effect against Bacterial Biofilms: In Vitro and In Vivo Study

In this study, a biodegradable poly-gamma-glutamic-acid nanopolymer (Ɣ-PGA NP) was investigated for its activity against clinical strains of Gram-positive (Staphylococcus aureus and Streptococcus pyogenes) and Gram-negative (Klebsiella pneumoniae and Escherichia coli), and reference strains of S. aureus ATCC 6538, S. pyogenes ATCC 19615 (Gram-positive), and Gram-negative E. coli ATCC 25922, and K. pneumoniae ATCC 13884 bacterial biofilms. The minimum inhibitory concentration (MIC) effect of Ɣ-PGA NP showed inhibitory effects of 0.2, 0.4, 1.6, and 3.2 μg/mL for S. pyogenes, S. aureus, E. coli, and K. pneumoniae, respectively. Also, MIC values were 1.6, 0.8, 0.2, and 0.2 μg/mL for K. pneumoniae ATCC 13884, E. coli ATCC 25922, S. aureus ATCC 6538, and S. pyogenes ATCC 19615, respectively. Afterwards, MBEC (minimum biofilm eradication concentration) and MBIC (minimum biofilm inhibitory concentration) were investigated to detect Ɣ-PGA NPs efficiency against the biofilms. MBEC and MBIC increased with increasing Ɣ-PGA NPs concentration or time of exposure. Interestingly, MBIC values were at lower concentrations of Ɣ-PGA NPs than those of MBEC. Moreover, MBEC values showed that K. pneumoniae was more resistant to Ɣ-PGA NPs than E. coli, S. aureus, and S. pyogenes, and the same pattern was observed in the reference strains. The most effective results for MBEC were after 48 h, which were 1.6, 0.8, 0.4, and 0.2 µg/mL for K. pneumoniae, E. coli, S. aureus, and S. pyogenes, respectively. Moreover, MBIC results were the most impactful after 24 h but some were the same after 48 h. MBIC values after 48 h were 0.2, 0.2, 0.2, and 0.1 μg/mL for K. pneumoniae, E. coli, S. aureus, and S. pyogenes, respectively. The most effective results for MBEC were after 24 h, which were 1.6, 0.8, 0.4, and 0.4 µg/mL for K. pneumoniae ATCC 13884, E. coli ATCC 25922, S. aureus ATCC 6538, and S. pyogenes ATCC 19615, respectively. Also, MBIC results were the most impactful after an exposure time of 12 h. MBIC values after exposure time of 12 h were 0.4, 0.4, 0.2, and 0.2 μg/mL for K. pneumoniae ATCC 13884, E. coli ATCC 25922, S. aureus ATCC 6538, and S. pyogenes ATCC 19615, respectively. Besides that, results were confirmed using confocal laser scanning microscopy (CLSM), which showed a decrease in the number of living cells to 80% and 60% for MBEC and MBIC, respectively, for all the clinical bacterial strains. Moreover, living bacterial cells decreased to 70% at MBEC while decreasing up to 50% at MBIC with all bacterial refence strains. These data justify the CFU quantification. After that, ImageJ software was used to count the attached cells after incubating with the NPs, which proved the variation in live cell count between the manual counting and image analysis methods. Also, a scanning electron microscope (SEM) was used to detect the biofilm architecture after incubation with the Ɣ-PGA NP. In in vivo wound healing experiments, treated wounds of mice showed faster healing (p < 0.00001) than both the untreated mice and those that were only wounded, as the bacterial count was eradicated. Briefly, the infected mice were treated faster (p < 0.0001) when infected with S. pyogenes > S. aureus > E. coli > K. pneumoniae. The same pattern was observed for mice infected with the reference strains. Wound lengths after 2 h showed slightly healing (p < 0.001) for the clinical strains, while treatment became more obvious after 72 h > 48 h > 24 h (p < 0.0001) as wounds began to heal after 24 h up to 72 h. For reference strains, wound lengths after 2 h started to heal up to 72 h.

Green Synthesis of Silver Nanoparticles and their Potential Applications in Mitigating Cancer

In recent years, the field of nanotechnology has brought about significant advancements that have transformed the landscape of disease diagnosis, prevention, and treatment, particularly in the realm of medical science. Among the various approaches to nanoparticle synthesis, the green synthesis method has garnered increasing attention. Silver nanoparticles (AgNPs) have emerged as particularly noteworthy nanomaterials within the spectrum of metallic nanoparticles employed for biomedical applications. AgNPs possess several key attributes that make them highly valuable in the biomedical field. They are biocompatible, cost-effective, and environmentally friendly, rendering them suitable for various bioengineering and biomedical applications. Notably, AgNPs have found a prominent role in the domain of cancer diagnosis. Research investigations have provided evidence of AgNPs' anticancer activity, which involves mechanisms such as DNA damage, cell cycle arrest, induction of apoptosis, and the regulation of specific cytokine genes. The synthesis of AgNPs primarily involves the reduction of silver ions by reducing agents. Interestingly, natural products and living organisms have proven to be effective sources for the generation of precursor materials used in AgNP synthesis. This comprehensive review aims to summarize the key aspects of AgNPs, including their characterization, properties, and recent advancements in the field of biogenic AgNP synthesis. Furthermore, the review highlights the potential applications of these nanoparticles in combating cancer.

The Combined Effect of Copper Nanoparticles and Microplastics on Transcripts Involved in Oxidative Stress Pathway in Rainbow Trout (Oncorhynchus Mykiss) Hepatocytes

Copper nanoparticles (CuNPs) and microplastics (MPs) are two emerging contaminants of freshwater systems. Despite their co-occurrence in many water bodies, the combined effects of CuNPs and MPs on aquatic organisms are not well-investigated. In this study, primary cultures of rainbow trout hepatocytes were exposed to dissolved Cu, CuNPs, MPs, or a combination of MPs and CuNPs for 48 h, and the transcript abundances of oxidative stress-related genes were investigated. Exposure to CuNPs or dissolved Cu resulted in a significant increase in the transcript abundances of two antioxidant enzymes, catalase (CAT) and superoxide dismutase (SOD). Exposure to CuNPs also led to an upregulation in the expression of Na+/K+ ATPase alpha 1 subunit (ATP1A1). Microplastics alone or in combination with CuNPs did not have a significant effect on abundances of the target gene transcripts. Overall, our findings suggested acute exposure to CuNPs or dissolved ions may induce oxidative stress in hepatocytes, and the Cu-induced effect on target gene transcripts was not associated with MPs.

Management and Mitigation of Vibriosis in Aquaculture: Nanoparticles as Promising Alternatives

Vibriosis is one of the most common diseases in marine aquaculture, caused by bacteria belonging to the genus Vibrio, that has been affecting many species of economically significant aquatic organisms around the world. The prevention of vibriosis in aquaculture is difficult, and the various treatments for vibriosis have their limitations. Therefore, there is an imperative need to find new alternatives. This review is based on the studies on vibriosis, specifically on the various treatments and their limitations, as well as the application of nanoparticles in aquaculture. One of the promising nanoparticles is graphene oxide (GO), which has been used in various applications, particularly in biological applications such as biosensors, drug delivery, and potential treatment for infectious diseases. GO has been shown to have anti-bacterial properties against both Gram-positive and Gram-negative bacteria, but no research has been published that emphasizes its impact on Vibrio spp. The review aims to explore the potential use of GO for treatment against vibriosis.

Fabrication of chitosan and Trianthema portulacastrum mediated copper oxide nanoparticles: Antimicrobial potential against MDR bacteria and biological efficacy for antioxidant, antidiabetic and photocatalytic activities

Biopolymer based metal oxide nanoparticles, prepared by eco-friendly approach, are gaining interest owing to their wide range of applications. In this study, aqueous extract of Trianthema portulacastrum was used for the green synthesis of chitosan base copper oxide (CH-CuO) nanoparticles. The nanoparticles were characterized through UV-Vis Spectrophotometry, SEM, TEM, FTIR and XRD analysis. These techniques provided evidence for the successful synthesis of the nanoparticles, having poly-dispersed spherical shaped morphology with average crystallite size of 17.37 nm. The antibacterial activity for the CH-CuO nanoparticles was determined against multi-drug resistant (MDR), Escherichia coli, Pseudomonas aeruginosa (gram-negative), Enterococcus faecium and Staphylococcus aureus (gram-positive). Maximum activity was obtained against Escherichia coli (24 ± 1.99 mm) while least activity was observed against Staphylococcus aureus (17 ± 1.54 mm). In-vitro analysis for biofilm inhibition, EPS and cell surface hydrophobicity showed >60 % inhibitions for all the bacterial isolates. Antioxidant and photocatalytic assays for the nanoparticles showed significant activities of radical scavenging (81 ± 4.32 %) and dye degradation (88 %), respectively. Antidiabetic activity for the nanoparticles, determined by in-vitro analysis of alpha amylase inhibition, showed enzyme inhibition of 47 ± 3.29 %. The study signifies the potential of CH-CuO nanoparticle as an effective antimicrobial agent against MDR bacteria along with the antidiabetic and photocatalytic activities.

Bacteria of Zoonotic Interest Identified on Edible Freshwater Fish Imported to Australia

Previous research has shown that freshwater edible fish imported into Australia are not compliant with Australian importation guidelines and as a result may be high risk for bacterial contamination. In the present study, the outer surface of imported freshwater fish were swabbed, cultured, confirmatory tests performed and antimicrobial patterns investigated. Channidae fish (Sp. A/n = 66) were contaminated with zoonotic Salmonella sp./Staphylococcus aureus (n = 1/66) and other bacteria implicated in cases of opportunistic human infection, these being Pseudomonas sp. (including P. mendocina and P. pseudoalcaligenes (n = 34/66)); Micrococcus sp. (n = 32/66); Comamonas testosteroni (n = 27/66) and Rhizobium radiobacter (n = 3/66). Pangasiidae fish (Species B/n = 47) were contaminated with zoonotic Vibrio fluvialis (n = 10/47); Salmonella sp. (n = 6/47) and environmental bacteria Micrococcus sp. (n = 3/47). One sample was resistant to all antimicrobials tested and is considered to be Methicillin Resistant S. aureus. Mud, natural diet, or vegetation identified in Sp. A fish/or packaging were significantly associated with the presence of Pseudomonas spp. The study also showed that visibly clean fish (Sp. B) may harbour zoonotic bacteria and that certain types of bacteria are common to fish groups, preparations, and contaminants. Further investigations are required to support the development of appropriate food safety recommendations in Australia.

Gelatin-Gallic Acid Microcomplexes Release GO/Cu Nanomaterials to Eradicate Antibiotic-Resistant Microbes and Their Biofilm

Wound-infecting bacteria are typically Pseudomonas aeruginosa and Staphylococcus epidermidis, both of which form biofilms and become resistant to antibiotics. To solve this problem, copper nanoparticles (Cu) on graphene oxide (GO) nanosheets were used as antibacterial materials. Since the excessive use of antibacterial substances is fatal to normal tissues, GO/Cu was encapsulated with a gelatin complex to lower the cytotoxicity. Among the catechol-based substances, gallic acid (GA), which has anti-inflammatory and antibacterial properties, was used in this study to impart stability to the gelatin complex. Gelatin (GE) and gallic acid (GA) were combined by a crosslinking method using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC)/N-hydroxysuccinimide (NHS) as a crosslinker, and the crosslinking was confirmed by Fourier transform infrared (FT-IR), ¹H NMR, and the fluorescence property of GA. The GO/Cu@GE-GA microcomplexes exhibited more antibacterial effect against Gram-positive bacteria (S. epidermidis) and Gram-negative bacteria (P. aeruginosa) than when GO/Cu alone was used, and the antibiofilm effect was also confirmed. The cytotoxicity evaluation for human skin cells (human dermal fibroblast (HDF)) at the same concentration showed that it had low cytotoxicity and biocompatibility. This study shows the potential of antimicrobial gelatin microcomplex in prohibiting infectious bacteria and their biofilms and controlling the release of antimicrobial substances.

Exploring Possible Ways to Enhance the Potential and Use of Natural Products through Nanotechnology in the Battle against Biofilms of Foodborne Bacterial Pathogens

Biofilms enable pathogenic bacteria to survive in unfavorable environments. As biofilm-forming pathogens can cause rapid food spoilage and recurrent infections in humans, especially their presence in the food industry is problematic. Using chemical disinfectants in the food industry to prevent biofilm formation raises serious health concerns. Further, the ability of biofilm-forming bacterial pathogens to tolerate disinfection procedures questions the traditional treatment methods. Thus, there is a dire need for alternative treatment options targeting bacterial pathogens, especially biofilms. As clean-label products without carcinogenic and hazardous potential, natural compounds with growth and biofilm-inhibiting and biofilm-eradicating potentials have gained popularity as natural preservatives in the food industry. However, the use of these natural preservatives in the food industry is restricted by their poor availability, stability during food processing and storage. Also there is a lack of standardization, and unattractive organoleptic qualities. Nanotechnology is one way to get around these limitations and as well as the use of underutilized bioactives. The use of nanotechnology has several advantages including traversing the biofilm matrix, targeted drug delivery, controlled release, and enhanced bioavailability, bioactivity, and stability. The nanoparticles used in fabricating or encapsulating natural products are considered as an appealing antibiofilm strategy since the nanoparticles enhance the activity of the natural products against biofilms of foodborne bacterial pathogens. Hence, this literature review is intended to provide a comprehensive analysis of the current methods in nanotechnology used for natural products delivery (biofabrication, encapsulation, and nanoemulsion) and also discuss the different promising strategies employed in the recent and past to enhance the inhibition and eradication of foodborne bacterial biofilms.

Unveiling the Anti-Biofilm Property of Hydroxyapatite on Pseudomonas aeruginosa: Synthesis and Strategy

Biofilm-related nosocomial infections may cause a wide range of life-threatening infections. In this regard, Pseudomonas aeruginosa biofilm is becoming a serious health burden due to its capability to develop resistance to natural and synthetic drugs. The utilization of nanoparticles that inhibit biofilm formation is one of the major strategies to control infections caused by biofilm-forming pathogens. Hydroxyapatite (HA) is a synthetic ceramic material having properties similar to natural bones. Herein, a co-precipitation method followed by microwave treatment was used to synthesize HA nanoparticles (HANPs). The resulting HANPs were characterized using X-ray diffraction and transmission electron microscopy. Then, their antibiofilm properties against P. aeruginosa ATCC 10145 were examined in vitro. The needle-shaped HANPs were 30 and 90 nm long in width and length, respectively. The synthesized HANPs inhibited the biofilm formation of P. aeruginosa ATCC 10145 in a concentration-dependent manner, which was validated by light and confocal laser scanning microscopy. Hence, this study demonstrated that HANPs could be used to control the biofilm-related infections of P. aeruginosa.

Impact of Copper Nanoparticles and Copper Ions on Transcripts Involved in Neural Repair Mechanisms in Rainbow Trout Olfactory Mucosa

Olfactory mucosa is well known for its lifelong ability for regeneration. Regeneration of neurons and regrowth of severed axons are the most common neural repair mechanisms in olfactory mucosa. Nonetheless, exposure to neurotoxic contaminants, such as copper nanoparticles (CuNPs) and copper ions (Cu²⁺), may alter the reparative capacity of olfactory mucosa. Here, using RNA-sequencing, we investigated the molecular basis of neural repair mechanisms that were affected by CuNPs and Cu²⁺ in rainbow trout olfactory mucosa. The transcript profile of olfactory mucosa suggested that regeneration of neurons was inhibited by CuNPs. Exposure to CuNPs reduced the transcript abundances of pro-inflammatory proteins which are required to initiate neuroregeneration. Moreover, the transcript of genes encoding regeneration promoters, including canonical Wnt/β-catenin signaling proteins and developmental transcription factors, were downregulated in the CuNP-treated fish. The mRNA levels of genes regulating axonal regrowth, including the growth-promoting signals secreted from olfactory ensheathing cells, were mainly increased in the CuNP treatment. However, the reduced transcript abundances of a few cell adhesion molecules and neural polarity genes may restrict axonogenesis in the CuNP-exposed olfactory mucosa. In the Cu²⁺-treated olfactory mucosa, both neural repair strategies were initiated at the transcript level. The stimulation of repair mechanisms can lead to the recovery of Cu²⁺-induced olfactory dysfunction. These results indicated CuNPs and Cu²⁺ differentially affected the neural repair mechanism in olfactory mucosa. Exposure to CuNP had greater effects on the expression of genes involved in olfactory repair mechanisms relative to Cu²⁺ and dysregulated the transcripts associated with stem cell proliferation and neural reconstitution.

Photocatalytic response in water pollutants with addition of biomedical and anti-leishmanial study of iron oxide nanoparticles

Public health is a major concern globally, owing to the presence of industrial dyes in the effluent. Nanoparticles with green synthesis are an enthralling research field with various applications. This study deals with investigating the photocatalytic potential of Fe-oxide nanoparticles (FeO-NPs) for the degradation of methylene blue dye and their potential biomedical investigations. Biosynthesis using Anthemis tomentosa flower extract showed to be an effective method for the synthesis of FeO-NPs. The freshly prepared FeO-NPs were characterized through UV/Vis spectroscopy showing clear peak at 318 nm. The prepared FeO-NPs were of smaller size and spherical shape having large surface area and porosity with no aggregations. The FeO-NPs were characterized using XRD, FTIR, HRTEM, SEM and EDX. The HRTEM results showed that the particle size of FeO-NPs was 60-90 nm. The antimicrobial properties of FeO-NPs were investigated against two bacterial Staphylococcus aureus 13 (±0.8) and Klebsiella pneumoniae 6(±0.6) and three fungal species Aspergillus Niger, Aspergillus flavus, and Aspergillus fumigatus exhibiting a maximum reduction of 57% 47% and 50%, respectively. Moreover, FeO-NPs exhibited high antioxidant properties evaluated against ascorbic acid. Overall, this study showed high photocatalytic, antimicrobial, and antioxidant properties of FeO-NPs owing to their small size and large surface area. However, the ecotoxicity study of methylene blue degradation products showed potential toxicity to aquatic organisms.

Eco-friendly, green synthesized copper oxide nanoparticle (CuNPs) from an important medicinal plant Turnera subulata Sm. and its biological evaluation

In this report, the green fabrication of copper oxide nanoparticles (CuNPs) using Turnera subulata leaf extract and assessed for the antibacterial and photocatalytic activities. The synthesis of CuNPs was performed using the leaves of T. subulata (TS-CuNPs) and characterized using UV-visible spectrophotometry, Fourier transforms infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), and Energy-dispersive X-ray spectroscopy (EDX). Produced TS-CuNPs showing transmittance peaks approximately 707-878 cm^-1, with a spherical shape particle with an average size of 58.5 nm. As synthesized TS-CuNPs were used as a coating material in cotton fabrics and tested the efficacy against Gram-negative and Gram-positive bacterial pathogens. TS-CuNPs inhibited the growth of Escherichia coli and Staphylococcus aureus on cotton fabrics. Antibiofilm activity of TS-CuNPs showed a 4-fold reduction in the biofilm formation of E. coli and S. aureus. Structural morphology of TS-CuNPs coated on cotton fabric analysis using SEM-EDX confirmed the attachment of TS-CuNPs and reduction in the bacterial attachment to the cotton fabrics. Thus, this study provides a potential strategy to improve the antibacterial property of cotton fabrics in textile production for medical, sportswear, and casual wear applications. Further, the photocatalytic activity against the tested dyes evident the potential in dye industry wastewater treatment. Hence, this work represents a simple, greener, and cost-effective route for in situ synthesis of CuNPs with the potential antibacterial and as a dye degradation agent for water remediation.

In vitro analysis of green synthesized copper nanoparticles using Chloroxylon swietenia leaves for dye degradation and antimicrobial application

Green fabrication of copper nanoparticles (CuNPs) is an environmentally friendly and cost-effective method of synthesis for biomedical and bioremediation applications. In recent times, bacterial pathogens contaminating or affecting food and food crops pose the greatest threat to the food industry. In addition to this issue, synthetic dyes released from the textile and dyeing industries are polluting aquatic ecosystems and agricultural lands. The combined impact of these two factors is considered a major threat to life. Therefore, the use of CuNPs will provide an effective and long-term solution as an antibacterial and dye removing agent. The current study focuses on the synthesis of CuNPs using the leaf extract of Chloroxylon swietenia (C-CuNPs). The formation of a peak at 390 nm and a change in color from yellow to dark brown confirmed the synthesis of C-CuNPs. Subsequent synthesis at pH 9 was suitable for preparing C-CuNPs. Structural and chemical characterization of C-CuNPs was performed using Fourier Transfer Infra-Red (FTIR), X-ray diffraction (XRD), Dynamic Light scattering (DLS), and Scanning Electron Microscopy (SEM) analysis. The synthesized C-CuNPs possess a crystalline nature, a functional group that resembles C. swietenia, and are negatively charged and spherical in shape. C-CuNPs were tested against Congo red, Coomassie blue, and crystal violet and they showed complete degradation within 24 h under optimum conditions. Disk diffusion and broth dilution assay were used to test the antibacterial activity of C-CuNPs against Staphylococcus nepalensis, Staphylococcus gallinarum, Pseudomonasstutzeri,Bacillus subtilis, and Enterococcus faecalis. Therefore, the present study represents the first report on C-CuNPs' ability to degrade synthetic dyes and kill foodborne bacterial pathogens. Thus, the study has shed light on the potential of green synthesized CuNPs as bioremediation and packaging material in the future.

Green fabrication of silver nanoparticles using Chloroxylon swietenia leaves and their application towards dye degradation and food borne pathogens

Green synthesized silver nanoparticles (AgNPs) are becoming an important candidate for bioremediation and biomedical applications. But in recent trends, more focus is given towards degradation of dyes and application against food pathogens. The synthesis of efficient AgNPs depends on the selection of potential biological material for synthesis. Therefore, in the present study, AgNPs were synthesized using Chloroxylon swietenia. The synthesis AgNPs was confirmed by the formation of dark brown precipitate. Further physicochemical characterization performed using XRD, FTIR, SEM and DLS showed the formation of crystalline structure, presence of functional group from the C. swietenia, dispersed spherical and rod-shaped nanoparticles (6.9 nm) and possess good stability due to the negative partial charges. The dye degrading efficacy of Chloroxylon swietenia mediated synthesized AgNPs (C-AgNPs) was >95%, 90% and >90% tested against Congo red (CR), Coomassie blue (CB) and crystal violet (CV) dye, respectively withing 24 h of treatment under optimum conditions. The antibacterial activity of C-AgNPs (10 mg/mL) was analysed against Staphylococcus nepalensis (3.03 ± 0.35 cm), Staphylococcus gallinarum (2.96 ± 0.15 cm), Bacillus subtilis (2.86 ± 0.23 cm), Enterococcous faecalis (2.8 ± 0.30 cm) and Pseudomonas stuteria (2.06 ± 0.25 cm) using Disc diffusion method, Minimum inhibitory concentration (MIC) and Minimum bactericidal activity (MBC). Therefore, the present study is the first and foremost report on C-AgNPs application as dye degrading and antibacterial agents against food dyes and pathogens. This will provide a major strategy to unveil the complications in food and packaging industries worldwide.

Biogenic Synthesis, Characterization and Antibacterial Properties of Silver Nanoparticles against Human Pathogens

Biogenic synthesis of silver nanoparticles (AgNPs) is more eco-friendly and cost-effective approach as compared to the conventional chemical synthesis. Biologically synthesized AgNPs have been proved as therapeutically effective and valuable compounds. In this study, the four bacterial strains Escherichia coli (MT448673), Pseudomonas aeruginosa (MN900691), Bacillus subtilis (MN900684) and Bacillus licheniformis (MN900686) were used for the biogenic synthesis of AgNPs. Agar well diffusion assay revealed to determine the antibacterial activity of all biogenically synthesized AGNPs showed that P. aeruginosa AgNPs possessed significantly high (p < 0.05) antibacterial potential against all tested isolates. The one-way ANOVA test showed that that P. aeruginosa AgNPs showed significantly (p < 0.05) larger zones of inhibition (ZOI: 19 to 22 mm) compared to the positive control (rifampicin: 50 µg/mL) while no ZOI was observed against negative control (Dimethyl sulfoxide: DMSO). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) concentration against four test strains also showed that among all biogenically synthesized NPs, P. aeruginosa AgNPs showed effective MIC (3.3-3.6 µg/mL) and MBC (4.3-4.6 µg/mL). Hence, P. aeruginosa AGNPs were characterized using visual UV vis-spectroscopy, X ray diffractometer (XRD), fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The formation of peak around 430 nm indicated the formation of AgNPs while the FTIR confirmed the involvement of biological molecules in the formation of nanoparticles (NPs). SEM revealed that the NPs were of approximately 40 nm. Overall, this study suggested that the biogenically synthesized nanoparticles could be utilized as effective antimicrobial agents for effective disease control.

Biofilm Inhibition and Antiviral Response of Cold Sprayed and Shot Peened Copper Surfaces: Effect of Surface Morphology and Microstructure

Antibacterial properties of copper against planktonic bacteria population are affected by surface microstructure and topography. However, copper interactions with bacteria in a biofilm state are less studied. This work aims at better understanding the difference in biofilm inhibition of bulk, cold-sprayed, and shot-peened copper surfaces and gaining further insights on the underlying mechanisms using optical and scanning electron microscopy to investigate the topography and microstructure of the surfaces. The biofilm inhibition ability is reported for all surfaces. Results show that the biofilm inhibition performance of cold sprayed copper, while initially better, decreases with time and results in an almost identical performance than as-received copper after 18h incubation time. The shot-peened samples with a rough and ultrafine microstructure demonstrated an enhanced biofilm control, especially at 18 hr. The biofilm control mechanisms were explained by the diffusion rates and concentration of copper ions and the interaction between these ions and the biofilm, while surface topography plays a role in the bacteria attachment at the early planktonic state. Furthermore, the data suggest that surface topography plays a key role in antiviral activity of the materials tested, with a smooth surface being the most efficient.

Graphical Abstract

Copper/Carbon Core/Shell Nanoparticles: A Potential Material to Control the Fish Pathogen Saprolegnia parasitica

Copper-based fungicides have a long history of usage in agriculture and aquaculture. With the rapid development of metal-based nanoparticles, copper-based nanoparticles have attracted attention as a potential material for prevention and control of Saprolegnia parasitica. The present study investigated the effectiveness of copper/carbon core/shell nanoparticles (CCCSNs) and a commercial CCCSNs filter product (COPPERWARE®) against S. parasitica in a recirculating system. Results showed that the growth of agar plugs with mycelium was significantly suppressed after exposure to both CCCSNs powder and COPPERWARE® filters. Even the lowest concentration of CCCSNs used in our study (i.e., 100 mg/mL) exhibited significant inhibitory effects on S. parasitica. The smallest quantity of the filter product COPPERWARE® (3.75 × 3.7 × 1.2 cm, 2.58 g) used in our aquarium study also demonstrated significant inhibition compared with the control group. However, we observed leaching of copper into the water especially when larger quantities of COPPERWARE® were used. Water turbidity issues were also observed in tanks with the filter material. Besides these issues, which should be further investigated if the product is to be used on aquatic species sensitive to copper, CCCSNs has promising potential for water disinfection.

Vibrio parahaemolyticus Infection Influenced Trace Element Homeostasis, Impaired Antioxidant Function, and Induced Inflammation Response in Litopenaeus vannamei

Vibrio parahaemolyticus (V. parahaemolyticus) caused huge diseases and economic losses in shrimp aquaculture. Understanding the infection mechanism might help develop new strategies for controlling pathogen outbreak. Redistribution of trace element homeostasis, accompanied by impairment of antioxidant status and immune response, was observed during various infections. Accordingly, we hypothesized that V. parahaemolyticus infection might influence trace element homeostasis, impair antioxidant function, and induce inflammation response in shrimp. In the present study, the aim of this study was to investigate the influence of V. parahaemolyticus infection on trace element homeostasis, antioxidant status, and inflammation response in Litopenaeus vannamei (L. vannamei). The results showed that compared with the control group, V. parahaemolyticus infection significantly increased (P < 0.05) intestinal V. parahaemolyticus number, serum copper (Cu) concentration at 24, 48, and 72 h and significantly increased (P < 0.05) serum zinc (Zn), iron (Fe), and manganese (Mn) concentrations at 24 h but decreased (P < 0.05) at 72 h. The intestinal gene expressions of metal transporters ZIP13, CTR1, and MT1 were significantly decreased at 24, 48, and 72 h, and DMT1 was significantly decreased at 48 h and 72 h in the infection group. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) were suppressed at 48 h and 72 h, and the malondialdehyde (MDA) content was increased at 24, 48, and 72 h in the infection group; the pro-inflammatory genes including necrosis factor-α (TNF-α), lipopolysaccharide-induced TNF-α factor (LITAF), and Ras-related protein Rab6A (RAB6A) were significantly upregulated at 48 and 72 h in the infection group. These results suggest that V. parahaemolyticus infection influenced trace element homeostasis, impaired antioxidant function, and induced inflammation response in L. vannamei, which might help understand the infection mechanism. The results provide a better understanding of the L. vannamei and V. parahaemolyticus interactions and may deliver the basis for further research in preventing the bacterial diseases.

Copper Surfaces in Biofilm Control

Biofilms are structures comprising microorganisms associated to surfaces and enclosed by an extracellular polymeric matrix produced by the colonizer cells. These structures protect microorganisms from adverse environmental conditions. Biofilms are typically associated with several negative impacts for health and industries and no effective strategy for their complete control/eradication has been identified so far. The antimicrobial properties of copper are well recognized among the scientific community, which increased their interest for the use of these materials in different applications. In this review the use of different copper materials (copper, copper alloys, nanoparticles and copper-based coatings) in medical settings, industrial equipment and plumbing systems will be discussed considering their potential to prevent and control biofilm formation. Particular attention is given to the mode of action of copper materials. The putative impact of copper materials in the health and/or products quality is reviewed taking into account their main use and the possible effects on the spread of antimicrobial resistance.

Cu Nanoparticle-Loaded Nanovesicles with Antibiofilm Properties. Part I: Synthesis of New Hybrid Nanostructures

Copper nanoparticles (CuNPs) stabilized by quaternary ammonium salts are well known as antimicrobial agents. The aim of this work was to study the feasibility of the inclusion of CuNPs in nanovesicular systems. Liposomes are nanovesicles (NVs) made with phospholipids and are traditionally used as delivery vehicles because phospholipids favor cellular uptake. Their capacity for hydrophilic/hydrophobic balance and carrier capacity could be advantageous to prepare novel hybrid nanostructures based on metal NPs (Me-NPs). In this work, NVs were loaded with CuNPs, which have been reported to have a biofilm inhibition effect. These hybrid materials could improve the effect of conventional antibacterial agents. CuNPs were electro-synthesized by the sacrificial anode electrolysis technique in organic media and characterized in terms of morphology through transmission electron microscopy (TEM). The NVs were prepared by the thin film hydration method in aqueous media, using phosphatidylcholine (PC) and cholesterol as a membrane stabilizer. The nanohybrid systems were purified to remove non-encapsulated NPs. The size distribution, morphology and stability of the NV systems were studied. Different quaternary ammonium salts in vesicular systems made of PC were tested as stabilizing surfactants for the synthesis and inclusion of CuNPs. The entrapment of charged metal NPs was demonstrated. NPs attached preferably to the membrane, probably due to the attraction of their hydrophobic shell to the phospholipid bilayers. The high affinity between benzyl-dimethyl-hexadecyl-ammonium chloride (BDHAC) and PC allowed us to obtain stable hybrid NVs c.a. 700 nm in diameter. The stability of liposomes increased with NP loading, suggesting a charge-stabilization effect in a novel antibiofilm nanohybrid material.

Synthesis of Silver Nanoparticles and their Biomedical Applications - A Comprehensive Review

Generally, silver is considered as a noble metal used for treating burn wound infections, open wounds and cuts. However, the emerging nanotechnology has made a remarkable impact by converting metallic silver into silver nanoparticles (AgNPs) for better applications. The advancement in technology has improved the synthesis of NPs using biological method instead of physical and chemical methods. Nonetheless, synthesizing AgNPs using biological sources is ecofriendly and cost effective. Till date, AgNPs are widely used as antibacterial agents; therefore, a novel idea is needed for the successful use of AgNPs as therapeutic agents to uncertain diseases and infections. In biomedicine, AgNPs possess significant advantages due to their physical and chemical versatility. Indeed, the toxicity concerns regarding AgNPs have created the need for non-toxic and ecofriendly approaches to produce AgNPs. The applications of AgNPs in nanogels, nanosolutions, silver based dressings and coating over medical devices are under progress. Still, an improvised version of AgNPs for extended applications in an ecofriendly manner is the need of the hour. Therefore, the present review emphasizes the synthesis methods, modes of action under dissipative conditions and the various biomedical applications of AgNPs in detail.

Influence of surface copper content on Stenotrophomonas maltophilia biofilm control using chlorine and mechanical stress

This work aimed to evaluate the action of materials with different copper content (0, 57, 96 and 100%) on biofilm formation and control by chlorination and mechanical stress. Stenotrophomonas maltophilia isolated from drinking water was used as a model microorganism and biofilms were developed in a rotating cylinder reactor using realism-based shear stress conditions. Biofilms were characterized phenotypically and exposed to three control strategies: 10 mg l^-1 of free chlorine for 10 min, an increased shear stress (a fluid velocity of 1.5 m s^-1 for 30s), and a combination of both treatments. These shock treatments were not effective in biofilm control. The benefits from the use of copper surfaces was found essentially in reducing the numbers of non-damaged cells. Copper materials demonstrated better performance in biofilm prevention than chlorine. In general, copper alloys may have a positive public health impact by reducing the number of non-damaged cells in the water delivered after chlorine exposure.

Bioactivity of magnesium oxide nanoparticles synthesized from cell filtrate of endobacterium Burkholderia rinojensis against Fusarium oxysporum

The present study was performed to synthesize, for the first time, the magnesium oxide nanoparticles (MgO NPs) using the cell filtrate of the endobacterium Burkholderia rinojensis. The MgO NPs were characterized by Ultraviolet-visible (UV-Vis), Fourier-transform infrared (FTIR), X-ray diffraction (XRD), Energy dispersive X-ray (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and zeta potential (ZP). The UV spectrum of the MgO NPs showed a sharp absorption peak at 330 nm. The FTIR results confirm that the bioactive compounds act as reducing and capping agents of synthesized MgO NPs. The XRD pattern showed three major peaks of the crystalline metallic MgO NPs. Presence of magnesium and oxygen were confirmed by EDX profile. Both SEM and TEM revealed the MgO NPs as roughly spherical granular structures, and the size was 26.70 nm. The zeta potential was -32.1 mV, which indicated the stability of the MgO NPs in suspension. The MgO NPs showed considerable antifungal and antibiofilm activities against Fusarium oxysporum f. sp. lycopersici. At the concentration of 15.36 μg/ml, the MgO NPs completely inhibited the mycelial growth of the fungus. The biofilm formation of the pathogen was completely suppressed by MgO NPs at 1.92 μg/ml. The MgO NPs caused severe morphological changes on the hyphal morphology and biofilm formation of the fungus with significant damage on the fungal membrane integrity.

Biogenic phytochemicals (cassinopin and isoquercetin) capped copper nanoparticles (ISQ/CAS@CuNPs) inhibits MRSA biofilms

Purified glycosides, Isoquercetin and Cassinopin from Crotalaria candicans were selected for the synthesis of biogenic copper nanoparticles (CuNPs).The designed biogenic CuNPs was characterized and when evaluated against panel of gram negative and positive bacteria, the biogenic CuNPs were found to be more effective against methicillin resistant Staphylococcus aureus (MRSA). Antibacterial, anti-biofilm effects and time kill studies confirmed the ability of biogenic CuNPs to curtail MRSA. Scanning electron microscopy, Crystal violet staining and fluorescent live-dead imaging showed that treatment with sub lethal levels of glycoside capped CuNPs resulted in greater than 50% decline in biofilm formation by MRSA, which implies that anti-biofilm effect of biogenic CuNPs is not dependent on antibacterial effect. Alizarin red assay implied that prolonged treatment of biogenic CuNPs in presence of MRSA, releases Cu(II) ions and hence antibiofilm effect is primarily mediated by NP and is not due to released Cu(II) ion. The NPs caused altered membrane permeability and reduced surface hydrophobicity, thus accounting for its antibiofilm effect.