Bioactivity, mechanism of action, and cytotoxicity of copper-based nanoparticles: A review

A novel "cells-on-particles" cytotoxicity testing platform in vitro: design, characterization, and validation against engineered nanoparticle aerosol

The presented research introduces the "Cells-on-Particles" integrated aerosol sampling and cytotoxicity testing in vitro platform, which allows for the direct assessment of the biological effects of captured aerosol particles on a selected cell type without the need for extraction or resuspension steps. By utilizing particles with unaltered chemical and physical properties, the method enables simple and fast screening of biological effects on specific cell types, making it a promising tool for assessing the cytotoxicity of particulate matter in ambient and occupational air. Platforms fabricated from cellulose acetate (CA) and poly[ε]caprolactone (PCL) were proven to be biocompatible and promoted the attachment and growth of the human bronchial epithelial cell line BEAS-2B. The PCL platforms were exposed to simulated occupational aerosols of silver, copper, and graphene oxide nanoparticles. Each nanoparticle type exhibited different and dose-dependent cytotoxic effects on cells, evidenced by reduced cell viability and distinct, particle type-dependent gene expression patterns. Notably, copper nanoparticles were identified as the most cytotoxic, and graphene oxide the least. Comparing the "Cells-on-Particles" and submerged exposure ("Particles-on-Cells") testing strategies, BEAS-2B cells responded to selected nanoparticles in a comparable manner, suggesting the developed testing system could be proposed for further evaluation with more complex environmental aerosols. Despite limitations, including particle agglomeration and the need for more replicates to address variability, the "Cells-on-Particles" platform enables effective detection of toxicity induced by relatively low levels of nanoparticles, demonstrating good sensitivity and a relatively simpler procedure compared to standard 2D cell exposure methods.

Effect of sub-acute exposure of metal-organic framework-199 on cognitive function and oxidative stress level of brain tissue in rat

Metal-Organic Framework-199 (MOF-199) is a subgroup of MOFs that is utilized in different medical fields such as drug delivery. In the current study, the effect of sub-acute exposure to MOF-199 on spatial memory, working memory, inflammatory mediators' expression, and oxidative stress level of brain tissue has been investigated. Thirty-two male Wistar rats were randomly divided into four groups as vehicle, MOF-199 at doses 0.3, 3, or 6 mg/kg. After four injections of relevant interventions via tail vein during 14 days, behavioral parameters were investigated using Y-maze and Morris Water Maze (MWM) tests. Oxidative stress was measured by ferric reducing antioxidant power (FRAP) and thiobarbituric acid-reacting substance (TBARS) tests. The expression levels of TNF-α and IL-1β were assessed by quantitative real-time reverse-transcription PCR (qRT-PCR). No significant differences were observed in working memory, spatial learning and memory of MOF-199 receiving rats. Additionally, the level of oxidative stress and inflammatory genes expression were not remarkably changed in the brain tissues of MOF-199 treated rats. Despite the lack of remarkable toxic effects of sub-acute exposure to MOF-199, more studies with a longer duration of administration are necessary to use this substance for drug delivery systems in diseases related to the nervous system.

The potent effect of selenium nanoparticles: insight into the antifungal activity and preservation of postharvest strawberries from gray mold diseases

BACKGROUND

Most microorganisms that cause food decay and the lower the shelf life of foods are fungi. Nanotechnologies can combat various diseases and deal with the application of nanomaterial to target cells or tissues. In this study selenium nanoparticles (Se-NPs) were synthesized using ascorbic acid and characterized by ultraviolet-visible spectroscopy, transmission electron microscopy (TEM), X-ray diffraction and zeta potential. The different concentrations of As/Se-NPs were tested against various fungi, including Alternaria linicola, Alternaria padwickii, Botrytis cinerea, Bipolaris sp., Cephalosporium acremonium, Fusarium moniliform and Fusarium semitectum. This study tested the influence of coated As/Se-NPs on healthy strawberry fruits and those infected with Botrytis cinerea during 16 days of storage, with regard to shelf life, decay percentage, weight loss, total titratable acidity percentage, total soluble solids content (TSS) and anthocyanin content.

RESULTS

Energy-dispersive X-ray analysis showed only two elements: selenium and oxygen. TEM images showed that the nanoparticles ranged in size between 26 to 39 nm and were rhombohedral in shape. Se-NPs showed antifungal activity against all tested fungi, the most effective being against Botrytis cinerea, Cephalosporium acremonium and Fusarium semitectum. During storage periods of strawberries fruits coated with As/Se-NPs, the shelf life was increased, and the number of decaying fruits was less than in control (uncoated) and coated infected fruits. The decline in weight loss was lower in coated fruits than in control fruits.

CONCLUSION

These findings demonstrated that As/Se-NPs could effectively maintain the postharvest quality of strawberries, even when the fruit was infected with B. cinerea. © 2024 Society of Chemical Industry.

Developing a novel antibacterial copper tetraamine fluoride

OBJECTIVE

To develop a novel and biocompatible copper tetraamine fluoride (CTF) with antibacterial and nondiscolouring properties.

METHOD

This study used copper fluoride and ammonia solution to develop CTF solution. The CTF was characterized by X-ray photoelectron spectroscopy (XPS). Cytotoxicity was evaluated by stem cells from human exfoliated deciduous teeth (SHED) and human gingival fibroblasts (HGF-1). The fluoride concentration was determined using ion-selective electrode. The alkalinity was measured by a pH electrode. The human dentine blocks were treated with CTF and then incubated with Streptococcus mutans to evaluate the antimicrobial and discolouring effects. The silver diamine fluoride (SDF) was employed as the positive control, and water was the negative control. The colony-forming units (CFUs) and confocal laser scanning microscopy (CLSM) were used to examine the kinetics and viability of the biofilm. The discolouring property on dentine was assessed by spectrophotometry. One-way analysis of variance with the Bonferroni post hoc test was performed to assess and compare the data.

RESULTS

XPS confirmed synthesis of CTF solution. The half-maximal inhibitory concentration of CTF on SHED and HGF-1 was 195±16 ppm and 137±11 ppm. The fluoride concentration was 121,000±5,000 ppm. The pH value was 9. Log10 CFU of the CTF, SDF and water group were 5.0 ± 0.2, 4.9 ± 0.1 and 7.4 ± 0.1 (p < 0.001, CTF, SDFWater). Spectrophotometry showed that the ΔE of the CTF, SDF and water group were 5 ± 2, 6 ± 3 and 45±2 (p < 0.001, CTF, Water

CONCLUSION

This study developed an alkaline 58% CTF solution, which is biocompatible, antibacterial and non-discolouring.

CLINICAL SIGNIFICANCE

If CTF is successfully translated into clinical care, CTF can be a simple and affordable anti-caries agent for clinicians to prevent dental caries.

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Key Words

• Antibacterial
• Caries
• Copper
• Dentine
• Fluoride

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MESH Headings Collapse

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Affiliation(s)

Veena Wenqing Xu Faculty of Dentistry, University of Hong Kong, Hong Kong, China
Iris Xiaoxue Yin Faculty of Dentistry, University of Hong Kong, Hong Kong, China
John Yun Niu Faculty of Dentistry, University of Hong Kong, Hong Kong, China
Ollie Yiru Yu Faculty of Dentistry, University of Hong Kong, Hong Kong, China
Mohammed Zahedul Islam Nizami Faculty of Dentistry, University of Hong Kong, Hong Kong, China; Department of Mineralized Tissue Biology and Bioengineering, The Forsyth Institute, Cambridge, MA, USA.
Chun Hung Chu Faculty of Dentistry, University of Hong Kong, Hong Kong, China.

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Souza AB, Levita DP, Mello CC, da Silva AFM, dos Santos TC, Ronconi CM. Innovating Leishmaniasis Treatment: A Critical Chemist's Review of Inorganic Nanomaterials

Leishmaniasis, a critical Neglected Tropical Disease caused by Leishmania protozoa, represents a significant global health risk, particularly in resource-limited regions. Conventional treatments are effective but suffer from serious limitations, such as toxicity, prolonged treatment courses, and rising drug resistance. Herein, we highlight the potential of inorganic nanomaterials as an innovative approach to enhance Leishmaniasis therapy, aligning with the One Health concept by considering these treatments' environmental, veterinary, and public health impacts. By leveraging the adjustable properties of these nanomaterials─including size, shape, and surface charge, tailored treatments for various diseases can be developed that are less harmful to the environment and nontarget species. We review recent advances in metal-, oxide-, and carbon-based nanomaterials for combating Leishmaniasis, examining their mechanisms of action and their dual use as standalone treatments or drug delivery systems. Our analysis highlights a promising yet underexplored frontier in employing these materials for more holistic and effective disease management.

Is Copper Still Safe for Us? What Do We Know and What Are the Latest Literature Statements?

Copper (Cu) is a precious metal and one of the three most abundant trace elements in the body (50-120 mg). It is involved in a large number of cellular mechanisms and pathways and is an essential cofactor in the function of cellular enzymes. Both its excess and deficiency may be harmful for many diseases. Even small changes in Cu concentration may be associated with significant toxicity. Consequently, it can be damaging to any organ or tissue in our body, beginning with harmful effects already at the molecular level and then affecting the degradation of individual tissues/organs and the slow development of many diseases, such as those of the immunological system, skeletal system, circulatory system, nervous system, digestive system, respiratory system, reproductive system, and skin. The main purpose of this article is to review the literature with regard to both the healthiness and toxicity of copper to the human body. A secondary objective is to show its widespread use and sources, including in food and common materials in contact with humans. Its biological half-life from diet is estimated to range from 13 to 33 days. The retention or bioavailability of copper from the diet is influenced by several factors, such as age, amount and form of copper in the diet, lifestyle, and genetic background. The upper limit of normal in serum in healthy adults is approximately 1.5 mg Cu/L, while the safe upper limit of average intake is set at 10-12 mg/day, the reference limit at 0.9 mg/day, and the minimum limit at 0.6-0.7 mg/day. Cu is essential, and in the optimal dose, it provides antioxidant defense, while its deficiency reduces the body's ability to cope with oxidative stress. The development of civilization and the constant, widespread use of Cu in all electrical devices will not be stopped, but the health of people directly related to its extraction, production, or distribution can be controlled, and the inhabitants of nearby towns can be protected. It is extremely difficult to assess the effects of copper on the human body because of its ubiquity and the increasing reports in the literature about its effects, including copper nanoparticles.

Unveiling the antifungal mechanisms of CTP, a new copper(II)-theophylline/1,10-phenanthroline complex, on drug-resistant non-albicans Candida species

Candida species undeniably rank as the most prevalent opportunistic human fungal pathogens worldwide, with Candida albicans as the predominant representative. However, the emergence of non-albicans Candida species (NACs) has marked a significant shift, accompanied by rising incidence rates and concerning trends of antifungal resistance. The search for new strategies to combat antifungal-resistant Candida strains is of paramount importance. Recently, our research group reported the anti-Candida activity of a coordination compound containing copper(II) complexed with theophylline (theo) and 1,10-phenanthroline (phen), known as "CTP" - Cu(theo)2phen(H2O).5H2O. In the present work, we investigated the mechanisms of action of CTP against six medically relevant, antifungal-resistant NACs, including C. auris, C. glabrata, C. haemulonii, C. krusei, C. parapsilosis and C. tropicalis. CTP demonstrated significant efficacy in inhibiting mitochondrial dehydrogenases, leading to heightened intracellular reactive oxygen species production. CTP treatment resulted in substantial damage to the plasma membrane, as evidenced by the passive incorporation of propidium iodide, and induced DNA fragmentation as revealed by the TUNEL assay. Scanning electron microscopy images of post-CTP treatment NACs further illustrated profound alterations in the fungal surface morphology, including invaginations, cavitations and lysis. These surface modifications significantly impacted the ability of Candida cells to adhere to a polystyrene surface and to form robust biofilm structures. Moreover, CTP was effective in disassembling mature biofilms formed by these NACs. In conclusion, CTP represents a promising avenue for the development of novel antifungals with innovative mechanisms of action against clinically relevant NACs that are resistant to antifungals commonly used in clinical settings.

Spray-dried ternary bioactive glass microspheres: Direct and indirect structural effects of copper-doping on acellular degradation behavior

Silicate-based bioactive glass nano/microspheres hold significant promise for bone substitution by facilitating osteointegration through the release of biologically active ions and the formation of a biomimetic apatite layer. Cu-doping enhances properties such as pro-angiogenic and antibacterial behavior. While sol-gel methods usually yield homogeneous spherical particles for pure silica or binary glasses, synthesizing poorly aggregated Cu-doped ternary glass nano/microparticles without a secondary CuO crystalline phase remains challenging. This article introduces an alternative method for fabricating Cu-doped ternary microparticles using sol-gel chemistry combined with spray-drying. The resulting microspheres exhibit well-defined, poorly aggregated particles with spherical shapes and diameters of a few microns. Copper primarily integrates into the microspheres as Cu0 nanoparticles and as Cu2+ within the amorphous network. This doping affects silica network connectivity, as calcium and phosphorus are preferentially distributed in the glass network (respectively as network modifiers and formers) or involved in amorphous calcium phosphate nano-domains depending on the doping rate. These differences affect the interaction with simulated body fluid. Network depolymerization, ion release (SiO44-, Ca2+, PO43-, Cu2+), and apatite nanocrystal layer formation are impacted, as well as copper release. The latter is mainly provided by the copper involved in the silica network and not from metal nanoparticles, most of which remain in the microspheres after interaction. This understanding holds promising implications for potential therapeutic applications, offering possibilities for both short-term and long-term delivery of a tunable copper dose. STATEMENT OF SIGNIFICANCE: A novel methodology, scalable to industrial levels, enables the synthesis of copper-doped ternary bioactive glass microparticles by combining spray-drying and sol-gel chemistry. It provides precise control over the copper percentage in microspheres. This study explores the influence of synthesis conditions on the copper environment, notably Cu0 and Cu2+ ratios, characterized by EPR spectroscopy, an aspect poorly described for copper-doped bioactive glass. Additionally, copper indirectly affects silica network connectivity and calcium/phosphorus distribution, as revealed by SSNMR. Multiscale characterization illustrates how these features impact acellular degradation in simulated body fluid, highlighting the therapeutic potential for customizable copper dosing to address short- and long-term needs.

Development of silver-doped copper oxide and chitosan nanocomposites for enhanced antimicrobial activities

Antimicrobial resistance (AMR) has emerged as a significant and pressing public health concern, posing serious challenges to effectively preventing and treating persistent diseases. Despite various efforts made in recent years to address this problem, the global trends of AMR continue to escalate without any indication of decline. As AMR is well-known for antibiotics, developing new materials such as metal containing compounds with different mechanisms of action is crucial to effectively address this challenge. Copper, silver, and chitosan in various forms have demonstrated significant biological activities and hold promise for applications in medicine and biotechnology. Exploring the biological properties of these nanoparticles is essential for innovative therapeutic approaches in treating bacterial and fungal infections, cancer, and other diseases. To this end, the present study aimed to synthesize silver@copper oxide (Ag@CuO) nanoparticles and its chitosan nanocomposite (Chi-Ag@CuO) to investigate their antimicrobial efficacy. Various established spectroscopic and microscopic methods were employed for characterization purposes, encompassing scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Subsequently, the antimicrobial activity of the nanoparticles was assessed through MIC (minimum inhibitory concentration), MBC (minimum bactericidal concentration), and well-disk diffusion assays against Pseudomonas aeruginosa, Acinetobacter baumannii Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans. The size of the CuO-NPs, Ag@CuO, and Chi-Ag@CuO NPs was found to be 70-120 nm with a spherical shape and an almost uniform distribution. The nanocomposites were found to possess a minimum inhibitory concentration (MIC) of 5 μg/mL and a minimum bactericidal concentration (MBC) of 250 μg/mL. Moreover, these nanocomposites generated varying clear inhibition zones, with diameters ranging from a minimum of 9 ± 0.5 mm to a maximum of 25 ± 0.5 mm. Consequently, it is evident that the amalgamation of copper-silver-chitosan nanoparticles has exhibited noteworthy antimicrobial properties in the controlled laboratory environment, surpassing the performance of other types of nanoparticles.

Balancing Risks versus Benefits: Vitamin C Therapy versus Copper Oxide Nanoparticles Toxicity in Albino Rats' Submandibular Salivary Gland

OBJECTIVES

 This study aimed to examine the suppressive effect of the natural antioxidant vitamin C (VC) against submandibular gland toxicity induced by copper oxide nanoparticles (CuO-NPs).

MATERIALS AND METHODS

 Three groups of 30 mature male albino rats (4 weeks old) weighing between 150 and 200 g were selected. The rats were randomly assigned for 6 weeks to receive: intraperitoneal injection (IP) of vehicle (control group); IP of 2.5 mg/kg body weight (bw) of CuO-NPs (CuO-NPs group); and IP of 2.5 mg/kg bw of CuO-NPs, combined with a daily oral dose of 100 mg/kg bw of VC in drinking water via gavage (CuO-NPs/VC group). The rats were euthanized, and their submandibular glands were dissected for histological evaluation, including hematoxylin and eosin staining and immunohistochemistry for Ki-67 and caspase-3.

STATISTICAL ANALYSIS

 The area expression for Ki-67 and caspase-3 was statistically analyzed using GraphPad Prism. Following analysis of variance analysis, Tukey's post hoc was used for multiple comparisons. The significance level was set at p < 0.05.

RESULTS

 CuO-NPs caused significant cytotoxic effects on submandibular salivary gland cells in albino rats. This led to an increase in Ki-67 and caspase-3 levels compared with the control group. VC administration improved tissue histology and reduced Ki-67 and caspase-3 levels in the VC/CuO-NPs group compared with rats treated with CuO-NPs alone.

CONCLUSION

 The study revealed significant cytotoxic effects of CuO-NPs on the submandibular salivary gland of albino rats. VC effectively mitigated these toxic effects, suggesting its potential as a readily available antioxidant.

Copper-based nanomaterials: Opportunities for sustainable agriculture

The exponential growth of the global population has resulted in a significant surge in the demand for food worldwide. Additionally, the impact of climate change has exacerbated crop losses caused by pests and pathogens. The transportation and utilization of traditional agrochemicals in the soil are highly inefficient, resulting in significant environmental losses and causing severe pollution of both the soil and aquatic ecosystems. Nanotechnology is an emerging field with significant potential for market applications. Among metal-based nanomaterials, copper-based nanomaterials have demonstrated remarkable potential in agriculture, which are anticipated to offer a promising alternative approach for enhancing crop yields and managing diseases, among other benefits. This review firstly performed co-occurrence and clustering analyses of previous studies on copper-based nanomaterials used in agriculture. Then a comprehensive review of the applications of copper-based nanomaterials in agricultural production was summarized. These applications primarily involved in nano-fertilizers, nano-regulators, nano-stimulants, and nano-pesticides for enhancing crop yields, improving crop resistance, promoting crop seed germination, and controlling crop diseases. Besides, the paper concluded the potential impact of copper-based nanomaterials on the soil micro-environment, including soil physicochemical properties, enzyme activities, and microbial communities. Additionally, the potential mechanisms were proposed underlying the interactions between copper-based nanomaterials, pathogenic microorganisms, and crops. Furthermore, the review summarized the factors affecting the application of copper-based nanomaterials, and highlighted the advantages and limitations of employing copper-based nanomaterials in agriculture. Finally, insights into the future research directions of nano-agriculture were put forward. The purpose of this review is to encourage more researches and applications of copper-based nanomaterials in agriculture, offering a novel and sustainable strategy for agricultural development.

Alleviative effect of betaine against copper oxide nanoparticles-induced hepatotoxicity in adult male albino rats: histopathological, biochemical, and molecular studies

Background

Copper oxide nanoparticles (CuO-NPs) have gained interest due to their availability, efficiency, and their cost-effectiveness. Betaine is an essential methyl donor and takes part in various physiological activities inside the body; it is found to have protective and curative effects against various liver diseases. The present study aimed to evaluate the hepatotoxic effect of CuO-NPs on adult male albino rats and the ability of betaine to alleviate such hepatotoxicity.

Methods

Forty adult male albino Wister rats were grouped into 4 groups (10 rats/group): group I a negative control, group II (CuO-NPs) injected with CuO-NPs intra peritoneal by insulin needle (0.5 mg/kg/day), group III (betaine + CuO-NPs) administered betaine orally by gavage needle (250 mg/kg/day 1 h before CuO-NPs) and CuO-NPs (0.5 mg/kg/day) finally, group IV (betaine) administered betaine orally by gavage needle (250 mg/kg/day) for consecutive 28 days. Blood and liver samples were gathered and processed for biochemical, molecular, histopathological, and immunohistochemical investigations.

Results

Group II displayed a marked rise in alanine aminotransferase (ALT), aspartate aminotransferase (AST), and malondialdehyde (MDA) levels. Furthermore, there is an excessive upregulation of the inflammatory biomarkers interleukin1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α). On the other hand, substantial reduction in glutathione (GSH) levels and significant downregulation at glutathione peroxidase (GPx) mRNA gene expression. Regarding the histopathological deviations, there were severe congestion, dilatation and hyalinization of blood vessels, steatosis, hydropic degeneration, hepatocytic necrosis, increased binucleation, degenerated bile ducts, hyperplasia of ducts epithelial lining, and inflammatory cells infiltration. Immunohistochemically, there was a pronounced immunoreactivity toward IL-1β. Luckily, the pre-administration of betaine was able to mitigate these changes. MDA was dramatically reduced, resulting in the downregulation of IL-1β and TNF-α. Additionally, there was a considerable rise in GSH levels and an upregulation of GPx. Histopathological deviations were substantially improved as diminished dilatation, hyalinization and congestion of blood vessels, hepatocytes, and bile ducts are normal to some extent. In addition, IL-1β immunohistochemical analysis revealed marked decreased intensity.

Conclusion

Betaine can effectively reduce the hepatotoxicity caused by CuO-NPs via its antioxidant properties and its ability to stimulate the cell redox system.

The Influence of the Variable Wettability Characteristics of Layers on the Transport of Nanoparticles in the Context of Drug Delivery in Skin Structures

The rapid development of nanotechnology has offered the possibility of creating nanosystems that can be used as drug carriers. The use of such carriers offers real opportunities for the development of non-invasive drug delivery through skin structures. However, in addition to the ability to create suitable nanocarriers, it is also necessary to know how they move through dermal layers. The human skin consists of layers with different wettability characteristics, which greatly complicates how introduced substances move through it. In this work, an experimental study of the diffusion process of nanoparticles through partitions with different wettability properties was carried out. Conventional diffusion tests using Franz chambers were used for this purpose. We quantified how the wettability of the barrier, the number of layers, and their mutual configuration affect the transport of nanoparticles. Based on the results, an analysis of the phenomena taking place, depending on the wettability of the partition, was carried out. A model relationship was also proposed to determine the effective diffusion coefficient, taking into account the influence of the wettability and porosity of the barrier.

Nanoparticles incorporated hydrogels for delivery of antimicrobial agents: developments and trends

The prevention and treatment of microbial infections is an imminent global public health concern due to the poor antimicrobial performance of the existing antimicrobial regime and rapidly emerging antibiotic resistance in pathogenic microbes. In order to overcome these problems and effectively control bacterial infections, various new treatment modalities have been identified. To attempt this, various micro- and macro-molecular antimicrobial agents that function by microbial membrane disruption have been developed with improved antimicrobial activity and lesser resistance. Antimicrobial nanoparticle-hydrogels systems comprising antimicrobial agents (antibiotics, biological extracts, and antimicrobial peptides) loaded nanoparticles or antimicrobial nanoparticles (metal or metal oxide) constitute an important class of biomaterials for the prevention and treatment of infections. Hydrogels that incorporate nanoparticles can offer an effective strategy for delivering antimicrobial agents (or nanoparticles) in a controlled, sustained, and targeted manner. In this review, we have described an overview of recent advancements in nanoparticle-hydrogel hybrid systems for antimicrobial agent delivery. Firstly, we have provided an overview of the nanoparticle hydrogel system and discussed various advantages of these systems in biomedical and pharmaceutical applications. Thereafter, different hybrid hydrogel systems encapsulating antibacterial metal/metal oxide nanoparticles, polymeric nanoparticles, antibiotics, biological extracts, and antimicrobial peptides for controlling infections have been reviewed in detail. Finally, the challenges and future prospects of nanoparticle-hydrogel systems have been discussed.

Protein-templated ligand discovery via the selection of DNA-encoded dynamic libraries

DNA-encoded chemical libraries (DELs) have become a powerful technology platform in drug discovery. Dual-pharmacophore DELs display two sets of small molecules at the termini of DNA duplexes, thereby enabling the identification of synergistic binders against biological targets, and have been successfully applied in fragment-based ligand discovery and affinity maturation of known ligands. However, dual-pharmacophore DELs identify separate binders that require subsequent linking to obtain the full ligands, which is often challenging. Here we report a protein-templated DEL selection approach that can identify full ligand/inhibitor structures from DNA-encoded dynamic libraries (DEDLs) without the need for subsequent fragment linking. Our approach is based on dynamic DNA hybridization and target-templated in situ ligand synthesis, and it incorporates and encodes the linker structures in the library, along with the building blocks, to be sampled by the target protein. To demonstrate the performance of this method, 4.35-million- and 3.00-million-member DEDLs with different library architectures were prepared, and hit selection was achieved against four therapeutically relevant target proteins.

Reduced toxic effects of nano‑copper sulfate in comparison of bulk CuSO4 on biochemical parameters in the Rohu (Labeo rohita)

Considering the wide application of nanoparticles in various fields of life and growing concern regarding their toxic effects, the present study was designed with the aim to evaluate the potential risks of using copper sulfate nanoparticles (CuSO4-NPs) in comparison to bulk form. Nanoparticles of CuSO4, having mean size of 73 nm were prepared by ball milling method, and fingerlings of Labeo rohita were exposed to two levels, 20 and 100 μg L-1 of CuSO4 in both bulk and nano forms for 28 days and their comparative effects on the metallothioneins (MTs), heat shock proteins 70 (HSP 70), lipid profile, cholesterol (CHOL) and triglyceraldehyde (TG) levels, activities of some metabolic enzymes Alanine transaminase (ALT), Aspartate transaminase (AST) Akaline phosphatase (ALP), and genes expressions of HSP-70, TNF-α and IL1-ß were investigated. CuSO4 showed the concentration and particle type dependent effects. The over expression of HSPs and MTs, significant decreases in CHOL, TG, low density lipid (LDL) levels and ALP activity, while significant increases in high density lipid (HDL)level as well as ALT and AST activities and HSP-70, TNF-α and IL1-β expressions were observed in response to higher concentration of both bulk and nano form of copper sulfate. At lower concentration (20 μg L-1), however, only bulk form showed toxicity. Thus, low concentrations of CuSO4-NPs pose negligible threat to freshwater fish.

Assessing cytotoxicity and endoplasmic reticulum stress in human blood-brain barrier cells due to silver and copper oxide nanoparticles

In recent years, it has been generally accepted that metal-based nanoparticles (NPs) may induce stress in the endoplasmic reticulum (ER), a key organelle where protein folding occurs. We examined ER stress in immortalized human cerebral microvascular cells (hCMEC/D3) after exposure to silver-NPs (Ag-NPs)- and copper oxide-NPs (CuO-NPs) induced toxicity at < 10 nm and < 40 nm or < 50 nm diameters, respectively. In cytotoxicity assessments, cells were exposed to different CuO-NPs (5-400 µg/mL) or Ag-NPs (1-10 µg/mL) concentration ranges for 24 h and 72 h, and tetrazole salt reduction assays (EZ4U) were performed. Also, Ag-NP or CuO-NP effects on cell proliferation, apoptosis (caspase 3/7 assays), and ER stress and cell morphology were evaluated. In ER stress assessments, RNA-like endoplasmic reticulum kinase (PERK), activating transcription factor 6 (ATF6), inositol-requiring enzyme 1 (IRE1a), and others stress factor mRNA levels were determined after 24 h treatment using Real-Time PCR. Increased stress sensors (IRE1a, PERK, and ATF6) mRNA levels were observed after exposure to Ag-NPs (< 10 and < 40 nm) or CuO-NPs (< 50 nm). We investigated the expression of tight junction (TJ) proteins (barrier junctions) and showed that both types of NP reduced of OCLN gene expression. Morphological changes were observed after Ag-NP or CuO-NP exposure using holotomographic microscopy. Our data suggest that Ag- and CuO-NPs should undergo future in vitro and in vivo toxicology studies, especially for downstream biomedical application and occupational risk assessments.

Metal-organic framework-based advanced therapeutic tools for antimicrobial applications

The escalating concern over conventional antibiotic resistance has emphasized the urgency in developing innovative antimicrobial agents. In recent times, metal-organic frameworks (MOFs) have garnered significant attention within the realm of antimicrobial research due to their multifaceted antimicrobial attributes, including the sustained release of intrinsic or exogenous antimicrobial components, chemodynamically catalyzed generation of reactive oxygen species (ROS), and formation of photogenerated ROS. This comprehensive review provides a thorough overview of the synthetic approaches employed in the production of MOF-based materials, elucidating their underlying antimicrobial mechanisms in depth. The focal point lies in elucidating the research advancements across various antimicrobial modalities, encompassing intrinsic component release system, extraneous component release system, auto-catalytical system, and energy conversion system. Additionally, the progress of MOF-based antimicrobial materials in addressing wound infections, osteomyelitis, and periodontitis is meticulously elucidated, culminating in a summary of the challenges and potential opportunities inherent within the realm of antimicrobial applications for MOF-based materials. STATEMENT OF SIGNIFICANCE: Growing concerns about conventional antibiotic resistance emphasized the need for alternative antimicrobial solutions. Metal-organic frameworks (MOFs) have gained significant attention in antimicrobial research due to their diverse attributes like sustained antimicrobial components release, catalytic generation of reactive oxygen species (ROS), and photogenerated ROS. This review covers MOF synthesis and their antimicrobial mechanisms. It explores advancements in intrinsic and extraneous component release, auto-catalysis, and energy conversion systems. The paper also discusses MOF-based materials' progress in addressing wound infections, osteomyelitis, and periodontitis, along with existing challenges and opportunities. Given the lack of related reviews, our findings hold promise for future MOF applications in antibacterial research, making it relevant to your journal's readership.

Biochemical Approach to Poly(Lactide)-Copper Composite-Impact on Blood Coagulation Processes

The paper presents the investigation of the biological properties of Poly(Lactide)-Copper composite material obtained by sputter deposition of copper onto Poly(lactide) melt-blown nonwoven fabrics. The functionalized composite material was subjected to microbial activity tests against colonies of Gram-positive (Staphylococcus aureus), Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria, Chaetomium globosum and Candida albicans fungal mold species and biochemical-hematological tests including the evaluation of the Activated Partial Thromboplastin Time, Prothrombin Time, Thrombin Time and electron microscopy fibrin network imaging. The substantial antimicrobial and antifungal activities of the Poly(Lactide)-Copper composite suggests potential applications as an antibacterial/antifungal material. The unmodified Poly(Lactide) fabric showed accelerated human blood plasma clotting in the intrinsic pathway, while copper plating abolished this effect. Unmodified PLA itself could be used for the preparation of wound dressing materials, accelerating coagulation in the case of hemorrhages, and its modifications with the use of various metals might be applied as new customized materials where blood coagulation process could be well controlled, yielding additional anti-pathogen effects.

In-situ green synthesis of copper tannic acid framework in the presence of graphene quantum dots: Improved colloidal and antibacterial properties

This work reports the preparation of a copper tannic acid MOF (CuTA) and graphene quantum dot (GQD) nanocomposite, GQD/CuTA, by a simple, environmentally friendly, and inexpensive method with exceptionally enhanced antibacterial properties. To end this, GQDs were first fabricated from citric acid using a neoteric, simple and straightforward hydrolysis approach and followed by they effectively anchor MOF nanoparticles (CuTA) by a green hydrothermal in situ synthesizing method. The constructed GQD/CuTA nanomaterials were characterized and validated using XRD, FT-IR, TEM, DLS, UV-vis, and PL techniques. Significant antibacterial activity against E. coli bacteria for both CuTA and GQD/CuTA (0 CFU/mL) and S. aureus bacteria for CuTA and GQD/CuTA (300 and 40 CFU/mL) was observed for the GQD/CuTA nanocomposite. The MTT assay showed good cytocompatibility for the GQD/CuTA nanocomposite against human dermal fibroblast cells (HFF-2). The result suggests that the synthesized GQD/CuTA nanocomposite with improved colloidal and antibacterial properties has the potential to be used as a safe photoluminescent nanoplatform with strong antimicrobial activity.

Metal-based nanoparticles in antibacterial application in biomedical field: Current development and potential mechanisms

The rise in drug resistance in pathogenic bacteria greatly endangers public health in the post-antibiotic era, and drug-resistant bacteria currently pose a great challenge not only to the community but also to clinical procedures, including surgery, stent implantation, organ transplantation, and other medical procedures involving any open wound and compromised human immunity. Biofilm-associated drug failure, as well as rapid resistance to last-resort antibiotics, necessitates the search for novel treatments against bacterial infection. In recent years, the flourishing development of nanotechnology has provided new insights for exploiting promising alternative therapeutics for drug-resistant bacteria. Metallic agents have been applied in antibacterial usage for several centuries, and the functional modification of metal-based biomaterials using nanotechnology has now attracted great interest in the antibacterial field, not only for their intrinsic antibacterial nature but also for their ready on-demand functionalization and enhanced interaction with bacteria, rendering them with good potential in further translation. However, the possible toxicity of MNPs to the host cells and tissue still hinders its application, and current knowledge on their interaction with cellular pathways is not enough. This review will focus on recent advances in developing metallic nanoparticles (MNPs), including silver, gold, copper, and other metallic nanoparticles, for antibacterial applications, and their potential mechanisms of interaction with pathogenic bacteria as well as hosts.

Novel Antibacterial and Biocompatible Nanostructured Gels Based on One-step Synthesis as a Potential Disinfectant for Endodontic Infection Control

AIM

The objective of this study was to develop nanostructured gels as biocompatible intracanal disinfectants by one-step microwave radiation-assisted synthesis.

METHODS

Polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) were used as a support network, and polyethylene glycol (PEG) was used as a reducing agent. The gels were characterized by measuring the swelling ratio (SR) and rheological properties and by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The antibacterial effects of each gel were evaluated against the endodontic clinical strain Enterococcus faecalis. Then, the viability of the 21-day mature multispecies bacterial biofilm was assessed using confocal microscopy in an ex vivo model, where the biofilm was exposed to the mix of nanogels. The cell proliferation, viability, and morphology of human periodontal ligament (HPDL) cells were quantified using a real-time IncuCyte® S3 Live-Cell System. Viability was measured by confocal microscopy using an ex vivo model exposing a 21-day mature multispecies bacterial biofilm to the mix of nanogels.

RESULTS

The antibacterial activity of the gels coincided with the superficial characterization and the solubility of the gel in the growth medium. Gels with higher viscosity (327.85-980.58 Pa s), higher dissolution (42-70%SR), and lower porosity (no porosity and 611.63 nm) showed excellent antibacterial activity against E. faecalis. Despite their physicochemical characteristics, CuNPs gels showed greater effectiveness against E. faecalis.These nanostructured gels with high PVA concentrations promote HPDL cells proliferation while still exerting antibacterial properties. Mix of nanogels showed an increase non-viable cells biomass from at of application.

CONCLUSIONS

The use of biocompatible polymers influences the physicochemical, bactericidal, and cytotoxic response, making these materials potential disinfectant agents against resistant bacteria with good biocompatibility and improved HPDL cells proliferation.

Facile Microwave-Assisted Hydrothermal Synthesis of Copper Oxide Nanoneedle Arrays for Practical Biomedical Applications

INTRODUCTION

Copper oxide nanoneedle arrays (CuO NAs) have been widely used as antibacterial agents and in therapeutic applications because of their unique physicochemical features, low cytotoxicity, low cost, exceptional antibacterial action, and significant interest in biomedicine. Various analytical techniques were used to assess the related phase constitution, optical characteristics, elemental content, and surface morphology. The X-ray diffraction (XRD) patterns and field-emission scanning electron microscopy (FE-SEM) micrographs revealed that the CuO NAs had a monoclinic phase with a nanoneedle-like shape. Our findings may cover the progress of innovative and effective anti-bacterial capabilities based on CuO NAs, which have been shown to be effective against various pathogens, making them ideal options for fighting bacterial infections.  Objective: This research aimed to synthesize CuO NAs using microwave-solvothermal (MW-ST) technology, explore their effectiveness, and assess their biological activity.

METHODS

The CuO NAs were synthesized using the MW-ST process, and their properties were assessed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), energy dispersive analysis (EDS), field emission transmission microscopy (FE-TEM), and ultraviolet-visible (UV-Vis) techniques. The biocompatibility of CuO NAs was determined through hemolytic assays, and their bioactivities like antioxidant and anti-inflammatory assays were also determined.

RESULTS

The CuO NAs were successfully developed, and various analytical tools were used to characterize and validate their morphology, size, crystallinity, and elemental compositions. It has been shown in in-vitro investigations that a strong anti-inflammatory impact is demonstrated by the inhibition of protein denaturation with low hemolytic potential. As a result, CuO NAs have the potential to be an excellent choice for anti-inflammatory solicitations.

CONCLUSION

CuO NAs were synthesized and characterized with various advanced techniques, revealing the formation of nanoneedles-like morphology. Based on the experimental findings, CuO NAs have the potential for anti-microbial, anti-oxidant, anti-inflammatory, and anti-hemolytic activities. However, additional in-vivo testing is essential to properly evaluate their efficiency and safety.

Dissolution kinetics of copper oxide nanoparticles in presence of glyphosate

Recently CuO nanoparticles (n-CuO) have been proposed as an alternative method to deliver a Cu-based pesticide for controlling fungal infestations. With the concomitant use of glyphosate as an herbicide, the interactions between n-CuO and this strong ligand need to be assessed. We investigated the dissolution kinetics of n-CuO and bulk-CuO (b-CuO) particles in the presence of a commercial glyphosate product and compared it to oxalate, a natural ligand present in soil water. We performed experiments at concentration levels representative of the conditions under which n-CuO and glyphosate would be used (∼0.9 mg/L n-CuO and 50 μM of glyphosate). As tenorite (CuO) dissolution kinetics are known to be surface controlled, we determined that at pH 6.5, T ∼ 20 °C, using KNO3 as background electrolyte, the presence of glyphosate leads to a dissolution rate of 9.3 ± 0.7 ×10-3 h-1. In contrast, in absence of glyphosate, and under the same conditions, it is 2 orders of magnitude less: 8.9 ± 3.6 ×10-5 h-1. In a more complex multi-electrolyte aqueous solution the same effect is observed; glyphosate promotes the dissolution rates of n-CuO and b-CuO within the first 10 h of reaction by a factor of ∼2 to ∼15. In the simple KNO3 electrolyte, oxalate leads to dissolution rates of CuO about two times faster than glyphosate. However, the kinetic rates within the first 10 h of reaction are about the same for the two ligands when the reaction takes place in the multi-electrolyte solution as oxalate is mostly bound to Ca2+ and Mg2+.

Synthetic graphene-copper nanocomposites interact with the hACE-2 enzyme and inhibit its biochemical activity

This study demonstrates the copper nanocomposite-induced enzymatic inhibition of human angiotensin I-converting enzyme-2 (hACE-2) by complex stabilization through the formation of the enzyme nanocomposite. The immediate application of this work is related to ACE-2 as a mechanism of SARS-CoV-2 entry into cells. Moreover, ACE-2 enzyme regulation is a potential therapeutic strategy in hypertension and cardiovascular disease, diabetes, lung injury, and fibrotic disorders. Thus, inhibition of ACE-2 with nanocomposite therapy, may have pharmacologic application with regard to infectious and non-infectious diseases. Synthesized copper nanocomposites described here alone with a commercially available compound, were tested for their potential to inhibit hACE-2 activities. Following wet chemical synthesis, Cu/CuO nanoparticles and graphene-copper (GO-Cu) complexes were synthesized and characterized for their chemical integrity. Cu/CuO formed well-dispersed clusters of 390 ± 100 nm, that when complexed with the hACE-2 enzyme exhibited larger clusters of 506 ± 56 nm. The formation of the Cu/CuO and hACE-2 enzyme complex was monitored by analyzing the zeta potential, which reflected the surface charge distribution of the complex. A negatively charged Cu/CuO nanocomposite nearly becomes neutral when complexed with hACE-2 further assuring the complex formation. Formation of this complex and its inactivation of hACE-2 was evaluated using a standardized protocal for enzymatic activity. Similarly, carboxylate-functionalized graphene was complexed with copper, and its inhibitory effect was studied. Each step in the GO-Cu composite formation was monitored by characterizing its surface electrical properties, resulting in a decrease in its zeta potential and conductivity when complexed with copper. The interaction of the nanocomposites with hACE-2 was confirmed by 2D-FDS and gel electrophoresis analysis. GO-Cu was a rapid and efficacious inhibitor compared to Cu-CuO, especially at lower concentrations (2 μg ml-1). Considering the environmental friendliness of copper and graphene and their use in industries as surface coating materials, we anticipate that use of these composites once proven effective, may have future antimicrobial application. Utility of nanocomposites as antimicrobials, either as a surface antimicrobial or as an in vivo therapeutic, could be invisioned for use against current unknown and/or emergent pathogens.

Blood Coagulation Activities of Cotton-Alginate-Copper Composites

Alginate-based materials have gained significant attention in the medical industry due to their biochemical properties. In this article, we aimed to synthesize Cotton-Alginate-Copper Composite Materials (COT-Alg(-)Cu(2+)). The main purpose of this study was to assess the biochemical properties of new composites in the area of blood plasma coagulation processes, including activated partial thromboplastin time (aPTT), prothrombin time (PT), and thrombin time (TT). This study also involved in vitro antimicrobial activity evaluation of materials against representative colonies of Gram-positive and Gram-negative bacteria and antifungal susceptibility tests. The materials were prepared by immersing cotton fibers in an aqueous solution of sodium alginate, followed by ionic cross-linking of alginate chains within the fibers with Cu(II) ions to yield antimicrobial activity. The results showed that the obtained cotton-alginate-copper composites were promising materials to be used in biomedical applications, e.g., wound dressing.

Use of copper-functionalized cotton waste in combined chemical and biological processes for production of valuable chemical compounds

Cotton textiles modified with copper compounds have a documented mechanism of antimicrobial action against bacteria, fungi, and viruses. During the COVID-19 pandemic, there was pronounced interest in finding new solutions for textile engineering, using modifiers and bioactive methods of functionalization, including introducing copper nanoparticles and complexes into textile products (e.g. masks, special clothing, surface coverings, or tents). However, copper can be toxic, depending on its form and concentration. Functionalized waste may present a risk to the environment if not managed correctly. Here, we present a model for managing copper-modified cotton textile waste. The process includes pressure and temperature-assisted hydrolysis and use of the hydrolysates as a source of sugars for cultivating yeast and lactic acid bacteria biomass as valuable chemical compounds.

Cytotoxicity, Antimicrobial, Anti-inflammatory and Antioxidant Activity of Camellia Sinensis and Citrus Mediated Copper Oxide Nanoparticle-An In vitro Study

Aim

Several applications of copper oxide nanoparticles (CuONPs) have been documented in various fields, including healthcare, dentistry, medication delivery, tissue and cancer imaging, biolabeling, and biosensing. Therefore, this study aimed to synthesize CuONPs using the plant extracts of Camellia Sinesis (CS) and citrus limon (CL). The nanoparticles were then evaluated for their cytotoxicity, antibacterial, anti-inflammatory, and antioxidant activities.

Materials and Methods

CuONPs were prepared using CS and CL through the green synthesis method. The Zone of Inhibition (ZOI) test was used to assess the antibacterial activity against strains of Staphylococcus aureus, Enterococcus faecalis, Streptococcus mutans, and Candida albicans. The albumin denaturation assay was used to assess the substances' anti-inflammatory activity. The cytotoxicity was determined by conducting the brine shrimp lethality test. Additionally, the antioxidant nature was tested using the 1,1-diphenyl-2-picryl hydrazyl method.

Results

CuONPs mediated by CS and CL were successfully synthesized. The nanoparticles demonstrated significant antimicrobial activity against the bacteria being studied, specifically S. aureus. The cytotoxic effect was observed to be the least when the concentrations were below 20 µL. A potent antioxidant effect, characterized by its maximum absorbance at 517 nm, was observed at a concentration of 50 µL. A significant anti-inflammatory effect was noted for all tested concentrations.

Conclusion

The use of CS- and CL-mediated CuONPs demonstrates a favorable antimicrobial effect with reduced cytotoxicity, as well as improved anti-inflammatory and antioxidant effects at higher concentrations.

Multifunctional bioactive glasses with spontaneous degradation for simultaneous osteosarcoma therapy and bone regeneration

For the treatment of tumor-related bone defects resulting from surgical resection, simultaneous eradication of residual tumor cells and repair of bone defects represent a challenge. To date, photothermal therapy based on photothermal materials is used to remove residual tumor cells under near infrared light. However, most of photothermal materials have no function for bone repair, and even if combined with bioactive materials to enhance osteogenesis, they still cause potential harm to the body due to inability to degrade or poor degradability. Herein, multifunctional bioactive glasses (PGFe5-1100, PGCu5-1100) based on phosphate glass doped with transition metal elements were prepared for photothermal ablation, bone regeneration, and controllable degradation. The glasses exhibited excellent photothermal effect, which was derived from the electron in-band transition after light absorption due to energy level splitting of doped transition metal element and the subsequent electron nonradiative relaxation. The photothermal performance can be controlled by laser power density, element doping content and glass melting temperature. Moreover, the hyperthermia induced by the glasses can effectively kill tumor cells in vitro. In addition, the glasses degraded over time, and the released P, Ca, Na, Fe could promote bone cell proliferation and osteogenic differentiation. Therefore, these results successfully demonstrated that transition metal element-doped phosphate glasses have multifunctional abilities of tumor elimination, bone regeneration, and spontaneous degradation simultaneously with better biosecurity and bioactivity, which is believed to pave the way for the design of novel biomaterials for osteosarcoma treatment.

Peelable Alginate Films Reinforced by Carbon Nanofibers Decorated with Antimicrobial Nanoparticles for Immediate Biological Decontamination of Surfaces

This study presents the synthesis and characterization of alginate-based nanocomposite peelable films, reinforced by carbon nanofibers (CNFs) decorated with nanoparticles that possess remarkable antimicrobial properties. These materials are suitable for immediate decontamination applications, being designed as fluid formulations that can be applied on contaminated surfaces, and subsequently, they can rapidly form a peelable film via divalent ion crosslinking and can be easily peeled and disposed of. Silver, copper, and zinc oxide nanoparticles (NPs) were synthesized using superficial oxidized carbon nanofibers (CNF-ox) as support. To obtain the decontaminating formulations, sodium alginate (ALG) was further incorporated into the colloidal solutions containing the antimicrobial nanoparticles. The properties of the initial CNF-ox-NP-ALG solutions and the resulting peelable nanocomposite hydrogels (obtained by crosslinking with zinc acetate) were assessed by rheological measurements, and mechanical investigations, respectively. The evaluation of Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) for the synthesized nanoparticles (silver, copper, and zinc oxide) was performed. The best values for MIC and MBC were obtained for CNF-ox decorated with AgNPs for both types of bacterial strains: Gram-negative (MIC and MBC values (mg/L): E. coli-3 and 108; P. aeruginosa-3 and 54) and Gram-positive (MIC and MBC values (mg/L): S. aureus-13 and 27). The film-forming decontaminating formulations were also subjected to a microbiology assay consisting of the time-kill test, MIC and MBC estimations, and evaluation of the efficacity of peelable coatings in removing the biological agents from the contaminated surfaces. The best decontamination efficiencies against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa varied between 97.40% and 99.95% when employing silver-decorated CNF-ox in the decontaminating formulations. These results reveal an enhanced antimicrobial activity brought about by the synergistic effect of silver and CNF-ox, coupled with an efficient incorporation of the contaminants inside the peelable films.

Enhanced Antibacterial Activity at Ag-Cu Nanojunctions: Unveiling the Mechanism with Simple Surfaces of CuNPs-on-Ag Films

Deposition of CuNPs on silver film gives rise to the formation of active Ag-Cu interfaces leading to dramatic enhancements in antibacterial activity against Escherichia coli. Transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDAX) analyses reveal that CuNPs are covered in a thin Cu2O shell, while X-ray photoelectron spectroscopy measurements (XPS) reveal that the Ag film samples contain significant amounts of Ag2O. XPS analyses show that the deposition of CuNPs on Ag films leads to the formation of a photoactive Ag2O-Cu2O heterostructure. Following a Z-scheme mechanism, electrons from the conduction band of Ag2O recombine with photogenerated holes from the valence band of Cu2O. Consequently, electrons at Cu2O's conduction band render Cu reduced and cause reductive activation of surface oxygen species on Cu forming reactive oxygen species (ROS). Interaction between metallic Cu and ROS species leads to the formation of a Cu(OH)2 phase. Both ROS and Cu(OH)2 species have previously been reported to lead to enhanced antibacterial properties. Holes on Ag2O produce a highly oxidized AgO phase, a phase reported to exhibit excellent antibacterial properties. Quantitative analysis of Cu and Ag high-resolution X-ray photoelectron spectroscopy (HR-XPS) spectra directly reveals several-fold increases in these active phases in full agreement with the observed increase in antibacterial activities. This study provides insight and surface design parameters by elucidating the important roles of Ag and Cu's bifunctionality as active antibacterial materials.

Efficacy of copper nanoparticles encapsulated in soya lecithin liposomes in treating breast cancer cells (MCF-7) in vitro

Cancer is one of the leading causes of death, which has attracted the attention of the scientific world to the search for efficient methods for treatment. With the great development and regeneration of nanotechnology over the last 25 years, various nanoparticles in different structures, shapes and composites provide good potential for cancer therapy. There are several drugs approved by FDA used in breast cancer treatment like Cyclophosphamide, Doxorubicin Hydrochloride, Femara, Herceptin, etc. Each has several side effects as well as treatment, which limits the use of drugs due to heart failure, pulmonary dysfunction, or immunodeficiency. Recently, such side effects are greatly reduced by using innovative delivery techniques. Some drugs have been approved for use in cancer treatment under the concept of drug delivery, such as Doxil (liposomal loaded doxorubicin). The purpose of this study is to investigate the effect of copper nanoparticles (CuNPs) as a drug model for cancer treatment, either in their free form or encapsulated in Soy lecithin liposomes (SLP) from plant origin as a cheap source of lipids. CuNPs were prepared by the chemical reduction method and loaded onto SLP through the thin film hydration method. The drug model Cu/SLP was successfully combined. The characteristics of the free CuNPs, liposomes, and the combined form, zeta potential, size distribution, drug encapsulation efficiency (EE%), drug release profile, Fourier transform infrared (FTIR), and transmission electron microscopy (TEM), were checked, followed by an in vitro study on the breast cancer cell line Mcf-7 as a model for cytotoxicity evaluation. The optimal Cu/SLP had a particle mean size of 81.59 ± 14.93 nm, a negative zeta potential of - 50.7 ± 4.34 mV, loaded CuNPs showed an EE% of 78.9%, a drug release profile for about 50% of the drug was released after 6 h, and FTIR analysis was recorded. The cytotoxicity assay showed that the IC50 of Cu/SLP is smaller than that of free CuNPs. These results give clear evidence of the efficacy of using the combined Cu/SLP rather than CuNPs alone as a model drug carrier prepared from plant origin against cancer, both medically and economically.

Nanotechnology innovations for increasing the productivity of poultry and the prospective of nanobiosensors

Nanotechnology is an innovative, promising technology with a great scope of applications and socioeconomic potential in the poultry industry sector. Nanoparticles (NPs) show the advantages of high absorption and bioavailability with more effective delivery to the target tissue than their bulk particles. Various nanomaterials are available in different forms, sizes, shapes, applications, surface modifications, charges and natures. Nanoparticles can be utilised in the delivery of medicines, targeting them to their right effective site in the body and, at the same time, decreasing their toxicity and side effects. Furthermore, nanotechnology can be beneficial in the diagnosis of diseases and prevention of them and in enhancing the quality of animal products. There are different mechanisms through which NPs could exert their action. Despite the vast benefits of NPs in poultry production, some concerns about their safety and hazardous effects should be considered. Therefore, this review article focuses on NPs' types, manufacture, mechanism of action and applications regarding safety and hazard impact.

48-month clinical evaluation of a copper-containing universal adhesive in non-carious cervical lesions: A double-blind randomised clinical trial

OBJECTIVES

This study aimed to evaluate the effect of copper nanoparticles (CuNp) on the clinical performance of a universal adhesive system used as an etch-and-rinse or self-etch strategy.

METHODS

A total of 216 class V (non-carious lesions) restorations were randomly placed in 36 subjects according to the following groups: ERcu, adhesive in etch-and-rinse with 0.1% CuNp; ERct, adhesive in etch-and-rinse without CuNp; SEcu, adhesive in self-etch with 0.1% CuNp; and Sect, adhesive in self-etch without CuNp. Restorations were evaluated at baseline and at 6, 12, 18, 36, and 48 months, using the FDI and USPHS criteria. Appropriate statistical analyses were performed (α = 0.05).

RESULTS

After 48 months, 14 restorations were lost (two for ERcu, five for SEcu, and seven for SEct) and the retention rates (95% confidence interval [CI]) were 74.1% for ERcu (95% CI 61.1-83.8); 81.5% for ERct (95% CI 69.2-89.6); 64.8% (95% CI 51.5-76.2) for SEcu; and 64.8% (95% CI 51.5-76.2) for SEct, with statistical differences between SEct vs. ERct and SEcu vs. ERct (p < 0.05). No significant differences between the groups were observed when the secondary parameters were evaluated (p > 0.05). Nineteen restorations (two for ERcu, two for ERct, six for SEcu, and nine for SEct) showed minor marginal staining, and 44 restorations (7 for ERcu, 8 for ERct, 14 for SEcu, and 15 for SEct) presented minimal marginal adaptation defects.

SIGNIFICANCE

This is the first long-term clinical trial to show that the addition of CuNp to a universal adhesive system does not affect clinical performance.

Advances in preparation and application of antibacterial hydrogels

Bacterial infections, especially those caused by drug-resistant bacteria, have seriously threatened human life and health. There is urgent to develop new antibacterial agents to reduce the problem of antibiotics. Biomedical materials with good antimicrobial properties have been widely used in antibacterial applications. Among them, hydrogels have become the focus of research in the field of biomedical materials due to their unique three-dimensional network structure, high hydrophilicity, and good biocompatibility. In this review, the latest research progresses about hydrogels in recent years were summarized, mainly including the preparation methods of hydrogels and their antibacterial applications. According to their different antibacterial mechanisms, several representative antibacterial hydrogels were introduced, such as antibiotics loaded hydrogels, antibiotic-free hydrogels including metal-based hydrogels, antibacterial peptide and antibacterial polymers, stimuli-responsive smart hydrogels, and light-mediated hydrogels. In addition, we also discussed the applications and challenges of antibacterial hydrogels in biomedicine, which are expected to provide new directions and ideas for the application of hydrogels in clinical antibacterial therapy.

Chitosan/poly (ethylene oxide) nanofiber sponge with dual-responsive drug release and excellent antibacterial property

An ideal wound dressing can absorb wound exudate in time, and has the advantages of moisture permeability, oxygen permeability, rapid hemostatic performance, antibacterial and low-toxic, which are the key to wound healing. However, traditional wound dressings exist structural and functional defects, especially in controlling bleeding and active wound protection. Herein, a novel three-dimensional chitosan/ poly (ethylene oxide) sponge dressing (3D CS/PEO sponge-ZPC) consists of CS/PEO nanofiber sponge (carrier unit), Zn metal-organic framework grown in-situ (Zn-MOF, drug loading unit and antibacterial unit), curcumin (CUR, antibacterial unit), and poly[(N-isopropylacrylamide)-co-(methacrylic acid)] (P(NIPAM-co-MAA), 'gatekeepers' unit) to promote the wound healing by absorb exudate in time, accelerate hemostasis and inhibit bacteria growth. Due to the unique structure of the as-prepared 3D CS/PEO sponge-ZPC was endowed with smart stimuli-responsive drug release mode, rapid hemostatic performance and strong antibacterial property. The result of CUR release showed smart "ON-OFF" drug release mode. Antibacterial results verified strong antibacterial property up to 99.9 %. Hemolysis test showed that hemolysis ratio of 3D CS/PEO sponge-ZPC met the acceptable standard. The rapid hemostatic property was demonstrated by hemostatic test. High wound healing effect was confirmed in vivo. These results provide an important research basis for the design of new smart dressing.

Synthesis of Cu and CuO nanoparticles from e-waste and evaluation of their antibacterial and photocatalytic properties

Waste printed circuit boards (WPCBs) contain a plethora of valuable metals, considered an attractive secondary resource. In the current research, a hydrometallurgical process combined ammonia/ammonium chloride leaching and reduction (using L-ascorbic acid) to recover copper and its oxide (CuO) as nanosized particles from WPCBs was investigated. The results of leaching indicated that 96.7% of copper could be recovered at a temperature of 35 °C for a leaching duration of 2 h with ammonium chloride and ammonia concentration of 2 mol/L at a solid:liquid ratio of 1:10 g/cm3. The synthesized particles exhibit spherical and distorted sphere morphology with average particle size of 460 nm and 50 nm for Cu and CuO NPs, respectively. The antibacterial activity of Cu, CuO, and a (1:1) blend of both (Cu/CuO) has been examined against five different bacterial and fungal strains. The highest zone of inhibition was measured as 21.2 mm for Cu NPs toward Escherichia coli and 16.7 mm for Cu/CuO blend toward Bacillus cereus bacteria. The highest zone of inhibition was measured as 13 mm and 13.8 mm for Cu/CuO blend toward Fusarium proliferatum and Penicillium verrucosum fungi. Cu/CuO blend showed notable photocatalytic activity towards Rhodamine B dye under visible light irradiation with 96% degradation rate within 120 min. Using the process developed in this study, copper and its oxide as nanoparticles can be produced from WPCBs and used for multifunctional applications.

Antibacterial and biofilm-inhibiting cotton fabrics decorated with copper nanoparticles grown on graphene nanosheets

Infectious pathogens can be transmitted through textiles. Therefore, additional efforts are needed to develop functional fabrics containing antimicrobial substances to prevent the growth of antibiotic-resistant bacteria and their biofilms. Here, we developed a cotton fabric coated with reduced graphene oxide (rGO) and copper nanoparticles (Cu NPs), which possessed hydrophobic, antimicrobial, and anti-biofilm properties. Once the graphene oxide was dip-coated on a cellulose cotton fabric, Cu NPs were synthesized using a chemical reduction method to fabricate an rGO/Cu fabric, which was analyzed through FE-SEM, EDS, and ICP-MS. The results of our colony-forming unit assays indicated that the rGO/Cu fabric possessed high antibacterial and anti-biofilm properties against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, Corynebacterium xerosis, and Micrococcus luteus. Particularly, the fabric could inhibit the growth of E. coli, C. xerosis, and M. luteus with a 99% efficiency. Furthermore, our findings confirmed that the same concentrations of rGO/Cu had no cytotoxic effects against CCD-986Sk and Human Dermal Fibroblast (HDF), human skin cells, and NIH/3T3, a mouse skin cell. The developed rGO/Cu fabric thus exhibited promising applicability as a cotton material that can maintain hygienic conditions by preventing the propagation of various bacteria and sufficiently suppressing biofilm formation while also being harmless to the human body.

Antibacterial Biomaterial Based on Bioglass Modified with Copper for Implants Coating

Biofilm-related implant infections pose a substantial threat to patients, leading to inflammation in the surrounding tissue, and often resulting in implant loss and the necessity for additional surgeries. Overcoming this implantology challenge is crucial to ensure the success and durability of implants. This study shows the development of antibacterial materials for implant coatings by incorporating copper into 45S5 Bioglass^®. By combining the regenerative properties of Bioglass^® with the antimicrobial effects of copper, this material has the potential to prevent infections, enhance osseointegration and improve the long-term success of implants. Bioglasses modified with various concentrations of CuO (from 0 to 8 mol%) were prepared with the melt-quenching technique. Structural analysis using Raman and FTIR spectroscopies did not reveal significant alterations in the bioglasses structure with the addition of Cu. The antibacterial activity of the samples was assessed against Gram-positive and Gram-negative bacteria, and the results demonstrated significant inhibition of bacterial growth for the bioglass with 0.5 mol% of CuO. Cell viability studies indicated that the samples modified with up to 4 mol% of CuO maintained good cytocompatibility with the Saos-2 cell line at extract concentrations up to 25 mg/mL. Furthermore, the bioactivity assessment demonstrated the formation of a calcium phosphate (CaP)-rich layer on the surfaces of all bioglasses within 24 h. Our findings show that the inclusion of copper in the bioglass offers a significant enhancement in its potential as a coating material for implants, resulting in notable advancements in both antibacterial efficacy and osteointegration properties.

Toxicity Mechanisms of Copper Nanoparticles and Copper Surfaces on Bacterial Cells and Viruses

Copper is a metal historically used to prevent infections. One of the most relevant challenges in modern society are infectious disease outbreaks, where copper-based technologies can play a significant role. Currently, copper nanoparticles and surfaces are the most common antimicrobial copper-based technologies. Despite the widespread use of copper on nanoparticles and surfaces, the toxicity mechanism(s) explaining their unique antimicrobial properties are not entirely known. In general, toxicity effects described in bacteria and fungi involve the rupture of membranes, accumulation of ions inside the cell, protein inactivation, and DNA damage. A few studies have associated Cu-toxicity with ROS production and genetic material degradation in viruses. Therefore, understanding the mechanisms of the toxicity of copper nanoparticles and surfaces will contribute to developing and implementing efficient antimicrobial technologies to combat old and new infectious agents that can lead to disease outbreaks such as COVID-19. This review summarizes the current knowledge regarding the microbial toxicity of copper nanoparticles and surfaces and the gaps in this knowledge. In addition, we discuss potential applications derived from discovering new elements of copper toxicity, such as using different molecules or modifications to potentiate toxicity or antimicrobial specificity.

Copper oxide nanoparticles: In vitro and in vivo toxicity, mechanisms of action and factors influencing their toxicology

Copper oxide nanoparticles (CuO NPs) have received increasing interest due to their distinctive properties, including small particle size, high surface area, and reactivity. Due to these properties, their applications have been expanded rapidly in various areas such as biomedical properties, industrial catalysts, gas sensors, electronic materials, and environmental remediation. However, because of these widespread uses, there is now an increased risk of human exposure, which could lead to short- and long-term toxicity. This review addresses the underlying toxicity mechanisms of CuO NPs in cells which include reactive oxygen species generation, leaching of Cu ion, coordination effects, non-homeostasis effect, autophagy, and inflammation. In addition, different key factors responsible for toxicity, characterization, surface modification, dissolution, NPs dose, exposure pathways and environment are discussed to understand the toxicological impact of CuO NPs. In vitro and in vivo studies have shown that CuO NPs cause oxidative stress, cytotoxicity, genotoxicity, immunotoxicity, neurotoxicity, and inflammation in bacterial, algal, fish, rodents, and human cell lines. Therefore, to make CuO NPs a more suitable candidate for various applications, it is essential to address their potential toxic effects, and hence, more studies should be done on the long-term and chronic impacts of CuO NPs at different concentrations to assure the safe usage of CuO NPs.

Copolymer-Green-Synthesized Copper Oxide Nanoparticles Enhance Folate-Targeting in Cervical Cancer Cells In Vitro

Cervical cancer is fast becoming a global health crisis, accounting for most female deaths in low- and middle-income countries. It is the fourth most frequent cancer affecting women, and due to its complexity, conventional treatment options are limited. Nanomedicine has found a niche in gene therapy, with inorganic nanoparticles becoming attractive tools for gene delivery strategies. Of the many metallic nanoparticles (NPs) available, copper oxide NPs (CuONPs) have been the least investigated in gene delivery. In this study, CuONPs were biologically synthesized using Melia azedarach leaf extract, functionalized with chitosan and polyethylene glycol (PEG), and conjugated to the targeting ligand folate. A peak at 568 nm from UV-visible spectroscopy and the characteristic bands for the functional groups using Fourier-transform infrared (FTIR) spectroscopy confirmed the successful synthesis and modification of the CuONPs. Spherical NPs within the nanometer range were evident from transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). The NPs portrayed exceptional binding and protection of the reporter gene, pCMV-Luc-DNA. In vitro cytotoxicity studies revealed cell viability >70% in human embryonic kidney (HEK293), breast adenocarcinoma (MCF-7), and cervical cancer (HeLa) cells, with significant transgene expression, obtained using the luciferase reporter gene assay. Overall, these NPs showed favorable properties and efficient gene delivery, suggesting their potential role in gene therapy.

Engineered Cross-Linked Silane with Urea Polymer Thin Durable Coatings onto Polymeric Films for Controlled Antiviral Release of Activated Chlorine and Essential Oils

In March 2020, the World Health Organization announced a pandemic attributed to SARS-CoV-2, a novel beta-coronavirus, which spread widely from China. As a result, the need for antiviral surfaces has increased significantly. Here, the preparation and characterization of new antiviral coatings on polycarbonate (PC) for controlled release of activated chlorine (Cl+) and thymol separately and combined are described. Thin coatings were prepared by polymerization of 1-[3-(trimethoxysilyl)propyl] urea (TMSPU) in ethanol/water basic solution by modified Stöber polymerization, followed by spreading the formed dispersion onto surface-oxidized PC film using a Mayer rod with appropriate thickness. Activated Cl-releasing coating was prepared by chlorination of the PC/SiO2-urea film with NaOCl through the urea amide groups to form a Cl-amine derivatized coating. Thymol releasing coating was prepared by linking thymol to TMSPU or its polymer via hydrogen bonds between thymol hydroxyl and urea amide groups. The activity towards T4 bacteriophage and canine coronavirus (CCV) was measured. PC/SiO2-urea-thymol enhanced bacteriophage persistence, while PC/SiO2-urea-Cl reduced its amount by 84%. Temperature-dependent release is presented. Surprisingly, the combination of thymol and chlorine had an improved antiviral activity, reducing the amount of both viruses by four orders of magnitude, indicating synergistic activity. For CCV, coating with only thymol was inactive, while SiO2-urea-Cl reduced it below a detectable level.

Copper-based nanoparticles against microbial infections

Drug-resistant bacteria and highly infectious viruses are among the major global threats affecting the human health. There is an immediate need for novel strategies to tackle this challenge. Copper-based nanoparticles (CBNPs) have exhibited a broad antimicrobial capacity and are receiving increasing attention in this context. In this review, we describe the functionalization of CBNPs, elucidate their antibacterial and antiviral activity as well as applications, and briefly review their toxicity, biodistribution, and persistence. The limitations of the current study and potential solutions are also shortly discussed. The review will guide the rational design of functional nanomaterials for antimicrobial application. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease.

Virus Management Using Metal-Organic Framework-Based Technologies

The eradication and isolation of viruses are two concurrent approaches to protect ourselves from viral infections and diseases. The quite versatile porous materials called metal-organic frameworks (MOFs), have recently emerged as efficient nanosized tools to manage viruses, and several strategies to accomplish these tasks have been developed. This review describes these strategies employing nanoscale MOFs against SARS-CoV-2, HIV-1, tobacco mosaic virus, etc., which include the sequestration by host-guest penetration inside pores, mineralization, design of a physical barrier, controlled delivery of organic and inorganic antiviral drugs or bioinhibitors, photosensitization of singlet oxygen, and direct contact with inherently cytotoxic MOFs.

Recent advances of antibacterial starch-based materials

Starch has attracted a lot of attention because it is biodegradable, renewable, nontoxic and low cost. By adding antibacterial substances to starch, starch-based materials have antibacterial properties. The composite with other materials can improve the comprehensive performance of starch-based materials, thus broadening the application field of the material. In this paper, we focus on antibacterial starch-based materials and review their preparation and applications. It was found that antibacterial starch-based materials were most widely used in packaging, followed by medicine, and the research on smart starch-based materials was relatively less. This review may provide some reference value for subsequent studies of starch-based materials.

A Recent Update on the Impact of Nano-Selenium on Plant Growth, Metabolism, and Stress Tolerance

Selenium (Se) is a microelement that plays an important nutrient role by influencing various physiological and biochemical traits in plants. It has been shown to stimulate plant metabolism, enhancing secondary metabolites and lowering abiotic and biotic stress in plants. Globally, the enormous applications of nanotechnology in the food and agricultural sectors have vastly expanded. Nanoselenium is more active than bulk materials, and various routes of synthesis of Se nanoparticles (Se-NPs) have been reported in which green synthesis using plants is more attractive due to a reduction in ecological issues and an increase in biological activities. The Se-NP-based biofortification is more significant because it increases plant stress tolerance and positively impacts their metabolism. Se-NPs can enhance plant resistance to various oxidative stresses, promote growth, enhance soil nutrient status, enhance plant antioxidant levels, and participate in the transpiration process. Additionally, they use a readily available, biodegradable reducing agent and are ecologically friendly. This review concentrates on notable information on the different modes of Se-NPs' synthesis and characterization, their applications in plant growth, yield, and stress tolerance, and their influence on the metabolic process.

Structural Engineering of Ionic MOF@COF Heterointerface for Exciton-Boosting Sunlight-Driven Photocatalytic Filter

Sunlight-driven photocatalytic filters against pathogenic bioaerosols have attracted a lot of interest. However, developing an efficient interception system that shows enhanced visible-light harvesting, controllable charge dynamic, and boosted ROS generation remains a grand challenge. Here, we designed an ionic ZIF-8@iCOF nanocomposite as a sunlight-driven photocatalytic filter through elaborate structural engineering of the heterointerface between ZIF-8 and cationic iCOF layers. The photoactive experiments reveal significant improvements in the visible light absorption and sunlight-driven exciton-enhanced intersystem crossing to boost the generation of singlet oxygen (220%) and also obtain antibacterial efficiency of 99.99999% after 15 min irradiation. After combining with commercial polymer, resultant ZIF-8@iCOF/polyacrylonitrile (PAN) fibrous membranes exhibited high interception efficiency for both PM₁₀ and PM_2.5 (98%), being close to the commercial N95. This fibrous membrane also possesses good biocompatibility and strong elimination of bacteria under sunlight conditions, satisfying for the long-lasting contact usage. This finding not only showcases the promise of the porous materials-based fibrous membranes for efficient photocatalytic filter against pathogenic bioaerosols but also highlights the importance of accurate structural engineering for the advancement of sunlight-driven photocatalytic systems in environment and energy-related fields.