In situ antimicrobial behavior of materials with copper-based additives in a hospital environment

Advances in nanotechnology-assisted photodynamic therapy for neurological disorders: a comprehensive review

Neurological disorders such as neurodegenerative diseases and nervous system tumours affect more than one billion people throughout the globe. The physiological sensitivity of the nervous tissue limits the application of invasive therapies and leads to poor treatment and prognosis. One promising solution that has generated attention is Photodynamic therapy (PDT), which can potentially revolutionise the treatment landscape for neurological disorders. PDT attracted substantial recognition for anticancer efficacy and drug conjugation for targeted drug delivery. This review thoroughly explained the basic principles of PDT, scientific interventions and advances in PDT, and their complicated mechanism in treating brain-related pathologies. Furthermore, the merits and demerits of PDT in the context of neurological disorders offer a well-rounded perspective on its feasibility and challenges. In conclusion, this review encapsulates the significant potential of PDT in transforming the treatment landscape for neurological disorders, emphasising its role as a non-invasive, targeted therapeutic approach with multifaceted applications.

An Antimicrobial Copper-Plastic Composite Coating: Characterization and In Situ Study in a Hospital Environment

A method has been proposed for creating an operationally durable copper coating with antimicrobial properties for the buttons of electrical switches based on the gas dynamic spray deposition of copper on acrylonitrile butadiene styrene (ABS) plastic. It is shown that during the coating process, a polymer film is formed on top of the copper layer. Comparative in situ studies of microbial contamination have shown that the copper-coated buttons have a significant antimicrobial effect compared to standard buttons. Analysis of swabs over a 22-week study in a hospital environment showed that the frequency of contamination for a copper-coated button with various microorganisms was 2.7 times lower than that of a control button. The presented results allow us to consider the developed copper coating for plastic switches an effective alternative method in the fight against healthcare-associated infections.

Biocidal activity of multifunctional cuprite-doped anion exchanger - Influence of bacteria type and medium composition

The study presents unconventional, bifunctional, heterogeneous antimicrobial agents - Cu2O-loaded anion exchangers. The synergetic effect of a cuprous oxide deposit and polymeric support with trimethyl ammonium groups was studied against the reference strains of Enterococcus faecalis ATCC 29212 and Pseudomonas aeruginosa ATCC 27853. Biological testing (minimum bactericidal concentration, MBC), time- and dose-dependent bactericidal effect (under different conditions - medium composition and static/dynamic culture) demonstrated promising antimicrobial activity and confirmed its multimode character. The standard values of MBC, for all studied hybrid polymers and bacteria, were similar (64-128 mg/mL). However, depending on the medium conditions, due to the copper release into the bulk solution, bacteria were actively killed even at much lower doses of the hybrid polymer (25 mg/mL) and low Cu(II) concentrations in solution (0.01 mg/L). Simultaneously, confocal microscopic studies confirmed the effective inhibition of bacterial adhesion and biofilm formation on their surface. The studies conducted under different conditions showed also the influence of the structure and physical properties of studied materials on the biocidal efficacy and an antimicrobial action mechanism was proposed that could be significantly affected by electrostatic interactions and copper release to the solution. Although the antibacterial activity was also dependent on various strategies of bacterial cell resistance to heavy metals present in the aqueous medium, the studied hybrid polymers are versatile and efficient biocidal agents against bacteria of both types, Gram-positive and Gram-negative. Therefore, they can be a convenient alternative for point-of-use water disinfection systems providing water quality in medical devices such as dental units, spa equipment, and aesthetic devices used in the cosmetic sector.

Effectiveness of copper as a preventive tool in health care facilities. A systematic review

INTRODUCTION

Hospital-acquired infections (HAIs) are a significant clinical and economic burden on health systems worldwide. Copper alloys have been certified by the US EPA as solid antimicrobial materials, but their effectiveness in reducing HAIs is not well established OBJECTIVES: This systematic review aimed to assess copper surfaces in situ efficacy in reducing health care's microbial burden compared to control surfaces.

MATERIALS AND METHODS

A literature search was conducted using three electronic databases: Web of Science, PubMed, and Scopus, with the keywords "copper" and "surfaces" and "antimicrobial" and "antibacterial" and "infections." Studies from 2010 to 2022 were included. The quality of the studies was independently screened and assessed using the Newcastle Ottawa Scale.

RESULTS

A total of 56 articles were screened, with 8 included in the review and 7, added from references. Two third of the studies report a significant reduction in the microbial burden on copper objects compared to control objects. The 2 studies with the highest scores on NOS evaluation indicated that using copper or copper alloys in healthcare settings can effectively decrease the number of bacterial contaminations on touch surfaces.

CONCLUSIONS

The results suggest the potential effectiveness of copper as a preventive tool in healthcare facilities, but further studies and longer trials are needed to establish a relationship between copper and reduced nosocomial infections.

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.

Cellulosic fiber nanocomposite application review with zinc oxide antimicrobial agent nanoparticle: an opt for COVID-19 purpose

Cellulosic fiber (CF) in nanoform is emergingly finding its way for COVID-19 solution for instance via nanocomposite/nanoparticle from various abundant biopolymeric waste materials, which may not be widely commercialized when the pandemic strikes recently. The possibility is wide open but needs proper collection of knowledge and research data. Thus, this article firstly reviews CF produced from various lignocellulosic or biomass feedstocks' pretreatment methods in various nanoforms or nanocomposites, also serving together with metal oxide (MeO) antimicrobial agents having certain analytical reporting. CF-MeO hybrid product can be a great option for COVID-19 antimicrobial resistant environment to be proposed considering the long-established CF and MeO laboratory investigations. Secondly, a preliminary pH investigation of 7 to 12 on zinc oxide synthesis discussing on Fouriertransform infrared spectroscopy (FTIR) functional groups and scanning electron microscope (SEM) images are also presented, justifying the knowledge requirement for future stable nanocomposite formulation. In addition to that, recent precursors suitable for zinc oxide nanoparticle synthesis with emergingly prediction to serve as COVID-19 purposes via different products, aligning with CFs or nanocellulose for industrial applications are also reviewed.

Significance of additive manufacturing amidst the pandemic

In the light of COVID-19 pandemic, a global shortage for Personnel Protective Equipment (PPE) led to the search for an alternative to fill the gap where additive manufacturing made necessary development of rapid design and adaptive filtering masks for local manufacturing using 3D printing to help the frontline workers. The review focuses on the utilization of antimicrobial materials in additive manufacturing with the use of bespoke design to facilitate and respond to the disruptions in the medical supply chain. Previous studies confirmed the age-old theory of copper as an antimicrobial material with contact killing properties. The antimicrobial properties of copper have been registered at the U.S. Environmental Protection Agency as the first solid antimicrobial material. Combining the properties of copper in a PLA (Polylactic Acid) filament as a nano composite, Copper-3D facilitates the antimicrobial properties to any 3D printed object. Provided this flexibility of 3D printing, the use of masks designed distinctively based on the 3D scan of an individual's facial structures as an efficient Personnel Protective Equipment is also addressed. Additive manufacturing as a support to the shortage of medical devices and a responsive method to the disruption in the supply chain is discussed.

Stimuli-Activable Metal-Bearing Nanomaterials and Precise On-Demand Antibacterial Strategies

Bacterial infections remain the leading cause of death worldwide today. The emergence of antibiotic resistance has urged the development of alternative antibacterial technologies to complement or replace traditional antibiotic treatments. In this regard, metal nanomaterials have attracted great attention for their controllable antibacterial functions that are less prone to resistance. This review discusses a particular family of stimuli-activable metal-bearing nanomaterials (denoted as SAMNs) and the associated on-demand antibacterial strategies. The various SAMN-enabled antibacterial strategies stem from basic light and magnet activation, with the addition of bacterial microenvironment responsiveness and/or bacteria-targeting selectivity and therefore offer higher spatiotemporal controllability. The discussion focuses on nanomaterial design principles, antibacterial mechanisms, and antibacterial performance, as well as emerging applications that desire on-demand and selective activation (i.e., medical antibacterial treatments, surface anti-biofilm, water disinfection, and wearable antibacterial materials). The review concludes with the authors' perspectives on the challenges and future directions for developing industrial translatable next-generation antibacterial strategies.

Antibacterial Activity of Copper Particles Embedded in Knitted Fabrics

The composition and antibacterial properties of copper particles synthesized by a very simple reduction method were studied. For the preparation of particles in knitted fabrics, copper(II) sulfate was used as a precursor and ascorbic acid as a reducing natural agent. X-ray diffraction analysis showed the crystalline nature of the obtained particles. The round or oval particles and their agglomerates in knitted fabrics consisted of copper with traces of copper(I) oxide-cuprite. The element maps and energy dispersive X-ray spectra showed a high content of copper in the samples. The samples of wool and cotton knitted fabrics with copper particles had excellent antibacterial activity against gram-positive Staphylococcus aureus (S. aureus) and gram-negative Escherichia coli (E. coli) bacterial strains. The maximum zones of inhibition were 19.3 mm for S. aureus and 18.3 mm for E. coli using wool knitted fabric and 14.7 mm and 15.3 mm using cotton knitted fabric, respectively. The obtained results showed that the modified wool and cotton fabrics are suitable for use as inserts in reusable masks due to their noticeable and long-term activity against pathogenic bacteria.

Silver-Polymethylhydrosiloxane-Quaternary Ammonium Coating on Anodized Aluminum with Excellent Antibacterial Property

Multidrug-resistant bacteria are known to survive on high-touch surfaces for days, weeks, and months, contributing to the rise in nosocomial infections. Inducing antibacterial property in such surfaces can presumably reduce the overall microbial burden and subsequent nosocomial infections in hygiene critical environments. In the present study, a one-pot sol-gel process has been deployed to incorporate silver (Ag) and quaternary ammonium salt (QUAT) bactericides in a polymethylhydrosiloxane (PMHS) matrix. The Ag-PMHS-QUAT nanocomposite was coated on anodized aluminum (AAO/Al) by a simple ultrasound-assisted deposition process. The morphological features and chemical composition of the Ag-PMHS-QUAT nanocomposite have been characterized using SEM, XRD spectroscopy, and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) to confirm the formation of Ag-QUAT nanocomposites within the polymeric network of PMHS. The Ag-PMHS-QUAT nanocomposite coating on anodized aluminum oxide (AAO/Al) coupon exhibited superior antibacterial property with a 6-log bacterial reduction compared to the 5-log reduction for the commercially available antimicrobial copper coupon.

Nanotechnological interventions of the microbiome as a next-generation antimicrobial therapy

The rise of antimicrobial resistance (AMR) impacts public health due to the diminished potency of existing antibiotics. The microbiome plays an important role in the host's immune system activity and shows the history of exposure to antimicrobials and its manipulation in combating antimicrobial resistance. Advancements in gene technologies, DNA sequencing, and computational biology have emerged as powerful platforms to better understand the relationship between animals and microorganisms (MOs). The past few years have witnessed an increase in the use of nanotechnology, both in industry and in academia, as tools to tackle antimicrobial resistance. New strategies of microbiome manipulation have been developed, such as the use of prebiotics, probiotics, peptides, antibodies, an appropriate diet, phage therapy, and the use of various nanotechnological techniques. Owing to the research outcomes, targeted delivery of antimicrobials with some modifications with nanoparticles can lead to the destruction of resistant microbial cells. In addition, nanoparticles have been studied for their potential antimicrobial effects both in vitro and in vivo. In this review, we highlight key opportunistic areas for applying nanotechnologies with the aim of manipulating the microbiome for the treatment of antimicrobial resistance. Besides providing a detailed review on various nanomaterials, technologies, opportunities, technical needs, and potential approaches for the manipulation of the microbiome to address these challenges, we discuss future challenges and our perspective.

Development and In Vitro Validation of Antibacterial Paints Containing Chloroxylenol and Terpineol

The establishment of self-disinfecting surfaces is an important method to avoid surface contamination. Recently, paints with antimicrobial properties have been developed to be applied on different surfaces, avoiding contamination with pathogens. In this work, self-disinfecting paints containing Chloroxylenol (CLX), Terpineol (TRP), and a mixture of both substances were developed. The goal was to evaluate and validate these paints using international standards for eventual commercialization and application in scenarios where surface contamination represents a problem. The paints were challenged with five different bacteria, Gram-positive and Gram-negative, before and after a scrub resistance test, where the long-term efficacy of the paints was evaluated. The antibacterial activity assessment was performed following ISO 22196 and JIS Z2801. In general, the paints showed very promising results, demonstrating their antibacterial activity, before and after scrub resistance test. The paint incorporating the mixture of CLX and TRP (CLX+TRP) stood out by revealing consistent results of antibacterial activity both before and after the scrub resistance test for most of the tested bacteria. The cytotoxicity of the developed paints was assessed in vitro by performing tests by direct contact with a human skin cell line, HaCaT, and testes on extracts with HaCaT and a pulmonary cell line, A549. The methodologies for cytotoxicity assessment were developed based in ISO 10993. For genotoxicity assessment, alkaline comet assay was conducted on both cell lines. The cytotoxicity assessment revealed promising results with the paints, demonstrating values of cellular viability above 70% and values of lactate dehydrogenase (LDH) leakage below 30%. The genotoxic assessment also revealed acceptable values of primary DNA damage for the developed antibacterial paints. In general, the selected methodologies presented good potential to be applied in the validation of both efficacy and safety of the antimicrobial paints, aiming to be applied in real scenarios.

Anodized Aluminum Surface with Topography-Mediated Antibacterial Properties

Topography-mediated antibacterial surfaces that inactivate bacteria by physical contact have gained attention in recent years. Contrary to conventional antibacterial coatings, topography-mediated antibacterial surfaces do not suffer from coating instability and possible toxicity problems. In this study, a one-step hard anodization process has been deployed to fabricate a topography-mediated antibacterial aluminum surface. By optimizing anodization parameters, such as the concentration of the electrolyte, current density, and anodization time, desirable features of micronanoscale morphology were achieved. The optimum conditions of anodized aluminum that provided pores of a diameter of 151 ± 37 nm effectively killed 100% of E. coli bacteria.

Recent advances and applications of polymeric materials in healthcare sector and COVID-19 management

The coronavirus disease pandemic is considered at its worst and all nations are collectively fighting to improve global public health. In this outlook, polymers and their related materials (including plastics) are the primary sources in the manufacturing of medical and personal protective equipment. Plastics can be mass-produced, economical, and sterilized, which makes them an inevitable material in the medical and healthcare sector. Along with plastics, antibacterial and antiviral coatings, polymeric nanomaterials and nanocomposites, and functional polymers have become excellent materials for COIVD-19. This review centres on the applications of polymer materials in managing the COVID-19 outbreak. Moreover, the utilization of plastics with its healthcare applications are reviewed. Apart from this, major challenges and future directions of these materials have also been discussed. This review will help aspiring researchers to develop the basic understanding of polymeric materials currently employed in medical sector.

Past and Current Progress in the Development of Antiviral/Antimicrobial Polymer Coating towards COVID-19 Prevention: A Review

The astonishing outbreak of SARS-CoV-2 coronavirus, known as COVID-19, has attracted numerous research interests, particularly regarding fabricating antimicrobial surface coatings. This initiative is aimed at overcoming and minimizing viral and bacterial transmission to the human. When contaminated droplets from an infected individual land onto common surfaces, SARS-CoV-2 coronavirus is able to survive on various surfaces for up to 9 days. Thus, the possibility of virus transmission increases after touching or being in contact with contaminated surfaces. Herein, we aim to provide overviews of various types of antiviral and antimicrobial coating agents, such as antimicrobial polymer-based coating, metal-based coating, functional nanomaterial, and nanocomposite-based coating. The action mode for each type of antimicrobial agent against pathogens is elaborated. In addition, surface properties of the designed antiviral and antimicrobial polymer coating with their influencing factors are discussed in this review. This paper also exhibits several techniques on surface modification to improve surface properties. Various developed research on the development of antiviral/antimicrobial polymer coating to curb the COVID-19 pandemic are also presented in this review.

Antimicrobial coatings for environmental surfaces in hospitals: a potential new pillar for prevention strategies in hygiene

Recent reports provide evidence that contaminated healthcare environments represent major sources for the acquisition and transmission of pathogens. Antimicrobial coatings (AMC) may permanently and autonomously reduce the contamination of such environmental surfaces complementing standard hygiene procedures. This review provides an overview of the current status of AMC and the demands to enable a rational application of AMC in health care settings. Firstly, a suitable laboratory test norm is required that adequately quantifies the efficacy of AMC. In particular, the frequently used wet testing (e.g. ISO 22196) must be replaced by testing under realistic, dry surface conditions. Secondly, field studies should be mandatory to provide evidence for antimicrobial efficacy under real-life conditions. The antimicrobial efficacy should be correlated to the rate of nosocomial transmission at least. Thirdly, the respective AMC technology should not add additional bacterial resistance development induced by the biocidal agents and co- or cross-resistance with antibiotic substances. Lastly, the biocidal substances used in AMC should be safe for humans and the environment. These measures should help to achieve a broader acceptance for AMC in healthcare settings and beyond. Technologies like the photodynamic approach already fulfil most of these AMC requirements.

Occurrence, Antibiotic Resistance, Virulence Factors, and Genetic Diversity of Bacillus spp. from Public Hospital Environments in South Africa

This study aimed to assess the molecular dissemination of Bacillus species in public hospitals in South Africa. The study conducted over 3 months during 2017 involved representative samples obtained from three wards (general ward, intensive care unit, and pediatric unit) from four public hospitals denoted as A (Central), B (Tertiary), C (Regional), and D (District). Swabs collected from 11 distinct hospital surfaces were screened using selective media, biochemical testing, and molecular methods. Overall, 17% (135/777) isolates were identified with a prevalence of 24% (32/135) for central, 33% (45/135) for tertiary, 27% (36/135) for regional, and 16% (22/135) for district hospital. Bacillus species were further confirmed to belong to Bacillus cereus (129/135; 96%) and Bacillus subtilis (6/135; 4%). Prevalence was similar across the wards, averaging 33.3% (45/135). The highest prevalence of Bacillus isolates was found on the drip stands (11.8%), sink (11.8%), ward phone (11.5%), and nurses' tables (10.3%). Minimum inhibitory concentration analyses revealed high resistance to β-lactams, fluoroquinolones, and tetracyclines. The most common resistance genes detected were ermB (56%) and tetM (5%). Enterotoxin virulence genes hblA (77%) and hblD (88%) associated with the diarrheal syndrome were most detected; however, no ces genes (cereulide toxin) for emetic syndrome was found. The enterobacterial repetitive intergenic consensus PCR revealed considerable diversity at the different levels of health care, although the clonal spread of strains between the sites/wards within each specific hospital was revealed. The study highlighted the dissemination of drug-resistant Bacillus spp. in public hospital environments and calls for the design of optimal strategies to curb their spread.

Hospital Wastewater-Source of Specific Micropollutants, Antibiotic-Resistant Microorganisms, Viruses, and Their Elimination

Municipal wastewaters can generally provide real-time information on drug consumption, the incidence of specific diseases, or establish exposure to certain agents and determine some lifestyle consequences. From this point of view, wastewater-based epidemiology represents a modern diagnostic tool for describing the health status of a certain part of the population in a specific region. Hospital wastewater is a complex mixture of pharmaceuticals, illegal drugs, and their metabolites as well as different susceptible and antibiotic-resistant microorganisms, including viruses. Many studies pointed out that wastewater from healthcare facilities (including hospital wastewater), significantly contributes to higher loads of micropollutants, including bacteria and viruses, in municipal wastewater. In addition, such a mixture can increase the selective pressure on bacteria, thus contributing to the development and dissemination of antimicrobial resistance. Because many pharmaceuticals, drugs, and microorganisms can pass through wastewater treatment plants without any significant change in their structure and toxicity and enter surface waters, treatment technologies need to be improved. This short review summarizes the recent knowledge from studies on micropollutants, pathogens, antibiotic-resistant bacteria, and viruses (including SARS-CoV-2) in wastewater from healthcare facilities. It also proposes several possibilities for improving the wastewater treatment process in terms of efficiency as well as economy.

Antibacterial metals and alloys for potential biomedical implants

Metals and alloys, including stainless steel, titanium and its alloys, cobalt alloys, and other metals and alloys have been widely used clinically as implant materials, but implant-related infection or inflammation is still one of the main causes of implantation failure. The bacterial infection or inflammation that seriously threatens human health has already become a worldwide complaint. Antibacterial metals and alloys recently have attracted wide attention for their long-term stable antibacterial ability, good mechanical properties and good biocompatibility in vitro and in vivo. In this review, common antibacterial alloying elements, antibacterial standards and testing methods were introduced. Recent developments in the design and manufacturing of antibacterial metal alloys containing various antibacterial agents were described in detail, including antibacterial stainless steel, antibacterial titanium alloy, antibacterial zinc and alloy, antibacterial magnesium and alloy, antibacterial cobalt alloy, and other antibacterial metals and alloys. Researches on the antibacterial properties, mechanical properties, corrosion resistance and biocompatibility of antibacterial metals and alloys have been summarized in detail for the first time. It is hoped that this review could help researchers understand the development of antibacterial alloys in a timely manner, thereby could promote the development of antibacterial metal alloys and the clinical application.

Can Copper Products and Surfaces Reduce the Spread of Infectious Microorganisms and Hospital-Acquired Infections?

Pathogen transfer and infection in the built environment are globally significant events, leading to the spread of disease and an increase in subsequent morbidity and mortality rates. There are numerous strategies followed in healthcare facilities to minimize pathogen transfer, but complete infection control has not, as yet, been achieved. However, based on traditional use in many cultures, the introduction of copper products and surfaces to significantly and positively retard pathogen transmission invites further investigation. For example, many microbes are rendered unviable upon contact exposure to copper or copper alloys, either immediately or within a short time. In addition, many disease-causing bacteria such as E. coli O157:H7, hospital superbugs, and several viruses (including SARS-CoV-2) are also susceptible to exposure to copper surfaces. It is thus suggested that replacing common touch surfaces in healthcare facilities, food industries, and public places (including public transport) with copper or alloys of copper may substantially contribute to limiting transmission. Subsequent hospital admissions and mortality rates will consequently be lowered, with a concomitant saving of lives and considerable levels of resources. This consideration is very significant in times of the COVID-19 pandemic and the upcoming epidemics, as it is becoming clear that all forms of possible infection control measures should be practiced in order to protect community well-being and promote healthy outcomes.

Innovation in a Time of Crisis: A Systematic Review of Three-Dimensional Printing in the COVID-19 Pandemic

The coronavirus (COVID-19) global pandemic resulted in the breakdown of traditional supply chains responsible for providing essential equipment to hospitals and personal protective equipment (PPE) for health and social care workers. The three-dimensional (3D) printing community has responded to emerging need by recognizing shortages across health care systems and providing innovative solutions in real time, circumventing short-term global supply issues. A systematic review was undertaken to investigate the role of 3D printing in the COVID-19 pandemic in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using the MEDLINE, EMBASE, and World Health Organization (WHO) COVID-19 databases. Newspaper and internet article sources were identified using the NEXIS media database. All studies and articles on the application of 3D printed solutions during the peak of the COVID-19 pandemic were included. The literature search identified 26 related articles, and 13 studies met inclusion criteria and were suitable for full-text review. One thousand two hundred and one unique digital media articles were identified; after removal of duplicates and screening of headlines for the inclusion and exclusion criteria, 460 articles were suitable for full-text review. The cross-collaboration between the 3D printing community and health care systems has aided in the provision of innovative solutions to combat the COVID-19 crisis. The applications for 3D printing ranged from oxygenation equipment to noninvasive and invasive ventilatory parts and innovative solutions for infection control and quarantine hubs. This review has identified that 3D printing technology has made the biggest contribution to the production of PPE in particular face shields, mirroring the areas of greatest shortage and need. Additive manufacturing has played a pivotal role in aligning disciplines in engineering, science, and medicine for the greater good. We have witnessed the rapid reconfiguration of traditional supply chains to circumvent global shortages, while making advancements in effort to limit the impact of this and future pandemics.

Brief survey on organometalated antibacterial drugs and metal-based materials with antibacterial activity

Rising bacterial antibiotic resistance is a global threat. To deal with it, new antibacterial agents and antiseptic materials need to be developed. One alternative in this quest is the organometallic derivatization of well-established antibacterial drugs and also the fabrication of advanced metal-based materials having antibacterial properties. Metal-based agents and materials often show new modes of antimicrobial action which enable them to overcome drug resistance in pathogenic bacterial strains. This review summarizes recent (2017-2020) progress in the field of organometallic-derived antibacterial drugs and metal-based materials having antibacterial activity. Specifically, it covers organometallic derivatives of antibacterial drugs including β-lactams, ciprofloxacin, isoniazid, trimethoprim, sulfadoxine, sulfamethoxazole, and ethambutol as well as non-antibacterial drugs like metformin, phenformin and aspirin. Recent advances and reported clinical trials in the use of metal-based nanomaterials as antibiofouling coatings on medical devices, as photocatalytic agents in indoor air pollutant control, and also as photodynamic/photothermal antimicrobial agents are also summarized.

Copper-Modified Polymeric Membranes for Water Treatment: A Comprehensive Review

In the last decades, the incorporation of copper in polymeric membranes for water treatment has received greater attention, as an innovative potential solution against biofouling formation on membranes, as well as, by its ability to improve other relevant membrane properties. Copper has attractive characteristics: excellent antimicrobial activity, high natural abundance, low cost and the existence of multiple cost-effective synthesis routes for obtaining copper-based materials with tunable characteristics, which favor their incorporation into polymeric membranes. This study presents a comprehensive analysis of the progress made in the area regarding modified membranes for water treatment when incorporating copper. The notable use of copper materials (metallic and oxide nanoparticles, salts, composites, metal-polymer complexes, coordination polymers) for modifying microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), forward osmosis (FO) and reverse osmosis (RO) membranes have been identified. Antibacterial and anti-fouling effect, hydrophilicity increase, improvements of the water flux, the rejection of compounds capacity and structural membrane parameters and the reduction of concentration polarization phenomena are some outstanding properties that improved. Moreover, the study acknowledges different membrane modification approaches to incorporate copper, such as, the incorporation during the membrane synthesis process (immobilization in polymer and phase inversion) or its surface modification using physical (coating, layer by layer assembly and electrospinning) and chemical (grafting, one-pot chelating, co-deposition and mussel-inspired PDA) surface modification techniques. Thus, the advantages and limitations of these modifications and their methods with insights towards a possible industrial applicability are presented. Furthermore, when copper was incorporated into membrane matrices, the study identified relevant detrimental consequences with potential to be solved, such as formation of defects, pore block, and nanoparticles agglomeration during their fabrication. Among others, the low modification stability, the uncontrolled copper ion releasing or leaching of incorporated copper material are also identified concerns. Thus, this article offers modification strategies that allow an effective copper incorporation on these polymeric membranes and solve these hinders. The article finishes with some claims about scaling up the implementation process, including long-term performance under real conditions, feasibility of production at large scale, and assessment of environmental impact.

Long-term antibacterial composite via alginate aerogel sustained release of antibiotics and Cu used for bone tissue bacteria infection

Bone related-bacterial diseases including wound infections and osteomyelitis (OM) remain a serious problem accompanied with amputation in most severe cases. In this work, we report an exceptional effective antibacterial alginate aerogel, which consists of tigecycline (TGC) and octahedral Cu crystal as an organo-inorganic synergy platform for antibacterial and local infection therapy applications. The alginate aerogel could greatly prolong the release of copper ions and maintain effective antibacterial concentration over 18 days. The result of in-vitro experiments demonstrated that the alginate aerogel has an exceptional effective function on antibacterial activity. Cytotoxicity tests indicated that the alginate aerogel has low biological toxicity (average cell viability >75%). These remarkable results suggested that the alginate aerogel exhibits great potential for the treatment of OM, and has a prosperous future of application in bone tissue engineering.

Size-Controlled Transformation of Cu2O into Zero Valent Copper within the Matrix of Anion Exchangers via Green Chemical Reduction

Composite materials containing zero valent copper (ZVC) dispersed in the matrix of two commercially available strongly basic anion exchangers with a macroreticular (Amberlite IRA 900Cl) and gel-like (Amberlite IRA 402OH) structure were obtained. Cu0 particles appeared in the resin phase as the product of the reduction of the precursor, i.e., copper oxide(I) particles previously deposited in the two supporting materials. As a result of a one-step transformation of preformed Cu2O particles as templates conducted using green reductant ascorbic acid and under mild conditions, macroporous and gel-type hybrid products containing ZVC were obtained with a total copper content of 7.7 and 5.3 wt%, respectively. X-ray diffraction and FTIR spectroscopy confirmed the successful transformation of the starting oxide particles into a metallic deposit. A scanning electron microscopy study showed that the morphology of the deposit is mainly influenced by the type of matrix exchanger. In turn, the drying steps were crucial to its porosity and mechanical resistance. Because both the shape and size of copper particles and the internal structure of the supporting solid materials can have a decisive impact on the potential applications of the obtained materials, the results presented here reveal a great possibility for the design and synthesis of functional nanocrystalline solids.

DFC, Medina E, Sinche F, Santiago Vispo N, Dahoumane SA, Alexis F. Biomedical Science to Tackle the COVID-19 Pandemic: Current Status and Future Perspectives

The coronavirus infectious disease (COVID-19) pandemic emerged at the end of 2019, and was caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which has resulted in an unprecedented health and economic crisis worldwide. One key aspect, compared to other recent pandemics, is the level of urgency, which has started a race for finding adequate answers. Solutions for efficient prevention approaches, rapid, reliable, and high throughput diagnostics, monitoring, and safe therapies are needed. Research across the world has been directed to fight against COVID-19. Biomedical science has been presented as a possible area for combating the SARS-CoV-2 virus due to the unique challenges raised by the pandemic, as reported by epidemiologists, immunologists, and medical doctors, including COVID-19's survival, symptoms, protein surface composition, and infection mechanisms. While the current knowledge about the SARS-CoV-2 virus is still limited, various (old and new) biomedical approaches have been developed and tested. Here, we review the current status and future perspectives of biomedical science in the context of COVID-19, including nanotechnology, prevention through vaccine engineering, diagnostic, monitoring, and therapy. This review is aimed at discussing the current impact of biomedical science in healthcare for the management of COVID-19, as well as some challenges to be addressed.

Can Nanotechnology and Materials Science Help the Fight against SARS-CoV-2?

Since 2004, we have been developing nanomaterials with antimicrobial properties, the so-called nanoantimicrobials. When the coronavirus disease 2019 (COVID-19) emerged, we started investigating new and challenging routes to nanoantivirals. The two fields have some important points of contact. We would like to share with the readership our vision of the role a (nano)materials scientist can play in the fight against the COVID-19 pandemic. As researchers specifically working on surfaces and nanomaterials, in this letter we underline the importance of nanomaterial-based technological solutions in several aspects of the fight against the virus. While great resources are understandably being dedicated to treatment and diagnosis, more efforts could be dedicated to limit the virus spread. Increasing the efficacy of personal protection equipment, developing synergistic antiviral coatings, are only two of the cases discussed. This is not the first nor the last pandemic: our nanomaterials community may offer several technological solutions to challenge the ongoing and future global health emergencies. Readers' feedback and suggestions are warmly encouraged.

Copper stress in Staphylococcus aureus leads to adaptive changes in central carbon metabolism

Copper toxicity has been a long-term selection pressure on bacteria due to its presence in the environment and its use as an antimicrobial agent by grazing protozoa, by phagocytic cells of the immune system, and in man-made medical and commercial products. There is recent evidence that exposure to increased copper stress may have been a key driver in the evolution and spread of methicillin-resistant Staphylococcus aureus, a globally important pathogen that causes significant mortality and morbidity worldwide. Yet it is unclear how S. aureus physiology is affected by copper stress or how it adapts in order to be able to grow in the presence of excess copper. Here, we have determined quantitatively how S. aureus alters its proteome during growth under copper stress conditions, comparing this adaptive response in two different types of growth regime. We found that the adaptive response involves induction of the conserved copper detoxification system as well as induction of enzymes of central carbon metabolism, with only limited induction of proteins involved in the oxidative stress response. Further, we identified a protein that binds copper inside S. aureus cells when stressed by copper excess. This copper-binding enzyme, a glyceraldehyde-3-phosphate dehydrogenase essential for glycolysis, is inhibited by copper in vitro and inside S. aureus cells. Together, our data demonstrate that copper stress leads to the inhibition of glycolysis in S. aureus, and that the bacterium adapts to this stress by altering its central carbon utilisation pathways.

Iron-Doping of Copper Oxide Nanoparticles Lowers Their Toxic Potential on C6 Glioma Cells

Copper oxide nanoparticles (CuO-NPs) are well known for their cytotoxicity which in part has been attributed to the release of copper ions from CuO-NPs. As iron-doping has been reported to reduce the susceptibility of CuO-NPs to dissolution, we have compared pure CuO-NPs and CuO-NPs that had been doped with 10% iron (CuO-Fe-NPs) for copper release and for their toxic potential on C6 glioma cells. Physicochemical characterization revealed that dimercaptosuccinate (DMSA)-coated CuO-NPs and CuO-Fe-NPs did not differ in their size or zeta potential. However, the redox activity and liberation of copper ions from CuO-Fe-NPs was substantially slower compared to that from CuO-NPs, as demonstrated by cyclic voltammetry and by the photometric quantification of the copper ion-bathocuproine complex, respectively. Exposure of C6 cells to these NPs caused an almost identical cellular copper accumulation and each of the two types of NPs induced ROS production and cell toxicity. However, the time- and concentration-dependent loss in cell viability was more severe for cells that had been treated with CuO-NPs compared to cells exposed to CuO-Fe-NPs. Copper accumulation and toxicity after exposure to either CuO-NPs or CuO-Fe-NPs was prevented in the presence of copper chelators, while neutralization of the lysosomal pH by bafilomycin A1 prevented toxicity without affecting cellular copper accumulation or ROS production. These data demonstrate that iron-doping does not affect cellular accumulation of CuO-NPs and suggests that the intracellular liberation of copper ions from CuO-NPs is slowed by the iron doping, which in turn lowers the cell toxic potential of iron-doped CuO-NPs.

The effect of copper-oxide-treated soft and hard surfaces on the incidence of healthcare-associated infections: a two-phase study

BACKGROUND

Copper-oxide-impregnated linens and hard surfaces within the hospital environment have emerged as a novel technology to reduce environmental contamination and thereby potentially reduce the risk of healthcare-associated infections (HCAIs).

METHODS

This was a two-phase study. Phase 1 was a prospective, cluster-randomized, cross-over clinical trial in which one pod (eight beds) of our general ICU (GICU) utilized copper-oxide-impregnated linens whereas the other pod (eight beds) used standard hospital linens. Phase 2 was a two-year before-after study, following the relocation of three ICUs into a new ICU tower in which all the hard surfaces were treated with copper oxide (in addition to copper-impregnated linens). HCAIs were recorded using the National Healthcare Safety Network definitions.

FINDINGS

A total of 1282 patients were enrolled in phase 1. There was no difference in the rate of HCAI between the patients who received standard compared with copper oxide linen. In phase 2 there was a significant reduction in the number of infections due to Clostridioides difficile (2.4 per 1000 vs 0.7 per 1000 patient-days; incidence rate ratio: 3.3; 95% confidence interval: 1.4-8.7; P = 0.002) but no difference in the rate of central-line-associated bloodstream infections nor of catheter-associated urinary tract infections.

CONCLUSION

Copper-oxide-impregnated linens alone had no effect on the rate of HCAI. Our data suggest that copper-oxide-treated hard surfaces reduced the rate of infections due to C. difficile; however, important confounders cannot be excluded.

In vitro evaluation of antimicrobial efficacy and durability of three copper surfaces used in healthcare

Antimicrobial properties of solid copper (Cu) surfaces against various microorganisms have been demonstrated, but little is known about the durability and relative antimicrobial efficacy of different Cu formulations currently used in healthcare. The aim of this study was to assess whether three different formulations of copper-bearing alloys (integral, spray-on and Cu-impregnated surfaces) and a stainless steel control differed in their antimicrobial efficacy, durability, and compatibility with hospital-grade cleaner/disinfectants. The U.S. Environmental Protection Agency draft protocol for the evaluation of bactericidal activity of Cu containing alloys was modified to more accurately reflect cleaning methods in healthcare. The three different Cu alloys were evaluated using 25 × 25 × 3 mm disks subjected to one year of simulated cleaning and disinfection using the Wiperator™ with microfiber cloths presoaked in three common hospital disinfectants: accelerated hydrogen peroxide, quaternary ammonium, or sodium hypochlorite solutions. Bactericidal activity was evaluated using Staphylococcus aureus and Pseudomonas aeruginosa. While all Cu formulations exhibited some antimicrobial activity, integral and spray-on Cu alloys showed the greatest efficacy. Assessments of durability included documentation of changes in mass, morphological changes by scanning electron microscopy, chemical composition alteration by energy-dispersive x-ray spectroscopy, and surface roughness alteration using profilometry over one year of simulated use. The integral Cu alloy had the least mass loss (0.20% and 0.19%) and abrasion-corrosion rate (6.28 and 6.09 μm/yr) compared to stainless steel. The integral product also showed the highest durability. Exposure to disinfectants affected both the antimicrobial efficacy and durability of the various copper products.

Importance of Surface Coating to Accumulation Dynamics and Acute Toxicity of Copper Nanomaterials and Dissolved Copper in Daphnia magna

We evaluated the effect of copper oxide nanomaterials (CuO NMs), uncoated and with 3 different surface coatings (carboxylated, pegylated, and ammonia groups), on acute toxicity and accumulation dynamics in Daphnia magna. With the use of biodynamic modelling, biosorption and elimination rate constants were determined for D. magna following waterborne exposure to dissolved Cu and CuO NMs. The relationship between modeled parameters and acute toxicity endpoints was evaluated to investigate whether accumulation dynamics parameters could be used as a predictor of acute toxicity. The Langmuir equation was used to characterize the biosorption dynamics of Cu NMs and Cu chloride, used as dissolved Cu control. Uptake rates showed the following NM rankings: pristine-CuO > NH₃ -CuO > aqueous Cu > polyethylene glycol (PEG)-CuO > COOH-CuO. To determine Cu elimination by D. magna, a one-compartment model was used. Different elimination rate constants were estimated for each chemical substance tested. Those that were easily biosorbed were also easily removed from organisms. Biosorption and depuration properties of NMs were correlated with zeta potential values and diameters of NM agglomerates in the suspensions. No link was found between biosorption and toxicity. Waterborne exposures to more difficult-to-biosorb CuO NMs were more likely to induce adverse effects than those that biosorbed easily. It is proposed that some physicochemical properties of NMs in media, including zeta potential and agglomerate diameter, can lead to higher biosorption but do not necessarily affect toxicity. The mode of interaction of the NMs with the organism seems to be complex and to depend on chemical speciation and physicochemical properties of the NMs inside an organism. Moreover, our findings highlight that coating type affects the biosorption dynamics, depuration kinetics, and dissolution rate of NMs in media. Environ Toxicol Chem 2020;39:287-299. © 2019 SETAC.

Design and antibacterial activity assessment of “green” synthesized 1,4-disubstituted 1,2,3-triazoles via an Fe3O4/silicalite-1/PVA/Cu(i) nanocomposite catalyzed three component reaction

The preparation of an Fe₃O₄/silicalite-1/PVA/Cu(i) bionanocomposite is presented, completely characterized and applied for the green synthesis of 1,4-disubstituted-1,2,3-triazoles.

Gene expression is influenced due to 'nano' and 'ionic' copper in pre-formed Pseudomonas aeruginosa biofilms

Today, researchers across the globe suggest the use of antimicrobial coatings containing copper nanoparticles (CuNPs) complementing the traditional protocols to prevent hospital-acquired infections (HAIs). Since Pseudomonas aeruginosa is one of the commonest opportunistic pathogens, we assessed the anti-biofilm activity of CuNPs in P. aeruginosa MTCC 3541 and compared it with Cu²⁺ (copper sulphate) since the latter continues to be used as an antimicrobial-of-choice in food industries, agriculture and water treatment. In this study, we synthesized and characterized stable poly-acrylic acid (PAA) coated CuNPs with a size of 66-150 nm and zeta potential -13 mV. Pseudomonas aeruginosa MTCC 3541 biofilms were highly resistant to both CuNPs and Cu²⁺ (minimum biofilm inhibitory concentration, MBIC 300 and >600 μg/mL respectively). Scanning electron microscopy revealed alterations in cell morphology upon treatment with CuNPs. A closer analysis of the biofilm-specific gene expression (qRT-PCR) revealed that CuNPs downregulated the genes involved in biofilm matrix formation, motility, efflux, membrane lipoprotein synthesis and DNA replication. Both, CuNPs and Cu²⁺ up regulated copper resistance and biofilm dispersion genes. Copper did not affect the bacterial communication system as evidenced by downregulation of the negative regulator of quorum sensing. The gene expression analysis reveals multiple cellular targets for CuNPs and ionic Cu. The present study highlights the fact that CuNPs affect the membrane functions adversely damaging the cell surface. In pre-formed biofilms, CuNPs were more toxic and displayed distinct responses attributable due to 'nano' and 'ionic' copper. Our findings thus support the use of CuNPs for curbing HAIs.

Anti-Biofouling and Desalination Properties of Thin Film Composite Reverse Osmosis Membranes Modified with Copper and Iron Nanoparticles

The anti-biofouling and desalination properties of thin film composite reverse osmosis membranes (TFC-RO), modified by the incorporation of copper and iron nanoparticles, were compared. Nanoparticles of metallic copper (CuNPs) and an iron crystalline phase mix (Fe and Fe₂O₃, FeNPs) were obtained by oxide-reduction-precipitation and reduction reactions, respectively, and characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. Modified membranes (PA+0.25Cu-PSL and PA+0.25Fe-PSL) were obtained by incorporating these nanoparticles during the interfacial polymerization process (PI). These membranes were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and contact angle measurements. Bactericidal tests by a Colony Forming Unit (CFU) were performed using Escherichia coli, and anti-adhesion properties were confirmed by fluorescence microscopy estimating the percentage of live/dead cells. The permeate flow and rejection of salts was evaluated using a crossflow cell. An increase of the membrane’s roughness on the modified membrane was observed, influencing the desalination performance more strongly in the presence of the FeNPs with respect to the CuNPs. Moreover, a significant bactericidal and anti-adhesion effect was obtained in presence of both modifications with respect to the pristine membrane. An important decrease in CFU in the presence of modified membranes of around 98% in both modifications was observed. However, the anti-adhesion percentage and reduction of live/dead cells were higher in the presence of the copper-modified membrane in comparison to the iron-modified membrane. These facts were attributed to the differences in antimicrobial action mechanism of these types of nanoparticles. In conclusion, TFC-RO membranes modified by the incorporation of CuNPs during PI represent one alternative material to attend to the biofouling impact in the desalination process.

Copper metal-organic frameworks loaded on chitosan film for the efficient inhibition of bacteria and local infection therapy

Although multiple advanced antibacterial and sterilization materials are available, bacterial infections still remain a big challenge in wound healing as they usually induce serious complications and cannot be thoroughly eliminated. Herein, we report an antibacterial film composed of the naturally derived polysaccharide chitosan (CS) and a copper metal-organic framework (HKUST-1) as a multifunctional platform for antibacterial and local infection therapy applications. As expected, the as-prepared HKUST-1/CS film possessed versatile abilities such as slow release of copper ions and reduced cytotoxicity; moreover, fluorescent staining and morphological changes of the bacteria treated with the HKUST-1/CS film confirmed the antibacterial activity of the fabricated film. Furthermore, in vivo results revealed that the HKUST-1/CS film could simultaneously kill bacteria and promote vessel regeneration; this resulted in an enhanced wound closure rate during the local infection therapy process. Overall, these results highlight that the HKUST-1/CS film exhibits significant potential as a suitable and promising wound dressing.

Antibacterial and antioxidant potential of biosynthesized copper nanoparticles mediated through Cissus arnotiana plant extract

Environment friendly methods for the synthesis of copper nanoparticles have become a valuable trend in the current scenario. The utilization of phytochemicals from plant extracts has become a unique technology for the synthesis of nanoparticles, as they possess dual nature of reducing and capping agents to the nanoparticles. In the present investigation we have synthesized copper nanoparticles (CuNPs) using a rare medicinal plant Cissus arnotiana and evaluated their antibacterial activity against gram negative and gram positive bacteria. The morphology and characterization of the synthesized CuNPs were studied and done using UV-Visible spectroscopy at a wavelength range of 350-380 nm. XRD studies were performed for analyzing the crystalline nature; SEM and TEM for evaluating the spherical shape within the size range of 60-90 nm and AFM was performed to check the surface roughness. The biosynthesized CuNPs showed better antibacterial activity against the gram-negative bacteria, E. coli with an inhibition zone of 22.20 ± 0.16 mm at 75 μg/ml. The antioxidant property observed was comparatively equal with the standard antioxidant agent ascorbic acid at a maximum concentration of 40 μg/ ml. This is the first study reported on C. arnotiana mediated biosynthesis of copper nanoparticles, where we believe that the findings can pave way for a new direction in the field of nanotechnology and nanomedicine where there is a significant potential for antibacterial and antioxidant activities. We predict that, these could lead to an exponential increase in the field of biomedical applications, with the utilization of green synthesized CuNPs, due to its remarkable properties. The highest antibacterial property was observed with gram-negative strains mainly, E. coli, due to its thin peptidoglycan layer and electrostatic interactions between the bacterial cell wall and CuNPs surfaces. Hence, CuNPs can be potent therapeutic agents in several biomedical applications, which are yet to be explored in the near future.

Specificity in the Susceptibilities of Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus Clinical Isolates to Six Metal Antimicrobials

In response to the occurrence of antibiotic resistance, there has been rapid developments in the field of metal-based antimicrobials. Although it is largely assumed that metals provide broad-spectrum microbial efficacy, studies have shown that this is not always the case. Therefore, in this study, we compared the susceptibilities of 93 clinical isolates belonging to the species Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus against six metals, namely aluminum, copper, gallium, nickel, silver and zinc. To provide qualitative comparative information, the resulting zones of growth inhibition were compared to the minimal inhibitory concentrations of three indicator strains E. coli ATCC 25922, P. aeruginosa ATCC 27853 and S. aureus ATCC 25923. Here, we demonstrate that the metal efficacies were species- and isolate-specific. Only several isolates were either resistant or sensitive to all of the six metals, with great variability found between isolates. However, the greatest degree of similarity was found with the E. coli isolates. In contrast, the susceptibilities of the remaining two collections, S. aureus and P. aeruginosa, were more highly dispersed. Using this information, we have shown that metals are not equal in their efficacies. Hence, their use should be tailored against a particular microorganism and care should be taken to ensure the use of the correct concentration.