Nanoparticles (NPs) are increasingly used to target bacteria as an alternative to antibiotics. Nanotechnology may be particularly advantageous in treating bacterial infections. Examples include the utilization of NPs in antibacterial coatings for implantable devices and medicinal materials to prevent infection and promote wound healing, in antibiotic delivery systems to treat disease, in bacterial detection systems to generate microbial diagnostics, and in antibacterial vaccines to control bacterial infections. The antibacterial mechanisms of NPs are poorly understood, but the currently accepted mechanisms include oxidative stress induction, metal ion release, and non-oxidative mechanisms. The multiple simultaneous mechanisms of action against microbes would require multiple simultaneous gene mutations in the same bacterial cell for antibacterial resistance to develop; therefore, it is difficult for bacterial cells to become resistant to NPs. In this review, we discuss the antibacterial mechanisms of NPs against bacteria and the factors that are involved. The limitations of current research are also discussed.

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The antimicrobial activity of nanoparticles: present situation and prospects for the future

In materials science, “green” synthesis has gained extensive attention as a reliable, sustainable, and eco-friendly protocol for synthesizing a wide range of materials/nanomaterials including
 metal/metal oxides nanomaterials, hybrid materials, and bioinspired materials. As such, green synthesis is regarded as an important tool to reduce the destructive effects associated with the traditional methods of synthesis for nanoparticles commonly utilized in laboratory and industry. In this review, we summarized the fundamental processes and mechanisms of “green” synthesis approaches, especially for metal and metal oxide [e.g., gold (Au), silver (Ag), copper oxide (CuO), and zinc oxide (ZnO)] nanoparticles using natural extracts. Importantly, we explored the role of biological components, essential phytochemicals (e.g., flavonoids, alkaloids, terpenoids, amides, and aldehydes) as reducing agents and solvent systems. The stability/toxicity of nanoparticles and the associated surface engineering techniques for achieving biocompatibility are also discussed. Finally, we covered applications of such synthesized products to environmental remediation in terms of antimicrobial activity, catalytic activity, removal of pollutants dyes, and heavy metal ion sensing.

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‘Green’ synthesis of metals and their oxide nanoparticles: applications for environmental remediation

In the last decade we have witnessed a dramatic increase in the proportion and absolute number of bacterial pathogens resistant to multiple antibacterial agents. Multidrug-resistant bacteria are currently considered as an emergent global disease and a major public health problem. The B-Debate meeting brought together renowned experts representing the main stakeholders (i.e. policy makers, public health authorities, regulatory agencies, pharmaceutical companies and the scientific community at large) to review the global threat of antibiotic resistance and come up with a coordinated set of strategies to fight antimicrobial resistance in a multifaceted approach. We summarize the views of the B-Debate participants regarding the current situation of antimicrobial resistance in animals and the food chain, within the community and the healthcare setting as well as the role of the environment and the development of novel diagnostic and therapeutic strategies, providing expert recommendations to tackle the global threat of antimicrobial resistance.

https://wrap.warwick.ac.uk/67444/1/WRAP_main.pdf

The global threat of antimicrobial resistance: science for intervention

Biofilm is a complex structure of microbiome having different bacterial colonies or single type of cells in a group; adhere to the surface. These cells are embedded in extracellular polymeric substances, a matrix which is generally composed of eDNA, proteins and polysaccharides, showed high resistance to antibiotics. It is one of the major causes of infection persistence especially in nosocomial settings through indwelling devices. Quorum sensing plays an important role in regulating the biofilm formation. There are many approaches being used to control infections by suppressing its formation but CRISPR-CAS (gene editing technique) and photo dynamic therapy (PDT) are proposed to be used as therapeutic approaches to subside bacterial biofim infections, especially caused by deadly drug resistant bad bugs.

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Antibiotics versus biofilm: an emerging battleground in microbial communities

Despite numerous existing potent antibiotics and other antimicrobial means, bacterial infections are still a major cause of morbidity and mortality. Moreover, the need to develop additional bactericidal means has significantly increased due to the growing concern regarding multidrug-resistant bacterial strains and biofilm associated infections. Consequently, attention has been especially devoted to new and emerging nanoparticle-based materials in the field of antimicrobial chemotherapy. The present review discusses the activities of nanoparticles as an antimicrobial means, their mode of action, nanoparticle effect on drug-resistant bacteria, and the risks attendant on their use as antibacterial agents. Factors contributing to nanoparticle performance in the clinical setting, their unique properties, and mechanism of action as antibacterial agents are discussed in detail.

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Alternative Antimicrobial Approach: Nano-Antimicrobial Materials

Nanotechnology as a therapeutic tool to combat microbial resistance.

Topical hypochlorous acid (HOCl) has recently been proposed as a treatment of pruritus. However, it is not known whether topical HOCl decreases or promotes pruritus. This review sheds light on this poorly understood subject. This article describes the pathophysiology of pruritus, current treatments of pruritus, and how pH determines the properties of HOCl in solution. The article then proposes two mechanisms by which HOCl may reduce pruritus: 1) HOCl is microbicidal to cutaneous pathogens, especially Staphylococcus aureus in atopic dermatitis; 2) HOCl is anti-inflammatory and reduces the activities of histamine, leukotriene B4, and interleukin-2, all of which are implicated in the pathophysiology of itch. Lastly, this article describes conditions under which HOCl may actually cause pruritus as an adverse effect. For example, HOCl increases the activity of nerve growth factor, which promotes itch. Prolonged or high-dose HOCl exposure may also cause irritant contact dermatitis, or less commonly, allergic contact dermatitis.

/pdf/topical-hypochlorous-acid-hocl-as-a-potential-treatment-of-31trdl52pp.pdf

Topical Hypochlorous Acid (HOCl) as a Potential Treatment of Pruritus

/pdf/s-nitrosocaptopril-nanoparticles-as-nitric-oxide-liberating-1b98mpas8n.pdf

Robert Y. Pelgrift

Papers

Nanotechnology as a therapeutic tool to combat microbial resistance.

Topical Hypochlorous Acid (HOCl) as a Potential Treatment of Pruritus

S-nitrosocaptopril nanoparticles as nitric oxide-liberating and transnitrosylating anti-infective technology