In vitro assessment of antimicrobial, antibiofilm and larvicidal activities of bioactive nickel metal organic framework

Novel Fabrication of Bio-polymeric Nanogel Loaded with Nalidixic Acid Formulations for the Effective Prevention of Bacterial Pathogens Leading Urinary Tract Infection and Its Biosafety Evaluation

Management of urinary tract infections (UTI) is a highly challenging process due to the biofilm-forming ability of human-pathogenic bacteria. Here, we designed to fabricate an effective nanogel with a combination of chitosan bio-polymer and nalidixic acid to prevent biofilm-forming bacterial pathogens. Chitosan-coated nalidixic acid nanogel (NA@CS) exhibits outstanding inhibition potential against bacterial strains. In vitro, anti-bacterial analysis methods (well diffusion, colony-forming assay, and anti-biofilm assay) were performed to study the bacterial inhibition potential of prepared nanogel, which reveals that NA@CS nanogel have greater inhibition potential against selected pathogens. The combination of nalidixic acid with chitosan biopolymer decreases the virulence and pathogenicity of biofilm-forming pathogens due to their ability to membrane phospholipids penetration. Furthermore, the fabricated NA@CS nanogel showed reliable in vitro bio-compatibility on L929 fibroblast cells and in vivo compatibility with Artemia salina animal model. Overall, the results demonstrate that NA@CS nanogel could be an effective therapeutic for treating urinary tract infections and urine bladder wound healing.

Antibacterial, antibiofilm, and antioxidant activities of two novel metal-organic frameworks (MOFs) based on 4,6-diamino-2-pyrimidinethiol with Zn and Co metal ions as coordination polymers

In the present era, the increase in free radical species (FRs) and multidrug-resistant (MDR) bacteria represents a major worldwide concern for public health. Biofilm development and the overuse and misuse of antibiotics could lead to the adaptation of bacteria to antimicrobial agents. Consequently, finding novel multifunctional species with antibacterial, antioxidant, and antibiofilm properties has become crucial in the fight against challenging bacterial infections and chronic inflammatory conditions. Metal-organic frameworks (MOFs) with zinc and cobalt metal centers are widely utilized in biological and environmental remediation owing to their versatility. In this study, multifunctional Zn-MOFs and Co-MOFs were successfully synthesized with zinc and cobalt as metal centers and 4,6-diamino-2-pyrimidinethiol as an organic linker using a hydrothermal technique. Numerous characterization techniques were used to fully examine the MOF structure, functionality, chemical makeup, crystalline structure, surface appearance, thermal behavior, and magnetic characteristics; the techniques included XPS, PXRD, FTIR, FESEM, EDX, UV-visible, BET, BJH, TGA/DTG, DSC, and magnetic susceptibility measurement. The antioxidant, antibacterial, and antibiofilm activities of the MOFs were examined, and they demonstrated potent activity in each of these aspects. The proposed mechanisms of antibacterial activity suggest that bacterial cell death results from multiple toxic effects, including electrostatic interaction and lipid peroxidation, when MOFs are attached to bacteria, leading to the formation of reactive oxygen species (ROSs). Zn-MOFs exhibit high antibacterial and antibiofilm efficacy owing to their large surface-to-volume ratio and porous nature, while Co-MOFs exhibit high antioxidant capacity owing to their redox properties.

Nano-Bio Interactions: Biofilm-Targeted Antibacterial Nanomaterials

Biofilm is a spatially organized community formed by the accumulation of both microorganisms and their secretions, leading to persistent and chronic infections because of high resistance toward conventional antibiotics. In view of the tunable physicochemical properties and the related unique biological behavior (e.g., size-, shape-, and surface charge-dependent penetration, protein corona endowed targeting, catalytic- and electronic-related oxidative stress, optical- and magnetic-associated hyperthermia, etc.), nanomaterials-based therapeutics are widely used for the treatment of biofilm-associated infections. In this review, the biological characteristics of biofilm are introduced. And the nanomaterials-based antibacterial strategies are further discussed via biofilm targeting, including preventing biofilm formation, enhancing biofilm penetration, disrupting the mature biofilm, and acting as drug delivery systems. In which, the interactions between biofilm and nanomaterials include mechanical disruption, electron transfer, enzymatic degradation, oxidative stress, and hyperthermia. Additionally, the current advances of nanomaterials for antibacterial nanomaterials by biofilm targeting are summarized. This review aims to present a complete vision of antibacterial nanomaterials-biofilm (nano-bio) interactions, paving the way for the future development and clinical translation of effective antibacterial nanomedicines.

Novel metal peroxide nanoboxes restrain Clostridioides difficile infection beyond the bactericidal and sporicidal activity

Clostridioides difficile spores are considered as the major source responsible for the development of C. difficile infection (CDI), which is associated with an increased risk of death in patients and has become an important issue in infection control of nosocomial infections. Current treatment against CDI still relies on antibiotics, which also damage normal flora and increase the risk of CDI recurrence. Therefore, alternative therapies that are more effective against C. difficile bacteria and spores are urgently needed. Here, we designed an oxidation process using H2O2 containing PBS solution to generate Cl- and peroxide molecules that further process Ag and Au ions to form nanoboxes with Ag-Au peroxide coat covering Au shell and AgCl core (AgAu-based nanoboxes). The AgAu-based nanoboxes efficiently disrupted the membrane structure of bacteria/spores of C. difficile after 30-45 min exposure to the highly reactive Ag/Au peroxide surface of the nano structures. The Au-enclosed AgCl provided sustained suppression of the growth of 2 × 107 pathogenic Escherichia coli for up to 19 days. In a fecal bench ex vivo test and in vivo CDI murine model, biocompatibility and therapeutic efficacy of the AuAg nanoboxes to attenuate CDI was demonstrated by restoring the gut microbiota and colon mucosal structure. The treatment successfully rescued the CDI mice from death and prevented their recurrence mediated by vancomycin treatment. The significant outcomes indicated that the new peroxide-derived AgAu-based nanoboxes possess great potential for future translation into clinical application as a new alternative therapeutic strategy against CDI.

Double Immobilized Superhydrophobic and Lubricated Slippery Surface with Antibacterial and Antifouling Properties

A "double immobilized" superhydrophobic and lubricated slippery surface was prepared by simultaneously immobilizing lubricating oil and bactericide molecules. The coordination function of metal organic frameworks (MOFs) was utilized to immobilize trimesic acid, a fungicide, as a ligand of the MOF by the cathodic electrodeposition technique. Aminated silicone oil was used as a lubricating oil and was immobilized to the superhydrophobic MOF film by the curing reaction with isocyanates. This technique is a facile strategy to conductive substrates for fabricating superhydrophobic and lubricated slippery surfaces with satisfactory antibacterial and antifouling properties.

ZnO-Doped Metal-Organic Frameworks Nanoparticles: Antibacterial Activity and Mechanisms

Metal-Organic Frameworks (MOFs) offer new ideas for the design of antibacterial materials because of their antibacterial properties, high porosity and specific surface area, low toxicity and good biocompatibility compared with other nanomaterials. Herein, a novel antimicrobial nanomaterial, MIL-101(Fe)@ZnO, has been synthesized by hydrothermal synthesis and characterized by FTIR, UV-vis, ICP-OES, XRD, SEM, EDS and BET to show that the zinc ions are doped into the crystal lattice of MIL-101(Fe) to form a Fe-Zn bimetallic structure. MIL-101(Fe)@ZnO was found to be effective against a wide range of antibacterial materials including Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Acinetobacter junii and Staphylococcus epidermidis. It has a significant antibacterial effect, weak cytotoxicity, high safety performance and good biocompatibility. Meanwhile, MIL-101(Fe)@ZnO was able to achieve antibacterial effects by causing cells to produce ROS, disrupting the cell membrane structure, and causing protein leakage and lipid preoxidation mechanisms. In conclusion, MIL-101(Fe)@ZnO is an easy-to-prepare antimicrobial nanomaterial with broad-spectrum bactericidal activity and low toxicity.

Metal-Organic Frameworks and Their Biodegradable Composites for Controlled Delivery of Antimicrobial Drugs

Antimicrobial resistance (AMR) is a growing global crisis with an increasing number of untreatable or exceedingly difficult-to-treat bacterial infections, due to their growing resistance to existing drugs. It is predicted that AMR will be the leading cause of death by 2050. In addition to ongoing efforts on preventive strategies and infection control, there is ongoing research towards the development of novel vaccines, antimicrobial agents, and optimised diagnostic practices to address AMR. However, developing new therapeutic agents and medicines can be a lengthy process. Therefore, there is a parallel ongoing worldwide effort to develop materials for optimised drug delivery to improve efficacy and minimise AMR. Examples of such materials include functionalisation of surfaces so that they can become self-disinfecting or non-fouling, and the development of nanoparticles with promising antimicrobial properties attributed to their ability to damage numerous essential components of pathogens. A relatively new class of materials, metal-organic frameworks (MOFs), is also being investigated for their ability to act as carriers of antimicrobial agents, because of their ultrahigh porosity and modular structures, which can be engineered to control the delivery mechanism of loaded drugs. Biodegradable polymers have also been found to show promising applications as antimicrobial carriers; and, recently, several studies have been reported on delivery of antimicrobial drugs using composites of MOF and biodegradable polymers. This review article reflects on MOFs and polymer-MOF composites, as carriers and delivery agents of antimicrobial drugs, that have been studied recently, and provides an overview of the state of the art in this highly topical area of research.

Facile Fabrication of Methyl Gallate Encapsulated Folate ZIF-L Nanoframeworks as a pH Responsive Drug Delivery System for Anti-Biofilm and Anticancer Therapy

Zeolitic imidazole frameworks are emerging materials and have been considered an efficient platform for biomedical applications. The present study highlights the simple fabrication of methyl gallate encapsulated folate-ZIF-L nanoframeworks (MG@Folate ZIF-L) by a simple synthesis. The nanoframeworks were characterized by different sophisticated instruments. In addition, the drug-releasing mechanism was evidenced by in vitro releasing kinetics at various pH conditions. The anti-biofilm potential confirmed by the biofilm architectural deformations against human infectious pathogens MRSA and N7 clinical strains. Furthermore, anticancer efficacy assessed against A549 lung cancer cells. The result reveals that the MG@Folate ZIF-L exposed a superior cytotoxic effect due to the pH-responsive and receptor-based drug-releasing mechanism. Based on the unique physicochemical and biological characteristics of nanoframeworks, it has overcome the problems of undesired side effects and uncontrolled drug release of existing drug delivery systems. Finally, the in vitro toxicity effect of MG@Folate ZIF-L was tested against the Artemia salina (A. salina) model organism, and the results show enhanced biocompatibility. Overall, the study suggested that the novel MG@Folate ZIF-L nanoframeworks is a suitable material for biomedical applications. It will be very helpful to the future design for targeted drug delivery systems.

MOFs and MOF-Derived Materials for Antibacterial Application

Bacterial infections pose a serious threat to people's health. Efforts are being made to develop antibacterial agents that can inhibit bacterial growth, prevent biofilm formation, and kill bacteria. In recent years, materials based on metal organic frameworks (MOFs) have attracted significant attention for various antibacterial applications due to their high specific surface area, high enzyme-like activity, and continuous release of metal ions. This paper reviews the recent progress of MOFs as antibacterial agents, focusing on preparation methods, fundamental antibacterial mechanisms, and strategies to enhance their antibacterial effects. Finally, several prospects related to MOFs for antibacterial application are proposed, aiming to provide possible research directions in this field.

Assessment of the biological effect of metal ions and their complexes using Allium cepa and Artemia salina assays: a possible environmental implementation of biological inorganic chemistry

The pollution of aquatic ecosystems due to the elevated concentration of a variety of contaminants, such as metal ions, poses a threat to humankind, as these ecosystems are in high relevance with human activities and survivability. The exposure in heavy metal ions is responsible for many severe chronic and pathogenic diseases and some types of cancer as well. Metal ions of the groups 11 (Cu, Ag, Au), 12 (Zn, Cd, Hg), 14 (Sn, Pb) and 15 (Sb, Bi) highly interfere with proteins leading to DNA damage and oxidative stress. While, the detection of these contaminants is mainly based on physicochemical analysis, the chemical determination, however, is deemed ineffective in some cases because of their complex nature. The development of biological models for the evaluation of the presence of metal ions is an attractive solution, which provides more insights regarding their effects. The present work critically reviews the reports published regarding the toxicity assessment of heavy metal ions through Allium cepa and Artemia salina assays. The in vivo toxicity of the agents is not only dose depended, but it is also strongly affected by their ligand type. However, there is no comprehensive study which compares the biological effect of chemical agents against Allium cepa and Artemia salina. Reports that include metal ions and complexes interaction with either Allium cepa or Artemia salina bio-indicators are included in the review.

Mapping of New Pharmacological Alternatives in the Face of the Emergence of Antibiotic Resistance in COVID-19 Patents Treated for Opportunistic Respiratory Bacterial Pathogens

BACKGROUND

The increase in bacterial resistance against antibiotics is thought to be another type of pandemic after COVID-19. Emergency treatment based on antibiotics is a major influence in increasing this resistance. Bacteria, such as Klebsiella pneumoniae, are the most affected by the indiscriminate use of antibiotics, since they are resistant to most antibiotics currently available on the market.

OBJECTIVE

This review aimed to evaluate patents of new drugs and formulations, for the treatment of infections caused by Klebsiella pneumoniae.

METHODS

The present patent review was carried out through a specialized search database Espacenet. The selection was based on the criteria of patents published from 2010 to May 2021, in any language, and containing the keywords in title or abstract. Also, a research was performed on the PubMed database, using the inclusion criteria.

RESULTS

Twenty-two patents were selected for the analysis according to the aim of the study. The advance of new patents has been mostly observed in the World Intellectual Property Organization, China, and United States. The results showed that the main approach was the drug association, followed by drug carriers, new isolated products, and vaccines.

CONCLUSION

It has been observed that few studies use new drug alternatives for the treatment, probably due to the higher cost of the development and lack of investments. The effectiveness and safety of these therapies depend on the acceptance, the correct prescription, and rational use of medicines. Therefore, this review can further develop new treatments as alternatives against Klebsiella pneumoniae and pneumonia caused by it.

A Ni-MOF based luminescent sensor for selective and rapid sensing of Fe(ii) and Fe(iii) ions

In this work, a bis(N,N-trimellitoyl)-4,4′-oxydianiline linker was synthesized and characterized by spectroscopic techniques. The molecular structure and luminescence intensity of the Ni-MOF treated with different metal ions were investigated.

Smart Metal-Organic Frameworks for Biotechnological Applications: A Mini-Review

In this pandemic situation it is evident that viruses and bacteria, more specifically, multiple drug resistant (MDR) bacteria, endanger human civilization severely. It is high time to design smart weapons to combat these pathogens for the prevention and cure of allied ailments. Metal-organic frameworks (MOFs) are porous materials designed from metal ions or inorganic clusters and multidentate organic ligands. Due to some unique features like high porosity, tunable pore shape and size, numerous possible metal-ligand combinations, etc., MOFs are ideal candidates to design "smart biotechnological tools". MOFs construct promising fluorescence based biosensing platforms for detection of viruses. MOFs also exhibit excellent antibacterial activity due to their ability for sustained release of active biocidal agents. There are several reviews that summarize the antibacterial applications of MOFs, but the biosensing platforms based on MOFs for detection of viruses have scarcely been summarized. This review carefully covers both the aspects including virus detection (nucleic acid recognition and immunological detection) with underlying mechanisms as well as antibacterial application of MOFs and doped MOFs or composites. This review will deliver valuable information and references for designing new, smarter antimicrobial agents based on MOFs.

Prospects of Exploring the Metal-Organic Framework for Combating Antimicrobial Resistance

Infectious diseases are a major public health concern globally. Infections caused by pathogens with resistance against commonly used antimicrobial drugs or antibiotics (known as antimicrobial resistance, AMR) are becoming extremely difficult to control. AMR has thus been declared as one of the top 10 global public health threats, as it has very limited solutions. The drying pipeline of effective antibiotics has further worsened the situation. There is no absolute treatment, and the limitations of existing methods warrant further development in antimicrobials. Recent developments in the nanomaterial field present them as promising therapeutics and effective alternative to conventional antibiotics and synthetic drugs. The metal-organic framework (MOF) is a recent addition to the antimicrobial category with superior properties. The MOF exerts antimicrobial action on a wide range of species and is highly biocompatible. Additionally, their porous structures allow the incorporation of biomolecules and drugs for synergistic antimicrobial action. This review provides an inclusive summary of the molecular events responsible for resistance development and current trends in antimicrobials to combat antibiotic resistance and explores the potential role of the MOF in tackling the drug-resistant microbial species.

Metal-Organic-Framework-Based Materials for Antimicrobial Applications

To address the serious threat of bacterial infection to public health, great efforts have been devoted to the development of antimicrobial agents for inhibiting bacterial growth, preventing biofilm formation, and sterilization. Very recently, metal-organic frameworks (MOFs) have emerged as promising materials for various antimicrobial applications owing to their different functions including the controlled/stimulated decomposition of components with bactericidal activity, strong interactions with bacterial membranes, and formation of photogenerated reactive oxygen species (ROS) as well as high loading and sustained releasing capacities for other antimicrobial materials. This review focuses on recent advances in the design, synthesis, and antimicrobial applications of MOF-based materials, which are classified by their roles as component-releasing (metal ions, ligands, or both), photocatalytic, and chelation antimicrobial agents as well as carriers or/and synergistic antimicrobial agents of other functional materials (antibiotics, enzymes, metals/metal oxides, carbon materials, etc.). The constituents, fundamental antimicrobial mechanisms, and evaluation of antimicrobial activities of these materials are highlighted to present the design principles of efficient MOF-based antimicrobial materials. The prospects and challenges in this research field are proposed.

A Simple in vivo Assay Using Amphipods for the Evaluation of Potential Biocompatible Metal-Organic Frameworks

In this study, the application of amphipods in vivo assays was evaluated. The main aim of this work was to check the potential use of this model in biocompatibility assessments of metal-organic frameworks (MOFs). Hence, six different MOFs were synthesized and the in vitro and ex vivo cytotoxicity was first assessed using a colorimetric assay and a macrophage cell line. Obtained results were compared to validate the in vivo toxicity tests carried out using amphipods and increasing concentrations of the different MOFs. Amphipods do not require the need of ethics approval and also are less expensive to keep than conventional in vivo models, showing its potential as a fast and reliable platform in toxicity studies. The obtained results showed that the amphipods based-assay was simple, easy to replicate and yielded toxicity data corresponding to the type of MOFs tested. In addition, it was observed that only CIM-80(Al) and CIM-84(Zr) did not show any toxicity to the animals at the different tested concentrations. Therefore, the developed in vivo model could be applied as a high-throughput toxicity screening method to evaluate the toxicity of numerous materials, chemicals and therapeutic agents among others.

Introducing reticular chemistry into agrochemistry

For survival and quality of life, human society has sought more productive, precise, and sustainable agriculture. Agrochemistry, which solves farming issues in a chemical manner, is the core engine that drives the evolution of modern agriculture. To date, agrochemistry has utilized chemical technologies in the form of pesticides, fertilizers, veterinary drugs and various functional materials to meet fundamental demands from human society, while increasing the socio-ecological consequences due to inefficient use. Thus, more useful, precise, and designable scaffolding materials are required to support sustainable agrochemistry. Reticular chemistry, which weaves molecular units into frameworks, has been applied in many fields based on two cutting-edge porous framework materials, namely metal-organic frameworks (MOFs) and covalent-organic frameworks (COFs). With flexibility in composition, structure, and pore chemistry, MOFs and COFs have shown increasing functionalities associated with agrochemistry in the last decade, potentially introducing reticular chemistry as a highly accessible chemical toolbox into agrochemical technologies. In this critical review, we will demonstrate how reticular chemistry shapes the future of agrochemistry in the fields of farm sensing, agro-ecological preservation and reutilization, agrochemical formulations, smart indoor farming, agrobiotechnology, and beyond.