Synthesis and antimicrobial activity of vancomycin–conjugated zinc coordination polymer nanoparticles against methicillin-resistant staphylococcus aureus

Potential of nanocarrier-mediated delivery of vancomycin for MRSA infections

INTRODUCTION

Methicillin-resistant Staphylococcus aureus (MRSA) threatens global health due to its resistance to vancomycin, which is the standard treatment despite limitations, including nephrotoxicity and low intracellular permeability. This necessitates the development of innovative strategies such as nanocarrier-mediated delivery to overcome such limitations. Nanocarriers serve as delivery systems for vancomycin and exhibit inherent antibacterial properties, potentially providing synergism and overcoming MRSA's resistance. Nanocarriers provide sustained release and targeted delivery of vancomycin to the infection site, achieving higher therapeutic concentrations and superior antibacterial activity with reduced doses, which minimizes systemic toxicity. Moreover, leveraging simulations techniques provides more insights on vancomycin-nanocarrier interactions, facilitating the optimization of nanosystems.

AREAS COVERED

The article discusses the potential of nanocarriers in delivering vancomycin to infection site, reducing systemic toxicity, and potentiating anti-MRSA activity. Additionally, it reviews modeling and simulation studies to provide a deeper understanding of vancomycin-nanocarrier interactions. The literature search included experimental articles from 2017 to 2024, searched in Web of Science, Google scholar, PubMed, and Scopus.

EXPERT OPINION

Nanocarrier-mediated delivery of vancomycin offers promising approaches to combat MRSA infections by enhancing therapeutic efficacy and reducing systemic toxicity. However, further research is required to optimize these nanoformulations and advance them to clinical trials and practical applications.

Recent advances in nanostructured delivery systems for vancomycin

Despite the development of new generations of antibiotics, vancomycin remained as a high-efficacy antibiotic for treating the infections caused by MRSA. Researchers have explored various nanoformulations, aiming to enhance the therapeutic efficacy of vancomycin. Such novel formulations improve the effectiveness of drug cargoes in treating bacterial infections and minimizing the risk of adverse effects. The vast of researches have focuses on enhancing the permeation ability of vancomycin through different biological barriers especially those of gastrointestinal tract. Increasing the drug loading and tuning the drug release from nanocarrier are other important goal for many conducted studies. This study reviews the newest nano-based formulations for vancomycin as a key antibiotic in treating hospitalized bacterial infections.

Zinc Oxide-Based Nanomaterials for Microbiostatic Activities: A Review

The world is fighting infectious diseases. Therefore, effective antimicrobials are required to prevent the spread of microbes and protect human health. Zinc oxide (ZnO) nano-materials are known for their antimicrobial activities. Because of their distinctive physical and chemical characteristics, they can be used in medical and environmental applications. ZnO-based composites are among the leading sources of antimicrobial research. They are effective at killing (microbicidal) and inhibiting the growth (microbiostatic) of numerous microorganisms, such as bacteria, viruses, and fungi. Although most studies have focused on the microbicidal features, there is a lack of reviews on their microbiostatic effects. This review provides a detailed overview of available reports on the microbiostatic activities of ZnO-based nano-materials against different microorganisms. Additionally, the factors that affect the efficacy of these materials, their time course, and a comparison of the available antimicrobials are highlighted in this review. The basic properties of ZnO, challenges of working with microorganisms, and working mechanisms of microbiostatic activities are also examined. This review underscores the importance of further research to better understand ZnO-based nano-materials for controlling microbial growth.

Gallic-Acid-Loaded PLGA Nanoparticles: A Promising Transdermal Drug Delivery System with Antioxidant and Antimicrobial Agents

The objective of this study was to develop an innovative gallic-acid (GA) drug delivery system that could be administered transdermally, resulting in enhanced therapeutic benefits and minimal negative consequences. The method employed involved the preparation of poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded with GA through nanoprecipitation-denoted GA@PLGANPs. The results reveal that this strategy led to perfectly spherical, homogeneous, and negatively charged particles, which are suitable for administration via skin patches or ointments. A further analysis indicates that these GA@PLGANPs exhibit remarkable antioxidant activity as well as potent antibacterial effects against a diverse range of microorganisms, making them ideal candidates for numerous applications. Additionally, it has been observed that these nanoparticles can effectively mitigate oxidative stress while also significantly inhibiting microbial growth by exerting detrimental effects on bacterial cell walls or membranes. In conclusion, on the basis of the findings presented in this study, there is strong evidence supporting the potential use of GA@PLGANPs as an effective therapy option with reduced side effects compared to conventional drug delivery methods.

Controlling the Evolution of Selective Vancomycin Resistance through Successful Ophthalmic Eye-Drop Preparation of Vancomycin-Loaded Nanoliposomes Using the Active-Loading Method

Vancomycin is the front-line defense and drug of choice for the most serious and life-threatening methicillin-resistant Staphylococcus aureus (MRSA) infections. However, poor vancomycin therapeutic practice limits its use, and there is a consequent rise of the threat of vancomycin resistance by complete loss of its antibacterial activity. Nanovesicles as a drug-delivery platform, with their featured capabilities of targeted delivery and cell penetration, are a promising strategy to resolve the shortcomings of vancomycin therapy. However, vancomycin's physicochemical properties challenge its effective loading. In this study, we used the ammonium sulfate gradient method to enhance vancomycin loading into liposomes. Depending on the pH difference between the extraliposomal vancomycin-Tris buffer solution (pH 9) and the intraliposomal ammonium sulfate solution (pH 5-6), vancomycin was actively and successfully loaded into liposomes (up to 65% entrapment efficiency), while the liposomal size was maintained at 155 nm. Vancomycin-loaded nanoliposomes effectively enhanced the bactericidal effect of vancomycin; the minimum inhibitory concentration (MIC) value for MRSA decreased 4.6-fold. Furthermore, they effectively inhibited and killed heteroresistant vancomycin-intermediate S.aureous (h-VISA) with an MIC of 0.338 μg mL^-1. Moreover, MRSA could not develop resistance against vancomycin that was loaded into and delivered by liposomes. Vancomycin-loaded nanoliposomes could be a feasible solution for enhancing vancomycin's therapeutic use and controlling the emerging vancomycin resistance.

Development and Evaluation of Novel Encapsulated Isoeugenol-Liposomal Gel Carrier System for Methicillin-Resistant Staphylococcus aureus

In recent years, methicillin-resistant Staphylococcus aureus (MRSA) bacteria have seriously threatened the health and safety of the world’s population. This challenge demands the development of alternative therapies based on plant origin. This molecular docking study ascertained the orientation and intermolecular interactions of isoeugenol within penicillin-binding protein 2a. In this present work, isoeugenol as an anti-MRSA therapy was selected by encapsulating it into a liposomal carrier system. After encapsulation into the liposomal carrier, it was evaluated for encapsulation efficiency (%), particle size, zeta potential, and morphology. The percentage entrapment efficiency (% EE) was observed to be 57.8 ± 2.89% with a particle size of 143.31 ± 7.165 nm, a zeta potential of (−)25 mV, and morphology was found to be spherical and smooth. After this evaluation, it was incorporated into a 0.5% Carbopol gel for a smooth and uniform distribution on the skin. Notably, the isoeugenol-liposomal gel was smooth on the surface with a pH of 6.4, suitable viscosity, and spreadability. Interestingly, the developed isoeugenol-liposomal gel was safe for human use, with more than 80% cell viability. The in vitro drug release study shows promising results with 75.95 ± 3.79% of drug release after 24 h. The minimum inhibitory concentration (MIC) was 8.236 µg/mL. Based on this, it can be concluded that encapsulating isoeugenol into the liposomal gel is a potential carrier for MRSA treatment.

Antioxidant, Antibacterial, and Anticancer Activity of Ultrasonic Nanoemulsion of Cinnamomum Cassia L. Essential Oil

Cinnamomum cassia (C. assia) has long been used in traditional holistic medicine for its medicinal properties. It is used as an antioxidant, antibacterial, anti-inflammatory and anticancer agent. Cinnamon, in particular, the essential oil of C. cassia, has significant biological properties. Despite this, the volatility, stability, and insolubility of C. cassia essential oil (CEO) remain the main disadvantages that limit its application, ultimately affecting its pharmacological efficacy. To find a solution to this problem, we developed the CEO nanoemulsion (CEO-NE). For lipophilic compounds, insoluble nanoemulsion-based formulations are a popular delivery strategy. In this research work, a highly stable dosage form named CEO-NE was successfully developed using polysorbate 80 and water. The findings show that the synthesized CEO has a uniform shape with a PDI of 0.380 and an adequate particle size of 221.8 nm. The antioxidant outcomes show excellent results for CEO-NE compared to CEO against DPPH and hydrogen peroxide. The obtained antibacterial activity of CEO-NE was more efficient than that of CEO against Klebsiella pneumonia (MTCC 8911) with 0.025% and 0.05%, respectively. The CEO-NE preparation was tested against an alveolar lung adenocarcinoma cell line (A549) with an IC₅₀ of 50.21 µg/mL for CEO and 18.05 µg/mL for CEO-NE, respectively. These results are encouraging for future translational studies on CEO-NE use in lung cancer therapy due to its excellent antioxidant, antibacterial, and killing kinetic properties.

Formulation, In Vitro and In Silico Evaluations of Anise (Pimpinella anisum L.) Essential Oil Emulgel with Improved Antimicrobial Effects

Over the past decade, researchers have made several efforts to develop gel-based formulations that provide an alternative to traditional hydrogels and emulgel. Due to its excellent antibacterial properties, anise, the main constituent of Pimpinella anisum L., widely used in pharmaceuticals, was selected as the active ingredient in this study. Since many bacteria have developed considerable antibiotic resistance, this research aimed to develop an herbal emulgel for treating skin infections caused by bacteria. Given these obstacles, we developed and evaluated a new, cost-effective topical emulgel solution containing anise essential oil against Escherichia coli (E. coli). Anise-based emulgels, potential drug delivery platforms, have been evaluated for various parameters, including physical properties, viscosity, pH, rheology, encapsulation efficiency, and in vitro release research. The AEOs emulgel demonstrated remarkable colloidal stability, with a zeta potential of 29 mV, a size of 149.05 nm, and considerable polydispersity. The efficacy of anise-loaded emulgels as antibacterial formulations was evaluated in vitro. E. coli was used as a model microbial organism for the antibacterial study. Human keratinocytes (HaCaT) were used to examine the biocompatibility of the emulgel. Molecular docking revealed that the essential oil components of Pimpinella anisum L. possess a high affinity for the bacterial adhesin protein FimH of E. coli. These findings indicate that the developed AEOs have the potential to be analyzed using E. coli as a model organism.

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.

Herbal Fennel Essential Oil Nanogel: Formulation, Characterization and Antibacterial Activity against Staphylococcus aureus

Antimicrobial resistance (AMR) is one of the greatest threats to humanity in the world. Antibiotic-resistant bacteria spread easily in communities and hospitals. Staphylococcus aureus (S. aureus) is a serious human infectious agent with threatening broad-spectrum resistance to many commonly used antibiotics. To prevent the spread of pathogenic microorganisms, alternative strategies based on nature have been developed. Essential oils (EOs) are derived from numerous plant parts and have been described as antibacterial agents against S. aureus. Fennel essential oils were selected as antibacterial agents encapsulated in nanoparticles of polylactic acid and glycolic acid (PLGA). The optimum size of the formulation after loading with the active ingredient was 123.19 ± 6.1595 nm with a zeta potential of 0.051 ± 0.002 (23 ± 1.15 mV). The results of the encapsulation efficiency analysis showed high encapsulation of EOs, i.e., 66.4 ± 3.127. To obtain promising carrier materials for the delivery of fennel EOs, they were incorporated in the form of nanogels. The newly developed fennel oils in PLGANPs nanogels have good drug release and MIC against S. aureus. These results indicate the potential of this novel delivery system for antimicrobial therapy.

Advancements in Polymeric Nanocarriers to Mediate Targeted Therapy against Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a destructive disease with a poor prognosis, low survival rate and high rate of metastasis. It comprises 15% of total breast cancers and is marked by deficiency of three important receptor expressions, i.e., progesterone, estrogen, and human epidermal growth factor receptors. This absence of receptors is the foremost cause of current TNBC therapy failure, resulting in poor therapeutic response in patients. Polymeric nanoparticles are gaining much popularity for transporting chemotherapeutics, genes, and small-interfering RNAs. Due to their exclusive properties such as great stability, easy surface modification, stimuli-responsive and controlled drug release, ability to condense more than one therapeutic moiety inside, tumor-specific delivery of payload, enhanced permeation and retention effect, present them as ideal nanocarriers for increasing efficacy, bioavailability and reducing the toxicity of therapeutic agents. They can even be used as theragnostic agents for the diagnosis of TNBC along with its treatment. In this review, we discuss the limitations of already existing TNBC therapies and highlight the novel approach to designing and the functionalization of polymeric nanocarriers for the effective treatment of TNBC.

Solubility Enhancement, Formulation Development, and Antibacterial Activity of Xanthan-Gum-Stabilized Colloidal Gold Nanogel of Hesperidin against Proteus vulgaris

The objective of the study was to develop a transdermal nanoformulation of hesperidin (HSP) against Proteus vulgaris (P. vulgaris). Based on the low water solubility of HSP, we prepared HSP-enabled AuNPs stabilized with xanthan gum (XA), referred to as HSP@XA@AuNPs. The HSP@XA@AuNP formulation was evaluated for particle size (43.16 nm), PDI (0.565), zeta potential (−31.9 mV), and entrapment efficiency (56.7%). The HSP@XA@AuNPs gel was developed by incorporating selected formulation grades into a 1% Carbopol gel base and characterized by physical evaluation and rheological studies. The color of the HSP@XA@AuNP gel was light pink, and the texture was very smooth and non-greasy. The gel was shown to be odorless. A field emission scanning electron microscope (FESEM) was used to investigate the shape of HSP@XA@AuNPs further. The drug release was 73.08% for the HSP@XA@AuNPs and 86.26% for the HSP@XA@AuNPs gel in 500 min. The prepared gel showed antimicrobial activity against P. vulgaris with an MIC of 1.78 μg/mL. In conclusion, the HSP@XA@AuNPs gel could be an advanced modality for treating P. vulgaris.

Site-Specific Evaluation of Bioactive Coumarin-Loaded Dendrimer G4 Nanoparticles against Methicillin Resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is a foremost treatment challenge in today's clinical practice. Natural coumarins contain a variety of bioactivities and have the ability to alter resistance in several ways. In developing effective drug delivery methods, the goal is to maximize biocompatibility while minimizing toxicity. With this in mind, this work investigated the site-specific potential of dendrimer G4 poloxamer nanoparticles loaded with bioactive coumarin. The goal of the current work is to deliver a complete evaluation of dendrimer G4 poloxamer nanoparticles against MRSA. Coumarin-loaded dendrimer G4 poloxamer nanoparticles were thoroughly investigated and characterized using various techniques, including particle size, shape, entrapment efficiency, in vitro drug release, hemolysis assay, cytotoxicity, antibacterial activity, and bactericidal kinetics. Studies showed that the newly developed dendrimer G4 poloxamer nanoparticles exhibited significantly lower levels of hemolysis and cytotoxicity. The results showed that the in vitro drug release of coumarin from dendrimer G4 poloxamer nanoparticles was slower compared to coumarin in its free form. This innovative therapeutic delivery technology may enhance the defense of coumarin against MRSA.

Coumarin-Encapsulated Solid Lipid Nanoparticles as an Effective Therapy against Methicillin-Resistant Staphylococcus aureus

Bacterial infections caused by antibiotic-resistant pathogens are a significant public health problem. This is because the transmission of infectious diseases is shifting, and new antibiotic-resistant strains of bacteria are emerging. The development of biofilms that are resistant to antibiotics poses another hurdle to drugs and treatment alternatives. Therefore, there is an urgent need to develop innovative strategies to effectively eliminate antibiotic-resistant microorganisms effectively. Natural coumarins have broad spectrum bioactivity and the potential for lower resistance. Coumarin is a secondary metabolite found in certain plants, fungi, and bacteria. It is highly effective against methicillin-resistant Staphylococcus aureus (MRSA). Therefore, coumarin can be used as an alternative to combat MRSA. However, most antibacterial agents lack selective targeting of pathological sites, limiting the efficacy of their antibacterial activity. Efficient MRSA treatments can be achieved through nanoparticle (NPs)-based targeted therapies. To address this challenge, a novel coumarin-loaded solid lipid nanocarrier for MRSA was developed to overcome this challenge. The developed systems exhibited a particle size of 138.5 ± 76.06 nm and a polydispersity index (PDI) of 0.245 ± 0.00. The zeta potential of coumarin-loaded SLNs was reported to be -22.2 ± 8.15 mV with a spherical shape. The encapsulation efficiency of coumarin was reported to be 63.09 ± 3.46% in the final formulation. The developed formulation was biocompatible with a minimum inhibitory concentration (MIC) of 1.08 µg/mL. This study suggests that coumarin-loaded SLNs can effectively treat MRSA infections.