Synergistic Effects Between Metal Nanoparticles and Commercial Antimicrobial Agents: A Review

The nano-paradox: addressing nanotoxicity for sustainable agriculture, circular economy and SDGs

Engineered nanomaterials (ENMs) have aroused extensive interest in agricultural, industrial, and medical applications. The integration of ENMs into the agricultural systems aligns with the principles of United Nations' sustainable development goals (SDGs), circular economy (CE) and bio-economy (BE) principles. This approach offers excellent opportunities to enhance productivity and address global climate change challenges. The revelation of the adverse effects of nanomaterials (NMs) on various organisms and ecosystems, however, has fueled the debate on 'Nano-paradox' leading to emergence of a new research domain 'Nanotoxicology'. ENMs have shown different interactions with biological and environmental systems as compared to their bulk counterparts. They bioaccumulate in organisms, soils, and other environmental matrices, move through food chains and reach higher trophic levels including humans ultimately resulting in oxidative stress and cellular damage. Understanding nano-bio interactions, the mechanism of gene- and cytotoxicity, and associated potential hazards, is therefore, essential to mitigate their toxicological outputs. This review comprehensively examines the cyto- and genotoxicity mechanisms of ENMs in biological systems, covering aspects such as their entry, uptake, cellular responses, dynamic interactions in biological environments their long-term effects and environmental risk assessment (ERA). It also discusses toxicological assessment methods, regulatory policies, strategies for toxicity management/mitigation and future research directions in nanotechnology, all within the context of SDGs, CE, promoting resource efficiency and sustainability. Navigating the nano-paradox involves balancing the benefits of nanomaterials with concerns about nanotoxicity. Prioritizing thorough research on above facets can ensure sustainability and safety, enabling responsible harnessing of nanotechnology's transformative potential in various applications including mitigating global climate change and enhancing agricultural productivity.

Water-borne chitosan/CuO-GO nanocomposite as an antibacterial coating for functional leather with enhanced mechanical and thermal properties

The advancement of eco-friendly and effective antibacterial outer surfaces for medical textiles and leather products is considered important by industries and end users. Herein, positively charged chitosan (CS) and copper oxide nanoparticle-decorated negatively charged graphene oxide (CuO-GO) were assembled layer-by-layer to create an innovative nanocomposite (CS/CuO-GO) coating onto the leather surface. GO was prepared from graphite powder. Eco-friendly synthesis of CuO nanoparticles with Aloe vera leaf extract was reported and utilized to prepare the CuO-GO nanocomposite. The as-prepared materials were tested through FTIR, XRD, UV-vis spectroscopy, TEM, and DLS analyses. Different amounts of CS/CuO-GO coated leathers showed efficient antibacterial activities against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) using a "kill-release" approach. This was largely attributed to the cooperative interaction between the contact-killing of the chitosan layer, the discharge of Cu2+ ions, and the bacterial-repelling properties of the anionic GO layer. The FE-SEM analysis confirms the existence of a CuO-GO layer on the leather surface with an effect on the macroscopic level performances. The XPS analysis confirms the chemical state of the coated materials on the leather surface. Tensile, tear, and stitch tear strength increased after coating with the CS/CuO-GO nanocomposite. The WVP of the coated leather remains within the range after coating with different wt% of the CS/CuO-GO nanocomposite. The durability of the nanocomposite coating on leather surfaces was thoroughly examined through dry and wet rub fastness tests. Results clearly showed that the strong coating greatly enhanced the antibacterial effectiveness of leather against mechanical wear. The impacts of CS/CuO-GO nanocomposite coating on the leather surface hydrophilicity were evaluated using water contact angle measurements. Water-borne chitosan-based CuO-GO nanocomposite showed a good eco-friendly leather finishing system. It could extend their applications to sports and medical textiles to impart antibacterial effects.

Engineering multifunctional high-entropy oxide nanozymes for robust marine antifouling

High-performance interfacial antifouling coatings are crucial for sustainable marine resource utilization. This work reports a novel high-entropy oxide (HEO) nanozyme, CrMnFeNiCuOX nanoparticles, where the synergistic interplay of polymetallic cations and defect engineering yield remarkable multi-enzyme mimetic activity combined with a photothermal conversion efficiency of 40.06%. Under simulated solar irradiation, the HEO nanozyme exhibited complete (100%) bactericidal activity against both Escherichia coli and Staphylococcus aureus, and effectively suppresses biofilm formation in a simulated marine environment. Mechanistic investigations demonstrated that the HEO nanozyme exhibits a tailored electronic structure and adsorption properties, enabling disruption of bacterial membrane integrity, perturbation of intracellular redox homeostasis, and suppression of quorum sensing signaling. This multifaceted approach offers a promising strategy for developing durable and environmentally friendly antifouling coatings for diverse marine applications.

Development of Biginelli-based ZnO-coupled carbomer-gel-coated wound dressing gauze with enhanced antibacterial activity

A multicomponent Biginelli reaction was used to produce biologically active dihydropyrimidones that were then combined with ZnO nanoparticles. Biginelli compounds synthesized with various alkyl chains were characterized using high-resolution mass spectrometry as well as 1H- and 13C-NMR spectroscopy. Efficient antibacterial gels were developed by introducing the prepared Biginelli compounds and ZnO nanoparticles into a carbomer polymer matrix. Antibacterial screening revealed that the ABS-G4 gel exhibited the highest antibacterial potential, with minimum inhibitory concentrations of 16 ± 2 and 12 ± 2 μg mL-1 against Escherichia coli and Staphylococcus aureus, respectively. The ABS-G4 gel was characterized using rheological studies, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, powder X-ray diffraction, and atomic force microscopy. The ABS-G4 gel was showing more antibacterial efficacy toward Gram-positive strains of bacteria than Gram-positive ones. An antibacterial dressing was formed by coating the developed gel onto a gauze dressing.

Novel nanomaterials-based combating strategies against drug-resistant bacteria

Numerous types of contemporary antibiotic treatment regimens have become ineffective with the increasing incidence of drug tolerance. As a result, it is pertinent to seek novel and innovative solutions such as antibacterial nanomaterials (NMs) for the prohibition and treatment of hazardous microbial infections. Unlike traditional antibiotics (e.g., penicillin and tetracycline), the unique physicochemical characteristics (e.g., size dependency) of NMs endow them with bacteriostatic and bactericidal potential. However, it is yet difficult to mechanistically predict or decipher the networks of molecular interaction (e.g., between NMs and the biological systems) and the subsequent immune responses. In light of such research gap, this review outlines various mechanisms accountable for the inception of drug tolerance in bacteria. It also delineates the primary factors governing the NMs-induced molecular mechanisms against microbes, specifically drug-resistant bacteria along with the various NM-based mechanisms of antibacterial activity. The review also explores future directions and prospects for NMs in combating drug-resistant bacteria, while addressing challenges to their commercial viability within the healthcare industry.

Antimicrobial Phenolic Materials: From Assembly to Function

Infectious diseases pose considerable challenges to public health, particularly with the rise of multidrug-resistant pathogens that globally cause high mortality rates. These pathogens can persist on surfaces and spread in public and healthcare settings. Advances have been made in developing antimicrobial materials to reduce the transmission of pathogens, including materials composed of naturally sourced polyphenols and their derivatives, which exhibit antimicrobial potency, broad-spectrum activity, and a lower likelihood of promoting resistance. This review provides an overview of recent advances in the fabrication of antimicrobial phenolic biomaterials, where natural phenolic compounds act as active antimicrobial agents or encapsulate other antimicrobial agents (e.g., metal ions, antimicrobial peptides, natural biopolymers). Various forms of phenolic biomaterials synthesized through these two strategies, including antimicrobial particles, capsules, hydrogels, and coatings, are summarized, with a focus on their application in wound healing, bone repair and regeneration, oral health, and antimicrobial coatings for medical devices. The potential of these advanced phenolic biomaterials provides a promising therapeutic approach for combating antimicrobial-resistant infections and reducing microbial transmission.

Computer-Aided Discovery of Synergistic Drug-Nanoparticle Combinations for Enhanced Antimicrobial Activity

Antibiotic resistance is a critical global public health challenge driven by the limited discovery of antibiotics, the rapid evolution of resistance mechanisms, and persistent infections that compromise treatment efficacy. Combination therapies using antibiotics and nanoparticles (NPs) offer a promising solution, particularly against multidrug-resistant (MDR) bacteria. This study introduces an innovative approach to identifying synergistic drug-NP combinations with enhanced antimicrobial activity. To carry this out, we compiled two groups of data sets to predict the minimal concentration (MC) and zone of inhibition (ZOI) of various drug-NP combinations. CatBoost regression models achieved the best 10-fold cross-validation R2 scores of 0.86 and 0.77, respectively. We then adopted a machine learning (ML)-reinforced genetic algorithm (GA) to identify synergistic antimicrobial NPs. The proposed approach was first validated by reproducing the previous experimental results. As a proof of concept for discovering drug-NP combinations, Au NPs were identified as highly synergistic NPs when paired with chloramphenicol, achieving a minimum bactericidal concentration (MBC) of 71.74 ng/mL against Salmonella typhimurium with a fractional inhibitory concentration index of 6.23 × 10-3. These findings present an effective strategy for identifying synergistic drug-NP combinations, providing a promising approach to combating drug-resistant pathogens and advancing targeted antimicrobial therapies.

An Australian perspective on clinical, economic and regulatory considerations in emerging nanoparticle therapies for infections

Antimicrobial resistance (AMR) poses a growing global health threat. Nanomedicine, combined with drug repurposing, may help extend the effective lifespan of current and new antimicrobials. This review, presents an Australian perspective on nanotechnology-based therapies, highlighting scientific and clinical challenges. Early consideration of the potential barriers to market access may help to accelerate research translation, regulatory approval and patient access to nano-antimicrobial (NAM) drugs for resistant pathogens, not only in Australia, but globally.

Preparation of Diosgenin-Functionalized Gold Nanoparticles: From Synthesis to Antitumor Activities

Cancer ranks among the top causes of illness and death globally. Nanotechnology holds considerable promise for enhancing the effectiveness of therapeutic and diagnostic approaches in cancer treatment. Our study presents a promising strategy for applying thiocompound nanomedicine in cancer therapy. Our first study aimed to investigate the biological properties of a new compound thiodiosgenin (TDG)-a new derivative of diosgenin-a natural compound with known antioxidant and anticancer properties. Our current second study aimed to compare the therapeutic efficacy of a new diosgenin-functionalized gold nanoparticles-with its precursor on prostate cancer (DU-145) cell lines. Moreover, the safety of the new thio-derivative and new conjugates was tested against the human epithelial line PNT-2. New advanced analytical techniques were developed for the characterization of nanomaterials using methods such as SP-ICP-MS, UV-Vis, TEM, NMR, FT-IR ELS, and TGA. Our synthetic approach was based, on the one hand, on the ligand exchange of citrates to thiodiosgenin (TDG) on gold nanoparticles, and on the other hand, on the attachment of DG through an ester bond to the linker, which was 3-mercaptopropionic acid (MPA) on gold nanoparticles. Initial in vitro studies indicate that TDG shows greater cytotoxic effects on cancer cells but poses risks to normal prostate epithelial cells (PNT-2). It was demonstrated that all the conjugates produced exhibited significant cytotoxic effects against cancer cells while being less harmful to normal prostate epithelial cells (PNT-2) compared to TDG itself. All the obtained conjugates showed antitumor properties; however, for targeted transport, the system referred to as AuNPs-MPAm1-DG is promising, due to the size of the nanoparticles of 53 nm, zeta potential of -30 mV, and loading content of 27.6%. New methods for synthesizing conjugates with diosgenin were developed and optimized for medical applications. Advanced new analytical methodologies were developed to characterize new conjugates, particularly the use of SP-ICP-MS, to solve existing differences in the shape and morphology of the surface of new conjugates.

Enhancing Flucytosine Anticandidal Activity Using PEGylated Squalene Nanocarrier

There is an emerging necessity for improved therapies against Candida-related infections, with significant implications for global healthcare. Current antifungal agents, limited in number, target specific pathways, but resistance remains a concern. Flucytosine (5FC) exhibits antifungal activity, particularly against Candida. However, monotherapy efficacy is limited, necessitating combination treatments. Herein, we report PEGylated squalene-based nanocarriers for 5FC loading, aiming to enhance its monotherapy efficacy against Candida strains. The loading of 5FC within micelles was achieved using the ultrasound-assisted solvent evaporation method. The 5FC-loaded micelles, together with non-loaded micelles, were thoroughly characterized and analyzed. STEM and DLS analysis confirmed the core-shell morphology with nanometric dimensions along with improved colloidal stability. The quantification of drug loading efficiency and drug loading capacity was calculated using the UV-Vis technique. The in vitro drug-release studies in simulated physiological conditions showed sustained release within 48 hours. Moreover, the release kinetics calculated using mathematical models showed a Fickian diffusion drug release mechanism in simulated physiological conditions with a slower diffusion rate. The in vitro antifungal activity was tested on Candida albicans, Candida glabrata, and Candida parapsilosis. The results showed improved antifungal activity for the nanotherapeutic and unchanged in vitro toxicity toward normal cells, suggesting promising advancements in 5FC therapy.

Ṯābit Ibn Qurrah's contributions to toxicology

Mankind has been familiar with poisons since ancient times. On the other hand, there is a wealth of knowledge in the medical books including medieval works of Middle Eastern polymaths such as Avicenna, "al-Rāzī," and "Ṯābit Ibn Qurrah." This study presented and analyzed the knowledge of medical toxicology in one of the mainstay works of "Ṯābit Ibn Qurrah" entitled "al-Ḏaḫirah Fy Ꜥilm al-Tibb" also known as The Treasury of Medicine after the translation of the book from Arabic to English carefully and faithfully. Also, related toxicological literature was applied wherever required using English, Arabic, and Persian databases including Scopus, PubMed, Web of Science, WorldCat, Magiran, IranDoc, Scientific Information Database, Noor Mags, Noorlib, and Al Manhal. Our research revealed that chapter 25 of the mentioned book specifically focused on toxicology. This chapter was divided into sections on different aspects of toxicology from the categorization of poisons to compound mixtures causing poisonings to introducing blade poisons to signs and symptoms of poisonings, preventive approaches, and therapeutic agents. Specific antidotes and general therapies were introduced that included medicinal plants, cupping therapy, and bandages, just to name a few. Also, there were some monographs on the common poisonous agents and their treatments. The toxicological data of the book was comparable with modern toxicology. Our study highlighted the contributions of "Ṯābit Ibn Qurrah" to medical toxicology by authoring The Treasury of Medicine. Further research is recommended to elucidate the full aspects of the history of toxicology including the contributions of the past scholars.

Synergistic antiviral potential of N-(2-hydroxy)propyl-3-trimethylammoniumchitosan-functionalized silver nanoparticles with oseltamivir against influenza A viruses

This study introduced a novel antiviral approach by combining three substances with different antiviral mechanisms: N-(2-hydroxy)propyl-3-trimethylammoniumchitosan (HTC), silver nanoparticles (AgNPs), and oseltamivir. First, positively surface-charged AgNPs were prepared using an environmentally friendly method. The surfaces of these AgNPs were capped with cationic quaternary chitosan HTC. It exhibits a positive zeta potential with extraordinary stability in aqueous solutions and facilitates substantial and rapid cellular uptake including entry into the cell nucleus. HTC-AgNPs display broad-spectrum antiviral activity against three influenza A viruses (H5N1, H3N2, and H1N1) at biocompatible concentrations. When blended with oseltamivir, HTC-AgNPs enhances the antiviral activity from that of oseltamivir alone by at least 20 times. After 24 h of combined treatment, the inhibition efficiency against influenza A virus can attain up to 99.9 %. We anticipate that this combination could reduce the effective dose of Tamiflu by 10-fold when used in clinic, thus shortening recovery period and lowering the medication costs. Moreover, the synergistic effects of the three active substances would reduce the likelihood of the emergence of drug-resistant viral strains. This would, in turn, enhance the effectiveness and safety of this medication.

Nanotechnology for Healthcare: Plant-Derived Nanoparticles in Disease Treatment and Regenerative Medicine

Nanotechnology has revolutionised biomedical research, offering innovative healthcare solutions. Plant-based nanotechnology is emerging as a sustainable alternative, minimising environmental impacts and enhancing therapeutic effectiveness. This paper explores the potential of plant-derived nanoparticles (PNPs) in medicine, highlighting their biocompatibility, multifunctionality, and eco-friendliness. PNPs, synthesised through green methods, have demonstrated promising applications in drug delivery, cancer therapy, antimicrobial treatments, and tissue regeneration. Their unique properties, such as a high surface area and bioactive components, enable improved drug delivery, targeting, and controlled release, reducing side effects and enhancing treatment efficacy. Additionally, plant-derived compounds' inherent antimicrobial and antioxidant properties, retained within platinum nanoparticles (PNPs), present innovative opportunities for combating antimicrobial resistance and promoting wound healing. Despite their potential, challenges remain in standardising PNP synthesis, ensuring consistency, and scaling up production for industrial applications. This review emphasises the need for further research on PNP toxicity, biocompatibility, and regulatory frameworks to fully harness their capabilities in clinical and commercial applications. Plant-based nanotechnology represents a promising, greener alternative for advancing healthcare solutions, aligning with global sustainability goals.

Superior Performance of Iron-Coated Silver Nanoparticles and Cefoxitin as an Antibiotic Composite Against Methicillin-Resistant Staphylococcus aureus (MRSA): A Population Study

The synergistic effects of antimicrobial nanostructures with antibiotics present a promising solution for overcoming resistance in methicillin-resistant Staphylococcus aureus (MRSA). Previous studies have introduced iron as a novel coating for silver nanoparticles (AgNPs) to enhance both economic efficiency and potency against S. aureus. However, there are currently no available data on the potential of these novel nanostructures to reverse MRSA resistance. To address this gap, a population study was conducted within the MRSA community, collecting a total of 48 S. aureus isolates from skin lesions. Among these, 21 isolates (43.75%) exhibited cefoxitin resistance as determined by agar disk diffusion assay. Subsequently, a PCR test confirmed the presence of the mecA gene in 20 isolates, verifying them as MRSA. These results highlight the cefoxitin disk diffusion susceptibility test as an accurate screening method for predicting mecA-mediated resistance in MRSA. Synergy tests were performed on cefoxitin, serving as a marker antibiotic, and iron-coated AgNPs (Fe@AgNPs) in a combination study using the checkerboard assay. The average minimal inhibitory concentration (MIC) and fractional inhibitory concentration (FIC) of cefoxitin were calculated as 11.55 mg/mL and 3.61 mg/mL, respectively. The findings indicated a synergistic effect (FIC index < 0.5) between Fe@AgNPs and cefoxitin against 90% of MRSA infections, while an additive effect (0.5 ≤ FIC index ≤ 1) could be expected in 10% of infections. These results suggest that Fe@AgNPs could serve as an economically viable candidate for co-administration with antibiotics to reverse resistance in MRSA infections within skin lesions. Such findings may pave the way for the development of future treatment strategies against MRSA infections.

Carbon nanodots as photosensitizer in photodynamic inactivation of Rickettsia slovaca

Carbon quantum dots (CQDs) are promising therapeutic agent due to their pro-oxidant, antioxidant, antiviral, antibacterial, and anticancer properties when exposed to visible light irradiation. Oxidative stress in bacteria is the main reason for bacteria death after exposure to blue light photoexcited quantum dots. Herein, we present the antibacterial activities of hydrophobic carbon quantum dots/polydimethylsiloxane nanocomposites, hydrophilic citric acid CQDs, and combinations of CQDs with methylene blue. We investigated the antirickettsial effect of hydrophilic and hydrophobic CQDs against Rickettsia slovaca, a tick-borne bacterial pathogen. Photodynamic activity against on rickettsiae reached 99.66% using CQDs with 470 nm blue light irradiation. Combining methylene blue with CQDs further enhanced the effect on rickettsial infection, achieving 99,98% efficacy. The obtained results reveal the in vitro antirickettsial properties of CQDs. Sequencing analysis on the genomic level of control and treated samples showed single nucleotide variants (SNVs). Based on snippy analysis SNVs were assigned to the rRNA genes, 16S rRNA and 30S rRNA genes. By freebayes analysis in treated samples, a stop-lost mutation was detected in pseudogene (RSL_RS06070), while the possible effect on down-stream genes including tsaD, acyl-CoA-desaturase, 30S ribosomal protein S6 and DUF424 family protein. The frameshift mutation was localized within clpB pseudogene belonging to stress-response heat-shock proteins.

Enhanced Efficacy of Some Antibiotics in the Presence of Silver Nanoparticles Against Clinical Isolate of Pseudomonas aeruginosa Recovered from Cystic Fibrosis Patients

Introduction

Given the increasing frequency of drug-resistant bacteria and the limited progress in developing new antibiotics, it is necessary to explore new methods of combating microbial infections. Nanoparticles, particularly silver nanoparticles (Ag-NPs), have shown exceptional antibacterial characteristics; however, elevated concentrations of Ag-NPs can produce noticeable levels of toxicity in mammalian cells.

Aim

This study examined the potential synergistic effect of combining a low dosage of Ag-NPs and anti-pseudomonas drugs against Pseudomonas aeruginosa (ATCC strain) and eleven clinical isolates from cystic fibrosis patients.

Methods

The Ag-NPs were chemically produced by utilizing a seed extract from Peganum Harmala and characterized via ultraviolet-visible spectroscopy and scanning electron microscopy. The broth microdilution technique was utilized to investigate the minimum inhibitory concentration (MIC) of Ag-NPs and eight antibiotics (Piperacillin, Ciprofloxacin, Levofloxacin, Meropenem, Amikacin, Ceftazidime, Gentamicin, Aztreonam). The fractional inhibitory concentration index (FICI) was determined via the checkerboard method to evaluate the synergistic effects of Ag-NPs and various antibiotics.

Results

The biosynthesized Ag-NPs were uniformly spherical and measured around 15 nm in size. When combined with antibiotics, Ag-NP produced statistically significant reductions in the amount of antibiotics required to completely prevent P. aeruginosa growth for all strains. The findings revealed that the MIC of Ag-NPs was 15 ug/mL for all strains which decreased substantially when administered with antibiotics at a dose of 1.875-7.5 ug/mL. The majority of Ag-NP and antibiotic combinations exhibited a synergistic or partially synergistic impact. This was particularly noticeable in combinations containing Meropenem, Ciprofloxacin, and Aztreonam (in which the FIC index was less than or equal to 0.5).

Conclusion

The findings revealed that combining Ag-NPs with antibiotics was more effective than using Ag-NPs or antibiotics in isolation and that combinations of Ag-NPs and antimicrobial agents displayed synergistic activity against the majority of strains assessed.

Extracellular Biosynthesis, Characterization and Antimicrobial Activity of Silver Nanoparticles Synthesized by Filamentous Fungi

The green synthesis of metal nanoparticles has received substantial attention due to their applications in various domains. The aim of the study was to obtain silver nanoparticles (AgNPs) by green synthesis with filamentous fungi, such as Cladosporium cladosporoides, Penicillium chrysogenum, and Purpureocillium lilacinum. Fungal species were grown on nutrient media and aqueous mycelium extracts were used to reduce Ag+ to Ag (0). The silver nanoparticles were analyzed by various techniques, such as UV-Visible spectroscopy (UV-Vis), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), dynamic light scattering (DLS), and Zeta potential. The formation of silver nanoparticles was confirmed by UV-Vis spectroscopy and the color change of the mixture containing metal precursor and aqueous mycelium extract. FTIR displayed different functional groups as capping and reducing agents for the biosynthesis of AgNPs. SEM and TEM provided information on the particles' morphology. DLS diagrams indicated mean particle diameters in the 124-168 nm region. All biosynthesized AgNPs had negative zeta values, which is a sign of good stability. Silver nanoparticles were evaluated for antimicrobial activity, and the most active were those synthesized with metabolites from Cladosporium, leading to 93.75% inhibition of Staphylococcus aureus, 67.20% of Escherichia coli, and 69.56% of Candida albicans. With the highest microbial inhibition percentage and a very good Poly Dispersion Index (Pd I), Cladosporium cladosporoides was selected as an environmentally friendly source of silver nanoparticles that could be used as a potential antimicrobial agent.

Optical Properties and Antimicrobial Activity of Si/PVP Hybrid Material Combined with Antibiotics

Silica-poly (vinylpyrrolidone) hybrid material was prepared using the sol-gel method. Tetramethyl ortosilane (TMOS) was used as a silica precursor. XRD analysis established that the as-prepared material is amorphous. The morphological structure of the final product was determined by the incorporated PVP. The UV-Vis analysis showed that the obtained hybrid exhibited absorption in the ultraviolet range. The antimicrobial activity of the SiO2/15PVP hybrid material was tested on Staphylococcus epidermidis ATCC 14990, Salmonella typhimurium ATCC BAA-2162, Candida albicans, and Saccharomyces cerevisiae in combination with the following antibiotics: Vancomycin for Gram-positive bacteria, Ciprofloxacin for Gram-negative bacteria, and Nystatin for yeast. The results confirmed a concentration-dependent synergistic effect of the antibiotic in combination with the TM15/PVP hybrid particles, especially at their highest concentration of 100 mg/mL on Gram-positive bacteria and for the Gram-negative Salmonella. On Candida albicans ATCC 18804 and Saccharomyces cerevisiae CCY 21-6-3, the effect was synergistic again, and a fungicidal effect was observed at 6.25 and 1.50 mg/mL for the antibiotic concentration and concentrations of hybrid material at 100 mg/mL. The toxicity on Daphnia magna was also tested. The registered prooxidant activity of SiO2/15PVP shows possible applications at very low concentrations. The obtained results demonstrate the possibility of clinical implementations of the newly synthesized hybrid material.

Synergistic antimicrobial nanofiber membranes based on metal incorporated silica nanoparticles as advanced antimicrobial layers

In this post-new-normal era, the public prioritizes preventive measures over curing, which is a constructive approach to staying healthy. In this study, an innovative antimicrobial membrane material has been developed, showcasing the promising potential for various applications. The metal-doped silica nanoparticles (Ag, Cu, and Co) were incorporated into a cellulose acetate (CA) polymer-based nanofiber membrane using the electrospinning technique. The metal nanoparticles were doped into a silanol network of silica nanoparticles. The fabricated membranes underwent detailed characterization using a wide range of techniques including PXRD, FTIR, Raman, SEM, TEM, TGA, and tensile testing. These analyses provided compelling evidence confirming the successful incorporation of metal-doped silica nanoparticles (Ag, Cu, and Co) into cellulose-based nanofibers. The band gap energies of the fabricated CA mats lie below 3.00 eV, confirming that they are visible light active. The trimetallic silica nanohybrid exhibited the lowest band gap energy of 2.84 eV, proving the self-sterilizing ability of the CA mats. The DPPH assay further confirmed the best radical scavenging activity by the trimetallic silica nanohybrid incorporated nanofiber mat (91.77 ± 0.88%). The antimicrobial activity was assessed by using the bacterial ATCC strains of Staphylococcus aureus, Streptococcus pneumoniae, MRSA (Methicillin-resistant Staphylococcus aureus), Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa and fungal strains; quality control samples of Trichophyton rubrum, Microsporum gypsium, and Aspergillus niger, as well as the ATCC strain of Candida albicans. The trimetallic silica nanohybrid-incorporated CA membranes demonstrated the most significant inhibition zones. The reported findings substantiate the self-sterilizing mat's viability, affordability, efficacy against a broad spectrum of microbial strains, cost-effectiveness, and biodegradability. Furthermore, the mat serves as a dual-purpose physical and biological barrier against microbes, affirming its potential impact.

Endolysin CHAP domain-carbosilane metallodendrimer complexes with triple action on Gram-negative bacteria: Membrane destabilization, reactive oxygen species production and peptidoglycan degradation

Bacterial resistance to antibiotics is a significant challenge that is associated with increased morbidity and mortality. Gram-negative bacteria are particularly problematic due to an outer membrane (OM). Current alternatives to antibiotics include antimicrobial peptides or proteins and multifunctional systems such as dendrimers. Antimicrobial proteins such as lysins can degrade the bacterial cell wall, whereas dendrimers can permeabilize the OM, enhancing the activity of endolysins against gram-negative bacteria. In this study, we present a three-stage action of endolysin combined with two different carbosilane (CBS) silver metallodendrimers, in which the periphery is modified with N-heterocyclic carbene (NHC) ligands coordinating a silver atom. The different NHC ligands contained hydrophobic methyl or N-donor pyridyl moieties. The effects of these endolysin/dendrimer combinations are based on OM permeabilization, peptidoglycan degradation, and reactive oxygen species production. The results showed that CBS possess a permeabilization effect (first action), significantly reduced bacterial growth at higher concentrations alone and in the presence of endolysin, increased ROS production (second action), and led to bacterial cell damage (third action). The complex formed between the CHAP domain of endolysin and a CBS silver metallodendrimer, with a triple mechanism of action, may represent an excellent alternative to other antimicrobials with only one resistance mechanism.

Precision-engineered metal and metal-oxide nanoparticles for biomedical imaging and healthcare applications

The growing field of nanotechnology has witnessed numerous advancements over the past few years, particularly in the development of engineered nanoparticles. Compared with bulk materials, metal nanoparticles possess more favorable properties, such as increased chemical activity and toxicity, owing to their smaller size and larger surface area. Metal nanoparticles exhibit exceptional stability, specificity, sensitivity, and effectiveness, making them highly useful in the biomedical field. Metal nanoparticles are in high demand in biomedical nanotechnology, including Au, Ag, Pt, Cu, Zn, Co, Gd, Eu, and Er. These particles exhibit excellent physicochemical properties, including amenable functionalization, non-corrosiveness, and varying optical and electronic properties based on their size and shape. Metal nanoparticles can be modified with different targeting agents such as antibodies, liposomes, transferrin, folic acid, and carbohydrates. Thus, metal nanoparticles hold great promise for various biomedical applications such as photoacoustic imaging, magnetic resonance imaging, computed tomography (CT), photothermal, and photodynamic therapy (PDT). Despite their potential, safety considerations, and regulatory hurdles must be addressed for safe clinical applications. This review highlights advancements in metal nanoparticle surface engineering and explores their integration with emerging technologies such as bioimaging, cancer therapeutics and nanomedicine. By offering valuable insights, this comprehensive review offers a deep understanding of the potential of metal nanoparticles in biomedical research.

Antibacterial Activity of Zinc-Doped Hydroxyapatite and Vancomycin-Loaded Gelatin Nanoparticles against Intracellular Staphylococcus aureus in Human THP-1 Derived Macrophages

Treating bone infections with common antibiotics is challenging, since pathogens like Staphylococcus aureus can reside inside macrophages. To target these intracellular bacteria, we have proposed nanoparticles (NPs) as drug carriers. This study aims to investigate the efficacy of hydroxyapatite and gelatin NPs, selected in view of their bone mimicry and potential for targeted delivery, as carriers for the antibacterial agents zinc and vancomycin. Therefore, two distinct NPs are fabricated: zinc-doped hydroxyapatite (ZnHA) and vancomycin-loaded gelatin (VGel) NPs. The NPs are characterized based on morphology, size, chemical composition, cellular internalization, and intracellular bactericidal efficacy. Specifically, the intracellular bactericidal efficacy is tested using a validated coculture model of human THP-1 derived macrophages and phagocytosed S. aureus bacteria. Scanning electron microscopy (SEM) and Fourier transform-infrared spectroscopy (FTIR) results show that the spherical NPs are synthesized successfully. These NPs are internalized by THP-1 cells and show >75% colocalization with lysosomes without compromising the viability of the THP-1 cells. Both ZnHA and VGel NPs substantially reduce the intracellular survival of S. aureus compared to the direct addition of dissolved zinc and vancomycin. Concluding, our NPs are highly effective drug delivery vehicles to kill intracellular S. aureus, which stress the potential of these NPs for future clinical translation.

Polyoxometalate-Polymer Directed Macromolecular Architectonics of Silver Nanoparticles as Effective Antimicrobials

A novel inorganic-organic-inorganic ternary bioactive material formulated on antimicrobial peptide-based polymer has been reported. Supramolecular approach has been employed to incorporate molecularly crowded tyrosine-based polymer stabilized silver nanoparticles into membrane bound vesicles exploiting polyoxometalate-triggered surface templating strategy. Utilizing the covalent reversible addition fragmentation chain transfer (RAFT) polymerization and exploiting templated supramolecular architectonics at biopolymer interface, the bioactive ternary polymeric nanohybrids have been designed against Shigellosis leveraging the antibacterial activities of silver nanoparticle, cationic amphiphilic tyrosine polymer and inorganic polyoxometalate. The detail investigation against Shigella flexneri 2a cell line demonstrates that the collaborative mechanism of the ternary hybrid composite enhances the bactericidal activity in comparison to only polyoxometalate and polymer stabilized silver nanoparticle with an altered mechanism of action which is established via detailed biological analysis.

Novel griseofulvin zinc nanohybrid emulsion for intensifying the antimicrobial control of dermatophytes and some opportunistic pathogens

Dermatophytosis is a critical sort of skin infection caused by dermatophytes. The long-term treatment of such skin infections may be improved through the application of nanotechnology. This study aimed to prepare griseofulvin zinc Nanohybrid emulsion (GF-Zn-NHE) to improve griseofulvin activity against dermatophytes and some opportunistic pathogenic yeasts and bacteria. The GF-Zn-NHE is prepared by ultra-homogenization ultra-sonication strategies and validated by UV-visible spectroscopy analysis that confirms presences of griseofulvin and Zn-NPs peaks at 265 and 360 nm, respectively. The GF-Zn-NHE has mean distribution size 50 nm and zeta potential in the range from -40 to -36 mV with no significant changes in size distribution and particle size within 120 day ageing. Fourier transform infrared spectroscopy spectrum confirmed the presence of griseofulvin and Zn-NPs stretching vibration peaks. Gamma ray has a negative influence on GF-Zn-NE production and stability. GF-Zn-NHE drug release 95% up to 24 h and 98% up to 72 h of GF was observed and Zinc 90% up to 24 h and 95% up to 72 h, respectively. High antimicrobial activity was observed with GF-Zn-NHE against dermatophytic pathogens in compare with GF, GF-NE, zinc nitrate and ketoconazole with inhibition zone ranged from 14 to 36 mm. The results have shown that the MIC value for Cryptococcus neoformans, Prophyromonas gingivalis and Pseudomonas aeruginosa is 0.125 mg ml -1 and for Trichophyton rubrum, L. bulgaricus and Escherichia coli value is 0.25 mg ml -1 and for Candida albicans, Malassezia furfur and Enterococcus faecalis is 0.5 mg ml -1 and finally 1 mg ml -1 for Streptococcus mutans. TEM of treated Cryptococcus neoformans cells with GF-Zn-NHE displayed essentially modified morphology, degradation, damage of organelles, vacuoles and other structures.

Advances in antimicrobial orthopaedic devices and FDA regulatory challenges

Implant-associated infections, caused by the formation of biofilms especially antibiotic resistant organisms, are among the leading causes of orthopaedic implant failure. Current strategies to combat infection and biofilm focus on either inhibiting bacterial growth or preventing bacterial adherence that could lead to biofilm creation. Despite research on developing numerous antimicrobial orthopaedic devices, to date, no robust solution has been translated to the clinic. One of the key bottlenecks is the disconnect between researchers and regulatory agencies. In this review, we outline recent strategies for minimizing orthopaedic implant-associated infections. In addition, we discuss the relevant Food and Drug Administration regulatory perspectives, challenges. We also highlight emerging technologies and the directions the field that is expected to expand. We discuss in depth challenges that include identifying strategies that render implants antibacterial permanently or for a long period of time without the use of antimicrobial compounds that could generate resistance in pathogens and negatively impact osseointegration.

Nanoarchitectonics for synergistic activity of multimetallic nanohybrids as a possible approach for antimicrobial resistance (AMR)

The global threat posed by antimicrobial resistance (AMR) to public health is an immensurable problem. The effectiveness of treating infections would be more at risk in the absence of effective antimicrobials. Researchers have shown an amplified interest in alternatives, such as developing advanced metallic nanohybrids as new therapeutic candidates for antibiotics due to their promising effectiveness against resistant microorganisms. In recent decades, the antimicrobial activity of monometallic nanoparticles has received extensive study and solid proof, providing new opportunities for developing multimetallic nanohybrid antimicrobials. Advanced metallic nanohybrids are an emerging remedy for a number of issues that develop in the field of medicine. Advanced metallic nanohybrids have shown a promising ability to combat resistant microorganisms due to their overall synergistic activity. Formulating advanced multimetallic nanohybrids falling under the umbrella of the growing field of nanoarchitectonics, which extends beyond nanotechnology. The underlying theory of nanoarchitectonics involves utilizing nanoscale units that follow the concepts of nanotechnology to architect nanomaterials. This review focuses on a comprehensive description of antimicrobial mechanisms of metallic nanohybrids and their enabling future insights on the research directions of developing the nanoarchitectonics of advanced multimetallic nanohybrids as novel antibiotics through their synergistic activity.

Antimicrobial activity of metal-based nanoparticles: a mini-review

The resistance of pathogenic microorganisms to antibiotics is one of the main problems of world health. Of particular concern are multidrug-resistant (MDR) bacteria. Infections caused by these microorganisms affect the appearance of acute or chronic diseases. In this regard, modern technologies, such as nanomaterials (NMs), especially promising nanoparticles (NPs), can possess antimicrobial properties or improve the effectiveness and delivery of known antibiotics. Their diversity and characteristics, combined with surface functionalization, enable multivalent interactions with microbial biomolecules. This article presents an overview of the most current research on replacing antibiotics with NPs, including the prospects and risks involved.

Advances in silver nanoparticles: a comprehensive review on their potential as antimicrobial agents and their mechanisms of action elucidated by proteomics

Nanoparticles play a crucial role in the field of nanotechnology, offering different properties due to their surface area attributed to their small size. Among them, silver nanoparticles (AgNPs) have attracted significant attention due to their antimicrobial properties, with applications that date back from ancient medicinal practices to contemporary commercial products containing ions or silver nanoparticles. AgNPs possess broad-spectrum biocidal potential against bacteria, fungi, viruses, and Mycobacterium, in addition to exhibiting synergistic effects when combined with certain antibiotics. The mechanisms underlying its antimicrobial action include the generation of oxygen-reactive species, damage to DNA, rupture of bacterial cell membranes and inhibition of protein synthesis. Recent studies have highlighted the effectiveness of AgNPs against various clinically relevant bacterial strains through their potential to combat antibiotic-resistant pathogens. This review investigates the proteomic mechanisms by which AgNPs exert their antimicrobial effects, with a special focus on their activity against planktonic bacteria and in biofilms. Furthermore, it discusses the biomedical applications of AgNPs and their potential non-preparation of antibiotic formulations, also addressing the issue of resistance to antibiotics.

Revolutionizing agriculture with nanotechnology: Innovative approaches in fungal disease management and plant health monitoring

Nanotechnology has emerged as a transformative force in modern agriculture, offering innovative solutions to address challenges related to fungal plant diseases and overall agricultural productivity. Specifically, the antifungal activities of metal, metal oxide, bio-nanoparticles, and polymer nanoparticles were examined, highlighting their unique mechanisms of action against fungal pathogens. Nanoparticles can be used as carriers for fungicides, offering advantages in controlled release, targeted delivery, and reduced environmental toxicity. Nano-pesticides and nano-fertilizers can enhance nutrient uptake, plant health, and disease resistance were explored. The development of nanosensors, especially those utilizing quantum dots and plasmonic nanoparticles, promises early and accurate detection of fungal pathogens, a crucial step in timely disease management. However, concerns about their potential toxic effects on non-target organisms, environmental impacts, and regulatory hurdles underscore the importance of rigorous research and impact assessments. The review concludes by emphasizing the significant prospects of nanotechnology in reshaping the future of agriculture but advocates for a balanced approach that prioritizes safety, sustainability, and environmental stewardship.

Time-kill kinetic of nano-ZnO-loaded nanoliposomes against Aspergillus niger and Botrytis cinerea

In vitro antimicrobial activity of nano-ZnO-loaded nanoliposomes at different levels of lecithin:nano-ZnO ratio (5:1, 15:1, and 25:1 w/w) against Aspergillus niger (IBRC-M 30095) and Botrytis cinerea (IBRC-M 30162) was evaluated. Nanoliposome formulations containing nano-ZnO were fabricated through thin-layer hydration sonication and heat methods. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of nano-ZnO-loaded nanoliposomes and free nano-ZnO against Aspergillus niger and Botrytis cinerea were determined. The time-kill experiments were performed for each isolate. Results showed that the encapsulation of nano-ZnO in nanoliposome systems significantly enhanced their antimicrobial activities by improving the penetration of ZnO nanoparticles the fungi cell membrane. In vitro antifungal activity of nano-ZnO-loaded nanoliposomes against Aspergillus niger and Botrytis cinerea was increased in thin-layer hydration sonication method compared with the heat method. The log phase for Aspergillus niger and Botrytis cinerea was around 70 h. Adding nano-ZnO-loaded nanoliposomes to the culture medium shortened the log phase for both Aspergillus niger and Botrytis cinerea. The highest antimicrobial activity of nanoliposomes was achieved using nanoliposomes containing the lecithin:nano-ZnO ratio of 25:1 (w/w) as compared to all samples. However, the length of the log phase growth cultures exposed to the nanoliposome formulations prepared by thin-layer hydration sonication method with the lecithin:nano-ZnO ratio of 25:1 (w/w) at MIC and MFC values was 60 and 40 h for both Aspergillus niger and Botrytis cinerea, respectively.

Eradication of Klebsiella pneumoniae pulmonary infection by silver oxytetracycline nano-structure

Targeted bactericidal nanosystems hold significant promise to improve the efficacy of existing antimicrobials for treatment of severe bacterial infections by minimizing the side effects and lowering the risk of antibiotic resistance development. In this work, Silver Oxytetracycline Nano-structure (Ag-OTC-Ns) was developed for selective and effective eradication of Klebsiella pneumoniae pulmonary infection. Ag-OTC-Ns were prepared by simple homogenization-ultrasonication method and were characterized by DLS, Zeta potential, TEM and FT-IR. The antimicrobial activity of Ag-OTC-Ns was evaluated in vitro using broth micro-dilution technique and time-kill methods. Our study showed that MICs of AgNO3, OTC, AgNPs and Ag-OTC-Ns were 100, 100, 50 and 6.25 µg/ml, respectively. Ag-OTC-Ns demonstrated higher bactericidal efficacy against the targeted Klebsiella pneumoniae at 12.5 µg/ml compared to the free Oxytetracycline, AgNO3 and AgNPs. In vivo results confirmed that, Ag-OTC-Ns could significantly eradicate K. pneumoniae from mice lung in compare with free Oxytetracycline, AgNO3 and AgNPs. In addition, Ag-OTC-Ns could effectually diminish the inflammatory biomarkers levels of Interferon Gamma and IL-12, and as a result it could effectively lower lung damage in K. pneumoniae infected mice. Ag-OTC-Ns has no significant toxicity on tested mice along the experimental period, there was no sign of behavioral abnormality in the surviving mice indicating that the Ag-OTC-Ns is safe at the used concentration. Furthermore, capability of 5 kGy Gamma ray to sterilize Ag-OTC-Ns solution without affecting it stability was proven.

Advances in the Optimization of Fe Nanoparticles: Unlocking Antifungal Properties for Biomedical Applications

In recent years, nanotechnology has achieved a remarkable status in shaping the future of biological applications, especially in combating fungal diseases. Owing to excellence in nanotechnology, iron nanoparticles (Fe NPs) have gained enormous attention in recent years. In this review, we have provided a comprehensive overview of Fe NPs covering key synthesis approaches and underlying working principles, the factors that influence their properties, essential characterization techniques, and the optimization of their antifungal potential. In addition, the diverse kinds of Fe NP delivery platforms that command highly effective release, with fewer toxic effects on patients, are of great significance in the medical field. The issues of biocompatibility, toxicity profiles, and applications of optimized Fe NPs in the field of biomedicine have also been described because these are the most significant factors determining their inclusion in clinical use. Besides this, the difficulties and regulations that exist in the transition from laboratory to experimental clinical studies (toxicity, specific standards, and safety concerns) of Fe NPs-based antifungal agents have been also summarized.

Green synthesis, characterization and applications of Phyllanthus emblica fruit extract mediated chromium oxide nanoparticles

The green synthesis of metallic nanoparticles is attributable towards diverse applications in various fields, recently. In this research, we report simple and eco-friendly synthesis of chromium oxide (Cr2O3) nanoparticles using the fruit extract of Phyllanthus emblica as a reducing and capping agent. The absorbance peaks at 350 nm and 450 nm validated the nanoparticle formation in UV-visible spectrum. FTIR spectrum revealed the nature of functional groups. The crystalline properties of nanoparticles were ascertained by XRD analysis. EDX spectrum corroborated the elemental composition of nanoparticles in which chromium and oxygen constituted 68% of total weight. SEM images demonstrated agglomeration of nanoparticles resulting in the formation of large irregularly shaped flakes. Cr2O3 nanoparticles demonstrated excellent antimicrobial properties against 11 bacterial isolates and 1 fungal isolate. The largest inhibition zone (53 mm) was measured against A. baumannii while the smallest inhibition zone (26 mm) was recorded against S. aureus. Minimum inhibitory concentration (MIC) values were < 1 µg/ml for all microbes. However, the synthesized nanoparticles did not reveal synergism with any of the selected antibiotics (FICI values > 1). Nanoparticles possessed potent anti-biofilm powers with maximum (77%) inhibition of E. coli biofilms and minimum (45%) inhibition of S. enterica biofilms. Photocatalytic activity of Cr2O3 nanoparticles was evaluated to determine their efficacy in environmental bioremediation. Outcomes demonstrated degradation of methyl red (84%) but not of methylene blue dye. Furthermore, the Cr2O3 nanoparticles displayed considerable antioxidant (43%) as well as anti-inflammatory (44%) potentials. Hence, the present study accounts for the versatile applications of P. emblica-mediated Cr2O3 nanoparticles which could be pursued for future biomedical and environmental applications.

Construction of Co-ZIF-derived CoS2@Cu hollow heterogeneous nanotube array for the detection of hydrazine in environmental water samples

As a neurotoxin, it is necessary to establish a low cost, stable and sensitive method for the quantitative detection of hydrazine. Using Co-ZIF (zeolite imidazole framework) nanorods as precursor, CoS2 hollow nanotube array heterogeneous structure loaded with Cu nanoparticles were prepared on carbon cloth (CC) by etching, calcination and plasma magnetron sputtering (CoS2@Cu HNTA/CC). As a self-supporting electrode, its hollow heterogeneous structure provides a large area of electron transfer channel for the oxidation of the food pollutant hydrazine. In addition, bimetallic synergies and in situ N doping regulated the electronic structure of CoS2@Cu HNTA/CC, and thus significantly improved the electrical conductivity and catalytic activity. As an efficient hydrazine sensor with a wide linear range of 1 μM L-1-10 mM (1 μM-1 mM and 1 mM-10 mM), its sensitivity and the limit of detection are 7996 μA mM-1 cm-2, 3772 μA mM-1 cm-2 and 0.276 μM (S/N = 3), respectively. This study provides a new strategy for the construction of MOFs (Metal Organic Framework)-derived bimetallic composites and their application in electrochemical sensing.

Combinational antimicrobial activity of biogenic TiO2 NP/ZnO NPs nanoantibiotics and amoxicillin-clavulanic acid against MDR-pathogens

The development of effective strategies against multidrug-resistant (MDR) pathogens is an urgent need in modern medicine. Nanoantibiotics (nABs) offer a new hope in countering the surge of MDR-pathogens. The aim of the current study was to evaluate the antibacterial activity of two attractive nABs, TiO2 NPs and ZnO NPs, and their performance in improving the antimicrobial activity of defined antibiotics (amoxicillin-clavulanic acid, amox-clav) against MDR-pathogens. The nABs were synthesized using a green method. The physicochemical characteristics of the synthesized nanoparticles were determined using standard methods. The results showed the formation of pure anatase TiO2 NPs and hexagonal ZnO NPs with an average particle size of 38.65 nm and 57.87 nm, respectively. The values of zeta potential indicated the high stability of the samples. At 8 mg/mL, both nABs exhibited 100 % antioxidant activity, while ZnO showed significantly higher activity at lower concentrations. The antibiofilm assay showed that both nABs could inhibit the formation of biofilms of Acinetobacter baumannii 80 and Escherichia coli 27G (MDR-isolates). However, ZnO NPs showed superior antibiofilm activity (100 %) against E. coli 27G. The MIC values were determined to be 8 (1), 2 (2), and 4 (4) mg/mL for amox-clav, TiO2 NPs, and ZnO NPs against A. baumannii 80 (E. coli 27G), respectively. The results showed that both nABs had synergistically enhanced antibacterial performance in combination with amox-clav. Specifically, an 8-fold reduction in MIC values of antibiotics was observed when they were combined with nABs. These findings highlight the potential of TiO2 NPs and ZnO NPs as effective nanoantibiotics against MDR-pathogens. The synergistic effect observed when combining nABs with antibiotics suggests a promising approach for combating antibiotic resistance. Further research and development in this area could lead to the development of more effective treatment strategies against MDR infections.

Synergistic bactericidal combinations between gentamicin and chitosan capped ZnO nanoparticles: A promising strategy for repositioning this first-line antibiotic

Gentamicin (GEN), a widely used broad-spectrum antibiotic, faces challenges amid the global emergency of antimicrobial resistance. This study aimed to explore the synergistic effects of zinc oxide nanoparticles (ZnO NPs) in combination with GEN on the bactericidal activity against various bacterial strains. Results showed ZnO NPs with MICs ranging from 0.002 to 1.5 μg/mL, while the precursor salt displayed a MIC range of 48.75-1560 μg/mL. Chitosan (CS)-capped ZnO NPs exhibited even lower MICs than their uncapped counterparts, with the CS-capped synthesized ZnO NPs demonstrating the lowest values. Minimal bactericidal concentrations (MBC) aligned with MIC trends. Combinations of CS-capped synthesized ZnO NPs and GEN proved highly effective, inhibiting bacterial growth at significantly lower concentrations than GEN or ZnO NPs alone. This phenomenon may be attributed to the conformation of CS on the ZnO NPs' surface, enhancing the positive particle surface charge. This possibly facilitates a more effective interaction between ZnO NPs and microorganisms, leading to increased accumulation of zinc and GEN within bacterial cells and an overproduction of reactive oxygen species (ROS). It's crucial to note that, while this study did not specifically involve resistant strains, its primary focus remains on enhancing the overall antimicrobial activity of gentamicin. The research aims to contribute to addressing the global challenge of antimicrobial resistance, recognizing the urgent need for effective strategies to combat this critical issue. The findings, particularly the observed synergy between ZnO NPs and GEN, hold significant implications for repositioning the first-line antibiotic GEN.

Nano-enabled antimicrobial thin films: design and mechanism of action

Antimicrobial thin films are types of protective coatings that are applied to surfaces such as medical devices, food packaging materials, water-resistant coatings, and other systems. These films prevent and reduce the spread of microbial organisms, including bacteria, fungi, and viruses. Antimicrobial thin films can be prepared from a variety of nanostructured materials including metal nanoparticles, metal oxides, plant materials, enzymes, bacteriocins and polymers. Their antimicrobial mechanism varies mostly based on the types of active agents from which the film is made of. Antimicrobial thin films are becoming increasingly popular microbial treatment methods due to their advantages such as enhanced stability, reduced toxicity levels, extended effectiveness over time and broad spectrum antimicrobial action without side effects on human health or the environment. This popularity and enhanced performance is mainly due to the extended possibility of film designs. Thin films offer convenient formulation methods which makes them suitable for commercial practices aiming at high turnover rates along with residential applications requiring frequent application cycles. This review focuses on recent developments in the possible processing methods and design approaches for assembling the various types of antimicrobial materials into nanostructured thin film-based delivery systems, along with mechanisms of action against microbes.

Metal doped silica nanohybrids with extensive bacterial coverage for antibacterial applications exhibit synergistic activity

Nanotechnology has triumphantly overcome several barriers that have formed in modern life. Bacterial infections are a critical public health issue. They emphasized the failure of conventional treatments, high mortality and morbidity rates, antibiotic resistance, and other factors leading to the development of novel and affordable antibacterial medications. In this study, three types of metals (Ag, Cu, and Co) were doped separately into a silanol network in silica nanoparticles. The synthesized monometallic nanohybrids were combined in equal proportions to formulate bi and trimetallic nanohybrids. They were characterized structurally and morphologically. Fourier transform infrared (FTIR) and Raman spectroscopy studies were used to investigate the formation of the bonds and the pertinent peak positions. X-ray diffractograms (XRD) validated the crystalline structures of the metal nanohybrids. X-ray photoelectron spectroscopic study (XPS) confirmed the successful addition of metals to the silanol network. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images were used to characterize the morphology of nanohybrids and demonstrate their dimensions are on the nanoscale. The fraction of each metal doped in the silanol network was determined using energy dispersive spectroscopy (EDS) and atomic absorption spectrometry (AAS). To assess activity and confirm antibacterial synergy, the antibacterial activity of all synthesized nanohybrids was examined. The minimum inhibitory concentration-MIC (Ranged from 12.25 to 1560.00 μg/mL), minimum bactericidal concentration-MBC (Ranged from 197.00 to 3125.00 μg/mL), IC50 values (Ranged from 30.56 to 1683.00 μg/mL-) and fractional inhibitory concentration index (FICI) were determined and compared. Well diffusion assay was conducted against both ATCC cultures and clinical samples of gram-positive bacteria; Staphylococcus aureus (ATCC 25923), Streptococcus pneumoniae (ATCC 49619), MRSA (ATCC 33591) and gram-negative bacteria; Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC BAA 1706) and Pseudomonas aeruginosa (ATCC 27853). The highest synergistic radical scavenging performance of trimetallic nanohybrid (90.67 ± 0.095 %) was established by the DPPH (2,2 diphenyl-1-picrylhydrazil) experiment. Finally, when compared to monometallic nanohybrids, it was demonstrated that the synthesized multimetallic nanohybrids have a substantial potential as an emerging and cost-effective antibacterial agent.

Immunomodulatory effects of copper nanoparticles against mitogen-stimulated rat splenic and thymic lymphocytes

In the present study, we have evaluated the effects of copper (Cu) nanoparticles (NPs) on the primary B-and T-lymphocytes proliferation, cytokine levels, and bio-distribution through in vitro, in vivo and ex-vivo studies to allow the possible exploitations of CuNPs in biomedical applications. CuNPs were characterized by UV-Visible spectroscopy, transmission electron microscopy (TEM), and nanoparticle tracking analysis (NTA). The proliferative response of lymphocytes was studied by 3H-thymidine incorporation assay and lymphocyte viability through trypan blue assay. The bio-distribution of CuNPs into lymphoid organs was examined by using ex-vivo imaging system. Cytokine levels in plasma of control and CuNPs treated animal groups were determined by enzyme-linked immunosorbent assay (ELISA) method along with other biochemical analysis. CuNPs significantly suppressed the proliferation of primary splenic and thymic lymphocytes in a dose dependent manner. Ex-vivo imaging exhibited the distribution of CuNPs in spleen and thymus. Oral administration of CuNPs (2 mg and 10 mg/kg body weight) significantly inhibited the proliferation of splenic and thymic lymphocytes along with lowered cytokines levels (TNF-alpha and IL-2) on comparison with controls. The results indicated the significant inhibition of lymphocytes proliferative response and secretion of cytokines, thus unveiling the immunomodulatory effects of CuNPs.

Extracellular synthesis of silver nanoparticle using yeast extracts: antibacterial and seed priming applicationss

The evolution and rapid spread of multidrug-resistant (MDR) bacterial pathogens have become a major concern for human health and demand the development of alternative antimicrobial agents to combat this emergent threat. Conventional intracellular methods for producing metal nanoparticles (NPs) using whole-cell microorganisms have limitations, including binding of NPs to cellular components, potential product loss, and environmental contamination. In contrast, this study introduces a green, extracellular, and sustainable methodology for the bio-materialization of silver NPs (AgNPs) using renewable resource cell-free yeast extract. These extracts serve as a sustainable, biogenic route for both reducing the metal precursor and stabilizing the surface of AgNPs. This method offers several advantages such as cost-effectiveness, environment-friendliness, ease of synthesis, and scalability. HR-TEM imaging of the biosynthesized AgNPs revealed an isotropic growth route, resulting in an average size of about ~ 18 nm and shapes ranging from spherical to oval. Further characterization by FTIR and XPS results revealed various functional groups, including carboxyl, hydroxyl, and amide contribute to enhanced colloidal stability. AgNPs exhibited potent antibacterial activity against tested MDR strains, showing particularly high efficacy against Gram-negative bacteria. These findings suggest their potential role in developing alternative treatments to address the growing threat of antimicrobial resistance. Additionally, seed priming experiments demonstrated that pre-sowing treatment with AgNPs improves both the germination rate and survival of Sorghum jowar and Zea mays seedlings. KEY POINTS: •Yeast extract enables efficient, cost-effective, and eco-friendly AgNP synthesis. •Biosynthesized AgNPs showed strong antibacterial activity against MDR bacteria. •AgNPs boost seed germination and protect against seed-borne diseases.

Nanocoating and its application as antimicrobials in the food industry: A review

Nanocoatings are ultra-thin layers on the nanoscale (<100 nm) that are deposited on the substrate to improve their properties and functionality. These nanocoatings provide significant advantages compared to traditional coating, including stain resistance, antimicrobial and antioxidant activities, odor control and delivery of active agents, and liquid repellence properties. In the food industry, nanocoating is widely used in the food packaging sector. In this regard, nanocoating offers antimicrobials and antioxidant properties to active food packaging by incorporating active bioactive compounds into materials used in already existing packaging. The application of nanocoating is applied to these kinds of food packaging with nano coating to improve shelf life, safety, and quality of food packaging. In smart/intelligent packaging, the active packaging coating is promising food packaging, which is designed by releasing preservatives and nanocoating as an antimicrobial, antifungal, antioxidant, barrier coating, and self-cleaning food contact surfaces. In addition, nanocoating can be used for food contact surfaces, kitchen utensils, and food processing equipment to create antimicrobial, antireflective, and dirt-repellent properties. These are critical properties for food processing, especially for meat and dairy processing facilities, which can reduce biofilm formation and prevent cross-contamination. Recently, appreciable growth in the development of the application of nanocoating as edible films for coating food products has emerged to improve food safety issues. In this regard, much scientific research in the area of nanocoating fruits and vegetables, and other food products was performed to address food safety issues. Hence, this promising technology can be a great addition to the agricultural and food industries. Thus, this review addresses the most relevant information about this technology and the applications of nanocoating in the food industry.

The Synergistic Effect of Biosynthesized Silver Nanoparticles and Phytocompound as a Novel Approach to the Elimination of Pathogens

Due to the wide applications of silver nanoparticles (AgNPs), research on their ecological synthesis has been extensive in recent years. In our study, biogenic silver nanoparticles were synthesized extracellularly using the white rot fungus Trametes versicolor via two cultivation methods: static and shaking. The cell filtrate of the fungus was used as a reducing agent in the process of nanoparticle synthesis. Characterization of the obtained nanoparticles was carried out using UV-VIS spectroscopy and scanning electron microscopy. The biosynthesized nanoparticles have antimicrobial potential against pathogenic bacteria, particularly in Gram-negative strains. The bactericidal effect was obtained for E. coli at a concentration of 7 µg/mL. The use of higher concentrations of compounds was necessary for Gram-positive bacteria. Taking into account the problem of the risk of cytotoxicity of AgNPs, combined therapy using a phytochemical was used for the first time, which was aimed at reducing the doses of nanoparticles. The most representative synergistic effect was observed in the treatment of 5 µg/mL silver nanoparticles in combination with 15 µg/mL ursolic acid against E. coli and P. aeruginosa with a bactericidal effect. Moreover, the coadministration of nanoparticles considerably reduced the growth of both Staphylococcus strains, with a bactericidal effect against S. aureus. The viability test confirmed the strong synergistic effect of both tested compounds. Silver nanoparticles synthesized using the T. versicolor showed excellent antibacterial potential, which opens perspectives for future investigations concerning the use of the nanoparticles as antimicrobials in the areas of health.

Microalga Broths Synthesize Antibacterial and Non-Cytotoxic Silver Nanoparticles Showing Synergy with Antibiotics and Bacterial ROS Induction and Can Be Reused for Successive AgNP Batches

The era of increasing bacterial antibiotic resistance requires new approaches to fight infections. With this purpose, silver-based nanomaterials are a reality in some fields and promise new developments. We report the green synthesis of silver nanoparticles (AgNPs) using culture broths from a microalga. Broths from two media, with different compositions and pHs and sampled at two growth phases, produced eight AgNP types. Nanoparticles harvested after several synthesis periods showed differences in antibacterial activity and stability. Moreover, an evaluation of the broths for several consecutive syntheses did not find relevant kinetics or activity differences until the third round. Physicochemical characteristics of the AgNPs (core and hydrodynamic sizes, Z-potential, crystallinity, and corona composition) were determined, observing differences depending on the broths used. AgNPs showed good antibacterial activity at concentrations producing no or low cytotoxicity on cultured eukaryotic cells. All the AgNPs had high levels of synergy against Escherichia coli and Staphylococcus aureus with the classic antibiotics streptomycin and kanamycin, but with ampicillin only against S. aureus and tetracycline against E. coli. Differences in the synergy levels were also dependent on the types of AgNPs. We also found that, for some AgNPs, the killing of bacteria started before the massive accumulation of ROS.

Modular Drug-Loaded Nanocapsules with Metal Dome Layers as a Platform for Obtaining Synergistic Therapeutic Biological Activities

Multifunctional drug-loaded polymer-metal nanocapsules have attracted increasing attention in drug delivery due to their multifunctional potential endowed by drug activity and response to physicochemical stimuli. Current chemical synthesis methods of polymer/metal capsules require specific optimization of the different components to produce particles with precise properties, being particularly complex for Janus structures combining polymers and ferromagnetic and highly reactive metals. With the aim to generate tunable synergistic nanotherapeutic actuation with enhanced drug effects, here we demonstrate a versatile hybrid chemical/physical fabrication strategy to incorporate different functional metals with tailored magnetic, optical, or chemical properties on solid drug-loaded polymer nanoparticles. As archetypical examples, we present poly(lactic-co-glycolic acid) (PLGA) nanoparticles (diameters 100-150 nm) loaded with paclitaxel, indocyanine green, or erythromycin that are half-capped by either Fe, Au, or Cu layers, respectively, with application in three biomedical models. The Fe coating on paclitaxel-loaded nanocapsules permitted efficient magnetic enhancement of the cancer spheroid assembly, with 40% reduction of the cross-section area after 24 h, as well as a higher paclitaxel effect. In addition, the Fe-PLGA nanocapsules enabled external contactless manipulation of multicellular cancer spheroids with a speed of 150 μm/s. The Au-coated and indocyanine green-loaded nanocapsules demonstrated theranostic potential and enhanced anticancer activity in vitro and in vivo due to noninvasive fluorescence imaging with long penetration near-infrared (NIR) light and simultaneous photothermal-photodynamic actuation, showing a 3.5-fold reduction in the tumor volume growth with only 5 min of NIR illumination. Finally, the Cu-coated erythromycin-loaded nanocapsules exhibited enhanced antibacterial activity with a 2.5-fold reduction in the MIC50 concentration with respect to the free or encapsulated drug. Altogether, this technology can extend a nearly unlimited combination of metals, polymers, and drugs, thus enabling the integration of magnetic, optical, and electrochemical properties in drug-loaded nanoparticles to externally control and improve a wide range of biomedical applications.

The Green Synthesis of Silver Nanoparticles from Avena fatua Extract: Antifungal Activity against Fusarium oxysporum f.sp. lycopersici

Using plant extracts as eco-friendly reducing and stabilizing agents for the synthesis of nanoparticles has gained significant attention in recent years. The current study explores the green synthesis of silver nanoparticles (AgNPs) using the Avena fatua extract and evaluates their antifungal activity against Fusarium oxysporum f.sp. lycopersici (Fol), a fungal plant pathogen. A green and sustainable approach was adopted to synthesize silver nanoparticles before these nanoparticles were employed for anti-fungal activity. The primary indication that AgNPs had formed was performed using UV-vis spectroscopy, where a strong peak at 425 nm indicated the effective formation of these nanoparticles. The indication of important functional groups acting as reducing and stabilizing agents was conducted using the FTIR study. Additionally, morphological studies were executed via SEM and AFM, which assisted with more effectively analyzing AgNPs. Crystalline behavior and size were estimated using powder XRD, and it was found that AgNPs were highly crystalline, and their size ranged from 5 to 25 nm. Synthesized AgNPs exhibited significant antifungal activity against Fol at a concentration of 40 ppm. Furthermore, the inhibitory index confirmed a positive correlation between increasing AgNPs concentration and exposure duration. This study suggests that the combined phytochemical mycotoxic effect of the plant extract and the smaller size of synthesized AgNPs were responsible for the highest penetrating power to inhibit Fol growth. Moreover, this study highlights the potential of using plant extracts as reducing and capping agents for the green synthesis of AgNPs with antifungal properties. The study concludes that A. fatua extract can synthesize antifungal AgNPs as a sustainable approach with robust antifungal efficacy against Fol, underscoring their promising potential for integration into plant protection strategies.

Current Overview of Metal Nanoparticles' Synthesis, Characterization, and Biomedical Applications, with a Focus on Silver and Gold Nanoparticles

Metal nanoparticles (NPs) have garnered considerable attention, due to their unique physicochemical properties, that render them promising candidates for various applications in medicine and industry. This article offers a comprehensive overview of the most recent advancements in the manufacturing, characterization, and biomedical utilization of metal NPs, with a primary focus on silver and gold NPs. Their potential as effective anticancer, anti-inflammatory, and antimicrobial agents, drug delivery systems, and imaging agents in the diagnosis and treatment of a variety of disorders is reviewed. Moreover, their translation to therapeutic settings, and the issue of their inclusion in clinical trials, are assessed in light of over 30 clinical investigations that concentrate on administering either silver or gold NPs in conditions ranging from nosocomial infections to different types of cancers. This paper aims not only to examine the biocompatibility of nanomaterials but also to emphasize potential challenges that may limit their safe integration into healthcare practices. More than 100 nanomedicines are currently on the market, which justifies ongoing study into the use of nanomaterials in medicine. Overall, the present review aims to highlight the potential of silver and gold NPs as innovative and effective therapeutics in the field of biomedicine, citing some of their most relevant current applications.

Metallic Nanoparticles: A Promising Arsenal against Antimicrobial Resistance-Unraveling Mechanisms and Enhancing Medication Efficacy

The misuse of antibiotics and antimycotics accelerates the emergence of antimicrobial resistance, prompting the need for novel strategies to combat this global issue. Metallic nanoparticles have emerged as effective tools for combating various resistant microbes. Numerous studies have highlighted their potential in addressing antibiotic-resistant fungi and bacterial strains. Understanding the mechanisms of action of these nanoparticles, including iron-oxide, gold, zinc oxide, and silver is a central focus of research within the life science community. Various hypotheses have been proposed regarding how nanoparticles exert their effects. Some suggest direct targeting of microbial cell membranes, while others emphasize the release of ions from nanoparticles. The most compelling proposed antimicrobial mechanism of nanoparticles involves oxidative damage caused by nanoparticles-generated reactive oxygen species. This review aims to consolidate knowledge, discuss the properties and mechanisms of action of metallic nanoparticles, and underscore their potential as alternatives to enhance the efficacy of existing medications against infections caused by antimicrobial-resistant pathogens.

Tailoring the Surface and Composition of Nanozymes for Enhanced Bacterial Binding and Antibacterial Activity

With the advantages of diverse structures, tunable enzymatic activity, and high stability, nanozymes are widely used in medicine, chemistry, food, environment, and other fields. As an alternative to traditional antibiotics, nanozymes attract more and more attention from the scientific researchers in recent years. Developing nanozymes-based antibacterial materials opens up a new avenue for the bacterial disinfection and sterilization. In this review, the classification of nanozymes and their antibacterial mechanisms are discussed. The surface and composition of nanozymes are critical for the antibacterial efficacy, which can be tailored to enhance both the bacterial binding and the antibacterial activity. On the one hand, the surface modification of nanozymes enables binding and targeting of bacteria that improves the antibacterial performance of nanozymes including the biochemical recognition, the surface charge, and the surface topography. On the other hand, the composition of nanozymes can be modulated to achieve enhanced antibacterial performance including the single nanozyme-mediated synergistic and multiple nanozymes-mediated cascade catalytic antibacterial applications. In addition, the current challenges and future prospects of tailoring nanozymes for antibacterial applications are discussed. This review can provide insights into the design of future nanozymes-based materials for the antibacterial treatments.

Environment-Responsive Therapeutic Platforms for the Treatment of Implant Infection

The application of medical implants has greatly improved the survival rate and life quality of patients. Nevertheless, in recent years, there are increasing cases of implant dysfunction or failure because of bacterial infections. Despite significant improvements in biomedicine, there are still serious challenges in the treatment of implant-related infections. With the formation of bacterial biofilms and the development of bacterial resistance, these limitations lead to a low efficacy of conventional antibiotics. To address these challenges, it is urgent to exploit innovative treatment strategies for implant-related infections. Based on these ideas, environment-responsive therapeutic platforms with high selectivity, low drug resistance, and minor dose-limiting toxicity have attracted widespread attention. By using exogenous/endogenous stimuli, the antibacterial activity of therapeutics can be activated on demand and exhibit remarkable therapeutic effects. Exogenous stimuli include photo, magnetism, microwave, and ultrasound. Endogenous stimuli mainly include the pathological characteristics of bacterial infections such as acidic pH, anomalous temperature, and abnormal enzymatic activities. In this review, the recent progress of environment-responsive therapeutic platforms with spatiotemporally controlled drug release/activation is systematically summarized. Afterward, the limitations and opportunities of these emerging platforms are highlighted. Finally, it is hoped that this review will offer novel ideas and techniques to combat implant-related infections.

Exploring nanocomposites for controlling infectious microorganisms: charting the path forward in antimicrobial strategies

Nanocomposites, formed by combining a matrix (commonly polymer or ceramic) with nanofillers (nano-sized inclusions like nanoparticles or nanofibers), possess distinct attributes attributed to their composition. Their unique physicochemical properties and interaction capabilities with microbial cells position them as a promising avenue for infectious disease treatment. The escalating prevalence of multi-drug resistant bacteria intensifies the need for alternative solutions. Traditional approaches involve antimicrobial agents like antibiotics, antivirals, and antifungals, targeting specific microbial aspects. This review presents a comprehensive overview of diverse nanocomposite types and highlights the potential of tailored matrix and antibacterial agent selection within nanocomposites to enhance treatment efficacy and decrease antibiotic resistance risks. Challenges such as toxicity, safety, and scalability in clinical applications are also acknowledged. Ultimately, the convergence of nanotechnology and infectious disease research offers the prospect of enhanced therapeutic strategies, envisioning a future wherein advanced materials revolutionize the landscape of medical treatment.