Probiotic Lactobacillus salivarius mediated synthesis of silver nanoparticles (AgNPs-LS): A sustainable approach and multifaceted biomedical application

Biogenic synthesis of silver nanoparticles (AgNPs) has emerged as an eco-friendly and sustainable approach with diverse biological applications. This study presents synthesis of AgNPs-LS using a probiotic strain Lactobacillus salivarius (L. salivarius) and explores their multifaceted biological activities, including antibacterial, antibiofilm, anti-quorum sensing, antifungal, antioxidant, anticancer, anticoagulant and thrombolytic properties. The biosynthesis of AgNPs-LS was successfully achieved using L. salivarius cell free supernatants, resulting in well-characterized nanoparticles as confirmed by UV-Vis spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and dynamic light scattering (DLS) and zeta potential analysis. The AgNPs-LS demonstrated potent antibacterial activity against different pathogenic bacteria (C. violaceum, P. aeruginosa, S. aureus, E. coli and S. marcescens), emphasizing their potential in combating bacterial infections. Moreover, these AgNPs-LS were effective in inhibiting biofilm formation (>60 % at 1/2 MIC), a key mechanism of bacterial virulence, highlighting their utility in preventing biofilm-related infections. AgNPs-LS exhibited anti-quorum sensing activity, disrupting bacterial communication systems and potentially reducing virulence factor such as, violacein production in C. violaceum, pyocyanin production in P. aeruginosa and prodigiosin production in S. marcescens. Additionally, AgNPs-LS also exhibited notable antifungal activity towards a different pathogenic fungus (F. proliferatum, P. purpurogenum, A. niger and R. stolonifer). In terms of health applications, the AgNPs-LS displayed significant antioxidant activity, effectively scavenging DPPH• (IC50 = 42.65 μg/mL) and ABTS•+ (IC50 = 53.77 μg/mL) free radicals. Furthermore, AgNPs-LS showed cytotoxicity against breast cancer cells (MCF-7) (IC50 = 52.29 μg/mL), positioning them as promising candidates for cancer therapy. Moreover, AgNPs-LS were also shown promising anticoagulant and thrombolytic activities under practical conditions. Therefore, the biogenic synthesis of AgNPs-LS using L. salivarius offers a sustainable and cost-effective route for producing AgNPs with an array of biological activities. These AgNPs-LS have the potential to address various challenges in healthcare, ranging from antimicrobial, anticancer applications to biofilm inhibition, antioxidant therapy, anticoagulant and thrombolytic agents.

Inorganic nanoparticles: An effective antibiofilm strategy

Biofilm is a common problem associated with human health. Pathogenicity and increase in resistance of bacteria require urgent development of effective ways for the treatment of bacterial diseases. Different strategies have been developed for the treatment of bacterial infections among which nanoparticles have shown greater prospects in battling with infections. Biofilms are resistant microbial colonies that possess resistance and, hence, cannot be killed by conventional drugs. Nanoparticles offer new avenues for treating biofilm-related infections involving multi-drug resistant organisms. They possess great antibiofilm properties, disrupting cell architecture and preventing colony formation. Green-synthesised nanoparticles are more effective and less toxic to human cells than commercially available or chemically synthesised antibiofilm nanoparticles. This review summarises the antibiofilm efficiency of plant-mediated nanoparticles and knowledge about biofilm inhibition.

Ecofriendly biosynthesis of copper nanoparticles from novel marine S. rhizophila species for enhanced antibiofilm, antimicrobial and antioxidant potential

Marine microorganisms offer a promising avenue for the eco-friendly synthesis of nanoparticles due to their unique biochemical capabilities and adaptability to various environments. This study focuses on exploring the potential of a marine bacterial species, Stenotrophomonas rhizophila BGNAK1, for the synthesis of biocompatible copper nanoparticles and their application for hindering biofilms formed by monomicrobial species. The study begins with the isolation of the novel marine S. rhizophila species from marine soil samples collected from the West coast region of Kerala, India. The isolated strain is identified through 16S rRNA gene sequencing and confirmed to be S. rhizophila species. Biosynthesis of copper nanoparticles using S. rhizophila results in the formation of nanoparticles with size of range 10-50 nm. The nanoparticles exhibit a face-centered cubic crystal structure of copper, as confirmed by X-Ray Diffraction analysis. Furthermore, the synthesized nanoparticles display significant antimicrobial activity against various pathogenic bacteria and yeast. The highest inhibitory activity was against Staphylococcus aureus with a zone of 27 ± 1.00 mm and the least activity was against Pseudomonas aeruginosa with a zone of 22 ± 0.50 mm. The zone of inhibition against Candida albicans was 16 ± 0.60 mm. The antibiofilm activity against biofilm-forming clinical pathogens was evidenced by the antibiofilm assay and SEM images. Additionally, the copper nanoparticles exhibit antioxidant activity, as evidenced by their scavenging ability against DPPH, hydroxyl, nitric oxide, and superoxide radicals, as well as their reducing power in the FRAP assay. The study highlights the potential of the marine bacterium S. rhizophila BGNAK1 for the eco-friendly biosynthesis of copper nanoparticles with diverse applications. Synthesized nanoparticles exhibit promising antibiofilm, antimicrobial, and antioxidant properties, suggesting their potential utility in various fields such as medicine, wastewater treatment, and environmental remediation.

Advances in bioinspired nanomaterials managing microbial biofilms and virulence: A critical analysis

Microbial virulence and biofilm formation stand as a big concern against the goal of achieving a green and sustainable future. Microbial pathogenesis is the process by which the microbes (bacterial, fungal, and viral) cause illness in their respective host organism. 'Nanotechnology' is a state-of-art discipline to address this problem. The use of conventional techniques against microbial proliferation has been challenging against the environment. To tackle this problem, there has been a revolution in this multi-disciplinary field, to address the aspect of bioinspired nanomaterials in the antibiofilm and antimicrobial sector. Bioinspired nanomaterials prove to be a potential antibiofilm and antimicrobial agent as they are non-hazardous to the environment and mostly synthesized using a single-step reduction protocol. They exhibit synergistic effects against bacterial, fungal, and viral pathogens and thereby, control the virulence. In this literature review, we have elucidated the potential of bioinspired nanoparticles as well as nanomaterials as a promising anti-microbial treatment pedagogy and throw light on the advancements in how smart photo-switchable platforms have been designed to exhibit both bacterial releasing as well as bacterial-killing properties. Certain limitations and possible outcomes of these bio-based nanomaterials have been discussed in the hope of achieving a green and sustainable ecosystem.

Nanomaterial in controlling biofilms and virulence of microbial pathogens

The escalating threat of antimicrobial resistance (AMR) poses a grave concern to global public health, exacerbated by the alarming shortage of effective antibiotics in the pipeline. Biofilms, intricate populations of bacteria encased in self-produced matrices, pose a significant challenge to treatment, as they enhance resistance to antibiotics and contribute to the persistence of organisms. Amid these challenges, nanotechnology emerges as a promising domain in the fight against biofilms. Nanomaterials, with their unique properties at the nanoscale, offer innovative antibacterial modalities not present in traditional defensive mechanisms. This comprehensive review focuses on the potential of nanotechnology in combating biofilms, focusing on green-synthesized nanoparticles and their associated anti-biofilm potential. The review encompasses various aspects of nanoparticle-mediated biofilm inhibition, including mechanisms of action. The diverse mechanisms of action of green-synthesized nanoparticles offer valuable insights into their potential applications in addressing AMR and improving treatment outcomes, highlighting novel strategies in the ongoing battle against infectious diseases.

Synthesis of Berberis aristate rhizome extract stabilized magnesium nanoparticles using green chemistry: rhizome characterization, in vitro antimicrobial and anti-inflammatory activity

In the present study, magnesium nanoparticles (Mg NPs) were synthesized utilizing an aqueous extract of Berberis aristate rhizome and evaluated for antimicrobial and anti-inflammatory activity. Technofunctional properties of rhizome powder were evaluated and during thermal stability evaluation four stages of decomposition with a maximum delta Y value of 76.04 % was observed. Optimization of Mg NPs was carried out by employing eight different concentrations (C1-C8)   and the C4 showed maximum absorbance at 330 nm confirming the NPs synthesis. The Mg NPs showed the particle size of 62 nm, zeta potential of -24.7 mV and hexagonal mprphology. Potential inhibition against S. aureus and E. coli (76.78 ± 0.05% and 74.62 ± 0.17%)and anti-inflammatory activity ranging from 42.43 ± 0.07-82.92 ± 0.04% was observed for Mg NPs. Therefore, green synthesis of Mg NPs is a promising approach for the development ofbiological active NPs to cure microbial infections.

Targeting bacterial biofilm-related genes with nanoparticle-based strategies

Persistent infection caused by biofilm is an urgent in medicine that should be tackled by new alternative strategies. Low efficiency of classical treatments and antibiotic resistance are the main concerns of the persistent infection due to biofilm formation which increases the risk of morbidity and mortality. The gene expression patterns in biofilm cells differed from those in planktonic cells. One of the promising approaches against biofilms is nanoparticle (NP)-based therapy in which NPs with multiple mechanisms hinder the resistance of bacterial cells in planktonic or biofilm forms. For instance, NPs such as silver (Ag), zinc oxide (ZnO), titanium dioxide (TiO2), copper oxide (Cu), and iron oxide (Fe3O4) through the different strategies interfere with gene expression of bacteria associated with biofilm. The NPs can penetrate into the biofilm structure and affect the expression of efflux pump, quorum-sensing, and adhesion-related genes, which lead to inhibit the biofilm formation or development. Therefore, understanding and targeting of the genes and molecular basis of bacterial biofilm by NPs point to therapeutic targets that make possible control of biofilm infections. In parallel, the possible impact of NPs on the environment and their cytotoxicity should be avoided through controlled exposure and safety assessments. This study focuses on the biofilm-related genes that are potential targets for the inhibition of bacterial biofilms with highly effective NPs, especially metal or metal oxide NPs.

Nano-elicitation and hydroponics: a synergism to enhance plant productivity and secondary metabolism

MAIN CONCLUSION

This review has explored the importance of using a synergistic approach of nano-elicitation and hydroponics to improve plant growth and metabolite production. Furthermore, it emphasizes the significance of green nanotechnology and eco-friendly practices while utilizing this approach to promote the development of a sustainable agriculture system. Nano-elicitation stimulates metabolic processes in plants using nanoparticles (NPs) as elicitors. The stimulation of these biochemical processes can enhance plant yield and productivity, along with the production of secondary metabolites. Nanoparticles have garnered the attention of scientific community because of their unique characteristics, such as incredibly small size and large surface-to-volume ratio, which make them effective elicitors. Hydroponic systems, which optimize growing conditions to increase plant production, are typically used to study the effect of elicitors. By integrating these two approaches, the qualitative and quantitative output of plants can be increased while employing minimal resources. As the global demand for high-quality crops and bioactive compounds surges, embracing this synergistic approach alongside sustainable farming practices can pave the way for resilient agricultural systems, ensuring food security and fostering an eco-friendly environment.

Antibacterial and Antibiofilm Activity of Ficus carica-Mediated Calcium Oxide (CaONPs) Phyto-Nanoparticles

The significance of nanomaterials in biomedicines served as the inspiration for the design of this study. In this particular investigation, we carried out the biosynthesis of calcium oxide nanoparticles (CaONPs) by employing a green-chemistry strategy and making use of an extract of Ficus carica (an edible fruit) as a capping and reducing agent. There is a dire need for new antimicrobial agents due to the alarming rise in antibiotic resistance. Nanoparticles' diverse antibacterial properties suggest that they might be standard alternatives to antimicrobial drugs in the future. We describe herein the use of a Ficus carica extract as a capping and reducing agent in the phyto-mediated synthesis of CaONPs for the evaluation of their antimicrobial properties. The phyto-mediated synthesis of NPs is considered a reliable approach due to its high yield, stability, non-toxicity, cost-effectiveness and eco-friendliness. The CaONPs were physiochemically characterized by UV-visible spectroscopy, energy-dispersive X-ray (EDX), scanning-electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). The biological synthesis of the calcium oxide nanoparticles revealed a characteristic surface plasmon resonance peak (SPR) at 360 nm in UV-Vis spectroscopy, which clearly revealed the successful reduction of the Ca²⁺ ions to Ca⁰ nanoparticles. The characteristic FTIR peak seen at 767 cm^-1 corresponded to Ca-O bond stretching and, thus, confirmed the biosynthesis of the CaONPs, while the scanning-electron micrographs revealed near-CaO aggregates with an average diameter of 84.87 ± 2.0 nm. The antibacterial and anti-biofilm analysis of the CaONPs showed inhibition of bacteria in the following order: P. aeruginosa (28 ± 1.0) > S. aureus (23 ± 0.3) > K. pneumoniae (18 ± 0.9) > P. vulgaris (13 ± 1.6) > E. coli (11 ± 0.5) mm. The CaONPs were shown to considerably inhibit biofilm formation, providing strong evidence for their major antibacterial activity. It is concluded that this straightforward environmentally friendly method is capable of synthesizing stable and effective CaONPs. The therapeutic value of CaONPs is indicated by their potential as a antibacterial and antibiofilm agents in future medications.

Immobilization of ZnO-TiO2 Nanocomposite into Polyimidazolium Amphiphilic Chitosan Film, Targeting Improving Its Antimicrobial and Antibiofilm Applications

This study presents a green protocol for the fabrication of a multifunctional smart nanobiocomposite (NBC) (ZnO-PIACSB-TiO2) for secure antimicrobial and antibiofilm applications. First, shrimp shells were upgraded to a polyimidazolium amphiphilic chitosan Schiff base (PIACSB) through a series of physicochemical processes. After that, the PIACSB was used as an encapsulating and coating agent to manufacture a hybrid NBC in situ by co-encapsulating ZnONPs and TiO2NPs. The physicochemical and visual characteristics of the new NBC were investigated by spectral, microscopic, electrical, and thermal methods. The antimicrobial indices revealed that the newly synthesized, PIACSB-coated TiO2-ZnO nanocomposite is an exciting antibiotic due to its amazing antimicrobial activity (MIC/MBC→0.34/0.68 μg/mL, 0.20/0.40 μg/mL, and 0.15/0.30 μg/mL working against S. aureus, E. coli, and P. aeruginosa, respectively) and antifungal capabilities. Additionally, ZnO-PIACSB-TiO2 is a potential fighter of bacterial biofilms, with the results being superior to those of the positive control (Cipro), which worked against S. aureus (only 8.7% ± 1.9 biofilm growth), E. coli (only 1.4% ± 1.1 biofilm growth), and P. aeruginosa (only 0.85% ± 1.3 biofilm growth). Meanwhile, the NBC exhibits excellent biocompatibility, as evidenced by its IC50 values against both L929 and HSF (135 and 143 µg/mL), which are significantly higher than those of the MIC doses (0.24-24.85 µg/mL) that work against all tested microbes, as well as the uncoated nanocomposite (IC50 = 19.36 ± 2.04 and 23.48 ± 1.56 µg/mL). These findings imply that the new PIACSB-coated nanocomposite film may offer promising multifunctional food packaging additives to address the customer demand for safe, eco-friendly food products with outstanding antimicrobial and antibiofilm capabilities.

Antibacterial and Antibiofilm Activity of Chemically and Biologically Synthesized Silver Nanoparticles

Bacterial biofilms are a significant problem in the food industry, as they are difficult to eradicate and represent a threat to consumer health. Currently, nanoparticles as an alternative to traditional chemical disinfectants have garnered much attention due to their broad-spectrum antibacterial activity and low toxicity. In this study, silver nanoparticles (AgNPs) were synthesized by a biological method using a Jacaranda mimosifolia flower aqueous extract and by a chemical method, and the factors affecting both syntheses were optimized. The nanoparticles were characterized by Ultraviolet-visible (UV-Vis) spectrophotometry, Fourier-transform infrared spectroscopy (FTIR), Dynamic light scattering (DLS), X-ray diffraction (XRD), and Transmission electron microscopy (TEM) with a spherical and uniform shape. The antibacterial and antibiofilm formation activity was carried out on bacterial species of Pseudomonas aeruginosa and Staphylococcus aureus with the capacity to form biofilm. The minimum inhibitory concentration was 117.5 μg/mL for the chemical and 5.3 μg/mL for the biological nanoparticles. Both types of nanoparticles showed antibiofilm activity in the qualitative Congo red test and in the quantitative microplate test. Antibiofilm activity tests on fresh lettuce showed that biological nanoparticles decreased the population of S. aureus and P. aeruginosa by 0.63 and 2.38 logarithms, respectively, while chemical nanoparticles had little microbial reduction. In conclusion, the biologically synthesized nanoparticles showed greater antibiofilm activity. Therefore, these results suggest their potential application in the formulation of sanitizing products for the food and healthcare industries.

Comparative analysis of phyto-fabricated chitosan, copper oxide, and chitosan-based CuO nanoparticles: antibacterial potential against Acinetobacter baumannii isolates and anticancer activity against HepG2 cell lines

The aim of this study was to provide a comparative analysis of chitosan (CH), copper oxide (CuO), and chitosan-based copper oxide (CH-CuO) nanoparticles for their application in the healthcare sector. The nanoparticles were synthesized by a green approach using the extract of Trianthema portulacastrum. The synthesized nanoparticles were characterized using different techniques, such as the synthesis of the particles, which was confirmed by UV-visible spectrometry that showed absorbance at 300 nm, 255 nm, and 275 nm for the CH, CuO, and CH-CuO nanoparticles, respectively. The spherical morphology of the nanoparticles and the presence of active functional groups was validated by SEM, TEM, and FTIR analysis. The crystalline nature of the particles was verified by XRD spectrum, and the average crystallite sizes of 33.54 nm, 20.13 nm, and 24.14 nm were obtained, respectively. The characterized nanoparticles were evaluated for their in vitro antibacterial and antibiofilm potential against Acinetobacter baumannii isolates, where potent activities were exhibited by the nanoparticles. The bioassay for antioxidant activity also confirmed DPPH scavenging activity for all the nanoparticles. This study also evaluated anticancer activities of the CH, CuO, and CH-CuO nanoparticles against HepG2 cell lines, where maximum inhibitions of 54, 75, and 84% were recorded, respectively. The anticancer activity was also confirmed by phase contrast microscopy, where the treated cells exhibited deformed morphologies. This study demonstrates the potential of the CH-CuO nanoparticle as an effective antibacterial agent, having with its antibiofilm activity, and in cancer treatment.

Synergistic Antibacterial Proficiency of Green Bioformulated Zinc Oxide Nanoparticles with Potential Fosfomycin Synergism against Nosocomial Bacterial Pathogens

The drug resistance of bacterial pathogens causes considerable morbidity and death globally, hence there is a crucial necessity for the development of effective antibacterial medicines to address the antibacterial resistance issue. The bioprepared zinc oxide nanoparticles (ZnO-NPs) were prepared utilizing the flower extract of Hibiscus sabdariffa and then characterized using different physicochemical techniques. The antibacterial effectiveness of the bioprepared ZnO-NPs and their synergism with fosfomycin were evaluated using disk diffusion assay against the concerned pathogens. Transmission electron microscopy (TEM) investigation of the bioprepared ZnO-NPs showed that their average particle size was 18.93 ± 2.65 nm. Escherichia coli expressed the highest sensitivity to the bioinspired ZnO-NPs with a suppressive zone of 22.54 ± 1.26 nm at a concentration of 50 µg/disk, whereas the maximum synergistic effect of the bioinspired ZnO-NPs with fosfomycin was noticed against Klebsiella pneumoniae strain with synergism ratio of 100.29%. In conclusion, the bioinspired ZnO-NPs demonstrated significant antibacterial and synergistic efficacy with fosfomycin against the concerned nosocomial bacterial pathogens, highlighting the potential of using the ZnO NPs-fosfomycin combination for effective control of nosocomial infections in intensive care units (ICUs) and health care settings. Furthermore, the biogenic ZnO-NPs’ potential antibacterial action against food pathogens such as Salmonella typhimurium and E. coli indicates their potential usage in food packaging applications.

Potential Antimicrobial and Antibiofilm Properties of Copper Oxide Nanoparticles: Time-Kill Kinetic Essay and Ultrastructure of Pathogenic Bacterial Cells

Mycosynthesis of nanoparticle (NP) production is a potential ecofriendly technology for large scale production. In the present study, copper oxide nanoparticles (CuONPs) have been synthesized from the live cell filtrate of the fungus Penicillium chrysogenum. The created CuONPs were characterized via several techniques, namely Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDX). Furthermore, the biosynthesized CuONPs were performed against biofilm forming Klebsiella oxytoca ATCC 51,983, Escherichia coli ATCC 35,218, Staphylococcus aureus ATCC 25,923, and Bacillus cereus ATCC 11,778. The anti-bacterial activity result was shown with the zone of inhibition determined to be 14 ± 0.31 mm, 16 ± 0.53 mm, 11 ± 0.57 mm, and 10 ± 0.57 mm respectively. Klebsiella oxytoca and Escherichia coli were more susceptible to CuONPs with minimal inhibitory concentration (MIC) values 6.25 and 3.12 µg/mL, respectively, while for Staphylococcus aureus and Bacillus cereus, MIC value was 12.5 and 25 μg/mL, respectively. The minimum biofilm inhibition concentration (MBIC) result was more evident, that the CuONPs have excellent anti-biofilm activity at sub-MIC levels reducing biofilm formation by 49% and 59% against Klebsiella oxytoca and Escherichia coli, while the results indicated that the MBIC of CuONPs on Bacillus cereus and Staphylococcus aureus was higher than 200 μg/mL and 256 μg/mL, respectively, suggesting that these CuONPs could not inhibit mature formatted biofilm of Bacillus cereus and Staphylococcus aureus in vitro. Overall, all the results were clearly confirmed that the CuONPs have excellent anti-biofilm ability against Klebsiella oxytoca and Escherichia coli. The prepared CuONPs offer a smart approach for biomedical therapy of resistant microorganisms because of its promoted antimicrobial action, but only for specified purposes.