Synthesis, purification and characterization of Plectonema derived AgNPs with elucidation of the role of protein in nanoparticle stabilization

Evaluation of the biological responses of silver nanoparticles synthesized using Pelargonium x hortorum extract

Silver nanoparticles (AgNPs) are one of the widely studied nanomaterials for diverse biomedical applications, in particular, as antimicrobial agents to kill bacteria, fungi, and viruses. In this report, AgNPs were synthesized using a geranium (Pelargonium x hortorum) leaves extract and tested for their antimicrobial and cytotoxic activity and reactive oxygen species (ROS) production. Using green biosynthesis, the leaves extract was employed as a reducing and stabilizing agent. Synthesis parameters like reaction time and precursor (silver nitrate AgNO3) volume final were modified, and the products were tested against Streptococcus mutans. For the first time, the metabolomic analysis of extract, we have identified more than 50 metabolites. The UV-Vis analysis showed a peak ranging from 410-430 nm, and TEM confirmed their nearly spherical morphology for all NPs. The antimicrobial activity of the NPs revealed a minimum inhibitory concentration (MIC) of 10 μg mL-1. Concerning cytotoxicity, a dose-time-dependent effect was observed with a 50% cellular cytotoxicity concentration (CC50) of 4.51 μg mL-1 at 24 h. Interestingly, the cell nuclei were visualized using fluorescence microscopy, and no significant changes were observed. These results suggest that synthesized spherical AgNPs are promising potential candidates for medical applications.

Recent advances in the synthesis, characterization and biomedical applications of zinc oxide nanoparticles

Zinc oxide nanoparticles (ZnONPs) have become the widely used metal oxide nanoparticles and drawn the interest of global researchers due to their biocompatibility, low toxicity, sustainability and cost-effective properties. Due to their unique optical and chemical properties, it emerges as a potential candidate in the fields of optical, electrical, food packaging and biomedical applications. Biological methods using green or natural routes are more environmentally friendly, simple and less use of hazardous techniques than chemical and/or physical methods in the long run. In addition, ZnONPs are less harmful and biodegradable while having the ability to greatly boost pharmacophore bioactivity. They play an important role in cell apoptosis because they enhance the generation of reactive oxygen species (ROS) and release zinc ions (Zn2+), causing cell death. Furthermore, these ZnONPs work well in conjunction with components that aid in wound healing and biosensing to track minute amounts of biomarkers connected to a variety of illnesses. Overall, the present review discusses the synthesis and most recent developments of ZnONPs from green sources including leaves, stems, bark, roots, fruits, flowers, bacteria, fungi, algae and protein, as well as put lights on their biomedical applications such as antimicrobial, antioxidant, antidiabetic, anticancer, anti-inflammatory, antiviral, wound healing, and drug delivery, and modes of action associated. Finally, the future perspectives of biosynthesized ZnONPs in research and biomedical applications are discussed.

Toxicological assessment of Phormidium sp. derived copper oxide nanoparticles for its biomedical and environmental applications

Driven by the need to biosynthesized alternate biomedical agents to prevent and treat infection, copper oxide nanoparticles (CuONPs) have surfaced as a promising avenue. Cyanobacteria-derived synthesis of CuONPs is of substantive interest as it offers an eco-friendly, cost-effective, and biocompatible route. In the present study biosynthesized CuONPs were characterized and investigated regarding their toxicity. Morphological analysis using TEM, SEM and AFM showed the spherical particle size of 20.7 nm with 96% copper that confirmed the purity of CuONPs. Biogenic CuONPs with IC₅₀ value of 64.6 µg ml^-1 showed 90% scavenging of free radicals in superoxide radical scavenging assay. CuONPs showed enhanced anti-inflammatory activity by 86% of protein denaturation with IC₅₀ value of 89.9 µg ml^-1. Biogenic CuONPs exhibited significant toxicity against bacterial strains with lowest MIC value of 62.5 µg ml^-1 for B. cereus and fungal strain with a MIC value of 125 µg ml^-1 for C. albicans. In addition CuONPs demonstrated a high degree of synergistic interaction when combined with standard drugs. CuONPs exhibited significant cytotoxicity against non-small cell lung cancer with an IC₅₀ value of 100.8 µg ml^-1 for A549 and 88.3 µg ml^-1 for the H1299 cell line with apoptotic activities. Furthermore, biogenic CuONPs was evaluated for their photocatalytic degradation potential against methylene blue dye and were able to removed 94% dye in 90 min. Free radical scavenging analysis suggested that CuONPs assisted dye degradation was mainly induced by hydroxide radicals. Biogenic CuONPs appears as an eco-friendly and cost effective photocatalyst for the treatment of wastewater contaminated with synthetic dyes that poses threat to aquatic biota and human health. The present study highlighted the blend of biomedical and photocatalytic potential of Phormidium derived CuONPs as an attractive approach for future applications in nanomedicine and bioremediation.

Biosynthesis of Silver Nanoparticles Produced Using Geobacillus spp. Bacteria

Silver nanoparticles (AgNPs) are well known for their unique physical and chemical properties, which can be incorporated into a wide range of applications. The growing resistance of microorganisms to antimicrobial compounds promoted the use of AgNPs in antimicrobial therapy. AgNPs can be obtained using physical and chemical methods, but these technologies are highly unfriendly to nature and produce large amounts of side compounds (for example, sodium borohydride and N,N-dimethylformamide). Therefore, alternative technologies are required for obtaining AgNPs. This report focuses on the biosynthesis of silver nanoparticles through the reduction of Ag⁺ with the cell-free secretomes of four Geobacillus bacterial strains, namely, 18, 25, 95, and 612. Only a few studies that involved Geobacillus bacteria in the synthesis of metal nanoparticles, including AgNPs, have been reported to date. The silver nanoparticles synthesized through bio-based methods were characterized using UV-Vis spectroscopy, scanning electron microscopy (SEM), dynamic light scattering (DLS), and zeta potential measurements. UV-Vis spectroscopy showed a characteristic absorbance peak at 410-425 nm, indicative of AgNPs. SEM analysis confirmed that most nanoparticles were spherical. DLS analysis showed that the sizes of the obtained AgNPs were widely distributed, with the majority less than 100 nm in diameter, while the zeta potential values ranged from -25.7 to -31.3 mV and depended on the Geobacillus spp. strain.

Regulation of Pro-Inflammatory Macrophage Polarization via Lipid Nanoparticles Mediated Delivery of Anti-Prostaglandin-E2 siRNA

Pro-inflammatory macrophage polarization is crucial in acute inflammatory diseases like Acute lung injury (ALI), and acute respiratory distress syndrome (ARDS). Prostaglandin E2 (PGE2) is believed to promote inflammation in such cases. Therefore, our study aimed to deliver anti-prostaglandin E synthase 2 small interfering RNA antibodies (anti-PGE2-siRNA) through lipid nanoparticles (LNPs) in RAW264.7 (The murine macrophage cell line) to find a possible cure to the acute inflammatory diseases. LNPs were synthesized by using thin layer evaporation method and were characterized by dynamic light scattering (DLS), Zeta potential, SEM and TEM analysis. The obtained NPs were spherical with an average size of 73 nm and zeta potential +29mV. MTT assay revealed that these NPs were non-toxic in nature. Gel retardation assay displayed 5:2 ratio of siRNA and NPs as the best siRNA:LNPs ratio for the delivery of siRNA into cells. After siRNA delivery by using LNPs, real time gene expression analysis revealed significant decrease in the expression of PGE2. Western blot results confirmed that silencing of PGE2 gene influence inducible nitric oxide synthase (iNOS) and interlukin-1β (1L-1β), markers involved in pro-inflammatory macrophage polarization. Our study revealed that LNPs synthesized in present study can be one of the effective methods to deliver anti-PGE2-siRNA to control pro-inflammatory macrophage polarization for the treatment of acute inflammatory response.

Streptomyces rochei MS-37 as a Novel Marine Actinobacterium for Green Biosynthesis of Silver Nanoparticles and Their Biomedical Applications

Periodontitis, as one of the most common diseases on a global scale, is a public health concern. Microbial resistance to currently available antimicrobial agents is becoming a growing issue in periodontal treatment. As a result, it is critical to develop effective and environmentally friendly biomedical approaches to overcome such challenges. The investigation of Streptomyces rochei MS-37's performance may be the first of its kind as a novel marine actinobacterium for the green biosynthesis of silver nanoparticles (SNPs) and potentials as antibacterial, anti-inflammatory, antibiofilm, and antioxidant candidates suppressing membrane-associated dental infections. Streptomyces rochei MS-37, a new marine actinobacterial strain, was used in this study for the biosynthesis of silver nanoparticles for various biomedical applications. Surface plasmon resonance spectroscopy showed a peak at 429 nm for the SNPs. The SNPs were spherical, tiny (average 23.2 nm by TEM, 59.4 nm by DLS), very stable (-26 mV), and contained capping agents. The minimum inhibitory concentrations of the SNPs that showed potential antibacterial action ranged from 8 to 128 µg/mL. Periodontal pathogens were used to perform qualitative evaluations of microbial adhesion and bacterial penetration through guided tissue regeneration membranes. The findings suggested that the presence of the SNPs could aid in the suppression of membrane-associated infection. Furthermore, when the anti-inflammatory action of the SNPs was tested using nitric oxide radical scavenging capacity and protein denaturation inhibition, it was discovered that the SNPs were extremely efficient at scavenging nitric oxide free radicals and had a strong anti-denaturation impact. The SNPs were found to be more cytotoxic to CAL27 than to human peripheral blood mononuclear cells (PBMCs), with IC50 values of 81.16 µg/mL in PBMCs and 34.03 µg/mL in CAL27. This study's findings open a new avenue for using marine actinobacteria for silver nanoparticle biosynthesis, which holds great promise for a variety of biomedical applications, in particular periodontal treatment.

Streptomyces catenulae as a Novel Marine Actinobacterium Mediated Silver Nanoparticles: Characterization, Biological Activities, and Proposed Mechanism of Antibacterial Action

Biosynthesized silver nanoparticles (Bio-SNPs) were synthesized from the marine actinobacterium strain Streptomyces catenulae M2 and characterized using a variety of techniques, including UV–vis spectrum, fourier transform infrared spectroscopy (FTIR), energy dispersive x-ray (EDX), transmission electron microscopy (TEM), dynamic light scattering (DLS), surface-enhanced Raman spectroscopy (SERS), and zeta potential. The antibacterial activity of Bio-SNPs alone and in combination with antibiotic was evaluated using a microtiter-dilution resazurin assay against multidrug-resistant (MDR) bacteria. Bio-SNPs’ minimum inhibitory concentration (MIC) against bacterial strains was determined. To assess the synergistic effect of Bio-SNPs in combination with antibiotics, the Fractional Inhibitory Concentration Index (FICI) was calculated. While the safety of Bio-SNPs in biomedical applications is dependent on their use, the in vitro cytotoxicity of Bio-SNPs on normal human epithelial colon cells (NCM460) and human colorectal adenocarcinoma cells (CaCo2) were evaluated using the [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) assay and cell lactate dehydrogenase (LDH) release. The presence of Bio-SNPs was revealed by UV–vis spectroscopy, which revealed a peak in the Surface Plasmon Resonance (SPR) spectrum at 439.5 nm. Bio-SNPs were spherical in shape and small in size (average 33 nm by TEM, 58.8 nm by DLS), with good stability (−30 mV) and the presence of capping agents. Bio-SNPs had MIC values ranging from 2 to 64 μg/ml against the bacteria tested. The MIC for P. aeruginosa was the lowest (2 μg/ml). Antibiotics have been shown to have a significant synergistic effect when combined with Bio-SNPs against tested bacteria. Bio-SNPs exhibited dose-dependent cytotoxicity against NCM460 and CaCo2 cancer cells, with the latter exhibiting far greater toxicity than  the  former.  NCM460  and CaCo2  cell   viability   decreased   from  99.3 to 95.7% and 92.3 to 61.8%, respectively, whereas LDH leakage increased from 200 to 215 nmol/ml and 261 to 730 nmol/ml, respectively. The half inhibitory concentrations (IC₅₀) for NCM460 and CaCo2 cancer cells were 79.46 and 10.41 μg/ml and 89.4 and 19.3 μg/ml, respectively. Bio-SNPs were found to be biocompatible and to have anti-inflammatory activity. Bio-SNPs are highly appealing for future nanomedicine applications due to their antibacterial and biocompatible properties and their inherent “green” and simple manufacturing.