Mode of Action of Biogenic Silver, Zinc, Copper, Titanium and Cobalt Nanoparticles Against Antibiotics Resistant Pathogens

Nanomedicines as a cutting-edge solution to combat antimicrobial resistance

Antimicrobial resistance (AMR) poses a critical threat to global public health, necessitating the development of novel strategies. AMR occurs when bacteria, viruses, fungi, and parasites evolve to resist antimicrobial drugs, making infections difficult to treat and increasing the risk of disease spread, severe illness, and death. Over 70% of infection-causing microorganisms are estimated to be resistant to one or several antimicrobial drugs. AMR mechanisms include efflux pumps, target modifications (e.g., mutations in penicillin-binding proteins (PBPs), ribosomal subunits, or DNA gyrase), drug hydrolysis by enzymes (e.g., β-lactamase), and membrane alterations that reduce the antibiotic's binding affinity and entry. Microbes also resist antimicrobials through peptidoglycan precursor modification, ribosomal subunit methylation, and alterations in metabolic enzymes. Rapid development of new strategies is essential to curb the spread of AMR and microbial infections. Nanomedicines, with their small size and unique physicochemical properties, offer a promising solution by overcoming drug resistance mechanisms such as reduced drug uptake, increased efflux, biofilm formation, and intracellular bacterial persistence. They enhance the therapeutic efficacy of antimicrobial agents, reduce toxicity, and tackle microbial resistance effectively. Various nanomaterials, including polymeric-based, lipid-based, metal nanoparticles, carbohydrate-derived, nucleic acid-based, and hydrogels, provide efficient solutions for AMR. This review addresses the epidemiology of microbial resistance, outlines key resistance mechanisms, and explores how nanomedicines overcome these barriers. In conclusion, nanomaterials represent a versatile and powerful approach to combating the current antimicrobial crisis.

A multi-omics approach reveals differences in toxicity and mechanisms in rice (Oryza sativa L.) exposed to anatase or rutile TiO2 nanoparticles

Titanium dioxide nanoparticles (TiO2 NPs) have been widely used in agriculture, which increased the risk to soil-plant systems. Studies have demonstrated that TiO2 NPs can induce phytotoxicity. However, the toxicity mechanisms, particularly under the stress of TiO2 NPs with different crystalline forms, remain inadequately reported. In this study, we combined transcriptomics and metabolomics to analyze the toxicity mechanisms in rice (Oryza sativa L.) under the stress of anatase (AT) or rutile (RT) TiO2 NPs (50 mg/kg, 40 days). The length (decreased by 1.1-fold, p = 0.021) and malondialdehyde concentration (decreased by 1.4-fold, p = 0.0027) of rice shoots was significantly reduced after AT exposure, while no significant changes were observed following RT exposure. Antioxidant enzyme activities were significantly altered both in the AT and RT groups, indicating TiO2 NPs induced rice oxidative damage (with changes of 1.1 to 1.4-fold, p < 0.05). Additionally, compared to the control, AT exposure altered 3247 differentially expressed genes (DEGs) and 56 significantly differentially metabolites in rice (collectively involved in pyrimidine metabolism, TCA cycle, fatty acid metabolism, and amino acid metabolism). After RT exposure, 2814 DEGs and 55 significantly differentially metabolites were identified, which were collectively involved in fatty acid metabolism and amino acid metabolism. Our results indicated that AT exposure led to more pronounced changes in biological responses related to oxidative stress and had more negative effects on rice growth compared to RT exposure. These findings provide new insights into the phytotoxic mechanisms of TiO2 NPs with different crystalline forms. Based on the observed adverse effects, the study emphasizes that any form of TiO2 NPs should be used with caution in rice ecosystems. This study is the first to demonstrate that AT is more toxic than RT in paddy ecosystems, providing crucial insights into the differential impacts and toxic mechanisms of TiO2 NPs with different crystalline forms. These findings suggest prioritizing the use of RT when TiO2 NPs are necessary in agricultural development to minimize toxicity risks.

Radical scavenging potential of spectrophotometric, spectroscopic, microscopic, and EDX observed zinc oxide nanoparticles from leaves, buds, and flowers extract of Bauhinia Variegata Linn: A thorough comparative insight

The present study incorporated an environment-friendly and cost-efficient green synthesis method for fabricating zinc oxide nanoparticles (ZnO-NPs) using various parts (leaves, buds, and flowers) of Bauhinia Variegate Linn. UV-Spectrophotometric analysis was used to confirm the synthesis of ZnO-NPs, which showed an absorption band within 360-380 nm range. Further techniques like FT-IR spectroscopy and (SEM) scanning electron microscopy equipped with a novel EDX were also included to confirm the synthesis, size, and shape of ZnO-NPs. Results obtained by FT-IR showed that the phytochemicals present in the ethanolic extract successfully acted as a capping agent. SEM micrographs confirmed irregularly shaped nanoparticles with an average size of 70-80 nm. The presence of Zinc and Oxygen peaks in EDX also confirmed the successful synthesis of ZnO nanoparticles. The radical scavenging (antioxidant) potential of prepared nanoparticles was also evaluated by DPPH radical assay. The ZnO-NPs obtained from the ethanolic extract of buds showed the highest %RSA (86%) as compared to the flowers (79%) and leaves (76%). The current study findings showed the versatile morphology of all parts of the plant with significant antioxidant potential, establishing the use of Bauhinia Variegate in biological systems for various biomedical applications. RESEARCH HIGHLIGHTS: A thorough comparative analysis of the radical scavenging power of major parts of the Bauhinia Variegate, which is 1st of its kind. Extensive characterization using UV-Vis spectrophotometry, FT-IR, SEM, and EDX to observe the conformational and morphological changes. Analysis of the reduction potential of leaves, buds, and flowers of a single plant for future directions in green synthesis.

Synthesis, Characterization, Phytochemistry, and Therapeutic Potential of Azadirachta indica Conjugated Silver Nanoparticles: A Comprehensive Study on Antidiabetic and Antioxidant Properties

Nanotechnology has become a major topic of study, particularly in the medical and health domains. Because nanomedicine has a higher recovery rate than other conventional drugs, it has attracted more attention. Green synthesis is the most efficient and sustainable method of creating nanoparticles. The current work used ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray, and X-ray diffraction to thoroughly characterize the synthesized silver nanoparticles (AgNPs) from Azadirachta indica leaf extract. Characterization confirmed the synthesis of the AgNPs along with the possible linkage of the phytochemicals with the silver as well as the quantitative analysis and nature of NPs. The antioxidant activity of AgNPs and neem extract was measured by the 2,2-diphenyl-1-picrylhydrazyl assay using various concentrations (20, 40, 60, 80, and 100 µg/ml). Additionally, using diabetic mice that had been given alloxan, the in vivo antidiabetic potential of biosynthesized AgNPs was assessed. Eight groups of mice were used to assess the antidiabetic activity: one control group and seven experimental groups (untreated, extract-treated, AgNPs at low and high doses, standard drug, low dose of AgNPs + drug, and high dose of AgNPs + drug). At days 0, 7, 14, 21, and 28, blood glucose levels and body weight were measured. After 28 days, the mice were dissected, and the liver, kidney, and pancreas were examined histologically. The results depicted that the AgNPs showed higher (significant) radical scavenging activity (IC50 = 35.2 µg/ml) than extract (IC50 = 93.0 µg/ml) and ascorbic acid (IC50 = 64.6 µg/ml). The outcomes demonstrated that biosynthesized AgNPs had a great deal of promise as an antidiabetic agent and exhibited remarkable effects in diabetic mice given AgNPs, extract, and drug. Remarkable improvement in the body weight and blood glucose level of mice treated with high doses of AgNPs and drug was observed. The body weight and blood glucose level of diabetic mice treated with a high dose of AgNPs + standard drug showed significant improvement, going from 28.7 ± 0.2 to 35.6 ± 0.3 g and 248 ± 0.3 to 109 ± 0.1 mg/dl, respectively. Significant regeneration was also observed in the histomorphology of the kidney, liver's central vein, and islets of Langerhans after treatment with biosynthesized AgNPs. Diabetic mice given a high dose of AgNPs and drug displayed architecture of the kidney, liver, and pancreas that was nearly identical to that of the control group. According to the current research, biosynthesized AgNPs have strong antioxidant and antidiabetic potential and may eventually provide a less expensive option for the treatment of diabetes.

Navigating Antibacterial Frontiers: A Panoramic Exploration of Antibacterial Landscapes, Resistance Mechanisms, and Emerging Therapeutic Strategies

The development of effective antibacterial solutions has become paramount in maintaining global health in this era of increasing bacterial threats and rampant antibiotic resistance. Traditional antibiotics have played a significant role in combating bacterial infections throughout history. However, the emergence of novel resistant strains necessitates constant innovation in antibacterial research. We have analyzed the data on antibacterials from the CAS Content Collection, the largest human-curated collection of published scientific knowledge, which has proven valuable for quantitative analysis of global scientific knowledge. Our analysis focuses on mining the CAS Content Collection data for recent publications (since 2012). This article aims to explore the intricate landscape of antibacterial research while reviewing the advancement from traditional antibiotics to novel and emerging antibacterial strategies. By delving into the resistance mechanisms, this paper highlights the need to find alternate strategies to address the growing concern.