Antimicrobial Applications Research Articles

Multifunctional Novel Lanthanide Complexes Based on Chromone Moiety for Corrosion Inhibition, Molecular Docking, and Anticancer and Antimicrobial Applications

ABSTRACTTwo novel multifunctional complexes [M(CCAM)2(NO3)](NO3)2·C2H5OH (M = Dy (III)/Er (III); CCAM = 2‐cyano‐N′‐((4‐oxo‐4H‐chromen‐3‐yl)methylene)acetohydrazide) were synthesized and characterized via elemental and thermal analyses, molar conductivity, UV–vis., and FT‐IR spectroscopy, revealing a 1:2 metal‐to‐ligand stoichiometry. The CCAM ligand coordinated with Dy(III) or Er(III) ions through nitrogen of azomethine and oxygen of the carbonyl and γ‐pyran groups. Corrosion inhibition studies for Dy(CCAM), Er(CCAM), and CCAM on carbon steel (C‐steel) in 1‐M HCl showed Dy(CCAM) and Er(CCAM) as highly efficient, with Er(CCAM) offering the best protection. In a 1‐M HCl solution, Fe2+ at the C‐steel surface interacts with the CCAM, Dy(CCAM), and Er(CCAM) compounds, as demonstrated by UV–vis spectroscopy. At a concentration of 10−3 M, the Dy(CCAM) and Er(CCAM) compounds showed greater performance efficiency in the weight loss test in 1‐M HCl solution, reaching 93.34% and 95.67%, respectively. The Langmuir adsorption isotherm pronounced the mixed adsorption mechanisms. The surface characteristics SEM, EDX, AFM, and contact angle measurements confirmed surface shielding. In vitro antibacterial and antifungal activity of the prepared compounds against organisms, including Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis as bacteria, and Candida albicans and Aspergillus fumigatus as fungi is carried out. Er(CCAM) inhibitor exhibits the greatest action against different tested antimicrobials. Additionally, the in vitro cytotoxicity of the produced complexes as growth inhibitory effects against Erlish Acities Carcinoma was ascertained. Er(CCAM) and Dy(CCAM) were found to have cytotoxic levels with (IC50 of 64 and 65 μM), respectively. As a result, Er(CCAM) inhibitor is a more effective therapeutic approach for the creation of novel antimicrobial and antitumor agents. For Er(CCAM) superior corrosion protection, the theoretical studies of molecular docking and DFT and MD simulations validated the experimental results.

Cellulose Nanomaterials Functionalized with Carboxylic Group Extracted from Lignocellulosic Agricultural Waste: Isolation and Cu(II) Adsorption for Antimicrobial Application

Cellulose Nanomaterials Functionalized with Carboxylic Group Extracted from Lignocellulosic Agricultural Waste: Isolation and Cu(II) Adsorption for Antimicrobial Application

Bio-Based Cationic Surfactants from 5-(Hydroxymethyl)furfural for Antimicrobial Applications: The Role of Cationic Substitutes, Alkyl Chains, and Ester Linkages.

A novel series of bio-based cationic surfactants, synthesized from the platform chemical 5-(hydroxymethyl)furfural (5-HMF), fatty acids, and bio-based amines, has been developed, offering a sustainable alternative to conventional surfactants. These compounds, referred to as surface-active ionic liquids (SAILs), have critical micelle concentration (CMC) values lower compared to conventional quaternary ammonium cationic surfactants, indicating enhanced surface activity. The surface properties of the SAILs are predominantly influenced by the type of substitution in the cationic head group, with morpholinium-based surfactants having significantly lower CMC values than diethyl ammonium ones. The length of the alkyl chain also plays a significant role in determining the physicochemical and biological characteristics of these surfactants, which vary depending on the chain length. Surfactants with longer alkyl substituents demonstrate enhanced thermal stability and surface activity. The newly synthesized amphiphiles exhibit antimicrobial activity comparable to known quaternary ammonium cationic agents but with lower cytotoxicity. Importantly, these surfactants show controlled degradation under temperature-driven hydrolysis and basic conditions while maintaining stability in acidic environments. These findings highlight the potential of developed bio-based surfactants to deliver high performance with reduced environmental impact, positioning them as potential candidates for antimicrobial applications and industrial uses focusing on sustainability goal.

Enhanced Dissolution and Antibacterial Potential of Cinacalcet Hydrochloride via Ternary Solid Dispersions

Cinacalcet hydrochloride (HCl), a calcium-sensing receptor agonist used to treat hyperparathyroidism, suffers from poor solubility, reducing its bioavailability. Recently, cinacalcet HCl has been probed for repurposing as antibacterial agent. This work investigates cinacalcet HCl's potential as an antibacterial agent and provides a formulation to improve the drug dissolution. Solid dispersion formulations using Poloxamer 407, with and without Soluplus®, were prepared via solvent evaporation and hot melt congealing methods. The resulting formulations were analyzed using differential scanning calorimetry, FTIR spectroscopy, X-ray powder diffraction, and dissolution studies. These formulations significantly enhanced cinacalcet HCl dissolution compared to the unprocessed form, achieving up to a 15-fold increase in Q5 (percent of cinacalcet HCl dissolved after 5 minutes). The dissolution efficiency rose from 28% for the pure drug to 94.8% and 87.8% for formulations F6 and F7, respectively. Microbiological evaluations confirmed the antibacterial effect of cinacalcet HCl, which was notably increased in the Poloxamer 407 and Soluplus® hybrid formulation (F7) with a MIC of 64-128 µg/ml. Antibiofilm activity was also observed, with qRT-PCR indicating downregulation of biofilm genes (icaA, icaD, and fnbA). This study introduces a cinacalcet HCl formulation prepared using a scalable, green approach, demonstrating significant potential for antimicrobial applications.

Inactivation of antibiotic resistant bacteria by nitrogen-doped carbon quantum dots through spontaneous generation of intracellular and extracellular reactive oxygen species.

The widespread antibiotic resistance has called for alternative antimicrobial agents. Carbon nanomaterials, especially carbon quantum dots (CQDs), may be promising alternatives due to their desirable physicochemical properties and potential antimicrobial activity, but their antimicrobial mechanism remains to be investigated. In this study, nitrogen-doped carbon quantum dots (N-CQDs) were synthesized to inactivate antibiotic-resistant bacteria and treat bacterial keratitis. N-CQDs synthesized via a facile hydrothermal approach displayed a uniform particle size of less than 10nm, featuring a graphitic carbon structure and functional groups including -OH and -NH2. The N-CQDs demonstrated antimicrobial activity against Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus, which was both dose- and time-dependent, reducing the survival rate to below 1%. The antimicrobial activity was confirmed by live/dead staining. In in vivo studies, the N-CQDs were more efficient in treating drug-resistant bacterial keratitis and reducing corneal damage compared to the common antibiotic levofloxacin. The N-CQDs were shown to generate intracellular and extracellular ROS, which potentially caused oxidative stress, membrane disruption, and cell death. This antimicrobial mechanism was supported by scanning and transmission electron microscopy, significant regulation of genes related to oxidative stress, and increased protein and lactate dehydrogenase leakage. This study has provided insight into the development, application, and mechanism of N-CQDs in antimicrobial applications.

Integrating Ni-MOF/g-C3N4/chitosan derived S-scheme photocatalyst for efficient visible light photodegradation of tetracycline and antibacterial activities.

Nickel MOF (Ni-MOF) nanoparticles were successfully anchored onto a polymeric graphitic carbon nitride (g-C3N4) and Chitosan nanostructure (NS) using an eco-friendly and straightforward synthesis method. These newly fabricated photocatalysts were thoroughly characterized with standard techniques, revealing that the nanoscale Ni-MOF particles were uniformly deposited on the sheet-like g-C3N4 matrix. This configuration demonstrated excellent antimicrobial properties and outstanding photodegradation of tetracycline hydrochloride under visible light exposure. The MOF@GC photocatalyst exhibited robust bactericidal activity against pathogens like Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Additionally, it achieved superior visible-light-driven degradation of tetracycline in a significantly shorter time compared to other studies, with approximately 96% of the tetracycline being degraded in just 70min under visible light. These findings suggest that the effective deposition of Ni-MOF onto the g-C3N4 structure reduces the recombination rate of photogenerated electrons and holes, thereby enhancing the photocatalytic efficiency of pure g-C3N4 under visible light. The proposed catalytic mechanism, informed by valence band (VB) and conduction band (CB) data from cyclic voltammetry measurements, further supports this conclusion. The MOF@GC photocatalyst is a promising nanostructured material for antimicrobial applications and visible-light-driven photocatalysis.

Eco-compatible ZnO nanoparticles synthesized using aloe barbadensis miller and azadirachta indica: Multifaceted characterization for antimicrobial applications

Eco-compatible ZnO nanoparticles synthesized using aloe barbadensis miller and azadirachta indica: Multifaceted characterization for antimicrobial applications

Orange peel essential oil in rice starch encapsulating material for antimicrobial application against Escherichia coli.

This study investigated the formation of fibers and capsules using rice starch as a wall material to encapsulate orange peel essential oil (OPEO) by electrospinning for antimicrobial applications. Rice starch at a concentration of 20% (w/v) and varying OPEO concentrations (30%, 40%, and 50%, w/w) were used to produce materials. Free OPEO was analyzed for its chemical profile and antimicrobial activity. The electrospun material was characterized for morphology, size distribution, loading capacity, functional groups, thermal properties, and antimicrobial activity against Escherichia coli. Limonene was identified as the main component of OPEO. The free OPEO was effective against E. coli and Salmonella Typhimurium. When different concentrations of OPEO were incorporated into 20% rice starch solutions, a decrease in electrical conductivity was observed, leading to the formation of fibers and capsules instead of just fibers. The loading capacities of the materials were 35%, 29%, and 28% for OPEO concentrations of 30%, 40%, and 50%, respectively. Encapsulation of OPEO resulted in increased thermal stability. The material with 50% OPEO achieved a 6-log reduction in E. coli, showing strong potential for active packaging to reduce food contamination. Future research should explore its practical use in food packaging.

Discovery, synthesis, and antibacterial activity of novel myrtucommulone analogs as inhibitors of DNA gyrase and topoisomerase IV.

Drug-resistant bacterial infections have emerged as a new challenge in anti-infective treatment, posing a significant threat to public health. DNA gyrase and topoisomerase IV (Topo IV) are promising targets for designing new antibiotics. Myrtus communis L. has long been used as a traditional herb for antisepsis and disinfection; however, the underlying mechanism of the antibacterial activity remains unclear. In this study, a class of novel myrtucommulone derivatives was synthesized and evaluated for DNA gyrase and Topo IV inhibitions. Analog 27 was the most potent DNA gyrase and Topo IV inhibitor. In bioactivity assays, molecule 27 exhibited a significant antibacterial effect against methicillin-resistant Staphylococcus aureus (MRSA). Additionally, it exhibited rapid bactericidal properties, low toxicity, and low inducing bacterial resistance. It demonstrated synergistic effects with ofloxacin, amikacin, cefepime, and ceftazidime, which make it a potential candidate for antimicrobial application. This work will facilitate the future development of myrtucommulone-based DNA gyrase and Topo IV inhibitors as novel antimicrobials to combat the increasing prevalence of multidrug-resistant bacteria.

Synthesis of novel Fe3O4@gly@Indole@CuNO3 magnetic nanoparticle as high-performance antibiotic absorbent, antimicrobial agent, and reusable magnetic Nano catalyst

The synthesis of nanoparticles has gained attention for their broad applications. Our research focused on developing a novel material, Fe3O4@gly@Indole (FGI), and exploring its diverse uses. FGI was synthesized in two steps using FeCl2.4H2O, FeCl3.6H2O, glycine, and indole-3-carboxaldehyde. Its structure was confirmed via FT-IR, XRD, VSM, SEM, TGA, and EDAX. Antimicrobial tests revealed FGI exhibited higher activity than some antibiotics, with a Minimum Inhibitory Concentration (MIC) of 1µg/mL against Staphylococcus aureus. To enhance its properties, a magnetic nanocatalyst (FGICu) was synthesized by combining FGI with Cu(NO3)2. FGICu proved effective in synthesizing chromeno[4,3-b]chromen-6-one derivatives, achieving 95% yield in 20minutes at 50°C. Additionally, FGICu outperformed FGI in antibacterial tests, showing a lower MIC of 0.5µg/mL and stronger bactericidal activity (MBC of 2-8µg/mL). FGICu also demonstrated significant potential as an adsorbent, with a maximum adsorption capacity of 500.8mg/g for tetracycline (TC). The adsorption mechanism involved electrostatic interactions, hydrogen bonding, and π-π stacking, with the SIPS model best fitting the isotherm and pseudo-second-order model describing the kinetics. FGICu maintained over 70% efficiency after five adsorption cycles, showing excellent stability and reusability. These findings suggest FGICu is a promising material for antimicrobial applications and pollutant removal from wastewater.

In vitro characterization the antioxidant and antibacterial properties of hemp (Cannabis sativa spp.) varieties cultivated in Northern Alabama

Plants, especially those recognized for their medicinal properties, are an excellent source of bioactive components and are attracting considerable interest in the food industry due to their natural bioactivity. In this context, hemp species (Cannabis sativa spp.) were investigated for such applications because of their well-documented antibacterial and antioxidant activities. However, the bioactive efficacy of varieties being introduced in Northern Alabama and their implications for food safety have not been studied. The purpose of this study was to evaluate the antibacterial and antioxidative potential of four hemp varieties grown at the Alabama A&M University, Winfred Thomas Agricultural Research Station in Northern Alabama using three different extraction solvents (deionized water, acetone, and ethanol). Antioxidant potential was evaluated by DPPH free radical scavenging activity (2, 2-diphenyl-1- picrylhydrazyl), Total phenolic and flavonoid contents. Antibacterial activity against cocktails of enteric pathogens, including Listeria monocytogenese, E. coli O157:H7, and Salmonella enterica was evaluated for optical density using a BioScreen-C microtiter. Also, the disc diffusion extraction yield was evaluated to determine the best extraction solvent. Data were expressed as mean ± standard error (n = 3) and ANOVA (P ≤ 0.05). The ethanolic extracts exhibited the the highest extraction yield at 25.29 ± 0.70% (RE), while the antioxidant result demonstrated that the ethanolic extracts had the highest DPPH free radical scavenging activity at 64.03 ± 0.26% (RE). The results of the antibacterial studies showed that ethanolic hemp extracts exhibited significantly higher growth inhibition against all foodborne pathogens > 70% (p ≤ 0.05). The results show that the ethanolic extracts has significant extraction yield and bioactivity, highlighting ethanolic extract utilization in future antimicrobial nanofiber application.

Exploring Recent Advancements in the Pharmacological Activities of Plant-derived Alkaloids and Glycosides: A Review

A wide spectrum of bioactive compounds is synthesised by plants, and these agents act as protection systems against different living and non-living stressors. They are also useful in the manufacturing of pharmaceutical medications which alleviate a range of human illnesses. Numerous plant metabolites, including glycosides as well as alkaloids, have been studied for potential uses as antioxidants and medicinal agents. Numerous research assessed the modes of action of compounds, therapeutic and pharmacological uses and noteworthy health advantages (such as antifungal, anti-swelling, antimicrobial and anti-tumour applications). As such, a bid has been made to offer an overview of the most recent research that has been done into the secondary metabolites found in medicinal plants. Major Findings: Recent advances in the pharmacological activity of plant-derived alkaloids and glycosides emphasize their expanded therapeutic potential through better drug delivery mechanisms and synergistic uses.

Silver Nanoparticles as Antimicrobial Agents in Veterinary Medicine: Current Applications and Future Perspectives

Silver nanoparticles (AgNPs) have gained significant attention in veterinary medicine due to their antimicrobial properties and potential therapeutic applications. Silver has long been recognized for its ability to combat a wide range of pathogens, and when engineered at the nanoscale, silver’s surface area and reactivity are greatly enhanced, making it highly effective against bacteria, viruses, and fungi. This narrative review aimed to summarize the evidence on the antimicrobial properties of AgNPs and their current and potential clinical applications in veterinary medicine. The antimicrobial action of AgNPs involves several mechanisms, including, among others, the release of silver ions, disruption of cell membranes and envelopes, induction of oxidative stress, inhibition of pathogens’ replication, and DNA damage. Their size, shape, surface charge, and concentration influence their efficacy against bacteria, viruses, and fungi. As a result, the use of AgNPs has been explored in animals for infection prevention and treatment in some areas, such as wound care, coating of surgical implants, animal reproduction, and airway infections. They have also shown promise in preventing biofilm formation, a major challenge in treating chronic bacterial infections. Additionally, AgNPs have been studied for their potential use in animal feed as a supplement to enhance animal health and growth. Research suggested that AgNPs could stimulate immune responses and improve the gut microbiota of livestock, potentially reducing the need for antibiotics in animal husbandry. Despite their promising applications, further research is necessary to fully understand the safety, efficacy, and long-term effects of AgNPs on animals, humans, and the environment.

Multifunctional metal–organic frameworks as promising nanomaterials for antimicrobial strategies

Abstract Bacterial infections pose a serious threat to human health. While antibiotics have been effective in treating bacterial infectious diseases, antibiotic resistance significantly reduces their effectiveness. Therefore, it is crucial to develop new and effective antimicrobial strategies. Metal–organic frameworks (MOFs) have become ideal nanomaterials for various antimicrobial applications due to their crystalline porous structure, tunable size, good mechanical stability, large surface area, and chemical stability. Importantly, the performance of MOFs can be adjusted by changing the synthesis steps and conditions. Pure MOFs can release metal ions to modulate cellular behaviors and kill various microorganisms. Additionally, MOFs can act as carriers for delivering antimicrobial agents in a desired manner. Importantly, the performance of MOFs can be adjusted by changing the synthesis steps and conditions. Furthermore, certain types of MOFs can be combined with traditional photothermal or other physical stimuli to achieve broad-spectrum antimicrobial activity. Recently an increasing number of researchers have conducted many studies on applying various MOFs for diseases caused by bacterial infections. Based on this, we perform this study to report the current status of MOFs-based antimicrobial strategy. In addition, we also discussed some challenges that MOFs currently face in biomedical applications, such as biocompatibility and controlled release capabilities. Although these challenges currently limit their widespread use, we believe that with further research and development, new MOFs with higher biocompatibility and targeting capabilities can provide diversified treatment strategies for various diseases caused by bacterial infections.

Zeolite Nanoparticles: The Eco-Friendly Solutions for Environmental Contamination

Abstract: This review highlighted the innovative utilization of zeolite Nanoparticles (NPs) in various environmental applications, emphasizing their role in transforming waste materials into valuable resources. Zeolite-confined metal NPs, particularly Palladium (Pd), exhibit enhanced catalytic performance in the deep oxidation of light alkanes due to their unique interfaces and protective zeolite structures. Developing electrospun membranes incorporating cellulose acetate and nano-zeolites demonstrates promising potential for effective oil removal from wastewater, achieving up to 97% separation efficiency. The synthesis of silver NPs from Tilapia fish waste and their valorization within natural zeolites showcases an eco-friendly approach for ammonia removal and antimicrobial applications. Integrating nano-silicon and nano-zeolite treatments in combating salinity stress in medicinal plants highlights sustainable agricultural practices. This review emphasizes the multifaceted benefits of zeolite NPs in addressing urgent environmental challenges and promotes future research directions to optimize their applications in pollution control and resource recovery. Prospects include scaling up production methods, exploring novel composite materials, and investigating the long-term environmental impacts of these nanomaterials to enhance their practical applicability in diverse settings.

In vitro evaluation of silver-zinc oxide-eugenol nanocomposite for enhanced antimicrobial and wound healing applications in diabetic conditions

Diabetic wounds with chronic infections present a significant challenge, exacerbated by the growing issue of antimicrobial resistance, which often leads to delayed healing and increased morbidity. This study introduces a novel silver-zinc oxide-eugenol (Ag+ZnO+EU) nanocomposite, specifically designed to enhance antimicrobial activity and promote wound healing. The nanocomposite was thoroughly characterized using advanced analytical techniques, confirming its nanoscale structure, stability and chemical composition. The Ag+ZnO+EU nanocomposite demonstrated potent antimicrobial efficacy against a range of wound associated pathogens, including standard and clinical isolates of Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. Minimum inhibitory concentrations of Ag+ZnO+EU for standard and clinical isolates were significantly lower than those of the individual components, highlighting the synergistic effect of the nanocomposite. Time-kill assays revealed rapid microbial eradication, achieving complete sterility within 240-min. Importantly, the nanocomposite effectively eliminated persister-like cells, which are typically resistant to conventional treatments, suggesting a potential solution for persistent infections. In vitro scratch assays using human keratinocyte cells demonstrated that the Ag+ZnO+EU nanocomposite significantly accelerated wound closure, with near-complete healing observed within 24-h, indicating enhanced cell migration and tissue regeneration. Additionally, the nanocomposite showed potential antidiabetic effects by increasing glucose uptake up to 97.21% in an in vitro assay using 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-D-glucose, a fluorescent glucose analog, suggesting potential applications beyond wound healing. These findings highlight the Ag+ZnO+EU nanocomposite as a promising candidate for addressing both antimicrobial resistance and impaired wound healing in diabetic contexts.Graphical

Moringa oleifera: technological innovations and sustainable therapeutic potencials

This article examines the diverse applications of Moringa oleifera, highlighting its role in areas such as water treatment, oil extraction, and the development of nanomaterials with antioxidant and antimicrobial properties. Based on recent studies, the review emphasizes the plant's potential as a renewable and efficient resource for industrial and therapeutic systems. Among the key practical applications are sustainable water treatment in vulnerable communities facing potable water shortages and the production of high-efficiency biofuels that contribute to reducing carbon emissions. Additionally, its use in the formulation of natural cosmetics is noteworthy, valued for its regenerative and antioxidant properties, particularly in protecting against free radicals. Recent findings indicate significant advancements in heavy metal removal through its seeds and the extraction of oils with high oxidative stability. Furthermore, the synthesis of carbon quantum dots derived from this plant shows innovative potential for antimicrobial applications. The discussion addresses challenges related to scaling up the sustainable use of Moringa oleifera and explores opportunities to maximize its environmental and socioeconomic impact, especially in vulnerable regions, establishing it as a multifunctional solution of great importance.

Epigynum auritum-Derived Near-Infrared Carbon Dots for Bioimaging and Antimicrobial Applications.

The use of biomass feedstocks for producing high-value-added chemicals is gaining significant attention in the academic community. In this study, near-infrared carbon dots (NIR-CDs) with antimicrobial and bioimaging functions were prepared from Epigynum auritum branches and leaves using a novel green synthesis approach. The spectral properties of the synthesized NIR-CDs were characterized by ultraviolet-visible (UV-Vis) absorption and fluorescence spectroscopy. The crystal structures of the NIR-CDs were further characterized by high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), and X-ray diffraction (XRD). The NIR-CDs exhibited minimal toxicity, excellent biocompatibility, and high penetrability in both in vivo and in vitro environments, making them ideal luminescent probes for bioimaging applications. Moreover, the antimicrobial activity of NIR-CDs was tested against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), showing significant bacterial growth inhibition. The antimicrobial effect is likely attributed to the NIR-CDs disrupting the cell membrane integrity, leading to the leakage of the intracellular contents. Therefore, NIR-CDs hold promise as fluorescent bioimaging probes and antimicrobial agents.

A REVIEW ON NANOTECHNOLOGY-DRIVEN GREEN SYNTHESIS OF SILVER NANOPARTICLES USING NIGELLA SATIVA

Background: Nanotechnology has revolutionized modern science by enabling the synthesis of nanoparticles with unique physicochemical properties. Among these advancements, green synthesis using plant-based resources has gained significant attention for being eco-friendly and cost-effective. Nigella sativa (black seed), known for its rich bioactive compounds like alkaloids, flavonoids, and phenolics, has traditionally been used for treating various ailments. Body: This review focuses on the green synthesis of silver nanoparticles (AgNPs) using Nigella sativa as a nanotechnology-driven resource. The process leverages plant extracts to produce AgNPs, showcasing reduced toxicity and environmental impact compared to conventional physical and chemical methods. Key topics include the historical evolution of nanotechnology, top-down and bottom-up synthesis approaches, and the superior antimicrobial and biomedical applications of AgNPs due to their high surface area to volume ratio. The potential of N. sativa in producing nanomaterials highlights its importance in sustainable nanotechnology for diagnostics, antimicrobial therapies, and other applications. Conclusion: The incorporation of nanotechnology and green synthesis has positioned Nigella sativa as a promising resource for environmentally safe and biocompatible nanoparticle synthesis. Its role in modern science underscores its potential in addressing global challenges in medicine and environmental management.

Toluidine blue O demethylated photoproducts as type II photosensitizers.

Toluidine blue O (TBO) is a type I-type II photosensitizer that has shown good efficacy and selectivity in antimicrobial and anticancer photodynamic therapy applications. However, its complex photochemistry with multiple photoproducts hinders its application as a photosensitizer. We have previously described the mechanism for photooxidative demethylation of TBO which in acetonitrile yields two main products: demethylated-TBO (d-TBO) and double-demethylated-TBO (dd-TBO). In the current work, we describe the photophysical properties of these two photoproducts. In acetonitrile and phosphate buffer, demethylation induces an hypsochromic shift in the absorption and fluorescence emission maxima. Fluorescence quantum yields increase slightly for the demethylated photoproducts, in agreement with the lengthening of the fluorescence lifetimes. Triplet excited states lifetimes in the presence of oxygen decreased slightly upon demethylation. However, the singlet oxygen quantum yield increased significantly reaching unity for the dd-TBO photoproduct. These results are interpreted in terms of the competing pathways of TBO photochemistry. For TBO, demethylation is the main pathway for deactivation of the excited state, while for d-TBO, demethylation and singlet oxygen generation are significant. For dd-TBO, singlet oxygen generation is the main deactivation pathway. Overall, TBO demethylated photoproducts demonstrate good potential as candidates for photodynamic therapy applications.