Deciphering the Mechanisms and Biotechnological Implications of Nanoparticle Synthesis Through Microbial Consortia

Nanomaterial synthesis is a growing study area because of its extensive range of uses. Nanoparticles' high surface-to-volume ratio and rapid interaction with various particles make them appealing for diverse applications. Traditional physical and chemical methods for creating metal nanoparticles are becoming outdated because they involve complex manufacturing processes, high energy consumption, and the formation of harmful by-products that pose major dangers to human health and the environment. Therefore, there is an increasing need to find alternative, cost-effective, dependable, biocompatible, and environmentally acceptable ways of producing nanoparticles. The process of synthesizing nanoparticles using microbes has become highly intriguing because of their ability to create nanoparticles of varying sizes, shapes, and compositions, each with unique physicochemical properties. Microbes are commonly used in nanoparticle production because they are easy to work with, can use low-cost materials, such as agricultural waste, are cheap to scale up, and can adsorb and reduce metal ions into nanoparticles through metabolic activities. Biogenic synthesis of nanoparticles provides a clean, nontoxic, ecologically friendly, and sustainable method using renewable ingredients for reducing metals and stabilizing nanoparticles. Nanomaterials produced by bacteria can serve as an effective pollution control method due to their many functional groups that can effectively target contaminants for efficient bioremediation, aiding in environmental cleanup. At the end of the paper, we will discuss the obstacles that hinder the use of biosynthesized nanoparticles and microbial-based nanoparticles. The paper aims to explore the sustainability of microorganisms in the burgeoning field of green nanotechnology.

A dual-sensing strategy for the early diagnosis of urinary tract infections via detecting biofilm cellulose using aromatic amino acid-capped Au and Ag nanoparticles

Currently, urinary tract infection (UTI) diagnosis focuses on planktonic cell detection rather than biofilm detection, but the facile identification of UPEC bacterial biofilms is crucial in UTI diagnosis as the biofilm formed by bacteria is the causative agent of recurrent and chronic UTIs. Therefore, in this work, we developed a simple, cost-effective, colorimetric, and electrochemical-based strategy for the detection of cellulose in urine. Cellulose, a biofilm matrix component, was detected using tyrosine-capped gold and silver nanoparticles through a visible colorimetric change with a decrease in the absorbance intensity and a decrease in current response in the case of cyclic voltammetry. The sensor displayed a linear detection range of 10-70 mg mL-1 for colorimetry and 10-300 μg mL-1 for cyclic voltammetry with a good selectivity of <2.8% and a recovery rate of 95-100% in real-time sample analysis. Moreover, the binding affinity of cellulose with tyrosine was investigated using molecular docking studies to validate the sensing mechanism. We anticipate that our work will aid clinicians in the implementation of rapid, cost-effective, and definitive diagnosis of UTIs.

Fungal-mediated synthesis of silver nanoparticles: a novel strategy for plant disease management

Various traditional management techniques are employed to control plant diseases caused by bacteria and fungi. However, due to their drawbacks and adverse environmental effects, there is a shift toward employing more eco-friendly methods that are less harmful to the environment and human health. The main aim of the study was to biosynthesize silver Nanoparticles (AgNPs) from Rhizoctonia solani and Cladosporium cladosporioides using a green approach and to test the antimycotic activity of these biosynthesized AgNPs against a variety of pathogenic fungi. The characterization of samples was done by using UV-visible spectroscopy, SEM (scanning electron microscopy), FTIR (fourier transmission infrared spectroscopy), and XRD (X-ray diffractometry). During the study, the presence of strong plasmon absorbance bands at 420 and 450 nm confirmed the AgNPs biosynthesis by the fungi Rhizoctonia solani and Cladosporium cladosporioides. The biosynthesized AgNPs were 80-100 nm in size, asymmetrical in shape and became spherical to sub-spherical when aggregated. Assessment of the antifungal activity of the silver nanoparticles against various plant pathogenic fungi was carried out by agar well diffusion assay. Different concentration of AgNPs, 5 mg/mL 10 mg/mL and 15 mg/mL were tested to know the inhibitory effect of fungal plant pathogens viz. Aspergillus flavus, Penicillium citrinum, Fusarium oxysporum, Fusarium metavorans, and Aspergillus aflatoxiformans. However, 15 mg/mL concentration of the AgNPs showed excellent inhibitory activity against all tested fungal pathogens. Thus, the obtained results clearly suggest that silver nanoparticles may have important applications in controlling various plant diseases caused by fungi.

Biogenic metallic nanoparticles: from green synthesis to clinical translation

Biogenic metallic nanoparticles (NPs) have garnered significant attention in recent years due to their unique properties and various applications in different fields. NPs, including gold, silver, zinc oxide, copper, titanium, and magnesium oxide NPs, have attracted considerable interest. Green synthesis approaches, utilizing natural products, offer advantages such as sustainability and environmental friendliness. The theranostics applications of these NPs hold immense significance in the fields of medicine and diagnostics. The review explores intricate cellular uptake pathways, internalization dynamics, reactive oxygen species generation, and ensuing inflammatory responses, shedding light on the intricate mechanisms governing their behaviour at a molecular level. Intriguingly, biogenic metallic NPs exhibit a wide array of applications in medicine, including but not limited to anti-inflammatory, anticancer, anti-diabetic, anti-plasmodial, antiviral properties and radical scavenging efficacy. Their potential in personalized medicine stands out, with a focus on tailoring treatments to individual patients based on these NPs' unique attributes and targeted delivery capabilities. The article culminates in emphasizing the role of biogenic metallic NPs in shaping the landscape of personalized medicine. Harnessing their unique properties for tailored therapeutics, diagnostics and targeted interventions, these NPs pave the way for a paradigm shift in healthcare, promising enhanced efficacy and reduced adverse effects.

Autophagy and mitophagy as potential therapeutic targets in diabetic heart condition: Harnessing the power of nanotheranostics

Autophagy and mitophagy pose unresolved challenges in understanding the pathology of diabetic heart condition (DHC), which encompasses a complex range of cardiovascular issues linked to diabetes and associated cardiomyopathies. Despite significant progress in reducing mortality rates from cardiovascular diseases (CVDs), heart failure remains a major cause of increased morbidity among diabetic patients. These cellular processes are essential for maintaining cellular balance and removing damaged or dysfunctional components, and their involvement in the development of diabetic heart disease makes them attractive targets for diagnosis and treatment. While a variety of conventional diagnostic and therapeutic strategies are available, DHC continues to present a significant challenge. Point-of-care diagnostics, supported by nanobiosensing techniques, offer a promising alternative for these complex scenarios. Although conventional medications have been widely used in DHC patients, they raise several concerns regarding various physiological aspects. Modern medicine places great emphasis on the application of nanotechnology to target autophagy and mitophagy in DHC, offering a promising approach to deliver drugs beyond the limitations of traditional therapies. This article aims to explore the potential connections between autophagy, mitophagy and DHC, while also discussing the promise of nanotechnology-based theranostic interventions that specifically target these molecular pathways.

Green synthesis of silver nanoparticle prepared with Ocimum species and assessment of anticancer potential

Silver nanoparticles (AgNPs) have gained much attention due to their unique physical, and chemical properties. Integration of phytochemicals in nanoformulation might have higher applicability in healthcare. Current work demonstrates the synthesis of green AgNPs with O. gratissimum (gr-AgNPs) O. tenuiflorum (te-AgNPs) and O. americanum (am-AgNPs) followed by an evaluation of their antimicrobial and anticancer properties. SEM analysis revealed spherical-shaped particles with average particle sizes of 69.0 ± 5 nm for te-AgNPs, 46.9 ± 9 nm for gr-AgNPs, and 58.5 ± 18.7 nm for am-AgNPs with a polydispersity index below 0.4. The synthesized am-AgNPs effectively inhibited Klebsiella pneumonia, Escherichia coli, Staphylococcus aureus, Aspergillus niger, and Candida albicans with 23 ± 1.58 mm, 20 ± 1.68 mm, 22 ± 1.80 mm, 26 ± 1.85 mm, and 22 ± 1.40 nm of zone of inhibition respectively. Synthesized AgNPs also induced apoptotic cell death in MCF-7 in concentration-dependent manner. IC50 values for am-AgNPs, te-AgNPs, and gr-AgNPs were 14.78 ± 0.89 µg, 18.04 ± 0.63 and 15.41 ± 0.37 µg respectively which suggested that am-AgNPs were the most effective against cancer. At higher dose size (20 µg) AgNPs were equally effective to commercial standard Doxorubicin (DOX). In comparison to te-AgNPs and gr-AgNPs, am-AgNPs have higher in vitro anticancer and antimicrobial effects. The work reported Ocimum americanum for its anticancer properties with chemical profile (GCMS) and compared it with earlier reported species. The activity against microbial pathogens and selected cancer cells clearly depicted that these species have distinct variations in activity. The results have also emphasized on higher potential of biogenic silver nanoparticles in healthcare but before formulation of commercial products, detailed analysis is required with human and animal models.

Untargeted metabolomics and molecular docking studies on green silver nanoparticles synthesized by Sarocladium subulatum: Exploring antibacterial and antioxidant properties

The biological synthesis of silver nanoparticles (Ag-NPs) with fungi has shown promising results in antibacterial and antioxidant properties. Fungi generate metabolites (both primary and secondary) and proteins, which aid in the formation of metal nanoparticles as reducing or capping agents. While several studies have been conducted on the biological production of Ag-NPs, the exact mechanisms still need to be clarified. In this study, Ag-NPs are synthesized greenly using an unstudied fungal strain, Sarocladium subulatum AS4D. Three silver salts were used to synthesize the Ag-NPs for the first time, optimized using a cell-free extract (CFE) strategy. Additionally, these NPs were assessed for their antimicrobial and antioxidant properties. Various spectroscopic and microscopy techniques were utilized to confirm Ag-NP formation and analyze their morphology, crystalline properties, functional groups, size, stability, and concentrations. Untargeted metabolomics and proteome disruption were employed to explore the synthesis mechanism. Computational tools were applied to predict metabolite toxicity and antibacterial activity. The study identified 40 fungal metabolites capable of reducing silver ions, with COOH and OH functional groups playing a pivotal role. The silver salt type impacted the NPs' size and stability, with sizes ranging from 40 to 52 nm and zeta potentials from -0.9 to -30.4 mV. Proteome disruption affected size and stability but not shape. Biosynthesized Ag-NPs using protein-free extracts ranged from 55 to 62 nm, and zeta potentials varied from -18 to -27 mV. Molecular docking studies and PASS results found no role for the metabolome in antibacterial activity. This suggests the antibacterial activity comes from Ag-NPs, not capping or reducing agents. Overall, the research affirmed the vital role of specific reducing metabolites in the biosynthesis of Ag-NPs, while proteins derived from biological extracts were found to solely affect their size and stability.

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.

Direct binding and characterization of laccase onto iron oxide nanoparticles

Iron oxide nanoparticles (IONPs) exhibit unique magnetic properties and possess a high surface-to-volume ratio, making them ideal candidates for the conjugation of substances, including enzymes. Laccase (EC 1.10.3.2), an oxidative enzyme with diverse applications, presents an opportunity for enhancing stability and reusability through innovative immobilization techniques, thus reducing overall process costs. In this study, we employed a direct binding procedure via carbodiimide activation to conjugate laccase onto IONPs synthesized using thermal chemical coprecipitation. Stabilization of the nanoparticles was achieved using thioglycerol and polyvinyl alcohol (PVA) as capping agents. Characterization of the synthesized nanoparticles was conducted using UV-spectroscopy, Fourier transform infrared spectroscopy (FTIR), x-ray diffraction, scanning electron microscopy, and energy dispersive x-ray spectroscopy. FTIR spectroscopy analysis confirmed successful laccase binding to magnetic nanoparticles, with binding efficiencies of 90.65% and 73.02% observed for thioglycerol and PVA capped IONPs, respectively. Furthermore, the conjugated enzyme exhibited remarkable stability, retaining nearly 50% of its initial activity after 20 reuse cycles. This research demonstrates that immobilizing laccase onto IONPs enhances its activity, stability, and reusability, with the potential for significant cost savings and expanded applications in various fields.

Synthesis of Spherical Mn2O3 Nanozymes from Different Green Precursors for their Innovative Applications in Catalytic Properties and Bioactivity

Here, spherical Mn2O3 nanozymes were synthesized via a one-step green method using different green precursors, and their physicochemical properties and biological activities were monitored with various green precursors. Powder X-ray diffraction (PXRD) was performed to determine the crystalline properties and phases involved in the formation of cubic Mn2O3 nanozymes. The synthesized nanozymes were spherical and examined by SEM and FESEM studies. All of the samples synthesized using different green precursors exhibited different sizes but similar spherical shapes. Moreover, all green-synthesized nanozymes catalyzed the oxidation reaction of the chromogenic substrate 3,3'5,5' tetramethylbenzidine (TMB) in the absence of H2O2, and A2 (lemon-mediated Mn2O3 nanozymes), which the followed Michaelis-Menten kinetics, showed the best activity. Therefore, A2 (lemon-mediated nanozyme) showed oxidase-mimicking activity with distinct Km and Vmax values calculated by the Lineweaver-Burk plot. Furthermore, the current nanozymes demonstrated a significant ability to kill both Gram-negative and Gram-positive bacteria as well as effectively destroy biofilms under physiological conditions. Moreover, the green-mediated nanozymes also displayed ROS-scavenging activity. Our nanozymes exhibited scavenging activity toward OH and O2-• radicals and metal chelation activity, which were investigated colorimetrically. Therefore, these nanozymes might be used as effective antibacterial agents and also for the consumption of reactive oxygen species.

Beauveria bassiana biogenic nanoparticles for the control of Noctuidae pests

BACKGROUND

Biogenic metallic and oxide metal nanoparticles have potential as alternatives for several current problems in agriculture, such as the control of caterpillars which cause huge losses in the production of important crops. In the present study, capped and uncapped silver, iron oxide and titanium dioxide nanoparticles were synthesized from the filtrate of Beauveria bassiana and evaluated in regard to physico-chemical characteristics, capping composition, cytotoxicity, genotoxicity and biological activity on Helicoverpa armigera and Spodoptera frugiperda caterpillars.

RESULTS

A difference in the physico-chemical parameters of the capped and uncapped nanoparticles was observed, with larger aggregation and lower stability of the uncapped. In regard to the study of the capping, the presence of functional groups of biomolecules as well as the activity of B. bassiana hydrolytic enzymes were observed. Cytotoxic effects on the tested cell lines were not observed and DNA damage levels increased with more intense effects of the uncapped nanoparticles. In regard to the biological activity against Noctuidae pests, the uncapped and capped iron oxide, and uncapped titanium dioxide nanoparticles occasioned higher mortality (76%, 60% and 51%, respectively) but no differences in LC50 were recorded. Moreover, sublethal effects were reported on Helicoverpa armigera whereas Spodoptera frugiperda showed low susceptibility to the nanoparticles.

CONCLUSION

The results demonstrate that biogenic metallic and oxide metal nanoparticles might show promising effects for the control of caterpillars which cause damage on important agricultural crops. Further investigations are necessary to understand the mechanisms of action and optimize the biological activity of these new nanomaterials. © 2023 Society of Chemical Industry.

Nanoengineered chitosan functionalized titanium dioxide biohybrids for bacterial infections and cancer therapy

Nanoengineered chitosan functionalized titanium dioxide biohybrids (CTiO2@NPs) were prepared with Amomum subulatum Roxb extract via one-pot green method and assessed by UV-Vis spectroscopy, XRD, SEM and EDAX analyses. As revealed by XRD pattern, the nanohybrids exhibits a rutile TiO2 crystallites around 45 nm in size. The emergence of the Ti-O-Ti bond is identified by observing a peak between 400 and 800 cm-1. A wide bandgap (4.8 eV) has been observed in CTiO2@NPs, due to the quantum confinement effects and the oxygen vacancies reveal the intriguing potential of developed nanohybrids for various applications. Surface flaws were identified by observing an emission band at 382, 437, 482, 517, and 556 nm. They also exhibit better antibacterial performances using well diffusion method against Staphylococcus aureus, Bacillus substilis, Klebsiella pneumonia, and Escherichia coli. CTiO2@NPs were discovered to have free radical scavenging activity on DPPH analysis and exhibit IC50 value as 95.80 μg/mL and standard (Vitamin C) IC50 is 87.62 μg/mL. CTiO2@NPs exhibited better anticancer properties against the osteosarcoma (MG-63) cell line. All these findings suggest that there is a forum for further useful therapeutic applications. Therefore, we claim that nano-engineered carbohydrated TiO2 phytohybrid is a promising solution for bacterial infections and bone cancer.

Gold Nanoparticles Bioproduced in Cyanobacteria in the Initial Phase Opened an Avenue for the Discovery of Corresponding Cerium Nanoparticles

The production of isolated metallic nanoparticles with multifunctionalized properties, such as size and shape, is crucial for biomedical, photocatalytic, and energy storage or remediation applications. This study investigates the initial particle formations of gold nanoparticles (AuNPs) bioproduced in the cyanobacteria Anabaena sp. using high-resolution transmission electron microscopy images for digital image analysis. The developed method enabled the discovery of cerium nanoparticles (CeNPs), which were biosynthesized in the cyanobacteria Calothrix desertica. The particle size distributions for AuNPs and CeNPs were analyzed. After 10 h, the average equivalent circular diameter for AuNPs was 4.8 nm, while for CeNPs, it was approximately 5.2 nm after 25 h. The initial shape of AuNPs was sub-round to round, while the shape of CeNPs was more roundish due to their amorphous structure and formation restricted to heterocysts. The local PSDs indicate that the maturation of AuNPs begins in the middle of vegetative cells and near the cell membrane, compared to the other regions of the cell.

Investigating the ecological implications of nanomaterials: Unveiling plants' notable responses to nano-pollution

The rapid advancement of nanotechnology has led to unprecedented innovations; however, it is crucial to analyze its environmental impacts carefully. This review thoroughly examines the complex relationship between plants and nanomaterials, highlighting their significant impact on ecological sustainability and ecosystem well-being. This study investigated the response of plants to nano-pollution stress, revealing the complex regulation of defense-related genes and proteins, and highlighting the sophisticated defense mechanisms in nature. Phytohormones play a crucial role in the complex molecular communication network that regulates plant responses to exposure to nanomaterials. The interaction between plants and nano-pollution influences plants' complex defense strategies. This reveals the interconnectedness of systems of nature. Nevertheless, these findings have implications beyond the plant domain. The incorporation of hyperaccumulator plants into pollution mitigation strategies has the potential to create more environmentally sustainable urban landscapes and improve overall environmental resilience. By utilizing these exceptional plants, we can create a future in which cities serve as centers of both innovation and ecological balance. Further investigation is necessary to explore the long-term presence of nanoparticles in the environment, their ability to induce genetic changes in plants over multiple generations, and their overall impact on ecosystems. In conclusion, this review summarizes significant scientific discoveries with broad implications beyond the confines of laboratories. This highlights the importance of understanding the interactions between plants and nanomaterials within the wider scope of environmental health. By considering these insights, we initiated a path towards the responsible utilization of nanomaterials, environmentally friendly management of pollution, and interdisciplinary exploration. We have the responsibility to balance scientific advancement and environmental preservation to create a sustainable future that combines nature's wisdom with human innovation.

Biosynthesis of gallic acid fabricated tellurium nanoparticles (GA-Te NPs) for enhanced antibacterial, antioxidant, and cytotoxicity applications

The development of antibiotic resistance and the onset of diverse forms of cancer necessitate the utilization of innovative multifunctional biocompatible materials. The synthesis of metal and metalloid nanoparticles through eco-friendly means demonstrates promising potential in therapeutic and diagnostic domains. Among these materials, Tellurium (Te) exhibits exceptional characteristics and finds application in numerous fields; nevertheless, its usage in biological applications has been somewhat limited, primarily due to its inherent toxicity. Furthermore, nanomaterials developed from Te have not garnered adequate research attention. Conversely, nanomaterials fashioned using biomolecules augment their biological efficacy and applicability. Therefore, the present work focuses on synthesizing the tellurium nanoparticles (Te NPs) using the antioxidant molecule gallic acid (GA) and evaluating their biological activity and toxicity for the first time. The study evidenced that GA-Te NPs are spherical and monodispersed, with an average size of 19.74 ± 5.3 nm. XRD analysis confirmed a hexagonal crystalline structure for GA-Te NPs, and FTIR analysis evidenced the capping of GA on Te NPs. GA-Te NPs (MIC: 1.56 μg/mL) strongly reduce the growth and biofilm formation of S. aureus, E. coli, and S. enterica. Additionally, GA-Te NPs at a concentration of 50 μg/mL cause a significant level of toxicity in BT474 breast cancer cells but not in NIH3T3 cells. Unexpectedly, GA-Te NPs at concentrations <250 μg/mL do not cause hemolysis in red blood cells (RBC) Besides, the way of utilizing the lower concentrations of therapeutics could result in ecological safety. Therefore, the study concludes that GA-Te NPs could be used as potential multifunctional agents.

Selenium Nanoparticles: Green Synthesis and Biomedical Application

Selenium nanoparticles (SeNPs) are extremely popular objects in nanotechnology. "Green" synthesis has special advantages due to the growing necessity for environmentally friendly, non-toxic, and low-cost methods. This review considers the biosynthesis mechanism of bacteria, fungi, algae, and plants, including the role of various biological substances in the processes of reducing selenium compounds to SeNPs and their further packaging. Modern information and approaches to the possible biomedical use of selenium nanoparticles are presented: antimicrobial, antiviral, anticancer, antioxidant, anti-inflammatory, and other properties, as well as the mechanisms of these processes, that have important potential therapeutic value.

Optimization of the biosynthesis of silver nanoparticles using bacterial extracts and their antimicrobial potential

In the present study, silver nanoparticles (AgNPs) were biosynthesized using the supernatant and the intracellular extract of Cupriavidus necator, Bacillus megaterium, and Bacillus subtilis. The characterization of the AgNPs was carried out using UV-Vis spectroscopy, FTIR, DLS and TEM. Resazurin microtiter-plate assay was used to determine the antimicrobial action of AgNPs against Escherichia coli. UV-Visible spectra showed peaks between 414 and 460 nm. TEM analysis revealed that the synthesized AgNPs showed mostly spherical shapes. DLS results determined sizes from 20.8 to 118.4 nm. The highest antimicrobial activity was obtained with the AgNPs synthesized with supernatant rather than those using the intracellular extract. Therefore, it was determined that the bacterial species, temperature, pH, and type of extract (supernatant or intracellular) influence the biosynthesis. This synthesis thus offers a simple, environmentally friendly, and low-cost method for the production of AgNPs, which can be used as antibacterial agents.

Synthesis of copper-reduced graphene oxide nanomaterials using glucose and study of its antibacterial and anticancer activities

In this work, glucose-capped copper nanoparticles decorated reduced graphene oxide nanomaterial are synthesized at 100 °C and 200 °C via chemical reduction method and studied for their antibacterial and anticancer activities. Synthesized nanomaterials were characterized using x-ray diffraction, Fourier-transform infrared, transmission electron microscope, and RAMAN. It is observed in transmission electron microscopy and selected area electron diffraction studies that copper nanoparticles deposited onto reduced graphene oxide are smaller than nanoparticles generated in the absence of reduced graphene oxide. Also, the size of copper nanoparticles synthesized at 200 °C is smaller than at 100 °C. Results suggest that Cu/Glu/rGO synthesized at both temperatures showed significant antibacterial activity againstEscherichia coliandBacillus anthracis,similarly, showed significant cell death in cancer cell lines [Cal33 and HCT-116 p53 (+/+)]. Interestingly, the nanomaterials were seen to be more effective against the cancer cell lines harboring aggregating mutant p53. Tumors with aggregating mutants of p53 are difficult to treat hence, Cu/Glu/rGO can be promising therapeutic agents against these difficult cancers. However, the antibacterial and anticancer activity of Cu/Glu/rGO synthesized at 100 °C where Cu2O form is obtained was found to be more effective compared to Cu/Glu/rGO synthesized at 200 °C where Cu form is obtained. Though fine-tuning of the material may be required for its commercial applications.

In situ capping of silver nanoparticles with cellulosic matrices from wheat straws in enhancing their antimicrobial activity: Synthesis and characterization

Silver nanoparticles have gained worldwide attention in the scientific community due to their high antimicrobial activity. However, they tend to agglomerate and lose their shape and properties, thus capping agents necessary to protect their shapes, sizes, and properties. To enhance their antimicrobial activity, this research aimed to cap silver nanoparticles with cellulosic matrices from wheat straws. The wheat straw was delignified with 6% HNO3, and the residual was treated with 1% NaOH and NaClO: CH3COOH (1:1), then used to synthesize cellulose nanocrystals via acid hydrolysis. AgNPs were incorporated into the CPC and CNCs by in-situ synthesis using NaHB4 as the reducing agent. Fourier Transform Infrared, Scanning Electron Microscopy, and X-ray diffraction were used to investigate their features. The findings exhibited crystallinity increased with subsequent treatments, according to XRD analysis. Ultraviolet-visible, FTIR, TEM, and XRD analysis confirmed the capping of AgNPs onto the cellulosic materials. Antibacterial activity against Staphylococcus aureus and Escherichia coli, with CNCs-AgNPs composite, exhibited higher activity compared to CPC-AgNPs composite due to the increased surface area and excellent binding on the surface of the composite.

Facile synthesis of CuONPs using Citrus limon juice for enhancing antibacterial activity against methicillin-resistant Staphylococcus aureus, beta-lactamase and tetracycline-resistant Escherichia coli

Antimicrobial resistance (AMR) resulting from indiscriminate use of antibiotics in various fields of agriculture such as livestock farming, aquaculture, and croup fields become an emerging catatroph for the health (human, animal) and environment. Among those, poultry farming has been considered as one of the major contributors of multidrug-resistant (MDR) bacteria. Focusing this, the present research is designed for green synthesis of copper oxide nanoparticles (CuONPs) with the aim of their application in antibiotic-free poultry farming for curving use of antibiotics in that sector. For that, antibacterial CuONPs were nanoformulated to decrease the required doses of bulk CuSO4. We used a CuSO4·5H2O solution as a Cu2+ source and Citrus limon juice as a reducing agent as well as capping agent. Particle yield was initially confirmed by the λmax specific to CuONPs (295 nm) using UV-Vis spectroscopy. The presence of the Cu-O group during particle formation and crystallinity with the purity of yielded NPs was confirmed with Fourier-transform infrared spectroscopy and X-ray diffractometry. The round to spherical CuONPs of 92-155 nm average size was confirmed with atomic force, scanning electron, and transmission electron microscopy. The concentration of yielded NPs was calculated with the dynamic light scattering. The physical characterization tools indicated a maximum CuONPs yield with a 0.001 M ion source with 15% reducing agents after 12 h reduction. Antibacterial effectivity was tested against methicillin-resistant Staphylococcus aureus and tetracycline- and beta-lactamase-resistant Escherichia coli, confirmed by PCR amplicon band at 163 bp, 643 bp, and 577 bp for the mecA, blaTEM-1 and tetA genes, respectively. An antibiogram assay of CuONPs showed a maximum zone of inhibition of 26 ± 0.5 mm for the synthesized particles. The minimum inhibitory and bactericidal concentrations were 1.6 μg ml-1 and 3.1 μg ml-1, respectively, for broad-spectrum application. Finally, the biocompatibility of CuONPs was determined by demonstrating a nonsignificant decrease of BHK-21 cell viability at <2 MIC doses for complying their future in vivo applicability.

The effect of cetyltrimethylammonium bromide (CTAB) addition on green synthesis of porous N-doped TiO2 for photoreduction of heavy metal ion Cr(vi)

In this study, porous TiO2 photocatalysts modified by nitrogen (NCT) were successfully synthesized using a combination of green synthesis methods by utilizing Aloe vera (L.) Burm. f. peel and hydrothermal method. In addition, TiO2 was modified by increasing the active surface area using Cetyltrimethylammonium Bromide (CTAB). The X-ray Diffraction (XRD) results indicated that the anatase phase was formed. The result of the Diffuse Reflectance Spectroscopy UV-Vis (DRS UV-Vis) using the Tauc-plot method showed that all porous N-doped TiO2 samples experienced a decrease in the energy gap. This indicates the successful modification of TiO2 by nitrogen, as confirmed by the Fourier Transform Infra-Red (FTIR) result. Field Emission Scanning Electron Microscopy (FESEM) result showed that the synthesized TiO2 had a spherical morphology of 10-30 nm diameter. The Braunauer, Emmett, and Teller (BET) result indicated that the type IV isotherm curve with a mesoporous structure was formed. The NCT0.75 sample had a surface area and pore size of 95.02 m2 g-1 and 8.021 nm, respectively, while the NTi0.75 sample had a surface area and pore size of 90.97 m2 g-1 and 5.161 nm, respectively. The photocatalytic activity of the porous N-doped TiO2 was tested on photoreduction of metal pollutant model Cr(vi). The result demonstrated that the NCT0.75 sample had the most optimal photocatalytic activity by reducing 89.42% of Cr(vi) metal ions.

Silver-cored Ziziphus spina-christi extract-loaded antimicrobial nanosuspension: overcoming multidrug resistance

Aims: To synthesize a silver-cored nanosuspension utilizing Ziziphus spina-christi fresh-leaf extract and evaluate their antimicrobial activity against multidrug-resistant pathogenic microbes. Materials and Methods: The prepared nanosuspension was analyzed by spectro-analytical techniques and tested for antimicrobial activity and resistance to biofilm formation. The leaf extract and nanosuspension were tested separately and together as a mixture. Results: Constituent nanoparticles were average-sized (∼34 nm) and were active against both Gram-positive and Gram-negative microbes and yeast. Candida albicans showed a 24.50 ± 1.50 mm inhibition zone, followed by Escherichia coli and Staphylococcus aureus. Increased bioactivity with the highest multifold increments, 150%, for erythromycin against all tested microbes was observed. Carbenicillin and trimethoprim showed 166%- and 300%-fold increments for antimicrobial activity against Pseudomonas aeruginosa, respectively. Conclusion: The nanosuspension exhibited strong potential as an antimicrobial agent and overcame multidrug resistance.

Improving the Production of Secondary Metabolites via the Application of Biogenic Zinc Oxide Nanoparticles in the Calli of Delonix elata: A Potential Medicinal Plant

The implementation of nanotechnology in the field of plant tissue culture has demonstrated an interesting impact on in vitro plant growth and development. Furthermore, the plant tissue culture accompanying nanoparticles has been showed to be a reliable alternative for the biosynthesis of secondary metabolites. Herein, the effectiveness of zinc oxide nanoparticles (ZnONPs) on the growth of Delonix elata calli, as well as their phytochemical profiles, were investigated. Delonix elata seeds were collected and germinated, and then the plant species was determined based on the PCR product sequence of ITS1 and ITS4 primers. Afterward, the calli derived from Delonix elata seedlings were subjected to 0, 10, 20, 30, 40, and 50 mg/L of ZnONPs. The ZnONPs were biologically synthesized using the Ricinus communis aqueous leaf extract, which acts as a capping and reducing agent, and zinc nitrate solution. The nanostructures of the biogenic ZnONPs were confirmed using different techniques like UV-visible spectroscopy (UV), zeta potential measurement, Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Adding 30 mg/L of ZnONPs to the MS media (containing 2.5 µM 2,4-D and 1 µM BAP) resulted in the highest callus fresh weight (5.65 g) compared to the control and other ZnONP treatments. Similarly, more phenolic accumulation (358.85 µg/g DW) and flavonoid (112.88 µg/g DW) contents were achieved at 30 mg/L. Furthermore, the high-performance liquid chromatography (HPLC) analysis showed significant increments in gallic acid, quercetin, hesperidin, and rutin in all treated ZnONP calli compared to the control. On the other hand, the gas chromatography and mass spectroscopy (GC-MS) analysis of the calli extracts revealed that nine phytochemical compounds were common among all extracts. Moreover, the most predominant compound found in calli treated with 20, 30, 40, and 50 mg/L of ZnONPs was bis(2-ethylhexyl) phthalate, with percentage areas of 27.33, 38.68, 22.66, and 17.98%, respectively. The predominant compounds in the control and in calli treated with 10 mg/L of ZnONPs were octadecanoic acid, 2-propenyl ester and heptanoic acid. In conclusion, in this study, green ZnONPs exerted beneficial effects on Delonix elata calli and improved their production of bioactive compounds, especially at a dose of 30 mg/L.

Multiheaded Cationic Surfactants with Dedicated Functionalities: Design, Synthetic Strategies, Self-Assembly and Performance

Contemporary research concerning surfactant science and technology comprises a variety of requirements relating to the design of surfactant structures with widely varying architectures to achieve physicochemical properties and dedicated functionality. Such approaches are necessary to make them applicable to modern technologies, such as nanostructure engineering, surface structurization or fine chemicals, e.g., magnetic surfactants, biocidal agents, capping and stabilizing reagents or reactive agents at interfaces. Even slight modifications of a surfactant's molecular structure with respect to the conventional single-head-single-tail design allow for various custom-designed products. Among them, multicharge structures are the most intriguing. Their preparation requires specific synthetic routes that enable both main amphiphilic compound synthesis using appropriate step-by-step reaction strategies or coupling approaches as well as further derivatization toward specific features such as magnetic properties. Some of the most challenging aspects of multicharge cationic surfactants relate to their use at different interfaces for stable nanostructures formation, applying capping effects or complexation with polyelectrolytes. Multiheaded cationic surfactants exhibit strong antimicrobial and antiviral activity, allowing them to be implemented in various biomedical fields, especially biofilm prevention and eradication. Therefore, recent advances in synthetic strategies for multiheaded cationic surfactants, their self-aggregation and performance are scrutinized in this up-to-date review, emphasizing their applications in different fields such as building blocks in nanostructure engineering and their use as fine chemicals.

Titanium biogenic nanoparticles to help the growth of Trichoderma harzianum to be used in biological control

BACKGROUND

The biogenic synthesis of metallic nanoparticles is a green alternative that reduces the toxicity of this nanomaterials and may enable a synergy between the metallic core and the biomolecules employed in the process enhancing biological activity. The aim of this study was to synthesize biogenic titanium nanoparticles using the filtrate of the fungus Trichoderma harzianum as a stabilizing agent, to obtain a potential biological activity against phytopathogens and mainly stimulate the growth of T. harzianum, enhancing its efficacy for biological control.

RESULTS

The synthesis was successful and reproductive structures remained in the suspension, showing faster and larger mycelial growth compared to commercial T. harzianum and filtrate. The nanoparticles with residual T. harzianum growth showed inhibitory potential against Sclerotinia sclerotiorum mycelial growth and the formation of new resistant structures. A great chitinolytic activity of the nanoparticles was observed in comparison with T. harzianum. In regard to toxicity evaluation, an absence of cytotoxicity and a protective effect of the nanoparticles was observed through MTT and Trypan blue assay. No genotoxicity was observed on V79-4 and 3T3 cell lines while HaCat showed higher sensitivity. Microorganisms of agricultural importance were not affected by the exposure to the nanoparticles, however a decrease in the number of nitrogen cycling bacteria was observed. In regard to phytotoxicity, the nanoparticles did not cause morphological and biochemical changes on soybean plants.

CONCLUSION

The production of biogenic nanoparticles was an essential factor in stimulating or maintaining structures that are important for biological control, showing that this may be an essential strategy to stimulate the growth of biocontrol organisms to promote more sustainable agriculture.

Size controlled biosynthesis of silver nanoparticles using Ophiorrhiza mungos, Ophiorrhiza harrisiana and Ophiorrhiza rugosa aqueous leaf extract and their antimicrobial activity

In this work, the aqueous leaf extracts of three Ophiorrhiza genus species, namely Ophiorrhiza mungos (Om), Ophiorrhiza harrisiana (Oh) and Ophiorrhiza rugosa (Or), have been used as the reducing and capping agents to control the size of AgNPs, Om-AgNPs, Oh-AgNPs and Or-AgNPs, respectively and found to be an effective antimicrobial agent against a wide range of bacteria and fungi. The biosynthesized AgNPs were studied by UV-Visible spectrophotometer, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray, transmission electron microscopy (TEM) and Fourier transform infrared spectrometer (FTIR). The average particle sizes of Om-AgNPs, Oh-AgNPs and Or-AgNPs were measured as 17 nm, 22 nm and 26 nm, respectively, and observed to be spherical and face-centered cubic crystals. The antibacterial test of synthesized AgNPs was performed against Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Vibrio cholerae where the maximum antibacterial activity was observed by reducing the nano-size and increasing the silver content of AgNPs. The antifungal effect of these three types of AgNPs on Penicillium notatum and Aspergillus niger was also evaluated and their growth with AgNPs concentrations of 450 μg/mL was inhibited up to 80-90% and 55-70%, respectively. The size-control synthesis of AgNPs using the Ophiorrhiza genus species is presented here for the first time where the synthesized AgNPs showed higher stability and antimicrobial activities. Therefore, this study might lead to synthesize AgNPs with different morphologies using plant extracts of the same genus but from different species and provide strong encouragement for future applications in treating infectious diseases.

Biosorption performance of the multi-metal tolerant fungus Aspergillus sp. for removal of some metallic nanoparticles from aqueous solutions

The wide spread of nanotechnology applications currently carries with it the possibility of polluting the environment with the residues of these nanomaterials, especially those in the metallic form. Therefore, it is necessary to study the possibility of treating and removing various nanoscale metal pollutants in environmentally friendly ways. The present study focused on the isolation of multi-metal tolerant fungi to be applied in the bioremoval of Zn, Fe, Se, and Ag nanoparticles as potential nanoscale metal pollutants. Aspergillus sp. has been isolated as multi-metal tolerant fingus and investigated in the bioremoval of targeted nanometals from their aquoues solutions. The effect of biomass age, pH, and contact time was studied to determine the optimal biosorption conditions for fungal pellets towards metal NPs. The results showed a high percentage of fungal biosorption on the of two-day-old cells, which amounted to 39.3, 52.2, 91.7, and 76.8% of zinc, iron, selenium, and silver, respectively. The pH 7 was recorded the highest percentage of NPs removal for the four studied metals i.e. 38.8, 68.1, 80.4, and 82.0% of Zn-, Fe-, Se- and Ag-NPs, respectively. The contact time required between Aspergillus sp. and the metal nanoparticles to obtain the best adsorption was only 10 min in the case of Zn and Ag, but it was 40 min for both Fe and Se NPs. The efficiency of living fungal pellets in removing the four metallic NPs exceeded that of dead biomass by 1.8, 5.7, 2.5, and 2.5 folds for Zn, Fe, Se and Ag, respectively. However, utilization of dead fungal biomass for metallic NPs removal could be considered more applicable to the actual environmental applications.

Preparation of Hydrogel Composites Using a Sustainable Approach for In Situ Silver Nanoparticles Formation

The recognized antibacterial properties of silver nanoparticles (AgNPs) characterize them as attractive nanomaterials for developing new bioactive materials less prone to the development of antibiotic resistance. In this work, we developed new composites based on self-assembling Fmoc-Phe3 peptide hydrogels impregnated with in situ prepared AgNPs. Different methodologies, from traditional to innovative and eco-sustainable, were compared. The obtained composites were characterized from a hydrodynamic, structural, and morphological point of view, using different techniques such as DLS, SEM, and rheological measurements to evaluate how the choice of the reducing agent determines the characteristics of AgNPs and how their presence within the hydrogel affects their structure and properties. Moreover, the antibacterial properties of these composites were tested against S. aureus, a major human pathogen responsible for a wide range of clinical infections. Results demonstrated that the hydrogel composites containing AgNPs (hgel@AgNPs) could represent promising biomaterials for treating S. aureus-related infections.

Biosynthesized magnesium oxide nanoparticles from Tamarindus indica seed attenuate doxorubicin-induced cardiotoxicity by regulating biochemical indexes and linked genes

The phytochemicals of Tamarindus indica seed hydroalcoholic extract were exploited as a biocatalyst for the sustainable synthesis of magnesium oxide nanoparticles (MgO-NPs). This research investigated the cardioprotective effects of biosynthesized magnesium oxide nanoparticle (MgO-NPs). The biosynthesized seed MgO-NPs were characterized by ultraviolet-visible spectroscopy (UV-Vis), X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy-dispersive X-ray diffraction (EDX), and Fourier-transform infrared spectroscopy (FT-IR). These methodological approaches demonstrated their capacity to synthesize crystalline and aggregated MgO-NPs with a size average of 13.38 ± 0.16 nm. The biogenic MgO-NPs were found to have a significant quantity of total phenolic contents (TPC) and total flavonoid contents (TFC), indicating the existence of phenol and flavonoid-like components. The biogenic MgO-NPs demonstrated a significant free radical scavenging effects compared to different standards as measured by the inhibition of free radicals produced in 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS•+), and Nitric oxide (NO) scavenging methods; they also exhibited higher ferric ion reducing capacity in FRAP assay. Moreover, they were found to be non-toxic in cytotoxic assessment. Pretreatment of Wistar Albino rats with seed MgO-NPs resulted in a significant reduction of cardiac biomarkers, i.e., cardiac Troponin-I (cTnI), creatine kinase (CK-MB), and aspartate aminotransferase (AST). The seed MgO-NPs were more successful in reducing lipid levels. The results of the mRNA expression analysis showed that seed MgO-NPs efficiently reduced the expression of the apoptotic genes p53 and Caspase-3 while restoring the expected levels of SOD gene expression. The histopathological observations were primarily focused on the disruption of cardiac fibers and myofibrillar disintegration, which are consistent with the biochemical findings. Therefore, our research suggests that MgO-NPs derived from the seeds of Tamarindus indica as a powerful antioxidant; the administration may be effective in protecting the heart from DOX-induced cardiotoxicity.

Multi-round recycling of green waste for the production of iron nanoparticles: synthesis, characterization, and prospects in remediation

Due to the widespread applications of metal nanoparticles (NPs), green synthesis strategies have recently advanced, e.g., methods that utilize extracts made from different plant wastes. A particularly innovative approach to reducing large amounts of available household/agricultural green wastes is their application in nanoparticle generation. Regarding this, the aim of our work was to examine the possibility of upgrading green nanoparticle syntheses from an innovative economic and environmental point of view, namely by investigating the multiple recyclabilities of green tea (GT), coffee arabica (CA), and Virginia creeper (Parthenocissus quinquefolia) (VC) waste residues for iron nanoparticle (FeNPs) synthesis. The plant extracts obtained by each extraction round were analyzed individually to determine the amount of main components anticipated to be involved in NPs synthesis. The synthesized FeNPs were characterized by X-ray powder diffraction and transmission electron microscopy. The activity of the generated FeNPs in degrading chlorinated volatile organic compounds (VOC) and thus their future applicability for remediation purposes were also assessed. We have found that VC and especially GT residues could be reutilized in multiple extraction rounds; however, only the first extract of CA was suitable for FeNPs' generation. All of the obtained FeNPs could degrade VOC with efficiencies GT1-Fe 91.0%, GT2-Fe 83.2%, GT3-Fe 68.5%; CA1-Fe 76.2%; VC1-Fe 88.2%, VC2-Fe 79.7%, respectively, where the number (as in GT3) marked the extraction round. These results indicate that the adequately selected green waste material can be reutilized in multiple rounds for nanoparticle synthesis, thus offering a clean, sustainable, straightforward alternative to chemical methods.

The Role of Silver Nanoparticles in the Diagnosis and Treatment of Cancer: Are There Any Perspectives for the Future?

Cancer is a fatal disease with a complex pathophysiology. Lack of specificity and cytotoxicity, as well as the multidrug resistance of traditional cancer chemotherapy, are the most common limitations that often cause treatment failure. Thus, in recent years, significant efforts have concentrated on the development of a modernistic field called nano-oncology, which provides the possibility of using nanoparticles (NPs) with the aim to detect, target, and treat cancer diseases. In comparison with conventional anticancer strategies, NPs provide a targeted approach, preventing undesirable side effects. What is more, nanoparticle-based drug delivery systems have shown good pharmacokinetics and precise targeting, as well as reduced multidrug resistance. It has been documented that, in cancer cells, NPs promote reactive oxygen species (ROS) production, induce cell cycle arrest and apoptosis, activate ER (endoplasmic reticulum) stress, modulate various signaling pathways, etc. Furthermore, their ability to inhibit tumor growth in vivo has also been documented. In this paper, we have reviewed the role of silver NPs (AgNPs) in cancer nanomedicine, discussing numerous mechanisms by which they render anticancer properties under both in vitro and in vivo conditions, as well as their potential in the diagnosis of cancer.

One-Step Phytofabrication Method of Silver and Gold Nanoparticles Using Haloxylon salicornicum for Anticancer, Antimicrobial, and Antioxidant Activities

Among various routes of metallic nanoparticle (NPs) fabrication, phytosynthesis has significant advantages over other conventional approaches. Plant-mediated synthesis of NPs is a fast, one-step, ecobenign, and inexpensive method with high scalability. Herein, silver (Ag) and gold (Au)-NPs were extracellularly synthesized using aqueous Haloxylon salicornicum (H@Ag-, H@Au-NPs) leaf extracts. GC-MS was performed to analyze the chemical compositions of H. salicornicum extract. H@Ag- and H@Au-NPs were characterized via UV-Vis spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, transmission and scanning electron microscopy, and Zetasizer. H@Ag- and H@Au-NPs have surface plasmon resonance at 435.5 and 530.3 nm, respectively. FTIR and GC-MS data suggest that secondary plant metabolites and hydrocarbons might be responsible for the reduction and stabilization of NPs. XRD demonstrated that both NPs have a crystalline nature. H@Ag-NPs have a uniform spherical shape, whereas H@Au-NPs are spherical with few oval and triangular shapes, and their average nanosizes were 19.1 ± 0.8 and 8.1 ± 0.3 nm, respectively. Hydrodynamic diameters of H@Ag-NPs and H@Au-NPs were 184.7 nm, 56.4, and 295.4 nm, and their potential charges were -24.0 and -24.4 mV, respectively. The inhibitory activity of 500 µg/mL H@Ag- and H@Au-NPs was tested against Sw480, Sw620, HCT-116, and Caco-2 colon cancer cell lines and two normal cell lines, including HFs and Vero. H@Ag-NPs revealed potent anticancer activity against all cancer cells at low concentrations. Sw480 was the most sensitive cell to H@Ag-NPs, whereas Sw620 was the least permeable one. These findings suggested that the antiproliferative activity of H@Ag-NPs is cell-response-dependent and may be influenced by a variety of factors, including the cellular metabolic state, which influences cellular charge and interactions with charged NPs. Although H@Au-NPs were smaller, their reactivity against cancer cells was weak, suggesting that the chemical properties, metal structure, quantity and chemistry of the functional groups on the NP surface may influence their reactivity. The biocidal activity of 1 mg/mL H@Ag- and H@Au-NPs against Staphylococcus aureus, Bacillus cereus, Escherichia coli and Klebsiella pneumoniae was assessed. H@Ag-NPs showed biocidal activity against Gram-positive bacteria compared to Gram-negative bacteria, whereas H@Au-NPs showed no inhibitory activity. FRAP and DPPH assays were used to determine the scavenging activity of the plant extracts and both NPs. H@Ag-NPs (1 mg/mL) had the greatest scavenging activity compared to tested drugs. These findings suggest that H@Ag-NPs are potent anticancer, antibacterial, and antioxidant agents, while H@Au-NPs may be used as a drug vehicle for pharmaceutical applications.

Burdock-Derived Composites Based on Biogenic Gold, Silver Chloride and Zinc Oxide Particles as Green Multifunctional Platforms for Biomedical Applications and Environmental Protection

Green nanotechnology is a rapidly growing field linked to using the principles of green chemistry to design novel nanomaterials with great potential in environmental and health protection. In this work, metal and semiconducting particles (AuNPs, AgClNPs, ZnO, AuZnO, AgClZnO, and AuAgClZnO) were phytosynthesized through a "green" bottom-up approach, using burdock (Arctium lappa L.) aqueous extract. The morphological (SEM/TEM), structural (XRD, SAED), compositional (EDS), optical (UV-Vis absorption and FTIR spectroscopy), photocatalytic, and bio-properties of the prepared composites were analyzed. The particle size was determined by SEM/TEM and by DLS measurements. The phytoparticles presented high and moderate physical stability, evaluated by zeta potential measurements. The investigation of photocatalytic activity of these composites, using Rhodamine B solutions' degradation under solar light irradiation in the presence of prepared powders, showed different degradation efficiencies. Bioevaluation of the obtained composites revealed the antioxidant and antibacterial properties. The tricomponent system AuAgClZnO showed the best antioxidant activity for capturing ROS and ABTS•⁺ radicals, and the best biocidal action against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The "green" developed composites can be considered potential adjuvants in biomedical (antioxidant or biocidal agents) or environmental (as antimicrobial agents and catalysts for degradation of water pollutants) applications.

Biogenic metallic nanoparticles as enzyme mimicking agents

The use of biological systems such as plants, bacteria, and fungi for the synthesis of nanomaterials has emerged to fill the gap in the development of sustainable methods that are non-toxic, pollution-free, environmentally friendly, and economical for synthesizing nanomaterials with potential in biomedicine, biotechnology, environmental science, and engineering. Current research focuses on understanding the characteristics of biogenic nanoparticles as these will form the basis for the biosynthesis of nanoparticles with multiple functions due to the physicochemical properties they possess. This review briefly describes the intrinsic enzymatic mimetic activity of biogenic metallic nanoparticles, the cytotoxic effects of nanoparticles due to their physicochemical properties and the use of capping agents, molecules acting as reducing and stability agents and which aid to alleviate toxicity. The review also summarizes recent green synthetic strategies for metallic nanoparticles.

Biofabrication of nanoparticles: sources, synthesis, and biomedical applications

Nanotechnology is an emerging applied science delivering crucial human interventions. Biogenic nanoparticles produced from natural sources have received attraction in recent times due to their positive attributes in both health and the environment. It is possible to produce nanoparticles using various microorganisms, plants, and marine sources. The bioreduction mechanism is generally employed for intra/extracellular synthesis of biogenic nanoparticles. Various biogenic sources have tremendous bioreduction potential, and capping agents impart stability. The obtained nanoparticles are typically characterized by conventional physical and chemical analysis techniques. Various process parameters, such as sources, ions, and temperature incubation periods, affect the production process. Unit operations such as filtration, purification, and drying play a role in the scale-up setup. Biogenic nanoparticles have extensive biomedical and healthcare applications. In this review, we summarized various sources, synthetic processes, and biomedical applications of metal nanoparticles produced by biogenic synthesis. We highlighted some of the patented inventions and their applications. The applications range from drug delivery to biosensing in various therapeutics and diagnostics. Although biogenic nanoparticles appear to be superior to their counterparts, the molecular mechanism degradation pathways, kinetics, and biodistribution are often missing in the published literature, and scientists should focus more on these aspects to move them from the bench side to clinics.

Recent Advances in the Development of Lipid-, Metal-, Carbon-, and Polymer-Based Nanomaterials for Antibacterial Applications

Infections caused by multidrug-resistant (MDR) bacteria are becoming a serious threat to public health worldwide. With an ever-reducing pipeline of last-resort drugs further complicating the current dire situation arising due to antibiotic resistance, there has never been a greater urgency to attempt to discover potential new antibiotics. The use of nanotechnology, encompassing a broad range of organic and inorganic nanomaterials, offers promising solutions. Organic nanomaterials, including lipid-, polymer-, and carbon-based nanomaterials, have inherent antibacterial activity or can act as nanocarriers in delivering antibacterial agents. Nanocarriers, owing to the protection and enhanced bioavailability of the encapsulated drugs, have the ability to enable an increased concentration of a drug to be delivered to an infected site and reduce the associated toxicity elsewhere. On the other hand, inorganic metal-based nanomaterials exhibit multivalent antibacterial mechanisms that combat MDR bacteria effectively and reduce the occurrence of bacterial resistance. These nanomaterials have great potential for the prevention and treatment of MDR bacterial infection. Recent advances in the field of nanotechnology are enabling researchers to utilize nanomaterial building blocks in intriguing ways to create multi-functional nanocomposite materials. These nanocomposite materials, formed by lipid-, polymer-, carbon-, and metal-based nanomaterial building blocks, have opened a new avenue for researchers due to the unprecedented physiochemical properties and enhanced antibacterial activities being observed when compared to their mono-constituent parts. This review covers the latest advances of nanotechnologies used in the design and development of nano- and nanocomposite materials to fight MDR bacteria with different purposes. Our aim is to discuss and summarize these recently established nanomaterials and the respective nanocomposites, their current application, and challenges for use in applications treating MDR bacteria. In addition, we discuss the prospects for antimicrobial nanomaterials and look forward to further develop these materials, emphasizing their potential for clinical translation.

The Effect of Capping Agents on Gold Nanostar Stability, Functionalization, and Colorimetric Biosensing Capability

Capping agents (organic ligands, polymers, and surfactants) are pivotal for stabilizing nanoparticles; however, they may influence the surface chemistry, as well as the physico-chemical and biological characteristics, of gold nanostar (AuNS)-based biosensors. In this study, we proved that various capping agents affected capped and bioconjugated AuNS stability, functionality, biocatalysis, and colorimetric readouts. Capped and bioconjugated AuNSs were applied as localized surface plasmon resonance (LSPR)-based H2O2 sensors using glucose oxidase (GOx) as a model enzyme. Furthermore, our analyses revealed that the choice of capping agent influenced the properties of the AuNSs, their stability, and their downstream applications. Our analyses provide new insights into factors governing the choice of capping agents for gold nanostars and their influences on downstream applications with conjugated enzymes in confined environments.

Nanomaterials-Based Combinatorial Therapy as a Strategy to Combat Antibiotic Resistance

Since the discovery of antibiotics, humanity has been able to cope with the battle against bacterial infections. However, the inappropriate use of antibiotics, the lack of innovation in therapeutic agents, and other factors have allowed the emergence of new bacterial strains resistant to multiple antibiotic treatments, causing a crisis in the health sector. Furthermore, the World Health Organization has listed a series of pathogens (ESKAPE group) that have acquired new and varied resistance to different antibiotics families. Therefore, the scientific community has prioritized designing and developing novel treatments to combat these ESKAPE pathogens and other emergent multidrug-resistant bacteria. One of the solutions is the use of combinatorial therapies. Combinatorial therapies seek to enhance the effects of individual treatments at lower doses, bringing the advantage of being, in most cases, much less harmful to patients. Among the new developments in combinatorial therapies, nanomaterials have gained significant interest. Some of the most promising nanotherapeutics include polymers, inorganic nanoparticles, and antimicrobial peptides due to their bactericidal and nanocarrier properties. Therefore, this review focuses on discussing the state-of-the-art of the most significant advances and concludes with a perspective on the future developments of nanotherapeutic combinatorial treatments that target bacterial infections.