Biogenic synthesis and cytotoxic effects of silver nanoparticles mediated by white rot fungi

Nicotinic acid modulates microglial TREM-2 gene in Phytohaemagglutinin-Induced in vitro model of Alzheimer's disease like pathology

Alzheimer's disease (AD) is a multifactorial,neurodegenerative disorder linked withextracellular amyloid beta (Aβ) plaques deposition and formation of intracellular neurofibrillary tangles (NFTs). Currently, no effective therapies are available to cure AD. Neuroinflammation isa well-known hallmark in the onset and advancement of AD and triggering receptor expressed on myeloid cells-2 (TREM-2), a microglial gene, is responsible for regulating inflammatory responses and clearance of cellular debris. Loss of TREM-2functionincreases neuroinflammation associated expression of pro-inflammatory markersthus resultingin reduced clearance of Aβ that further aid in disease progression.Therefore, targeting neuroinflammation is a good therapeutic approach for AD. This study aimed to determine the neuroprotective effect of nicotinic acid (NA) in vitro model of AD-like pathology induced in F-98 cell line using Phytohemagglutinin (PHA). MTT assay was employed for checking the cell viability as well as the proliferation of the cells following treatment with NA. PHA at the concentration of 10 μg/mL produces maximum plaques. The neuroprotective effect of NA was next evaluated against PHA-induced plaques and it was observed that NA reverses the damages induced by PHA i.e., by inhibiting the clustering of the cells and replacing the damaged cells with the new ones. Further, NA also increased the expression of TREM-2/DAP-12 with parallel decreased in the expression of IL-1β, TNF-α and iNOS. It also successfully altered disease associated ADAM-10 and BACE-1 compared to PHA control. These findings suggest that NA might be considered as a good therapeutic candidate for the treatment of neurodegenerative disorders like AD.

Macrofungal Mediated Biosynthesis of Silver Nanoparticles and Evaluation of Its Antibacterial and Wound-Healing Efficacy

Recently, the utilization of biological agents in the green synthesis of nanoparticles has been given interest. In this study, silver nanoparticles were synthesized from an aqueous extract of macrofungus (mushroom), namely Phellinus adamantinus, in a dark room using 20 µL of silver nitrate. Biosynthesized silver nanoparticles were confirmed by analyzing them using a UV-Vis (ultraviolet-visible) spectrophotometer. The synthesized silver nanoparticles were optimized at different pH and temperatures with various dosages of AgNO3 (silver nitrate) and fungal extracts. The synthesized AgNPs (silver nanoparticles) were characterized using TEM (transmission electron microscopy) and EDX (energy-dispersive X-ray) analyses, which confirmed the presence of silver nanoparticles. The size of the nanosilver particles was found to be 50 nm with higher stability. The mycosynthesized AgNPs showed effective antibacterial activity against strains of Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (E. coli and Pseudomonas aeruginosa) bacteria. The minimum inhibitory concentration (MIC) was found to be 3.125 μg/mL by MIC assay. The MTT assay (3-[4,5-dimethylthiazol-2-yl] 2,5-diphenyl-2H-tetrazolium bromide) was performed to study cytotoxicity, and reduced cell viability was recorded at 100 μg/mL. Silver-Polygalacturonic acid-Polyvinyl alcohol ((Ag-PGA)-PVA) nanofiber was prepared using the electrospinning method. The in vitro wound scratch assay was demonstrated to study the wound-healing efficacy of the prepared nanofiber. The wound-healing efficacy of the AgNP-incorporated nanofiber was found to be 20% after 24 h. This study will lay a platform to establish a unique route to the development of a novel nanobiomaterial and its application in antibacterial and wound-healing therapy.

Activities against Lung Cancer of Biosynthesized Silver Nanoparticles: A Review

Nanomedicine is an interdisciplinary field where nanostructured objects are applied to treat or diagnose disease. Nanoparticles (NPs) are a special class of materials at nanometric scale that can be prepared from lipids, polymers, or noble metals through bottom-up approaches. Biological synthesis is a reliable, sustainable, and non-toxic bottom-up method that uses phytochemicals, microorganisms, and enzymes to induce the reduction of metal ions into NPs. Silver (Ag) NPs exhibit potent therapeutic properties that can be exploited to overcome the limitations of current treatment modalities for human health issues such as lung cancer (LC). Here, we review the preparation of AgNPs using biological synthesis and their application against LC using in vitro and in vivo models. An overview of the staging, diagnosis, genetic mutations, and treatment of LC, as well as its main subtypes, is presented. A summary of the reaction mechanisms of AgNPs using microbial cell cultures, plant extracts, phytochemicals, and amino acids is included. The use of capping agents in the biosynthesis of AgNPs with anticancer activity is also detailed. The history and biological activities of metal-based nanostructures synthesized with gold, copper, palladium, and platinum are considered. The possible anticancer mechanisms of AgNPs against LC models are covered. Our perspective about the future of AgNPs in LC treatment and nanomedicine is added.

Biogenic Synthesis of Silver Nanoparticles Using Catharanthus roseus and Its Cytotoxicity Effect on Vero Cell Lines

Background: Type 2 diabetes mellitus (DM2) is a chronic and sometimes fatal condition which affects people all over the world. Nanotherapeutics have shown tremendous potential to combat chronic diseases—including DM2—as they enhance the overall impact of drugs on biological systems. Greenly synthesized silver nanoparticles (AgNPs) from Catharanthus roseus methanolic extract (C. AgNPs) were examined primarily for their cytotoxic and antidiabetic effects. Methods: Characterization of C. AgNPs was performed by UV−vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and atomic force microscopy (AFM). The C. AgNPs were trialed on Vero cell line and afterwards on an animal model (rats). Results: The C. AgNPs showed standard structural and functional characterization as revealed by FTIR and XRD analyses. The zetapotential analysis indicated stability while EDX analysis confirmed the formation of composite capping with Ag metal. The cytotoxic effect (IC50) of C. AgNPs on Vero cell lines was found to be 568 g/mL. The animal model analyses further revealed a significant difference in water intake, food intake, body weight, urine volume, and urine sugar of tested rats after treatment with aqueous extract of C. AgNPs. Moreover, five groups of rats including control and diabetic groups (NC1, PC2, DG1, DG2, and DG3) were investigated for their blood glucose and glycemic control analysis. Conclusions: The C. AgNPs exhibited positive potential on the Vero cell line as well as on experimental rats. The lipid profile in all the diabetic groups (DG1-3) were significantly increased compared with both of the control groups (p < 0.05). The present study revealed the significance of C. AgNPs in nanotherapeutics.

Fungi fabrication, characterization, and anticancer activity of silver nanoparticles using metals resistant Aspergillus niger

The purpose of this study was to assess the bio-fabrication possibilities of pre-isolated (from bauxite mine tailings) metal-tolerant Aspergillus niger biomass filtrate and the anticancer potential of synthesized silver nanoparticles (AgNPs) tested with a Human Cervical cancer cell line (HeLa cells: Henrietta Lacks cells). The nitrate reduction test demonstrated that A. niger has the ability to reduce nitrate, and filtrate derived from A. niger biomass efficiently fabricated AgNPs from AgNO₃, as demonstrated by a visible color change from pale greenish to brownish. The UV-visible spectroscopy analysis revealed an absorbance peak at 435 nm, which corresponded to the AgNPs. These AgNPs have been capped and stabilized with several functional groups related to various bioactive molecules such as aldehyde, benzene rings, aldehydic, amines, alcohols, and carbonyl stretch protein molecules. Fourier-Transform Infrared Spectroscopy (FTIR) analysis confirmed the capping and stabilizing chemical bonding pattern. Scanning Electron Microscopy (SEM) revealed that the synthesized AgNPs were spherical, with an average size of 21.38 nm. This bio-fabricated AgNPs has in-vitro anticancer potential when tested against the HeLa cell line due to its potential size and shape. At 100 g mL^-1 concentrations of this bio-fabricated AgNPs, the anticancer activity percentage was found to be 70.2%, and the IC₅₀ value was found to be 66.32 g m^-1. These findings demonstrated that the metal-tolerant A. niger cell filtrate could produce AgNPs with anticancer potential.

Recent Progress in Graphene- and Related Carbon-Nanomaterial-based Electrochemical Biosensors for Early Disease Detection

Graphene- and carbon-based nanomaterials are key materials to develop advanced biosensors for the sensitive detection of many biomarkers owing to their unique properties. Biosensors have attracted increasing interest because they allow efficacious, sensitive, selective, rapid, and low-cost diagnosis. Biosensors are analytical devices based on receptors for the process of detection and transducers for response measuring. Biosensors can be based on electrochemical, piezoelectric, thermal, and optical transduction mechanisms. Early virus identification provides critical information about potentially effective and selective therapies, extends the therapeutic window, and thereby reduces morbidity. The sensitivity and selectivity of graphene can be amended via functionalizing it or conjoining it with further materials. Amendment of the optical and electrical features of the hybrid structure by introducing appropriate functional groups or counterparts is especially appealing for quick and easy-to-use virus detection. Various techniques for the electrochemical detection of viruses depending on antigen-antibody interactions or DNA hybridization are discussed in this work, and the reasons behind using graphene and related carbon nanomaterials for the fabrication are presented and discussed. We review the existing state-of-the-art directions of graphene-based classifications for detecting DNA, protein, and hormone biomarkers and summarize the use of the different biosensors to detect several diseases, like cancer, Alzheimer's disease, and diabetes, to sense numerous viruses, including SARS-CoV-2, human immunodeficiency virus, rotavirus, Zika virus, and hepatitis B virus, and to detect the recent pandemic virus COVID-19. The general concepts, mechanisms of action, benefits, and disadvantages of advanced virus biosensors are discussed to afford beneficial evidence of the creation and manufacture of innovative virus biosensors. We emphasize that graphene-based nanomaterials are ideal candidates for electrochemical biosensor engineering due to their special and tunable physicochemical properties.

One-pot green synthesis of antimicrobial chitosan derivative nanocomposites to control foodborne pathogens

Food contamination by foodborne pathogens is considered a serious problem worldwide. This study aimed to show the efficacy of the one-pot green biosynthesis of nanocomposites as effective antimicrobial agents based on a water-soluble biodegradable polysaccharide and silver nitrate (AgNO₃). Silver (Ag) nanoparticles were synthesized using different concentrations of AgNO₃ solution (1, 2, and 3 mM) in the presence of N-quaternized chitosan and N,N,N-trimethyl chitosan chloride (TMC) as both a reducing and stabilizing agent. In addition, the structure of TMC/Ag nanocomposites was confirmed using different analytical tools including FTIR, UV-Vis, XRD, HR-TEM, FE-SEM, and EDX techniques. The FTIR spectra and UV-Vis spectra showed the main characteristic absorption peaks of Ag nanoparticles. In addition, FE-SEM images showed the formation of spherical bead-like particles on the surface of TMC. Correspondingly, the EDX spectrum showed a peak for silver, indicating the successful synthesis of Ag nanoparticles inside the TMC chains. Moreover, HR-TEM images exhibited the good distribution of Ag nanoparticles, which appeared as nano-spherical shapes. The antimicrobial activity of TMC/Ag nanocomposites was examined against three foodborne pathogens, including Salmonella Typhimurium as a Gram-negative bacterium, Bacillus subtilis as a Gram-positive bacterium and Aspergillus fumigatus as a fungus. The results showed that TMC/Ag nanocomposites had better antimicrobial activity compared with TMC alone and their antimicrobial activity increased with an increase in the concentration of Ag. The results confirmed that the TMC/Ag nanocomposites can be potentially used as an effective antimicrobial agent in food preservation.

This study aimed to show the efficacy of the one-pot green biosynthesis of nanocomposites as effective antimicrobial agents based on a water-soluble biodegradable polysaccharide and silver nitrate (AgNO₃).