Photochemical effect of silver nanoparticles on flesh fly larval biological system

Synthesis and application of Cobalt-Silver nanohybrid for antimicrobial wastewater treatment and agricultural productivity enhancement

1- This work emphasises the potential of Co@Ag-NPs as an efficient antimicrobial agent. The scientific community has recently shown silver nanohybrids to maintain plural consistency and their potential applications in wastewater treatment. Where these nanohybrids showed highly removing capacity of the three main contaminants (pesticides, microorganisms, and heavy metals) from waste water. The ability of silver and cobalt nanohybrids to inhibit bacteria and fungi that cause illnesses both in vitro and in vivo has made them an outstanding antimicrobial agent. Cobalt-silver nanohybrid particles (Co@AgNPs) have antibacterial properties against both Gram-positive and Gram-negative bacteria, including those that are resistant to multiple drugs. Co@AgNPs have several simultaneous modes of action, and when combined with organic chemicals or medicines that fight bacteria, they have demonstrated a synergistic effect on infections. Because of their unique properties, silver and cobalt nanohybrids can be used in medical and healthcare goods to effectively treat or prevent infections. The preparation and characterization of highly stable cobalt silver nanohybrid (Co@Ag) have been reported. Out of the water samples, four bacterial and seven fungal isolates are identified. Various concentrations of Co@Ag, ranging from 10- 1 to 10- 3, have been seen to impact and produce varying diameters of inhibition zones in bacterial isolates Shigella, Salmonella, E. coli, Pseudomonas aeruginosa and fungal isolates Aspergillus flavus var columnaris, and Aspergillus awamori. Water samples treated with Co@Ag nanoparticles when plated on LB and Czapek Dox agar did not show any growth of bacteria and fungi after five and seven days of incubation, respectively. Furthermore, data demonstrated that shoot and root length and germination percentage of wheat seeds irrigated by treated water increased progressively from 7.5 cm to 9.2 cm, from 9 cm to 11 cm and from 90 to 100%, respectively, as Co@Ag concentrations were elevated from 0 to 10 and 20 mg/l.

Reducing the effective dose of doxycycline using chitosan silver nanocomposite as a carriers on gram positive and gram-negative bacteria

Doxycycline (Doxy) is a tetracycline antibiotic with a potent antibacterial activity against a broad range of bacteria. Using nanotechnology is one feasible way to increase the antibiotics' ability to penetrate the body and increase their antibacterial effectiveness. In this work, we report the formation of a stable green synthesized silver nanoparticles (AgNPs) by chitosan with Doxy nanocomposite for the first time. The obtained nanoparticles were characterized by transmission electron microscopy (TEM), zeta-potential, UV-Visible spectroscopy and four transform infrared spectroscopy (FTIRs). The antibacterial effect of doxy, AgNPs and doxy/AgNPs were determined on Gram-positive Staphylococcus aureus, Streptococcus mutans and Gram-negative Escherichia coli, Klebsiella pneumonia. This combined therapeutic agent restored the susceptibility of doxy and showed an antibacterial activity against tested bacteria. AgNPs has absorption peak at 445 nm, mixing of Doxy with AgNPs causes all doxy absorptions to red shift and a broadening in surface plasmon resonance (SPR) for AgNPs and show a slight increase in particle size of AgNPs from 12 ± 2 nm to 14 ± 2 nm with high stability as zeta potential was 29 mv and 48.5mv for AgNPs and Doxy/AgNPs respectively. The antibacterial effect of Doxy/AgNPs nanocomposite was found to be twice effect of free doxy, suggesting a synergistic interaction between the two components. In conclusion, synergy of doxy with AgNPs is quite promising for antibiotic resistant strains. These results highlight the ability of AgNPs to boost the efficacy of the doxycycline.

Laser enhanced photothermal effect of silver nanoparticles synthesized by chemical and green method on Gram-positive and Gram-negative bacteria

PURPOSE

The antibacterial properties of silver nanoparticles (AgNPs) are extensively identified. In large quantities, they might be harmful. So many fields of nanotechnology have shown a great deal of interest in the development of an environmentally friendly, efficient method for synthesizing metal nanoparticles. Because of its antibacterial and antifungal properties toward a wide range of microbes, chitosan silver nanoparticles (AgNPs@Cs) constitute a newly developing class of bio-nanostructured hybrid materials. Furthermore, the use of photothermal therapy (PTT) has been suggested as a means of elimination of germs. These light-stimulated treatments are minimally invasive and have a few side effects. In the present work, the antibacterial effect of AgNPs at low concentrations; prepared by chemical and green methods as antimicrobial and photothermal agents in photothermal therapy; with laser irradiation were explored as combined treatment against MRSA, Pseudomonas aeruginosa, and Klebsiella pneumoniae.

METHODS

Silver nanoparticles were produced in two ways. First, by sodium borohydrides, second, by chitosan (as a natural eco-friendly reducing, and capping agent). The nanostructure of AgNPs and AgNPs@Cs was confirmed by UV-visible spectrometer, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIRs), and direct light scattering (DLS). The antibacterial activity of the prepared nanoparticles and the laser irradiation was tested against three bacterial species of zoonotic importance; MRSA, Pseudomonas aeruginosa, and Klebsiella pneumoniae; and was evaluated by measuring their minimum inhibitory concentrations (MIC).

RESULTS

Silver nanoparticles produced by the two methods had spherical shapes with nearly the same particle size. The analysis of DLS showed that AgNPs were very stable with zeta potential - 28.8 mv, and 47.7 mv by chemical and chitosan synthesis, respectively. Furthermore, AgNPs@Cs showed higher antibacterial activity toward the tested bacterial species than AgNPs by chemical method. Additionally, the bacterial viability using photothermal laser therapy was reduced compared to laser and AgNPs alone. The bactericidal activities were higher when laser diode was coupled with AgNPs@Cs than by chemical reduction.

CONCLUSION

The laser combined treatment had a higher antimicrobial effect than AgNPs alone or laser irradiation alone.

Evaluating larvicidal, ovicidal and growth inhibiting activity of five medicinal plant extracts on Culex pipiens (Diptera: Culicidae), the West Nile virus vector

Mosquitoes, one of the deadliest animals on the planet, cause millions of fatalities each year by transmitting several human illnesses. Synthetic pesticides were previously used to prevent the spread of diseases by mosquitoes, which was effective in protecting humans but caused serious human health problems, environmental damage, and developed mosquito pesticide resistance. This research focuses on exploring new, more effective, safer, and environmentally friendly compounds to improve mosquito vector management. Phytochemicals are possible biological agents for controlling pests and many are target-specific, rapidly biodegradable, and eco-friendly. The potential of extracts of Lantana camara, Melia azedarach, Nerium oleander, Ricinus communis, and Withania somnifera against 3rd instar Culex pipiens (Common house mosquito) larvae was evaluated. Methanol extracts had more toxic effects against Cx. pipiens larvae (95-100%, 24 h post-treatment) than aqueous extracts (63-91%, 24 h post-treatment). The methanol extracts of Nerium oleander (LC50 = 158.92 ppm) and Ricinus communis (LC50 = 175.04 ppm) were very effective at killing mosquito larvae, 24 h after treatment. N. oleander (LC50 = 373.29 ppm) showed high efficacy in aqueous plant extracts. Among the different extracts of the five plants screened, the methanol extract of R. communis recorded the highest ovicidal activity of 5% at 800 ppm concentration. Total developmental duration and growth index were highly affected by R. communis and M. azedarach methanol extracts. In field tests it was clear that plant extracts decreased mosquito larval density, especially when mixed with mosquito Bti briquette, with stability up to seven days for N. oleander. GC-MS results showed that the methanol extract had a higher number of chemical compounds, particularly with more terpene compounds. A high-performance liquid chromatography (HPLC) technique was used to detect the existence of non-volatile polyphenols and flavonoids. All five methanol extracts showed high concentrations of active ingredients such as gallic acid, chlorogenic acid (more than 100 μg/ml) and the rosmarinic acid was also found in all the five extracts in addition to 17 active polyphenols and flavonoids presented at moderate to low concentrations. Molecular modeling of 18 active ingredients detected by the HPLC were performed to the vicinity of one of the fatty acid binding proteins of lm-FABP (PDB code: 2FLJ). Rutin, Caffeic acid, coumaric acid and rosmarinic acid which presented densely in R. communis and N. oleander showed multiple and stable intermolecular hydrogen bonding and π-π stacking interactions. The inhibition ability of the fatty acid binding protein, FABP4, was evaluated with remarkable receptor inhibition evident, especially with R. communis and N. oleander having inhibitory concentrations of IC50 = 0.425 and 0.599 µg/mL, respectively. The active phytochemical compounds in the plants suggest promising larvicidal and ovicidal activity, and have potential as a safe and effective alternative to synthetic insecticides.

Reducing the effective dose of cisplatin using cobalt modified silver nano-hybrid as a carriers on MCF7 and HCT cell models

Cancer is a deadly illness with a convoluted pathogenesis. The most prevalent restrictions that frequently result in treatment failure for cancer chemotherapy include lack of selectivity, cytotoxicity, and multidrug resistance. Thus, considerable efforts have been focused in recent years on the establishment of a modernistic sector termed nano-oncology, which offers the option of employing nanoparticles (NPs) with the objective of detecting, targeting, and treating malignant disorders. NPs offer a focused approach compared to conventional anticancer methods, preventing negative side effects. In the present work, a successful synthetic process was used to create magnetic cobalt cores with an AgNPs shell to form bimetallic nanocomposites CoAg, then functionalized with Cis forming novel CoAg@Cis nanohybrid. The morphology and optical properties were determined by TEM, DLS, FTIRs and UV-vis spectroscopy, furthermore, anticancer effect of CoAg and CoAg@Cis nanohybrids were estimated using MTT assay on MCF7 and HCT cell lines. Our results showed that Co@Ag core shell is about 15 nm were formed with dark CoNPs core and AgNPs shell with less darkness than the core, moreover, CoAg@Cis has diameter about 25 nm which are bigger in size than Co@Ag core shell demonstrating the loading of Cis. It was observed that Cis, CoAg and CoAg@Cis induced a decline in cell survival and peaked at around 65%, 73%and 66% on MCF7 and 80%, 76%and 78% on HCT at 100 µg/ml respectively. Compared to Cis alone, CoAg and CoAg@Cis caused a significant decrease in cell viability. These findings suggest that the synthesized CoAg can be used as a powerful anticancer drug carrier.

Larvicidal activity of Acacia nilotica extracts against Culex pipiens and their suggested mode of action by molecular simulation docking

Mosquitoes are one of the deadliest and most hazardous animals on Earth, where they transmit several diseases that kill millions of people annually. There is an ongoing search almost everywhere in the world for more effective and contemporary ways to control mosquitoes other than pesticides. Phytochemicals are affordable, biodegradable biological agents that specialize in eliminating pests that represent a risk to public health. The effectiveness of Acacia nilotica methanol and aqueous leaf extracts against 4th instar larvae was evaluated. The results revealed that the methanol extract of A. nilotica had a noticeable influence on the mortality rate of mosquito larvae, especially at high concentrations. Not only did the mortality rate rise significantly, but the hatching of the mosquito eggs was potentially suppressed.Terpenes, fatty acids, esters, glycosides, pyrrolidine alkane, piperazine, and phenols were the most prevalent components in the methanol extract, while the aqueous extract of A. nilotica exclusively showed the presence of fatty acids. The insecticidal susceptibility tests of both aqueous and alcoholic extract of A. nilotica confirmed that the Acacia plant could serves as a secure and efficient substitute for chemical pesticides because of its promising effect on killing larvae and egg hatching delaying addition to their safety as one of the natural pesticides. Molecular docking study was performed using one of the crucial and life-controlling protein targets, fatty acid binding protein (FABP) and the most active ingredients as testing ligands to describe their binding ability. Most of the structurally related compounds to the co-crystallized ligand, OLA, like hexadecanoic acid furnished high binding affinity to the target protein with very strong and stable intermolecular hydrogen bonding and this is quite similar to OLA itself. Some other structural non-related compounds revealed extraordinarily strong binding abilities like Methoxy phenyl piperazine. Most of the binding reactivities of the majortested structures are due to high structure similarity between the positive control, OLA, and tested compounds. Such structure similarity reinforced with the binding abilities of some detected compounds in the A. nilotica extract could present a reasonable interpretation for its insecticidal activity via deactivating the FABP protein. The FABP4 enzyme inhibition activity was assessed for of both methanolic and aqueous of acacia plant extract and the inhibition results of methanol extract depicted noticeable potency if compared to orlistat, with half-maximal inhibitory concentration (IC50) of 0.681, and 0.535 µg/ml, respectively.

The Effect of Abamectin on Locusta Migratoria Neurosecretory Cells and Mid Gut, Using Ultrastructure Examination, Oxidative Stress Study, and In-Silico Molecular Docking

(1) Background: Few studies have been carried out to appraise abamectin toxicity toward Locusta migratoria nymphs. (2) Methods: This study aimed to evaluate the cytotoxic effect of abamectin as an insecticide through examining the changes and damage caused by this drug, in both neurosecretory cells and midgut, using L. migratoria nymphs as a model of the cytotoxic effect. Histopathological change in the brain was examined in both normal and abamectin-treated fifth-instar nymphs. Neurosecretory cells (NSCs) were also examined where there were loosely disintegrated cells or vacuolated cytoplasm. (3) Results: The results showed distinct histological changes in the gastrointestinal tract of L. migratoria nymphs treated with abamectin, with significant cellular damage and disorganization, i.e., characteristic symptoms of cell necrosis, a destroyed epithelium, enlarged cells, and reduced nuclei. The observed biochemical changes included an elevation in all measured oxidative stress parameters compared to untreated controls. The malondialdehyde activities (MDAs) of the treated nymphs had a five- to six-fold increase, with a ten-fold increase in superoxide dismutase (SOD), nine-fold increase in glutathione-S-transferase (GST), and four-fold increase in nitric oxide (NO). (4) Conclusions: To further investigate the theoretical method of action, a molecular docking simulation was performed, examining the possibility that abamectin is an inhibitor of the fatty acid-binding protein Lm-FABP (2FLJ) and that it binds with two successive electrostatic hydrogen bonds.

Enhancing the antibacterial effect of iron oxide and silver nanoparticles by extremely low frequency electric fields (ELF-EF) against S. aureus

Staphylococcus aureus is the cause of many infectious and inflammatory diseases and a lot of studies aim to discover alternative ways for infection control and treatment rather than antibiotics. This work attempts to reduce bacterial activity and growth characteristics of Staphylococcus aureus using nanoparticles (iron oxide nanoparticles and silver nanoparticles) and extremely low frequency electric fields (ELF-EF). Bacterial suspensions of Staphylococcus aureus were used to prepare the samples, which were evenly divided into groups. Control group, 10 groups were exposed to ELF-EF in the frequency range (0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1 Hz), iron oxide NPs treated group, iron oxide NPs exposed to 0.8 Hz treated group, silver NPs treated group and the last group was treated with silver NPs and 0.8 Hz. Antibiotic sensitivity testing, dielectric relaxation, and biofilm development for the living microbe were used to evaluate morphological and molecular alterations. Results showed that combination of nanoparticles with ELF-EF at 0.8 Hz enhanced the bacterial inhibition efficiency, which may be due to structural changes. These were supported by the dielectric measurement results which indicated the differences in the dielectric increment and electrical conductivity for the treated samples compared with control samples. This was also confirmed by biofilm formation measurements obtained. We may conclude that the exposure of Staphylococcus aureus bacteria to ELF-EF and NPs affected its cellular activity and structure. This technique is nondestructive, safe and fast and could be considered as a mean to reduce the use of antibiotics.

Nanoparticles: A Potential and Effective Method to Control Insect-Borne Diseases

Insects act as vectors to carry a wide range of bacteria and viruses that can cause multiple vector-borne diseases in humans. Diseases such as dengue fever, epidemic encephalitis B, and epidemic typhus, which pose serious risks to humans, can be transmitted by insects. Due to the absence of effective vaccines for most arbovirus, insect control was the main strategy for vector-borne diseases control. However, the rise of drug resistance in the vectors brings a great challenge to the prevention and control of vector-borne diseases. Therefore, finding an eco-friendly method for vector control is essential to combat vector-borne diseases. Nanomaterials with the ability to resist insects and deliver drugs offer new opportunities to increase agent efficacy compared with traditional agents, and the application of nanoagents has expanded the field of vector-borne disease control. Up to now, the reviews of nanomaterials mainly focus on biomedicines, and the control of insect-borne diseases has always been a neglected field. In this study, we analyzed 425 works of the literature about different nanoparticles applied on vectors in PubMed around keywords, such as"nanoparticles against insect," "NPs against insect," and "metal nanoparticles against insect." Through these articles, we focus on the application and development of nanoparticles (NPs) for vector control, discussing the lethal mechanism of NPs to vectors, which can explore the prospect of applying nanotechnology in the prevention and control of vectors.