Earthworm extracts utilized in the green synthesis of gold nanoparticles capable of reinforcing the anticoagulant activities of heparin

Eco-Friendly Synthesis, Characterization, and Biomedical Applications of Biosynthesized Bimetallic Silver-Gold Nanoparticles by Culture Supernatant of Aspergillus niger

Green synthesis of bimetallic nanoparticles of noble metals is highly desirable in nanomedicine because of their potential use as anticoagulant, thrombolytic and anticancer agents. In this study, it was discovered that the filamentous fungus Aspergillus niger proved effective in producing bimetallic Ag-Au nanoparticles. A. niger culture supernatant was able to produce Ag-AuNPs by reducing the solution of chloroauric acid/silver nitrate (1.0:1.0 mM) within 2 min at 100 °C and pH 8. Experimental Ag-AuNP detection was performed by visually observing the color change to reddish brown. The produced nanoparticles displayed maximal absorbance at 530 nm in UV-vis spectroscopy. According to transmission electron microscopy, most of the nanoparticles were spherical, with a mean diameter of 8-10 nm. The biosynthesis of Ag-AuNPs by A. niger was confirmed by Fourier transform infrared spectroscopy, X-ray diffraction and energy dispersive X-ray analytical techniques. Its zeta potential was discovered to be -34.01 mV. The biosynthesized Ag-AuNPs exhibited effective thrombolytic and antiplatelet aggregation actions by totally preventing and dissolving the blood clot which was verified by microscopic examination, amelioration of blood coagulation assays, and carrageenan-induced tail thrombosis model. The findings verified the effectiveness of biosynthesized Ag-AuNPs as a powerful antitumor agent against HepG2 and A549 cell lines with IC50 values of 15.57 and 27.07 μg/mL, respectively. Crystal violet assay validated the cytopathic effects of Ag-AuNPs on A549 and HepG2 cell lines. Therefore, the produced Ag-AuNPs from A. niger are a promising candidate in the management of thrombosis.

Nanobiotechnological approaches in anticoagulant therapy: The role of bioengineered silver and gold nanomaterials

Nanotechnology is a novel area that has exhibited various remarkable applications, mostly in medicine and industry, due to the unique properties coming with the nanoscale size. One of the notable medical uses of nanomaterials (NMs) that attracted enormous attention recently is their significant anticoagulant activity, preventing or reducing coagulation of blood, decreasing the risk of strokes, heart attacks, and other serious conditions. Despite successful in vitro experiments, in vivo analyses are yet to be confirmed and further research is required to fully prove the safety and efficacy of nanoparticles (NPs) and to introduce them as valid alternatives to conventional ineffective anticoagulants with various shortcomings and side-effects. NMs can be synthesized through two main routes, i.e., the bottom-up route as a more preferable method, and the top-down route. In numerous studies, biological fabrication of NPs, especially metal NPs, is highly suggested given its eco-friendly approach, in which different resources can be employed such as plants, fungi, bacteria, and algae. This review discusses the green synthesis and characterization of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) as two of the most useful metal NPs, and also their alloys in different studies focussing on their anticoagulant potential. Challenges and alternative approaches to the use of these NPs as anticoagulants have also been highlighted.

Synergistic effect of plant extract coupled silver nanoparticles in various therapeutic applications- present insights and bottlenecks

The phytocomponent conjugated silver nanoparticles (AgNPs) have been extensively explored for various therapeutic applications such as antimicrobial, antioxidant, anticancer, anti-inflammatory, antidiabetic and anticoagulant effects. The bio-conjugation of Ag-based nanomaterial with plant extracts reduces their toxicity to biological systems and enhances their therapeutic effectiveness. The diversity of phytochemicals or capping agents provided by the plant extracts and the small size and large surface area of AgNPs permits maximum adsorption of these capping agents onto their surfaces that further promote the therapeutic performance of phytoconjugated AgNPs in various biomedical applications. The mechanistic action involved in antimicrobial and anticancer functions of AgNPs is mainly dependent on the induction of reactive oxygen species (ROS) resulting in cellular apoptosis and necrosis. This review summarizes the recent studies of various plant extract assisted synthesis of AgNPs, potential biomedical applications with the possible mechanism of action and major shortcomings affecting their therapeutic efficacy.

Sol-Gel Co-Precipitation Synthesis, Anticoagulant and Anti-Platelet Activities of Copper-Doped Nickel Manganite Nanoparticles

Copper-substituted nickel manganites Ni_(1−x)Cu_xMn₂O₄ (Ni-TCE-NPs) were produced by co-precipitation route (sol–gel) at room temperature. Ni_(1−x)CuxMn₂O₄-Bio (NCB) NPs were studied by powder X-ray diffraction technique, scanning electron microscopy and Raman spectroscopy. XRD spectra authenticated the copper-doped nickel manganites’ formation with particle size 23–28 nm. A significant decrease in the lattice parameter confirmed the doping of copper ions into the nickel manganites. Microscopy (SEM) was used to estimate the grain size, shape and uniformity, revealing the non-uniform agglomerated polygon and plate-like microstructure. The NCB-NPs showed anticoagulant activity by enhancing the coagulation time of citrated plasma of human beings. NCB-NPs with x = 0.35 and 0.45 have increased clotting time from control 133 ± 4 s to 401 ± 7 s and 3554 ± 80 s, respectively, and others around 134 s. Additionally NCB-NPs with x = 0.35, 0.45 inhibited the platelet aggregation by 80% and 92%, while remaining inhibited with only 30%. NCB-NPs did not show hemolytic activity in RBC cells intimate its non-toxic nature. Finally, NCB-NPs were non-toxic and known to exhibit anti-blood-clotting and antiplatelet activities, which can be used in the field of biomedical applications, especially as antithrombotic agents.

Characterization, antimicrobial, antioxidant, and anticoagulant activities of silver nanoparticles synthesized from Petiveria alliacea L. leaf extract

Phytosynthesis of silver nanoparticles (AgNPs) using leaf extract of Petiveria alliacea (PA) was the focus of this research work. The PA-AgNPs were characterized by UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) study. Studies were made on the AgNPs for antibacterial, antifungal, anticoagulant, free-radical scavenging, and hydrogen peroxide scavenging activities. The crystalline PA-AgNPs were monodispersed, with a size range of 16.70-33.74 nm and maximum absorption at 410 nm. FTIR analysis displayed prominent peaks at 3430.6, 1711.8, and 1165.9/cm, which showed the existence of phenolic compounds and proteins in the synthesis of AgNPs. PA-AgNPs was active against Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus, with 100% inhibition. The PA-AgNPs also displayed good antifungal properties, as the concentrations of 100 and 150 µg/mL had 100% inhibition toward Aspergillus fumigatus and Aspergillus flavus. However, there was 66.67% inhibition of Aspergillus niger. It scavenged both DPPH and H₂O₂ by 70.69 and 89.02%, respectively. PA-AgNPs also prevented the coagulation of human blood. This study, being the first of its kind to use the leaf extract of PA for the synthesis of AgNPs has shown that PA-AgNPs can find biomedical applications.

Enterococcus species for the one-pot biofabrication of gold nanoparticles: Characterization and nanobiotechnological applications

In the current work, cell-free extracts of four strains of non-pathogenic Enterococcus species of food origin, were studied for the green synthesis of gold nanoparticles (AuNPs), and characterized by UV-Vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). The AuNPs were evaluated for their Anopheles gambiae larvicidal, dye degradation, antioxidant and thrombolytic activities. The blue-black colloidal AuNPs which absorbed maximally at 549-552nm were nearly spherical in shape, and crystalline in nature with size of 8-50nm. The EDX spectra showed formation of AuNPs to the tune of 89-94%. The prominent FTIR peaks obtained at 3251-3410, 2088 and 1641-1643cm^-1 alluded to the fact that proteins were involved in the biofabrication and capping of AuNPs. AuNPs degraded methylene blue and malachite green by 24.3-57.6%, and 88.85-97.36% respectively in 24h, whereas at 12h, larvicidal activities with LC₅₀ of 21.28-42.33μg/ml were obtained. DPPH scavenging activities of 33.24-51.47% were obtained for the biosynthesized AuNPs. The AuNPs prevented coagulation of blood and also achieved 9.4-94.6% lysis of blood clot showing potential nanomedical applications. This study has presented an eco-friendly and economical synthesis of AuNPs by non-pathogenic strains of Enterococcus species for various nanobiotechnological applications.

Biomedical and Catalytic Applications of Gold and Silver-Gold Alloy Nanoparticles Biosynthesized Using Cell-Free Extract of Bacillus Safensis LAU 13: Antifungal, Dye Degradation, Anti-Coagulant and Thrombolytic Activities

This study investigated the green biosynthesis of gold (Au) and silver-gold alloy (Ag-Au) nanoparticles using cell-free extract of Bacillus safensis LAU 13 strain (GenBank accession No: KJ461434). The biosynthesized AuNPs and Ag-AuNPs were characterized using UV-Vis spectroscopy, Fourier-transform infrared spectroscopy, and transmission electron microscopy. Evaluation of the antifungal activities, degradation of malachite green, anti-coagulation of blood, and thrombolysis of human blood clot by the biosynthesized nanoparticles were investigated. The AuNPs and Ag-AuNPs had maximum absorbance at 561 and 545 nm, respectively. The FTIR peaks at 3318, 2378, 2114, 1998, 1636, 1287, 446, 421 cm^-1 for AuNPs; and 3310, 2345, 2203, 2033, 1636, 1273, 502, 453, 424 cm^-1 for Ag-AuNPs indicated that proteins were the capping and stabilization molecules in the biosynthesized nanoparticles. The particles were fairly spherical in shape with size of 10-45 nm for AuNPs and 13-80 nm for Ag-AuNPs. Moreover, energy dispersive X-ray analysis of AuNPs revealed gold as the most prominent metal in the AuNPs solution, while silver and gold were the most prominent in the case of Ag-AuNPs. Selected area electron diffraction showed the biosynthesized nanoparticles as crystal structures with ring shape pattern. AuNPs and Ag-AuNPs displayed growth inhibitions of 66.67-90.78% against strains of Aspergillus fumigatus and A. niger at concentration of 200 μg/ml , and remarkable degradation (> 90%) of malachite green after 48 h. Furthermore, the nanoparticles prevented coagulation of blood, and also completely dissolved blood clots, indicating the biomedical potential of AuNPs and Ag-AuNPs in the management of blood coagulation disorders. This is the first report of the synthesis of AuNPs and Ag-AuNPs using a strain of B. safensis for biomedical and catalytic applications.

Earthworm-mediated synthesis of silver nanoparticles: A potent tool against hepatocellular carcinoma, Plasmodium falciparum parasites and malaria mosquitoes

The development of parasites and pathogens resistant to synthetic drugs highlighted the needing of novel, eco-friendly and effective control approaches. Recently, metal nanoparticles have been proposed as highly effective tools towards cancer cells and Plasmodium parasites. In this study, we synthesized silver nanoparticles (EW-AgNP) using Eudrilus eugeniae earthworms as reducing and stabilizing agents. EW-AgNP showed plasmon resonance reduction in UV-vis spectrophotometry, the functional groups involved in the reduction were studied by FTIR spectroscopy, while particle size and shape was analyzed by FESEM. The effect of EW-AgNP on in vitro HepG2 cell proliferation was measured using MTT assays. Apoptosis assessed by flow cytometry showed diminished endurance of HepG2 cells and cytotoxicity in a dose-dependent manner. EW-AgNP were toxic to Anopheles stephensi larvae and pupae, LC(50) were 4.8 ppm (I), 5.8 ppm (II), 6.9 ppm (III), 8.5 ppm (IV), and 15.5 ppm (pupae). The antiplasmodial activity of EW-AgNP was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of Plasmodium falciparum. EW-AgNP IC(50) were 49.3 μg/ml (CQ-s) and 55.5 μg/ml (CQ-r), while chloroquine IC(50) were 81.5 μg/ml (CQ-s) and 86.5 μg/ml (CQ-r). EW-AgNP showed a valuable antibiotic potential against important pathogenic bacteria and fungi. Concerning non-target effects of EW-AgNP against mosquito natural enemies, the predation efficiency of the mosquitofish Gambusia affinis towards the II and II instar larvae of A. stephensi was 68.50% (II) and 47.00% (III), respectively. In EW-AgNP-contaminated environments, predation was boosted to 89.25% (II) and 70.75% (III), respectively. Overall, this research highlighted the EW-AgNP potential against hepatocellular carcinoma, Plasmodium parasites and mosquito vectors, with little detrimental effects on mosquito natural enemies.

Glucomannan-mediated facile synthesis of gold nanoparticles for catalytic reduction of 4-nitrophenol

A facile one-pot approach for synthesis of gold nanoparticles with narrow size distribution and good stability was presented by reducing chloroauric acid with a polysaccharide, konjac glucomannan (KGM) in alkaline solution, which is green and economically viable. Here, KGM served both as reducing agent and stabilizer. The effects of KGM on the formation and stabilization of as-synthesized gold nanoparticles were studied systematically by a combination of UV-visible (UV-vis) absorption spectroscopy, transmission electron microscopy, X-ray diffraction, dynamic light scattering, and Fourier transform infrared spectroscopy. Furthermore, the gold nanoparticles exhibited a notable catalytic activity toward the reduction of 4-nitrophenol to 4-aminophenol.