A facile and rapid method for green synthesis of Achyranthes aspera stem extract-mediated silver nano-composites with cidal potential against Aedes aegypti L

Evaluation of phytochemical, antibacterial, thrombolytic, anti-inflammatory, and cytotoxicity profile of Achyranthes aspera aerial part extracts

This investigation was designed and performed to compare the phytochemical profiling, activities of antibacterial, thrombolytic, anti-inflammatory, and cytotoxicity of methanol extract (ME-E) and aqueous extract (AQ-E) of aerial parts of Achyranthes aspera through in-vitro approach. Also characterize the functional groups of bioactive compounds in the ME-E through Fourier-transform infrared (FTIR) spectroscopy analysis. Interestingly, qualitative phytochemical screening proved that the ME-E contain more number of vital phytochemicals such as phenolics. saponins, tannins, alkaloids, flavonoids, cardiac glycosides, steroids, and phlobatannins than AQ-E. Similarly, the ME-E showed notable antibacterial activity as dose dependent manner against Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa at 1000 μg mL-1 concentration. ME-E also showed 75.2 ± 2% of clot lysis (thrombolytic activity) at 1000 μg mL-1 dosage and it followed by AQ-E 51.24 ± 3%. The ME-E showed moderate and AQ-E demonstrate poor anti-inflammatory activity evidenced by albumin denaturation inhibition and anti-lipoxygenase assays. Furthermore, the ME-E demonstrated a dose dependent cytotoxicity was noted against brine shrimp larvae. In support of this ME-E considerable activities, the Fourier transform infrared (FTIR) analysis confirmed that this extract contain more number peaks attributed to the stretch of various essential functional groups belongs to different bioactive compounds. Hence this ME-E of A. aspera can be considered for further in depth scientific investigations to validate their maximum biomedical potential.

Green Synthesis of Silver Nanoparticles Derived from Papaver rhoeas L. Leaf Extract: Cytotoxic and Antimicrobial Properties

In the last few decades, the search for metal nanoparticles as an alternative to cancer treatments and antibiotics has increased. In this article, the spectroscopic (ultraviolet-visible (UV-vis), electron-dispersing X-ray (EDX), and Fourier transform infrared (FT-IR)), microscopic (field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM), and atomic force microscope (AFM)), structural (X-ray diffractometer (XRD) and zetasizer), and analytic (thermogravimetric/differential thermal analyzer (TGA-DTA)) characterization of the silver nanoparticles (AgNPs) produced from Papaver rhoeas (PR) L. leaf extract are presented. PR-AgNPs are generally spherical and have a maximum surface plasmon resonance of 464.03 nm. The dimensions of the manufactured nanomaterial are in the range of 1.47-7.31 nm. PR-AgNPs have high thermal stability and a zeta potential of -36.1 mV. The minimum inhibitory concentration (MIC) values (mg L-1) of PR-AgNPs on Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, and Candida albicans are 1.50, 0.75, 3.00, 6.00, and 0.37, respectively. In the study, the cytotoxic and proliferative effects of PR-AgNPs using the MTT (3-(4,5-dimethylthiazol-2-yl)-diphenyltetrazolium bromide) method on various cancer cell lines (CACO-2 (human colon adenocarcinoma cell), MCF-7 (human breast cancer cell), T98-G (glioblastoma multiforme cell), and healthy HUVEC (human umbilical vein endothelial cell)) cell lines are presented. After 24 and 48 h of the application, the half-maximum inhibitory concentration (IC50) values (μg mL-1) of PR-AgNPs on HUVEC, CACO-2, MCF-7, and T98-G lines are 2.365 and 2.380; 2.526 and 2.521; 3.274 and 3.318; 3.472 and 3.526, respectively. Comprehensive in vivo research of PR-AgNPs is proposed to reveal their potential for usage in sectors such as nanomedicine and nanochemistry.

Mosquito-Borne Diseases and Their Control Strategies: An Overview Focused on Green Synthesized Plant-Based Metallic Nanoparticles

Mosquitoes act as vectors of pathogens that cause most life-threatening diseases, such as malaria, Dengue, Chikungunya, Yellow fever, Zika, West Nile, Lymphatic filariasis, etc. To reduce the transmission of these mosquito-borne diseases in humans, several chemical, biological, mechanical, and pharmaceutical methods of control are used. However, these different strategies are facing important and timely challenges that include the rapid spread of highly invasive mosquitoes worldwide, the development of resistance in several mosquito species, and the recent outbreaks of novel arthropod-borne viruses (e.g., Dengue, Rift Valley fever, tick-borne encephalitis, West Nile, yellow fever, etc.). Therefore, the development of novel and effective methods of control is urgently needed to manage mosquito vectors. Adapting the principles of nanobiotechnology to mosquito vector control is one of the current approaches. As a single-step, eco-friendly, and biodegradable method that does not require the use of toxic chemicals, the green synthesis of nanoparticles using active toxic agents from plant extracts available since ancient times exhibits antagonistic responses and broad-spectrum target-specific activities against different species of vector mosquitoes. In this article, the current state of knowledge on the different mosquito control strategies in general, and on repellent and mosquitocidal plant-mediated synthesis of nanoparticles in particular, has been reviewed. By doing so, this review may open new doors for research on mosquito-borne diseases.

Morphological and physiological changes induced by Achyranthes aspera-mediated silver nanocomposites in Aedes aegypti larvae

Aedes aegypti is responsible for the global spread of several ailments such as chikungunya, dengue, yellow fever, and Zika. The use of synthetic chemicals is the primary intervention in mosquito management. However, their excessive utilization resulting in the spread of toxic ingredients in the environment and posing threats to beneficial organisms has prompted the recommendation for the use of biologically synthesized nanocomposites as a promising approach for vector control. Silver nanocomposites were synthesized using leaf (AL-AgNCs) and stem (AS-AgNCs) extracts of Achyranthes aspera. The early fourth instars of A. aegypti were exposed to lethal doses of these nanocomposites to evaluate their effects on larval development, behavior, morphology, and mid-gut histoarchitecture. The cellular damage and deposition of nanocomposite residues in the mid-gut were studied using light and transmission electron microscopy. The A. aspera silver nanocomposite (AA-AgNC)-exposed larvae exhibited dose-dependent extended duration of development and diminished adult emergence, but did not exhibit modified behavior. Intense damage to the cuticle membrane and slight contraction in the internal membrane of anal papillae were noticed. Morphologically, the mid-gut appeared disorganized, darkly pigmented, and shrunk. Histological investigations of the mid-gut revealed significantly disordered internal architecture with lysed cells, damaged peritrophic membrane and microvilli, disintegrated epithelial layer, and a ruptured and displaced basement membrane. Visualization of the larval mid-gut through TEM showed severe cellular damage and aggregation of black spots, indicating the deposition of silver particles released by AA-AgNCs. The investigations revealed the bio-efficacy of A. aspera-mediated AgNCs against A. aegypti inducing stomach and contact toxicity in the larvae. The utilization of AA-AgNCs is recommended for A. aegypti management as a safe and effective intervention.

Bio-fabricated silver nanoparticles for controlling dengue and filaria vectors and their characterization, as well as toxicological risk assessment in aquatic mesocosms

The present study is focused on synthesis of silver nanoparticles from weeds and an assessment of their mosquito larvicidal efficacy. This study also presented the toxicological effects as well as the stability of these nanoparticles in aquatic mesocosms. The weed Digiteria sanguinallis was first time used for the synthesis of silver nanoparticles. The synthesized nanoparticles were characterized by various analytical techniques, such as UV-VIS, TEM, FESEM, EDX, XRD, FTIR, and zeta potential study. The result revealed that the nanoparticles are crystalline, spherical shape with band gap 2.44 eV, and average size 18 nm. The LC₅₀ value of synthesized AgNPs were recorded as 7.47 and 6.31 mg/L at 24 h against Cx. quinquefasciatus and A. albopictus respectively. In contrast, larvicidal activity of weed extract was insignificant against two target species. In aquatic mesocosm study, AgNPs (LC₅₀ dose) does not alter the nature of water parameters within experimental period. However only EC % and ORP were changes because of silver ion oxidation. In biochemical parameters, only stress enzymes for animal and plant species were moderately altered under long term exposure. But glycogen, protein, and AchE of two mosquito species were significantly changed under same mesocosm setup within short exposure. Comparatively, in control mesocosm, synthesized AgNPs are naturally change their nano form within 20 days with the presence of all non-target species and pond sediment. Therefore, it can be concluded that biosynthesized AgNPs could be used as a larvicidal agent in near future with negligible effects on aquatic organisms.

Green Nano-Biotechnology: A New Sustainable Paradigm to Control Dengue Infection

Dengue is a growing mosquito-borne viral disease prevalent in 128 countries, while 3.9 billion people are at high risk of acquiring the infection. With no specific treatment available, the only way to mitigate the risk of dengue infection is through controlling of vector, i.e., Aedes aegypti. Nanotechnology-based prevention strategies like biopesticides with nanoformulation are now getting popular for preventing dengue fever. Metal nanoparticles (NPs) synthesized by an eco-friendly process, through extracts of medicinal plants have indicated potential anti-dengue applications. Green synthesis of metal NPs is simple, cost-effective, and devoid of hazardous wastes. The recent progress in the phyto-synthesized multifunctional metal NPs for anti-dengue applications has encouraged us to review the available literature and mechanistic aspects of the dengue control using green-synthesized NPs. Furthermore, the molecular bases of the viral inhibition through NPs and the nontarget impacts or hazards with reference to the environmental integrity are discussed in depth. Till date, major focus has been on green synthesis of silver and gold NPs, which need further extension to other innovative composite nanomaterials. Further detailed mechanistic studies are required to critically evaluate the mechanistic insights during the synthesis of the biogenic NPs. Likewise, detailed analysis of the toxicological aspects of NPs and their long-term impact in the environment should be critically assessed.

Recent Advancements in Green Synthesis of Nanoparticles for improvement of bioactivities: a Review

Natural products have widely been used in applications ranging from antibacterial, antiviral, antifungal and various other medicinal applications. Use of these natural products was recognized way before the establishment of basic chemistry behind the disease and the chemistry of plant metabolites. After the establishment of plant chemistry various new horizons evolved, and application of the natural products breached the orthodox limitations. In one such interdisciplinary area, use of plant materials in the synthesis of nano particles (NPs) has exponentially emerged. This advancement has offered various environment friendly methods where hazardous chemicals are completely replaced by natural products in the sophisticated and hectic synthesis processes. This review is an attempt to understand the mechanism of metal nano particles synthesis using plant materials. It includes details on the role of plant's secondary metabolites in the synthesis of nano particles including the mechanism of action. In addition, use of these nano materials has widely been discussed along with the possible mechanism behind their antimicrobial and catalytic action.

An Updated Review on Silver Nanoparticles in Biomedicine

Silver nanoparticles (AgNPs) represent one of the most explored categories of nanomaterials for new and improved biomaterials and biotechnologies, with impressive use in the pharmaceutical and cosmetic industry, anti-infective therapy and wound care, food and the textile industry. Their extensive and versatile applicability relies on the genuine and easy-tunable properties of nanosilver, including remarkable physicochemical behavior, exceptional antimicrobial efficiency, anti-inflammatory action and antitumor activity. Besides commercially available and clinically safe AgNPs-based products, a substantial number of recent studies assessed the applicability of nanosilver as therapeutic agents in augmented and alternative strategies for cancer therapy, sensing and diagnosis platforms, restorative and regenerative biomaterials. Given the beneficial interactions of AgNPs with living structures and their nontoxic effects on healthy human cells, they represent an accurate candidate for various biomedical products. In the present review, the most important and recent applications of AgNPs in biomedical products and biomedicine are considered.

Botanical insecticide-based nanosystems for the control of Aedes (Stegomyia) aegypti larvae

Aedes (Stegomyia) aegypti is a cosmopolitan species that transmits arbovirus of medical importance as dengue, Zika, and chikungunya. The main strategy employed for the control of this mosquito is the use of larvicidal agents. However, the overuse of synthetic chemical larvicides has led to an increase in resistant insects, making management difficult. Therefore, the use of botanical insecticide-based nanosystems as an alternative to the use of synthetic agents for the control of Ae. aegypti has gained more considerable attention in the last years, mainly due to the advantages of nanostructured delivery systems, such as (a) controlled release; (b) greater surface area; (c) improvement of biological activity; (d) protection of natural bioactive agents from the environment and thus achieving stability; and (e) lipophilic drugs are easier dispersed even in aqueous vehicles. This review summarizes the current knowledge about botanical insecticide-based nanosystems as larvicidal against Ae. aegypti larvae. The majority of papers used metallic nanoparticles (NPs) as larvicidal agents, mainly silver nanoparticles (AgNPs), showing potential for their use as an alternative, followed by nanoemulsions containing vegetable oils, most essential oils, nanosystems that allow the dispersion of this high hydrophobic product in water, the environment of larval development. The final section describes scientific findings about the mode of action of these NPs, showing the gap about this subject in literature.

Electrochemiluminescence immunoassay for the N-terminal pro-B-type natriuretic peptide based on resonance energy transfer between a self-enhanced luminophore composed of silver nanocubes on gold nanoparticles and a metal-organic framework of type MIL-125

The N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a marker of heart failure. A novel sandwich type electrochemiluminescence (ECL) immunoassay is described for the NT-proBNP. The method is based on ECL resonance energy transfer (RET) between silver nanocubes that were covered with semicarbazide-modified gold nanoparticles (AgNC-sem@AuNPs) as the donor, and a Ti(IV)-based metal-organic framework of type MIL-125 as the acceptor. The ECL signal was strongly amplified by increasing the luminous efficiency. ECL-RET occurs due to the partial overlap between the ECL emission of the AgNC-sem@AuNPs (emission wavelength at 470 nm to 900 nm) and the visible absorption spectrum of MIL-125 (absorption wavelength at 406 nm to 900 nm). This results in the quenching of ECL. The AgNC-sem@AuNPs were placed on the electrode. The antibody was immobilized on AgNC-sem@AuNPs via Au-NH₂ bond, and MIL-125 was utilized as a label for the secondary antibody. The assay works in the 0.25 pg mL^-1 to 100 ng mL^-1 concentration range and has a 0.11 pg mL^-1 lower detection limit (at S/N = 3). Graphical abstract Schematic representation of self-enhanced luminescence mechanism (semicarbazide (Sem) as co-reaction accelerator) and Electrochemiluminescence resonance energy transfer (ECL-RET): silver nanocubes (AgNCs) as the energy donor and MIL-125 as the energy acceptor.