Synthesis of Aloe vera-conjugated silver nanoparticles for use against multidrug-resistant microorganisms

Microbial mediated silver nanoparticles enhance the potential of bioactive metabolites in the medicinal plant Linum usitatissimum

Medicinal plants contain phytochemicals that confer therapeutic potentials, allowing plants to perform various biologically significant functions. However, the therapeutic potential of these bioactive metabolites against multidrug-resistant bacteria is limited. Hence, the potential use of rhizopheric bacteria to isolate silver nanoparticles to enhance the potential of bioactive metabolites has been adopted by researchers. Therefore, this research aimed to biogenically produce silver nanoparticles using the rhizospheric soil of Aloe barbadensis miller and to evaluate its impact in regulating the potential of bioactive metabolites produced from the medicinal plant Linum usitatissimum. The powder extract of Linum usitatissimum was macerated under four different environmental conditions including cold maceration, warm maceration, fermented, and unfermented for extraction of metabolites. Macerated extracts were then evaluated for phytochemical detection of bioactive metabolites like alkaloids, steroids, phenols, and saponins. Biogenic AgNPs were primarily confirmed by visible color change from colorless to brown and were further characterized using UV-vis spectroscopy, giving two absorbance peaks at 440 nm and 445 nm. Functional groups attached to biogenic AgNPs were detected by Fourier transform infrared (FTIR) analysis. The crystalline nature of biogenic AgNPs was evaluated by X-ray diffraction (XRD) giving a diffraction peak at angles of around 36°, 46°, 67°, and 77°. The particle size and morphological appearance of biogenic AgNPs were confirmed by Scanning Electron Microscopy (SEM). The total phenolic content of biogenic AgNPs and bioactive metabolites was estimated by the Folin-Ciocalteu (F-C) assay. The antimicrobial efficacy of biogenic AgNPs and bioactive metabolites against MDR bacterial strains was accessed. This research shows that biogenic AgNPs can be used as a strong agent in enhancing the antimicrobial potential of bioactive metabolites against MDR bacteria and they can be investigated for further experimental findings.

Therapeutic Potential of Aloe vera and Aloe vera-Conjugated Silver Nanoparticles on Mice Exposed to Hexavalent Chromium

Hexavalent chromium (Cr (VI)) is a hazardous heavy metal that induces hepatotoxicity and nephrotoxicity. Thus, this study was planned to explore the ameliorating capacity of Aloe vera leaf gel extract (AV) and their conjugated silver nanoparticles (AVNP) against Cr (VI) induced hepatotoxicity and renal toxicity. The organ indices, level of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, malondialdehyde, total protein, and creatinine in blood serum were measured. The histopathological and micrometric analysis of the hepatic and renal tissue sections were studied. The hepatosomatic index was raised significantly (0.098 ± 0.13 g) in Cr treated group. The blood serum level of AST (484 ± 10.7 U/L), ALT (163 ± 5.5 U/L), ALP (336.7 ± 9.5 U/L), MDA (642.3 ± 28.3 U/L), and creatinine (4.0 ± 0.1 mg/dL) were increased significantly, whereas total protein level was declined (2.8 ± 0.3 g/dL) significantly in Cr exposed group. In the histopathological study, necrosis, disturbed hepatic cords, impaired glomeruli, and Bowman's capsule were noted. Micrometric data from the liver and kidney revealed a significant surge in the size of hepatocytes and their nuclei (1188.2 ± 467.7 µ2 and 456.5 ± 205.6 µ2) and CSA of glomeruli and Bowman's capsule (9051.8 ± 249.8 µ2 and 11,835.5 ± 336.7 µ2) in Cr (VI) exposed group, whereas the brush border (10.2 ± 4.0 µ) size declined significantly. The administration of AV and AVNP reduced the oxidative stress induced by Cr (VI).

Aloe vera-An Extensive Review Focused on Recent Studies

Since ancient times, Aloe vera L. (AV) has attracted scientific interest because of its multiple cosmetic and medicinal properties, attributable to compounds present in leaves and other parts of the plant. The collected literature data show that AV and its products have a beneficial influence on human health, both by topical and oral use, as juice or an extract. Several scientific studies demonstrated the numerous biological activities of AV, including, for instance, antiviral, antimicrobial, antitumor, and antifungal. Moreover, its important antidepressant activity in relation to several diseases, including skin disorders (psoriasis, acne, and so on) and prediabetes, is a growing field of research. This comprehensive review intends to present the most significant and recent studies regarding the plethora of AV's biological activities and an in-depth analysis exploring the component/s responsible for them. Moreover, its morphology and chemical composition are described, along with some studies regarding the single components of AV available in commerce. Finally, valorization studies and a discussion about the metabolism and toxicological aspects of this "Wonder Plant" are reported.

Application of biomimetically synthesized silver nanoparticles as cathode catalyst, quorum-quencher, and anti-biofouling agent for the performance boosting of microbial fuel cell

A microbial fuel cell (MFC) is a cutting-edge bioelectrochemical technology, which demonstrates power and other valuables recovery while treating wastewater by cultivating electroactive microbes. However, rampant biofilm growth over the cathode surface of air cathode MFC exacerbates the oxidation-reduction reaction rate, triggering a dip in the overall performance of MFC. In this sense, biosynthesized silver nanoparticles (AgNPs) have garnered a plethora of potential applications as cathode catalysts as well as anti-biofouling agent for MFCs without harming nature. The MFC equipped with the mixture of aloe vera and algae (@5 mg/cm2) synthesized AgNPs on cathode generated a maximum power density of 66.5 mW/m2 and chemical oxygen demand removal efficiency of 85.2%, which was ca. 5.6 times and 1.2 times higher compared to control MFC operated without any catalyst on cathode. Thus, this investigation paves the way for using eco-amiable, low-cost bioderived organic compounds to assist MFC in achieving high power output and other valuables with minimal reliance on chemicals.

Characterization of aluminum composite reinforced by silver nanoparticles

This research investigates the mechanical properties improvement of reinforced Al6061 using powder metallurgy (PM) route. It utilizes the nanoparticles strengthening mechanism to enhance the prepared samples' mechanical properties. For this purpose, Silver Nano-Particles (AgNPs) with contents of 0 wt%, 1 wt%, and 2 wt% were used to reinforce the Al6061 Matrix Composition (AMC). For optimization purposes, many parameters have been considered during the research journey namely: compaction pressure, sintering temperature, dwelling time, and reinforcement contents. All samples are examined in terms of density, hardness, and compression strength. Additionally, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, mapping analysis, and XRD were used to investigate the microstructure. The experimental results revealed highest hardness values at 2 wt% AgNPs reinforced sample that was sintered at 600 °C, while the lowest was obtained at un-reinforced sample sintered at 550 °C. Furthermore, the compression strength of sample reinforced with 2 wt% AgNPs and sintered at 600 °C recorded an improvement of 25.8% of the maximum compression strength compared to the un-reinforced sample, as it reached 216 N/mm2. Regarding microstructural analysis, SEM imaging and EDX played an important role in exploring and interpreting many unusual test behaviors including the formation of intermetallic bonding, minor pores formation, and reinforcement dispersion un-homogeneity.

Therapeutic applications of electrospun nanofibers impregnated with various biological macromolecules for effective wound healing strategy - A review

A Non-healing infected wound is an ever-growing global epidemic, with increasing burden of mortality rates and management costs. The problems of chronic wound infections and their outcomes will continue as long as their underlying causes like diabetic wounds grow and spread. Commercial wound therapies employed have limited potential that inhibits pivotal functions and tissue re-epithelialization properties resulting in wound infections. Nanomaterial based drug delivery formulations involving biological macromolecules are developing areas of interest in wound healing applications which are utilized in the re-epithelialization of skin with cost-effective preparations. Research conducted on nanofibers has shown enhanced skin establishment with improved cell proliferation and growth and delivery of bioactive organic molecules at the wound site. However, drug targeted delivery with anti-scarring properties and tissue regeneration aspects have not been updated and discussed in the case of macromolecule impregnated nanofibrous mats. Hence, this review focuses on the brief concepts of wound healing and wound management, therapeutic commercialized wound dressings currently available in the field of wound care, effective electrospun nanofibers impregnated with different biological macromolecules and advancement of nanomaterials for tissue engineering have been discussed. These new findings will pave the way for producing anti-scarring high effective wound scaffolds for drug delivery.

Effects of Carbon Nanomaterials and Aloe vera on Melanomas-Where Are We? Recent Updates

Melanoma is an aggressive skin cancer that affects approximately 140,000 people worldwide each year, with a high fatality rate. Available treatment modalities show limited efficacy in more severe cases. Hence, the search for new treatment modalities, including immunotherapies, for curing, mitigating, and/or preventing cancer is important and urgently needed. Carbon nanoparticles associated with some plant materials, such as Aloe vera, have shown appealing antineoplastic activity, derived mainly from the compounds aloin, aloe-emodin, barbaloin acemannan, and octapeptide, thus representing new possibilities as antitumor agents. This systematic review aims to arouse interest and present the possibilities of using Aloe vera combined with carbon-based nanomaterials as an antineoplastic agent in the treatment and prevention of melanoma. Limitations and advances in melanoma treatment using functionalized carbon nanomaterials are discussed here. Moreover, this review provides the basis for further studies designed to fully explore the potential of carbon nanomaterials associated with Aloe vera in the treatment of various cancers, with a focus on melanoma.

Light-Emitting-Diode-Assisted, Fungal-Pigment-Mediated Biosynthesis of Silver Nanoparticles and Their Antibacterial Activity

Nanoparticle synthesis, such as green synthesis of silver nanoparticles (AgNPs) using biogenic extracts, is affected by light, which changes the characteristics of particles. However, the effect of light-emitting diodes (LEDs) on AgNP biosynthesis using fungal pigment has not been examined. In this study, LEDs of different wavelengths were used in conjunction with Talaromyces purpurogenus extracellular pigment for AgNP biosynthesis. AgNPs were synthesized by mixing 10 mL of fungal pigment with AgNO₃, followed by 24 h exposure to LEDs of different wavelengths, such as blue, green, orange, red, and infrared. All treatments increased the yield of AgNPs. The solutions exposed to blue, green, and infrared LEDs exhibited a significant increase in AgNP synthesis. All AgNPs were then synthesized to determine the optimum precursor (AgNO₃) concentration and reaction rate. The results indicated 5 mM AgNO₃ as the optimum precursor concentration; furthermore, AgNPs-blue LED had the highest reaction rate. Dynamic light scattering analysis, zeta potential measurement, transmission electron microscopy, and Fourier transform infrared spectroscopy were used to characterize the AgNPs. All LED-synthesized AgNPs exhibited an antimicrobial potential against Escherichia coli and Staphylococcus aureus. The combination of LED-synthesized AgNPs and the antibiotic streptomycin demonstrated a synergistic antimicrobial activity against both bacterial species.

An investigation on environmental pollution due to essential heavy metals: a prediction model through multilayer perceptrons

This research is to predict heavy metal levels in plants, particularly in Robinia pseudoacacia L., and soils using an effective artificial intelligence approach with some ecological parameters, thereby significantly eliminating common defects such as high cost and seriously tedious and time-consuming laboratory procedures. In this respect, the artificial neural network (ANN) is employed to estimate the concentrations of essential heavy metals such as Fe, Mn and Ni, depending on the Cu and Zn concentrations of plant and soil samples collected from five different locations. The derived relative errors for the constructed ANN model have been computed within the ranges 0.041-0.051, 0.017-0.025, and 0.026-0.029 for the training, testing and holdout data regarding Fe, Mn, and Ni, respectively. In addition, it has been realized that the relative errors could be diminished up to 0.007 for Fe, 0.014 for Mn and 0.022 for Ni by considering the Cu, Zn, location and plant parts as independent variables during the analysis. The results produced seem instructive and pioneering for environmentalists and scientists to design optimal study programs to leave a livable ecosystem.

Current Treatment Strategies Against Multidrug-Resistant Bacteria: A Review

There are several bacteria called superbugs that are resistant to multiple antibiotics which can be life threatening specially for critically ill and hospitalized patients. This article provides up-to-date treatment strategies employed against some major superbugs, like methicillin-resistant Staphylococcus aureus, carbapenem-resistant Enterobacteriaceae, vancomycin-resistant Enterococcus, multidrug-resistant Pseudomonas aeruginosa, and multidrug-resistant Escherichia coli. The pathogen-directed therapeutics decrease the toxicity of bacteria by altering their virulence factors by specific processes. On the other hand, the host-directed therapeutics limits these superbugs by modulating immune cells, enhancing host cell functions, and modifying disease pathology. Several new antibiotics against the global priority superbugs are coming to the market or are in the clinical development phase. Medicinal plants possessing potent secondary metabolites can play a key role in the treatment against these superbugs. Nanotechnology has also emerged as a promising option for combatting them. There is urgent need to continuously figure out the best possible treatment strategy against these superbugs as resistance can also be developed against the new and upcoming antibiotics in future. Rational use of antibiotics and maintenance of proper hygiene must be practiced among patients.