Facile synthesis of silver nanoparticles using leaf extract of Hyptis suaveolens (L.) Poit for environmental and biomedical applications

An overview of biogenic metallic nanoparticles for water treatment and purification: the state of the art

The environment is fundamental to human existence, and protecting it from dangerous contaminants should be a top priority for all stakeholders. Reducing garbage output has helped, but as the world's population grows, more waste will be generated. Tons of waste inadvertently and advertently received by environmental matrixes adversely affect the sustainable environment. The pollution caused by these activities affects the environment and human health. Conventional remediation processes ranging from chemical, physical, and biological procedures use macroaggregated materials and microorganisms to degrade or remove pollutants. Undesirable limitations of expensiveness, disposal challenges, maintenance, and formation of secondary contaminants abound. Additionally, multiple stages of treatments to remove different contaminants are time-consuming. The need to avoid these limitations and shift towards sustainable approaches brought up nanotechnology options. Currently, nanomaterials are being used for environmental rejuvenation that involves the total degradation of pollutants without secondary pollution. As nanoparticles are primed with vast and modifiable reactive sites for adsorption, photocatalysis, and disinfection, they are more useful in remediating pollutants. Review articles on metallic nanoparticles usually focus on chemically synthesized ones, with a particular focus on their adsorption capacity and toxicities. Therefore, this review evaluates the current status of biogenic metallic nanoparticles for water treatment and purification.

Synthesis and characterization of keratinase laden green synthesized silver nanoparticles for valorization of feather keratin

This study focuses on the efficient and cost-effective synthesis of silver nanoparticles (AgNPs) using plant extracts, which have versatile and non-toxic applications. The research objectives include synthesizing AgNPs from readily available plant extracts, optimizing their production and multi scale characterization, along with exploring their use for enzyme immobilization and mitigation of poultry feather waste. Among the plant extracts tested, the flower extract of Hibiscus rosa-sinensis (HF) showed the most potential for AgNP synthesis. The synthesis of HF-mediated AgNPs was optimized using response surface methodology (RSM) for efficient and environment friendly production. Additionally, the keratinase enzyme obtained from Bacillus sp. NCIM 5802 was covalently linked to AgNPs, forming a keratinase nanocomplex (KNC) whose biochemical properties were evaluated. The KNC demonstrated optimal activity at pH 10.0 and 60 °C and it displayed remarkable stability in the presence of various inhibitors, metal ions, surfactants, and detergents. Spectroscopic techniques such as FTIR, UV-visible, and X-ray diffraction (XRD) analysis were employed to investigate the formation of biogenic HF-AgNPs and KNC, confirming the presence of capping and stabilizing agents. The morphological characteristics of the synthesized AgNPs and KNC were determined using transmission electron microscopy (TEM) and particle size analysis. The study highlighted the antimicrobial, dye scavenging, and antioxidant properties of biogenic AgNPs and KNC, demonstrating their potential for various applications. Overall, this research showcases the effectiveness of plant extract-driven green synthesis of AgNPs and the successful development of keratinase-laden nanocomplexes, opening possibilities for their use in immobilizing industrial and commercial enzymes.

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.

Bioaccumulation of Silver and Impairment of Vital Organs in Clarias gariepinus from Co-Exposure to Silver Nanoparticles and Cow Dung Contamination

This study reports the implications of silver nanoparticles (AgNPs) and cow-dung contamination on water quality and oxidative perturbations in antioxidant biomarkers in the exposed Clarias gariepinus. Sixteen samples of C. gariepinus were exposed to fresh-water, 0.75 mg/mL each of AgNPs, cow-dung and a mixture of AgNPs-cow dung dosed water for 10 days. Cow-dung significantly (p < 0.05) depleted dissolved oxygen (DO) and increased biochemical oxygen demand (BOD) by 14% and 75% respectively. The trends of abundance and bioaccumulation of Ag in C. gariepinus exposed to different treatments followed kidney > muscle > gill > liver, implying the kidney was the worst affected organ. The AgNPs significantly (p < 0.05) perturbed vital organs in C. gariepinus by altering activities of antioxidant biomarkers, whereas AgNPs-cow dung had reduced perturbations implying organic matter bound Ag⁺ to reduce toxicity. These results conclude that AgNPs posed a challenging environment for C. gariepinus to thrive.

Plants-derived bioactives: Novel utilization as antimicrobial, antioxidant and phytoreducing agents for the biosynthesis of metallic nanoparticles

Medicinal and aromatic higher plants are sustainable resources for natural product compounds, including essential oils, phenolics, flavonoids, alkaloids, glycosides, and saponins. Extractives and essential oils as well as their bioactive compounds have many uses due to their antimicrobial, anticancer, and antioxidant properties as well as application in food preservation. These natural compounds have been reported in many works, for instance biofungicide with phenolic and flavonoid compounds being effective against mold that causes discoloration of wood. Additionally, the natural extracts from higher plants can be used to mediate the synthesis of nanoparticle materials. Therefore, in this review, we aim to promote and declare the use of natural products as environmentally eco-friendly bio-agents against certain pathogenic microbes and make recommendations to overcome the extensive uses of conventional pesticides and other preservatives.