Recent Advancements and Unexplored Biomedical Applications of Green Synthesized Ag and Au Nanoparticles: A Review

A comprehensive review of mycotoxins, their toxicity, and innovative detoxification methods

A comprehensive overview of food mycotoxins, their toxicity, and contemporary detoxification techniques is given in this article. Mycotoxins, which are harmful secondary metabolites generated by a variety of fungi, including Fusarium, Aspergillus, and Penicillium, provide serious health concerns to humans and animals. These include hepatotoxicity, neurotoxicity, and carcinogenicity. Mycotoxins are commonly found in basic food products, as evidenced by recent studies, raising worries about public health and food safety. The article discusses detection techniques such as enzyme-linked immunosorbent assays (ELISA), and quick strip tests. Moreover, the use of various control systems associated with the detoxification of mycotoxinis highlighted. In addition, novel detoxification strategies such as nanotechnology, plant extracts, and omics studies were also discussed. When taken as a whole, this analysis helps to clarify the pressing need for efficient management and monitoring techniques to prevent mycotoxin contamination in the food chain.

Biosynthesis of silver nanoparticles from plant extracts: a comprehensive review focused on anticancer therapy

Cancer is a deadly disease and is one of the primary causes of mortality worldwide. Cancer therapy presents significant challenges, such as chemotherapy resistance, high toxicity, recurrence, and metastasis. As a result, the development of novel therapeutic agents for cancer continues to be a top goal to expand the number of efficient treatments available. The advent of nanotechnology is an important turning point in several scientific disciplines. Owing to the increasing difficulty of this problem, researchers have begun to focus their attention on the possibility of employing plants or extracts from plants as a potential tumor treatment. More than 3,000 medicinal plant species have been documented worldwide for their utilization in cancer treatment. Nevertheless, crude plant extracts lack specificity, and their dosages are not clearly specified. To enhance the therapeutic efficacy of these natural substances, researchers have used them in conjunction with silver nanoparticles (AgNPs). Plants possess intricate phytochemical components including sugars, polyphenols, amino acids, flavonoids, terpenoids, alkaloids, and proteins, which can function as reducing and stabilizing agents. In recent years, the application of plant-derived AgNPs has increased significantly, particularly in cancer treatment. These green-synthesized AgNPs are regarded as outstanding tools for the detection of cancer and targeted drug delivery at the tumor site. By leveraging the distinctive characteristics of nanoparticles and the antioxidant and anticancer qualities of plants, these green-synthesized AgNPs selectively eradicate tumor cells while sparing normal healthy cells. This comprehensive review aimed to summarize the key aspects of plant extracts as anticancer agents, biosynthesis of AgNPs, and recent advancements in the antitumor efficacy of green-synthesized AgNPs.

Attapulgite-Assisted In Situ Anchoring of Ultrasmall Ag Nanoparticles for Enhanced Eradication of Multidrug-Resistant Bacterial Biofilms and Accelerated Wound Healing

Silver nanoparticles (Ag NPs) have emerged as a promising solution to combat biofilm-related infections caused by multidrug-resistant bacteria. However, their practical application remains limited due to their tendency to aggregate and exhibit high toxicity at elevated concentrations. Here, we developed a Citrus limon peel water extract-mediated hydrothermal process to facilitate the heterogeneous nucleation of Ag NPs on attapulgite (APT) nanorods and prepared Ag/APT nanocomposites with ultrasmall Ag NPs (<2 nm) uniformly anchored on APT nanorods. Ascorbic acid and polyphenols in Citrus limon peel extract acted as electron donors to reduce Ag+ to Ag0, while the interfacial interaction of APT nanorods induced heterogeneous nucleation and confined the growth of Ag nanocrystals, resulting in ultrasmall Ag NPs. As a result, due to the synergistic effect of the targeted biofilm-binding affinity of APT nanorods and the siginificantly increased specific surface area of Ag NPs conducive to the release of Ag+ ions, the obtained Ag/APT nanocomposites exhibited enhanced eradication activities on antimicrobial-resistant bacterial biofilms and accelerated wound healing in MRSA-infected wound models. Additionally, attributing to the low dosage of Ag, Ag/APT exhibited exceptional biocompatibility both in vitro and in vivo. This work provides a simple and green strategy for the preparation of highly active Ag-based antibacterial nanomaterials and sheds new light on the development of advanced antimicrobial agents for wound healing.

Salicylic Acid-Mediated Silver Nanoparticle Green Synthesis: Characterization, Enhanced Antimicrobial, and Antibiofilm Efficacy

Objectives: Silver nanoparticles (AgNPs) were synthesized via an easy and rapid biogenic synthesis approach, utilizing the dual capabilities of salicylic acid as both a reducing and capping agent. Methods: The characterization of Salicylic Acid-Mediated Silver Nanoparticle (SA-AgNPs) was conducted using a variety of techniques, including ultraviolet-visible spectroscopy, dynamic light scattering, scanning electron microscopy combined with energy dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, as well as thermogravimetric analysis paired with differential scanning calorimetry. Results: SA-AgNPs demonstrated significant antibacterial properties against both Gram-positive (methicillin-resistant Staphylococcus epidermidis, Staphylococcus aureus, Cutibacterium acnes, methicillin-resistant Staphylococcus aureus) and Gram-negative (Escherichia coli), with minimum inhibitory concentrations (MICs) of 8, 9, 8, 4, and 6 μg/mL, respectively. At a concentration of 32 μg/mL, SA-AgNPs exhibited 99.9% killing efficiency against Escherichia coli (E. coli), Cutibacterium acnes (C. acnes), and methicillin-resistant Staphylococcus aureus (MRSA), within 4, 16, and 12 h, respectively. At the same concentration, SA-AgNPs effectively inhibited 95.61% of MRSA biofilm formation. SA-AgNPs induced the leakage of intracellular macromolecular substances by increasing the membrane permeability, which ultimately caused bacterial apoptosis. Conclusions: Overall, this study presents a fast and environmentally friendly approach for synthesizing SA-AgNPs, with potential applications as nano antibiotics antibacterial coatings for implantable medical devices and wound dressings.

Sericin-Assisted Green Synthesis of Gold Nanoparticles as Broad-Spectrum Antimicrobial and Biofilm-Disrupting Agents for Therapy of Bacterial Infection

Background

Tens of millions of people die from wound infections globally each year, and nearly 80% of tissue infections are associated with bacterial biofilms. However, overuse of antibiotics can lead to bacterial resistance. Therefore, it is critical to develop simple and effective strategies to kill bacteria and remove biofilms.

Methods

The present study used sericin as a reducing and stabilizing agent to synthesize sericin-gold nanoparticles (Ser-Au NPs) and tested its colloidal stability under different pH and salt concentration conditions. Subsequently, functional gold nanocomposites (Ser-Au@MMI) were synthesized by combining Ser-Au NPs with 2-mercapto-1-methylimidazole (MMI). The antimicrobial effect of Ser-Au@MMI was checked by MIC, antimicrobial activity test, and in vitro cytotoxicity was assessed using CCK-8 assay. In vitro anti-biofilm effect was observed by fluorescence microscopy and SEM. Finally, the anti-infective therapeutic efficacy of Ser-Au@MMI was determined in an in vivo rat-infected wound model.

Results

Sericin as a reducing and stabilizing agent to synthesize Ser-Au NPs exhibited excellent colloidal stability under different pH and salt concentration conditions. The TEM, EDS, and XPS analyses confirmed the successful synthesis of Ser-Au@MMI. It exhibited higher antibacterial activity due to the synergistic effect of MMI and AuNP, which can achieve a bactericidal effect by destroying the integrity of bacterial cell walls and structure. In addition, Ser-Au@MMI10 (HAuCl4:MMI =1:10) concentration (64 μg/mL) could effectively disrupt biofilms formed by four species of bacteria and kill them, including P. aeruginosa, B. subtilis, E. coli, and S. aureus, but was not cytotoxic to mouse fibroblasts (L929) cells. Infected wound modeling showed that Ser-Au@MMI10 accelerated infected wound healing in vivo.

Conclusion

Ser-Au@MMI nanocomposites are prepared through a facile and environmentally friendly strategy and have the advantages of excellent bactericidal effect and low toxicity, which has the potential for application as a broad-spectrum antimicrobial agent and biofilm disrupting agent in healthcare.

Biofilm suppression of Pseudomonas aeruginosa by bio-engineered silver nanoparticles from Hellenia speciosa rhizome extract

Bacterial biofilm, a persistent issue in healthcare equipment and typical infections, is exacerbated by the pathogenesis and antibiotic tolerance of Pseudomonas aeruginosa. This bacterium remains a significant concern in the global healthcare sector. Silver nanoparticles, with their potent antibacterial properties, have emerged as a promising solution. This study, therefore, is of utmost importance as it aims to delve into the parameters influencing the biogenic nanoparticle-assisted regulation of bacterial adherence by Pseudomonas aeruginosa. The nano-sized particles were bioengineered using Hellenia speciosa rhizome extracts, which mainly included biologically active components such as mequinol, 4-hydroxy-3-methylacetophenone, and phenol, 2,6-dimethoxy, supplemented with the formation of silver nanostructured materials. The nanoclusters were characterized by UV-Vis spectrophotometry, X-ray scattering, and scanning electron microscopy (SEM). According to a microtiter plate experiment, the nanoparticle degraded biofilms up to 94.41 % at dosages varied from 0 to 25 μg/ml. The light microscopy study and the interface architecture of biofilm suppression by electron microscopy demonstrated the nano-sized particle's potential to prevent bacterial adherence.

Engineered M13-Derived Bacteriophages Capable of Gold Nanoparticle Synthesis and Nanogold Manipulations

For years, gold nanoparticles (AuNPs) have been widely used in medicine and industry. Although various experimental procedures have been reported for their preparation and manipulation, none of them is optimal for all purposes. In this work, we engineered the N-terminus of the pIII minor coat protein of bacteriophage (phage) M13 to expose a novel HLYLNTASTHLG peptide that effectively and specifically binds gold. In addition to binding gold, this engineered phage could synthesize spherical AuNPs of 20 nm and other sizes depending on the reaction conditions, aggregate them, and precipitate gold from a colloid, as revealed by transmission electron microscopy (TEM), atomic force microscopy (AFM), and scanning electron microscopy (SEM), as well as ultraviolet-visible (UV-vis) and Fourier-transform infrared (FTIR) spectroscopic methods. We demonstrated that the engineered phage exposing a foreign peptide selected from a phage-displayed library may serve as a sustainable molecular factory for both the synthesis of the peptide and the subsequent overnight preparation of AuNPs from gold ions at room temperature and neutral pH in the absence of strong reducing agents, such as commonly used NaBH4. Taken together, the results suggest the potential applicability of the engineered phage and the new, in vitro-identified gold-binding peptide in diverse biomimetic manipulations.

Biologically Synthesized Gold Nanoparticles with Enhanced Antioxidant and Catalytic Properties

Increasing levels of reactive oxygen species generate oxidative stress in the human body that can lead to various medical conditions. The use of nanomaterials exhibiting antioxidant properties may prevent these effects. The biological synthesis of metallic nanoparticles using plant extracts with antioxidant properties can offer benefits due to their active compounds. The used extracts contained reducing and stabilizing agents, which were shown to be transferred onto the gold nanoparticles, functionalizing them. Herin, we report a gold nanoparticle synthesis by eco-friendly biological methods (b-AuNPs) using extracts of sea buckthorn, lavender, walnuts, and grapes, obtained through ultrasound-assisted extraction and pressure-enhanced extraction. The obtained b-AuNPs were characterized by UV-Vis and FTIR spectroscopies and visualized using transmission electron microscopy. The catalytic and scavenging effect of the b-AuNPs towards H2O2 (as reactive oxygen species) was evaluated electrochemically, highlighting the protective behavior of b-AuNPs towards lipid peroxidation. All experiments demonstrated the stability and reproducibility of prepared b-AuNPs with enhanced antioxidant and catalytic properties, opening a new perspective for their use in biomedical applications.

Synthesis of Silver Nanoparticles Using Extracts from Different Parts of the Paullinia cupana Kunth Plant: Characterization and In Vitro Antimicrobial Activity

The green synthesis of silver nanoparticles (AgNPs) can be developed using safe and environmentally friendly routes, can replace potentially toxic chemical methods, and can increase the scale of production. This study aimed to synthesize AgNPs from aqueous extracts of guarana (Paullinia cupana) leaves and flowers, collected in different seasons of the year, as a source of active biomolecules capable of reducing silver ions (Ag+) and promoting the stabilization of colloidal silver (Ag0). The plant aqueous extracts were characterized regarding their metabolic composition by liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS/MS), phenolic compound content, and antioxidant potential against free radicals. The synthesized AgNPs were characterized by UV/Vis spectrophotometry, dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and scanning electron microscopy coupled to energy-dispersive X-ray spectrometry (EDX). The results demonstrated that the chemical characterization indicated the presence of secondary metabolites of many classes of compounds in the studied aqueous extracts studied, but alkaloids and flavonoids were predominant, which are widely recognized for their antioxidant capabilities. It was possible to notice subtle changes in the properties of the nanostructures depending on parameters such as seasonality and the part of the plant used, with the AgNPs showing surface plasmon resonance bands between 410 and 420 nm using the leaf extract and between 440 and 460 nm when prepared using the flower extract. Overall, the average hydrodynamic diameters of the AgNPs were similar among the samples (61.98 to 101.6 nm). Polydispersity index remained in the range of 0.2 to 0.4, indicating that colloidal stability did not change with storage time. Zeta potential was above -30 mV after one month of analysis, which is adequate for biological applications. TEM images showed AgNPs with diameters between 40.72 to 48.85 nm and particles of different morphologies. EDX indicated silver content by weight between 24.06 and 28.81%. The synthesized AgNPs exhibited antimicrobial efficacy against various pathogenic microorganisms of clinical and environmental interest, with MIC values between 2.12 and 21.25 µg/mL, which is close to those described for MBC values. Therefore, our results revealed the potential use of a native species of plant from Brazilian biodiversity combined with nanotechnology to produce antimicrobial agents.

From Nature to Technology: Exploring the Potential of Plant-Based Materials and Modified Plants in Biomimetics, Bionics, and Green Innovations

This review explores the extensive applications of plants in areas of biomimetics and bioinspiration, highlighting their role in developing sustainable solutions across various fields such as medicine, materials science, and environmental technology. Plants not only serve essential ecological functions but also provide a rich source of inspiration for innovations in green nanotechnology, biomedicine, and architecture. In the past decade, the focus has shifted towards utilizing plant-based and vegetal waste materials in creating eco-friendly and cost-effective materials with remarkable properties. These materials are employed in making advancements in drug delivery, environmental remediation, and the production of renewable energy. Specifically, the review discusses the use of (nano)bionic plants capable of detecting explosives and environmental contaminants, underscoring their potential in improving quality of life and even in lifesaving applications. The work also refers to the architectural inspirations drawn from the plant world to develop novel design concepts that are both functional and aesthetic. It elaborates on how engineered plants and vegetal waste have been transformed into value-added materials through innovative applications, especially highlighting their roles in wastewater treatment and as electronic components. Moreover, the integration of plants in the synthesis of biocompatible materials for medical applications such as tissue engineering scaffolds and artificial muscles demonstrates their versatility and capacity to replace more traditional synthetic materials, aligning with global sustainability goals. This paper provides a comprehensive overview of the current and potential uses of living plants in technological advancements, advocating for a deeper exploration of vegetal materials to address pressing environmental and technological challenges.