Influence of gold and silver nanoparticles on the germination and growth of Mimusops laurifolia seeds in the South-Western regions in Saudi Arabia

Small particles, big effects: How nanoparticles can enhance plant growth in favorable and harsh conditions

By 2050, the global population is projected to reach 9 billion, underscoring the imperative for innovative solutions to increase grain yield and enhance food security. Nanotechnology has emerged as a powerful tool, providing unique solutions to this challenge. Nanoparticles (NPs) can improve plant growth and nutrition under normal conditions through their high surface-to-volume ratio and unique physical and chemical properties. Moreover, they can be used to monitor crop health status and augment plant resilience against abiotic stresses (such as salinity, drought, heavy metals, and extreme temperatures) that endanger global agriculture. Application of NPs can enhance stress tolerance mechanisms in plants, minimizing potential yield losses and underscoring the potential of NPs to raise crop yield and quality. This review highlights the need for a comprehensive exploration of the environmental implications and safety of nanomaterials and provides valuable guidelines for researchers, policymakers, and agricultural practitioners. With thoughtful stewardship, nanotechnology holds immense promise in shaping environmentally sustainable agriculture amid escalating environmental challenges.

How Can Biological and Chemical Silver Nanoparticles Positively Impact Physio-Chemical and Chloroplast Ultrastructural Characteristics of Vicia faba Seedlings?

Through interactions with plant cells, silver nanoparticles (AgNPs) with both biological and chemical origins can stimulate physiological and metabolic processes in plants. To ensure their safe application in the food chain, it is necessary to investigate their effects on plant systems. Therefore, the effects of chemical AgNPs (chem-AgNPs) and biologically synthesized AgNPs (bio-AgNPs) at different levels (i.e., 0, 10, and 50 ppm) on physiological and biochemical traits {i.e., root and shoot growth traits, photosynthetic pigments (Chl a, Chl b, carotenoids, and total pigments), soluble sugars, total carbohydrates, starch, H₂O₂, and antioxidant enzyme activities} of Vicia faba L. seedlings were investigated. AgNPs were biosynthesized from silver nitrate (AgNO₃) by a green synthesis approach using Jatropha curcas seed extract. The synthesized AgNPs were characterized by UV-vis spectroscopy, transmission electron microscopy (TEM), zeta potential, Fourier-transform infrared spectra (FT-IR), and X-ray diffraction (XRD). The results showed that bio-AgNPs at 10 ppm resulted in the highest growth, physiological, and biological traits of faba bean seedlings in comparison with those obtained from both AgNO₃ and chem-AgNPs treatments. On the other hand, all AgNPs treatments adversely affected the chloroplast ultrastructure, however, fewer negative effects were obtained with the application of 10 ppm bio-AgNPs. In addition, the roots and shoots of seedlings contained the lowest Ag content under different treatments at 10 ppm AgNPs in comparison to the highest level of AgNPs (50 ppm), which indicates that additional studies should be incorporated to ensure safe use of lower concentrations of bio-AgNPs in seed priming. In conclusion, the application of biogenic nanoparticles at 10 ppm can be recommended to enhance plant growth and the productivity of strategic crops.

Nanotechnology for sustainable agro-food systems: The need and role of nanoparticles in protecting plants and improving crop productivity

The rapid population growth and environmental challenges in agriculture need innovative and sustainable solutions to meet the growing need for food worldwide. Recent nanotechnological advances found its broad applicability in agriculture's protection and post-harvesting. Engineered nanomaterials play a vital role in plant regulation, seed germination, and genetic manipulation. Their size, surface morphology, properties, and composition were designed for controlled release and enhanced properties in agriculture and the food industry. Nanoparticles can potentially be applied for the targeted and controlled delivery of fertilizers, pesticides, herbicides, plant growth regulators, etc. This help to eliminate the use of chemical-based pesticides and their water solubility, protect agrochemicals from breakdown and degradation, improve soil health, and naturally control crop pathogens, weeds, and insects, ultimately leading to enhanced crop growth and production capacity in the food industry. They can be effectively utilized for nano-encapsulation, seed germination, genetic manipulation, etc., for protecting plants and improving crop productivity, safe and improved food quality, and monitoring climate conditions. Nanoparticles played a crucial role in the uptake and translocation processes, genetically modifying the crops, high seed germination, and productivity. In this article, we have reviewed some important applications of nanoparticles for sustainable agro-food systems. The need and role of nanotechnology concerning challenges and problems faced by agriculture and the food industry are critically discussed, along with the limitations and future prospects of nanoparticles.

Nano-priming as emerging seed priming technology for sustainable agriculture-recent developments and future perspectives

Nano-priming is an innovative seed priming technology that helps to improve seed germination, seed growth, and yield by providing resistance to various stresses in plants. Nano-priming is a considerably more effective method compared to all other seed priming methods. The salient features of nanoparticles (NPs) in seed priming are to develop electron exchange and enhanced surface reaction capabilities associated with various components of plant cells and tissues. Nano-priming induces the formation of nanopores in shoot and helps in the uptake of water absorption, activates reactive oxygen species (ROS)/antioxidant mechanisms in seeds, and forms hydroxyl radicals to loosen the walls of the cells and acts as an inducer for rapid hydrolysis of starch. It also induces the expression of aquaporin genes that are involved in the intake of water and also mediates H₂O_2, or ROS, dispersed over biological membranes. Nano-priming induces starch degradation via the stimulation of amylase, which results in the stimulation of seed germination. Nano-priming induces a mild ROS that acts as a primary signaling cue for various signaling cascade events that participate in secondary metabolite production and stress tolerance. This review provides details on the possible mechanisms by which nano-priming induces breaking seed dormancy, promotion of seed germination, and their impact on primary and secondary metabolite production. In addition, the use of nano-based fertilizer and pesticides as effective materials in nano-priming and plant growth development were also discussed, considering their recent status and future perspectives.

Chitosan and Gold Nanoparticles Supplementation for Augmentation of Indole-3-Acetic Acid Production by Rhizospheric Pseudomonas aeruginosa and Plant Growth Enhancement

The present study has been focused to evaluate the effect of chitosan nanoparticles (CNPs) and gold nanoparticles (AuNPs) on the phytohormone production by rhizospheric Pseudomonas aeruginosa. The gold nanoparticles were synthesized biologically and characterized by UV-Visible spectrophotometry, transmission electron microscopy, and X-ray diffraction analysis. The indole-3-acetic acid (IAA) production by P. aeruginosa supplemented with CNPs and AuNPs was quantified by using Salkowski's method and confirmed by high-performance liquid chromatography (HPLC) analysis. This revealed the effect of 5 mg/mL CNPs and 100 µg/mL AuNPs to enhance the IAA production by P. aeruginosa. By Salkowski's method, 07.16 ± 0.28 and 09.56 ± 0.28 µg/mL of IAA could be detected in the samples prepared from P. aeruginosa supplemented with 5 mg/mL CNPs and 100 µg/mL AuNPs, respectively. HPLC analysis also confirmed the production of IAA by P. aeruginosa. The CNPs and AuNPs-supplemented P. aeruginosa was also found to have enhancement effect on the shoot length (25.25 ± 0.85 cm and 26.57 ± 0.73 cm) and fresh weight (0.94 ± 0.09 g and 0.96 ± 0.09 g) of Vigna unguiculata plants, which highlight the significance of the study and the agricultural promises of nanomaterials-supplemented rhizobacteria.

Recent advances on therapeutic potentials of gold and silver nanobiomaterials for human viral diseases

Viral diseases are prominent among the widely spread infections threatening human well-being. Real-life clinical successes of the few available therapeutics are challenged by pathogenic resistance and suboptimal delivery to target sites. Nanotechnology has aided the design of functionalised and non-functionalised Au and Ag nanobiomaterials through physical, chemical and biological (green synthesis) methods with improved antiviral efficacy and delivery. In this review, innovative designs as well as interesting antiviral activities of the nanotechnology-inclined biomaterials of Au and Ag, reported in the last 5 years were critically overviewed against several viral diseases affecting man. These include influenza, respiratory syncytial, adenovirus, severe acute respiratory syndromes (SARS), rotavirus, norovirus, measles, chikungunya, HIV, herpes simplex virus, dengue, polio, enterovirus and rift valley fever virus. Notably identified among the nanotechnologically designed promising antiviral agents include AuNP-M2e peptide vaccine, AgNP of cinnamon bark extract and AgNP of oseltamivir for influenza, PVP coated AgNP for RSV, PVP-AgNPs for SARS-CoV-2, AuNRs of a peptide pregnancy-induce d hypertension and AuNP nanocarriers of antigen for MERS-CoV and SARS-CoV respectively. Others are AgNPs of collagen and Bacillus subtilis for rotavirus, AgNPs labelled Ag30-SiO 2 for murine norovirus in water, AuNPs of Allium sativum and AgNPs of ribavirin for measles, AgNPs of Citrus limetta and Andrographis Paniculata for Chikungunya, AuNPs of efavirenz and stavudine, and AgNPs-curcumin for HIV, NPAuG3-S8 for HSV, AgNPs of Moringa oleifera and Bruguiera cylindrica for dengue while AgNPs of polyethyleneimine and siRNA analogues displayed potency against enterovirus. The highlighted candidates are recommended for further translational studies towards antiviral therapeutic designs.

A sandwich-type electrochemical immunosensor based on Au@Pd nanodendrite functionalized MoO2 nanosheet for highly sensitive detection of HBsAg

In this work, a sandwich-type electrochemical immunosensor was fabricated to the effective detection of hepatitis B surface antigen (HBsAg). The designed electrochemical immunosensor was based on Au core and Pd shell nanodendrites loaded on amino functionalized molybdenum dioxide nanosheets (Au@Pd NDS/NH₂-MoO₂ NSs) as the secondary antibody (Ab₂) label and silver nanoparticles were loaded by electrodeposited (D-Ag NPs) on the surface of electrode as the platform. Because of the synergistic effect and abundant catalytic activity sites provided by surface dendrite structure, Au@Pd NDs were more effective than single gold and palladium nanoparticles in catalytic reduction of hydrogen peroxide (H₂O₂). MoO₂ had the good catalytic capacity for reduction of H₂O₂ and favourable electrical conductivity. Hence, the obtained Au@Pd NDS/NH₂-MoO₂ NSs were more effective than Au@Pd NDs and NH₂-MoO₂ NSs in catalytic reduction of hydrogen peroxide attribute to a synergistic effect. Also, Ag NPs with admirable electrical conductivity and biocompatibility were used as sensing platforms and primary antibodies (Ab₁) carriers, which can accelerate the electron transfer and improve the sensitivity of the immunosensor. Here, the proposed electrochemical immunosensor offered a wide linear interval from 10 fg mL^-1 to 100 ng mL^-1 and the lower limit of detection of 3.3 fg mL^-1 (S/N = 3) for detection of HBsAg under optimal experimental conditions. Furthermore, the accuracy of the actual serum sample analysis was satisfactory, which showed that the electrochemical immunosensor possessed a good application prospect in clinical detection.