Due to their antibacterial and antiviral effects, silver nanoparticles (AgNP) are one of the most widely used nanomaterials worldwide in various industries, e.g., in textiles, cosmetics and biomedical-related products. Unfortunately, the lack of complete physicochemical characterization and the variety of models used to evaluate its cytotoxic/genotoxic effect make comparison and decision-making regarding their safe use difficult. In this work, we present a systematic study of the cytotoxic and genotoxic activity of the commercially available AgNPs formulation Argovit™ in Allium cepa. The evaluated concentration range, 5–100 µg/mL of metallic silver content (85–1666 µg/mL of complete formulation), is 10–17 times higher than the used for other previously reported polyvinylpyrrolidone (PVP)-AgNP formulations and showed no cytotoxic or genotoxic damage in Allium cepa. Conversely, low concentrations (5 and 10 µg/mL) promote growth without damage to roots or bulbs. Until this work, all the formulations of PVP-AgNP evaluated in Allium cepa regardless of their size, concentration, or the exposure time had shown phytotoxicity. The biological response observed in Allium cepa exposed to Argovit™ is caused by nanoparticles and not by silver ions. The metal/coating agent ratio plays a fundamental role in this response and must be considered within the key physicochemical parameters for the design and manufacture of safer nanomaterials.

Nowadays, Huanglongbing (HLB) disease, commonly known as “yellow dragon disease”, affects citrus crops worldwide and has a devastating effect in the agro-industrial sector. Significant efforts have been made to fight the illness, but still, there is no effective treatment to eradicate the disease. This work is the first approach to evaluate the capacity of silver nanoparticles (AgNPs) to directly eradicate the bacteria responsible for Huanglongbing disease, Candidatus Liberibacter asiaticus (CLas), in the field. The AgNPs were administered by foliar sprinkling and trunk injection of 93 sick trees with remarkable results. Both methods produce an 80–90% decrease of bacterial titre, quantified by qRT-PCR in collected foliar tissue, compared with the control group. Scanning electron microscopy images show an essential reduction of starch accumulation in phloem vessels after AgNP treatments without evidence of bacteria in the analyzed samples. Compared with other effective methods that involve β-lactam antibiotics, the potency of AgNPs is 3 to 60-times higher when it is administered by foliar sprinkling and from 75 to 750-fold higher when the administration was by trunk-injection. All these results allow us to propose this AgNP formulation as a promising alternative for the treatment of infected trees in the field.

The antimicrobial bioactivity of silver nanoparticles is well known, and they can be used widely in many applications, becoming especially important in the biomedical industry. On the other hand, the electrospun nanofibers possess properties that can enhance silver nanoparticle applicability. However, silver nanoparticle bioactivity differs depending on the loading of silver ions into electrospun nanofibers. This review is aimed at comparing different silver incorporation methods into electrospun nanofibers and their antimicrobial activity, discussing each procedures limitations, and presenting the most promising one. This review showed that the preferred techniques for incorporating silver nanoparticles were direct blending and ultraviolet irradiation methods due to their simplicity and efficient results. Besides, polyacrylonitrile nanofibers (PAN) have been the most reported system loaded with silver nanoparticles. Finally, independently of the technique used, silver nanoparticle-loaded nanofibers show high antimicrobial activity in all cases.

During the last 3 decades, there has been a slow advance to obtain new treatments for malignant melanoma that improve patient survival. In this work, we present a systematic study focused on the antiproliferative and antitumour effect of AgNPs. These nanoparticles are fully characterized, are coated with polyvinylpyrrolidone (PVP), and have an average size of 35±15nm and a metallic silver content of 1.2% wt. Main changes on cell viability, induction of apoptosis and necrosis, and ROS generation were found on B16-F10 cells after six hours of exposure to AgNPs (IC50=4.2μg/mL) or Cisplatin (IC50=2.0μg/mL). Despite the similar response for both AgNPs and Cisplatin on antiproliferative potency (cellular viability of 53.95±1.88 and 53.62±1.04) and ROS production (20.27±1.09% and 19.50±0.35%), significantly different cell death pathways were triggered. While AgNPs induce only apoptosis (45.98±1.88%), Cisplatin induces apoptosis and necrosis at the same rate (22.31±1.72% and 24.07±1.10%, respectively). In addition to their antiproliferative activity, in vivo experiments showed that treatments of 3, 6, and 12 mg/kg of AgNPs elicit a survival rate almost 4 times higher (P<0.05) compared with the survival rate obtained with Cisplatin (2 mg/kg). Furthermore, the survivor mice treated with AgNPs do not show genotoxic damage determined by micronuclei frequency quantification on peripheral blood cells. These results exhibit the remarkable antitumour activity of a nongenotoxic AgNP formulation and constitute the first advance toward the application of these AgNPs for melanoma treatment, which could considerably reduce adverse effects provoked by currently applied chemotherapeutics.

Worldwide demands of Vanilla planifolia lead to finding new options to produce large-scale and contaminant-free crops. Particularly, the Mexican Government has classified Vanilla planifolia at risk and it subject to protection programs since wild species are in danger of extinction and no more than 30 clones have been found. Nanotechnology could help to solve both demands and genetic variability, but toxicological concerns must be solved. In this work, we present the first study of the cytotoxic and genotoxic effects promoted by AgNPs in Vanilla planifolia plantlets after a very long exposure time of six weeks. Our results show that Vanilla planifolia plantlets growth with doses of 25 and 50 mg/L is favored with a small decrease in the mitotic index. A dose-dependency in the frequency of cells with chromosomal aberrations and micronuclei was found. However, genotoxic effects could be considered as minimum due to with the highest concentration employed (200 mg/L), the total percentage of chromatic aberrations is lower than 5% with only three micronuclei in 3000 cells, despite the long-time exposure to AgNP. Therefore, 25 and 50 mg/L (1.5 and 3 mg/L of metallic silver) were identified as safe concentrations for Vanilla planifolia growth on in vitro conditions. Exposure of plantlets to AgNPs increase the polymorphism registered by inter-simple sequence repeat method (ISSR), which could be useful to promote the genetic variability of this species.