Nanoparticles (NPs) physicochemical properties, such as size, shape, surface chemistry, charge, etc., play a critical role in biological systems interactions, which include NPs' cellular uptake, trafficking, activation, and toxicity. Although nano-bio interactions are multifaceted and complex, their assessment is essential for future therapeutic and diagnostic use since being carriers that deliver specific molecules (i.e., active pharmaceutical ingredients and imaging agents) in intracellular sites. The journey of NPs begins by reaching the plasma membrane and entering the cell mainly through endocytosis. After vesicles pinch off the cell membrane, the intracellular trafficking is mediated by a network of cellular endosomes which direct NPs to the different cellular components. Otherwise, NPs or their contents are released into the cytoplasm. In both cases, NPs can pass undetected or be recognized by the cell leading to a pro or anti-inflammatory response. Indeed, the cell response mostly depends on cell type and NPs physicochemical properties. The principal mechanism by which NPs activate the cell response is RONS production. Other mechanism includes signaling pathways modulation related to metabolic and enzymatic reactions, cell transduction, and immune modulation. Hence, the underlying mechanisms of cellular and subcellular interactions in vitro should be performed to provide insights into NPs' effect. This information helps us to improve their synthesis and design to maximize the clinical benefits while minimizing side effects. Most in vitro tests to evaluate NPs' effect in cells were developed focusing on cell dysfunctions, cytotoxicity, genotoxicity, immunogenicity, and cell death.

Silver selenide (Ag₂Se) is a promising nanomaterial due to its outstanding optoelectronic properties and countless bio-applications. To the best of our knowledge, we report, for the first time, a simple and easy method for the ultrasound-assisted synthesis of Ag₂Se nanoparticles (NPs) by mixing aqueous solutions of silver nitrate (AgNO₃) and selenous acid (H₂SeO₃) that act as Ag and Se sources, respectively, in the presence of dissolved fructose and starch that act as reducing and stabilizing agents, respectively. The concentrations of mono- and polysaccharides were screened to determine their effect on the size, shape and colloidal stability of the as-synthesized Ag₂Se NPs which, in turn, impact the optical properties of these NPs. The morphology of the as-synthesized Ag₂Se NPs was characterized by transmission electron microscopy (TEM) and both α- and β-phases of Ag₂Se were determined by X-ray diffraction (XRD). The optical properties of Ag₂Se were studied using UV–Vis spectroscopy and its elemental composition was determined non-destructively using scanning electron microscopy–energy-dispersive spectroscopy (SEM–EDS). The biological activity of the Ag₂Se NPs was assessed using cytotoxic and bactericidal approaches. Our findings pave the way to the cost-effective, fast and scalable production of valuable Ag₂Se NPs that may be utilized in numerous fields.

The search for new strategies to curb the spread of the SARS-CoV-2 coronavirus, which causes COVID-19, has become a global priority. Various nanomaterials have been proposed as ideal candidates to inactivate the virus; however, because of the high level of biosecurity required for their use, alternative models should be determined. This study aimed to compare the effects of two types of nanomaterials gold (AuNPs) and silver nanoparticles (AgNPs), recognized for their antiviral activity and affinity with the coronavirus spike protein using PhiX174 and enveloped Phi6 bacteriophages as models. To reduce the toxicity of nanoparticles, a species known for its intermediate antiviral activity, Solanum mammosum L. (Sm), was used. NPs prepared with sodium borohydride (NaBH₄) functioned as the control. Antiviral activity against PhiX174 and Phi6 was analyzed using its seed, fruit, leaves, and essential oil; the leaves were the most effective on Phi6. Using the aqueous extract of the leaves, AuNPs-Sm of 5.34 ± 2.25 nm and AgNPs-Sm of 15.92 ± 8.03 nm, measured by transmission electron microscopy, were obtained. When comparing NPs with precursors, both gold(III) acetate and silver nitrate were more toxic than their respective NPs (99.99% at 1 mg ml⁻¹). The AuNPs-Sm were less toxic, reaching 99.30% viral inactivation at 1 mg ml⁻¹, unlike the AgNPs-Sm, which reached 99.94% at 0.01 mg ml⁻¹. In addition, cell toxicity was tested in human adenocarcinoma alveolar basal epithelial cells (A549) and human foreskin fibroblasts. Gallic acid was the main component identified in the leaf extract using high performance liquid chromatography with diode array detection (HPLC-DAD). The FT-IR spectra showed the presence of a large proportion of polyphenolic compounds, and the antioxidant analysis confirmed the antiradical activity. The control NPs showed less antiviral activity than the AuNPs-Sm and AgNPs-Sm, which was statistically significant; this demonstrates that both the S. mammosum extract and its corresponding NPs have a greater antiviral effect on the surrogate Phi bacteriophage, which is an appropriate model for studying SARS-CoV-2.

The COVID-19 pandemic has had an enormous impact on economies and health systems globally, therefore a top priority is the development of increasingly better diagnostic and surveillance alternatives to slow down the spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In order to establish massive testing and contact tracing policies, it is crucial to have a clear view of the diagnostic options available and their principal advantages and drawbacks. Although classical molecular methods such as RT-qPCR are broadly used, diagnostic alternatives based on technologies such as LAMP, antigen, serological testing, or the application of novel technologies such as CRISPR-Cas for diagnostics, are also discussed. The present review also discusses the most important automation strategies employed to increase testing capability. Several serological-based diagnostic kits are presented, as well as novel nanotechnology-based diagnostic methods. In summary, this review provides a clear diagnostic landscape of the most relevant tools to track COVID-19.

At the northwestern edge of South America is located Ecuador. This place is a classical example of an active continental margin with widespread active volcanism. Detailed studies about the impact of volcanic ash on human health are still lacking. Therefore, the disease of exposed populations is unknown. The objective of the present investigation was to assess the biological impact of Pichincha volcanic ash on cell culture and inflammation in murine lung tissues that will contribute to the understanding of the hazards. In this study, thein vivophase was performed in mice C57BL/6 exposed to several doses of volcanic ash (0.5, 1, and 3.75 mg/100 g mouse body weight). The body weight and survival were controlled during seven days of treatment. The expression of inflammation markers NRLP 3, caspase-1, pro-IL-1, IL-1β, IL-6, IL-8, and h-HPRT was analyzed. Thein vitrophase was performed in lung cancer cells A549, peritoneal macrophages, and McCoy cells exposing them to different concentrations of volcanic ash (80, 320, and 1280 μg/cm3) to determine the cytotoxicity and the production of reactive oxygen species. The ash initiated activation of the inflammasome complex NRLP 3 and the initiation of a proinflammatory activity in the murine lung tissue depending on the concentration of this agent. The viability of A549 and McCoy cell decreased with the length of exposure and increased with the concentration of volcanic ash. The activity in superoxide dismutase decreased by about 60%, leading to the formation of reactive oxygen species. These results associated with compounds contained in Pichincha volcanic ash are considered hazardous elements which induce inflammation leading to activate inflammasome NRLP, releasing reactive oxygen species, and producing changes in cell morphology and density, all of which are expression of cytotoxicity.