Evaluation of the degradation of the graphene-polypropylene composites of masks in harsh working conditions

The recent COVID-19 outbreak has led health authorities to recommend at least the use of surgical masks, most preferably respirators (FFP2 or KN95), to prevent the spread of the virus. Non-woven fabrics have been chosen as the best option to manufacture the face masks, due to their filtration efficiency, low cost, and versatility. Modifying the mask filters with graphene has been of great interest due to its potential use as antibacterial and virucidal properties. Indeed, some companies have commercialized face masks in which graphene is coated and/or embedded. However, the Canadian sanitary authorities advised against using the Shandong Shengquan New Materials Co. graphene masks because of the possibility of pulmonary damage produced by graphene inhalation. Thus, we have analyzed the stability of the graphene filter of these masks and compared it with two other commercially available graphene mask filters, evaluating the morphological and spectroscopical change of the fibers, as well as the particles released during the endurance tests. Our work introduces the necessary tools and methodology to evaluate the potential degradation of face masks under extreme working conditions. These methods complement the present standard tests ensuring the security of the new filters based on composites or nanomaterialsWe thank Ministerio de Ciencia e Innovacion (projects PID2019- 106268GB-C31 and PID2019-106268GB-C32), the financial support through the “María de Maeztu” Programme for Units of Excellence in R&D (CEX2018-000805-M) and Banco de Santander CRUE (Fondo Supera COVID-19

Free PCR virus detection via few-layer bismuthene and tetrahedral DNA nanostructured assemblies

In this work we describe a highly sensitive method based on a biocatalyzed electrochemiluminescence approach. The system combines, for the first time, the use of few-layer bismuthene (FLB) as a platform for the oriented immobilization of tetrahedral DNA nanostructures (TDNs) specifically designed and synthetized to detect a specific SARS-CoV-2 gene sequence. In one of its vertices, these TDNs contain a DNA capture probe of the open reading frame 1 ab (ORF1ab) of the virus, available for the biorecognition of the target DNA/RNA. At the other three vertices, there are thiol groups that enable the stable anchoring/binding to the FLB surface. This novel geometry/approach enables not only the binding of the TDNs to surfaces, but also the orientation of the capture probe in a direction normal to the bismuthine surface so that it is readily accessible for binding/recognition of the specific SARS-CoV-2 sequence. The analytical signal is based on the anodic electrochemiluminescence (ECL) intensity of luminol which, in turn, arises as a result of the reaction with H2O2, generated by the enzymatic reaction of glucose oxidation, catalyzed by the biocatalytic label avidin-glucose oxidase conjugate (Av-GOx), which acts as co-reactant in the electrochemiluminescent reaction. The method exhibits a limit of detection (LOD) of 4.31 aM and a wide linear range from 14.4 aM to 1.00 μM, and its applicability was confirmed by detecting SARS-CoV-2 in nasopharyngeal samples from COVID-19 patients without the need of any amplification processPID2020-116728RB-I00, PID2020-116661RB-I00, PID2020-119352RB-I00, PDC2021-120782-C2, PID2022-138908NB-C31, CTQ2015-71955-REDT, S2018/NMT-434

Síntesis y aplicaciones de pnictógenos 2D de alta calidad: antimoneno y bismuteno

Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Inórganica. Fecha de Lectura: 20-04-2022The scientific community's interest in two-dimensional (2D) materials has been increasing since the appearance of graphene. Among the great variety of these nanomaterials, the elements of group 15 have attracted increasing attention due to their outstanding physical and chemical properties and their potential technological applications ranging from electronics to medicine. However, obtaining these materials in large quantities with the necessary quality remains challenging. For this reason, in this PhD Thesis, different production methods of these materials have been explored, analyzing the synthetic parameters and the quality of the obtained materials exhaustively. The introduction of this work aims to give a state-of-the-art overview of the large variety of 2D materials that currently exist, focusing on the elements of group 15 of the periodic table, and more specifically on antimonene and bismuthene, which are the main objectives of this work. This section points out the exceptional properties that these materials present compared to their bulk counterparts. In addition, a vision of the different approaches that can be followed for the preparation of these materials is given, and several examples of their use in a broad range of applications. The first work presented in this book describes the optimization of the liquid phase exfoliation process to obtain few-layer antimonene nanosheets. A selection of the experimental parameters affecting the preparation process has been analyzed to obtain high-quality suspensions in high concentrations. In the second study, chemical synthesis is used for the production of highquality antimonene nanolayers. To this end, the reaction parameters working in a discontinuous process have been analyzed, and the morphological and structural characteristics of the obtained material. Likewise, the same process is presented in a continuous flow procedure, which is developed to increase the yield of the reaction. Finally, the mechanical and electrical properties of the synthesized antimonene nanosheets are analyzed. The third work describes a procedure to synthesize bismuthene nanosheets of hexagonal shape using a colloidal synthesis approach. This new method is carried out through a two-step process under moderate conditions. In this study, the analysis of the synthetic parameters and an in-depth characterization of the obtained material is carried out. Finally, two additional works have been carried out with the aim to show the potential of these 2D materials as biosensors. The first study shows the modification of gold electrodes with antimonene nanosheets and the fabrication of simple devices able to detect mutations in specific sequences of DNA. The second study describes the fabrication of NADH biosensors by modifying graphene electrodes with bismuthene nanosheets. These two works suggest the high potential of these novel 2D materials for selected application

Switching TNF antagonists in patients with chronic arthritis: An observational study of 488 patients over a four-year period

The objective of this work is to analyze the survival of infliximab, etanercept and adalimumab in patients who have switched among tumor necrosis factor (TNF) antagonists for the treatment of chronic arthritis. BIOBADASER is a national registry of patients with different forms of chronic arthritis who are treated with biologics. Using this registry, we have analyzed patient switching of TNF antagonists. The cumulative discontinuation rate was calculated using the actuarial method. The log-rank test was used to compare survival curves, and Cox regression models were used to assess independent factors associated with discontinuing medication. Between February 2000 and September 2004, 4,706 patients were registered in BIOBADASER, of whom 68% had rheumatoid arthritis, 11% ankylosing spondylitis, 10% psoriatic arthritis, and 11% other forms of chronic arthritis. One- and two-year drug survival rates of the TNF antagonist were 0.83 and 0.75, respectively. There were 488 patients treated with more than one TNF antagonist. In this situation, survival of the second TNF antagonist decreased to 0.68 and 0.60 at 1 and 2 years, respectively. Survival was better in patients replacing the first TNF antagonist because of adverse events (hazard ratio (HR) for discontinuation 0.55 (95% confidence interval (CI), 0.34-0.84)), and worse in patients older than 60 years (HR 1.10 (95% CI 0.97-2.49)) or who were treated with infliximab (HR 3.22 (95% CI 2.13-4.87)). In summary, in patients who require continuous therapy and have failed to respond to a TNF antagonist, replacement with a different TNF antagonist may be of use under certain situations. This issue will deserve continuous reassessment with the arrival of new medications. © 2006 Gomez-Reino and Loreto Carmona; licensee BioMed Central Ltd