Nanotechnology meets immunology towards a rapid diagnosis solution: the COVID-19 outbreak challenge† † Electronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d2ra05096j

The current COVID-19 pandemic presents one of the greatest challenges in human history. There is a consensus that the rapid and accurate diagnosis of COVID-19 directly affects procedures to avoid dissemination, promote treatments, and favor the prognosis of infected patients. This interdisciplinary study aims at designing new synthetic peptides inspired by the SARS-CoV-2 spike protein (SARS-CoV-2S) to produce rapid detection tests relying on nanomaterial-based colorimetric properties. Hence, in silico analyses of SARS-CoV-2S were performed using advanced bioinformatic simulation tools and algorithms. Five novel peptide sequences were proposed, and three were selected (P2, J4, and J5) based on their prospective reactivity against positive serum from naturally COVID-19-infected humans. Next, hyperimmune sera against the selected peptides were produced in rabbits. Concurrently, gold nanoparticles (AuNP) were synthesized using a green aqueous method under mild conditions through in situ reduction by trisodium citrate salt. They were extensively characterized by their morphological, physicochemical, and optical properties. The AuNPs demonstrated colloidal chemical stability in aqueous media, with an average size of approximately 29 nm (metallic core), and zeta potential before and after bioconjugation of −43 mV and −31 mV, respectively. Moreover, they presented an intense reddish-bluish color due to the surface plasmon resonance (SPR) effect, with maxima at λ = 525 nm and 536 nm, before and after bioconjugation, respectively, evidencing their applicability as colorimetric biomarkers for antigen–antibody immunoassay detection. To develop a rapid COVID-19 diagnosis test using lateral flow assay (LFA), semi-purified anti-SARS-CoV-2S sera against the three selected peptides were bioconjugated to the AuNPs as the highly optically sensitive agents using a considerably low antibody concentration (0.2 mg mL−1). All tested peptide sequences (P2, J4, and J5) induced antibodies capable of identifying the presence of SARS-CoV-2 virus inactivate suspensions (1 : 10, 1 : 100, or 1 : 1000 dilutions). For LFA positive test control, an anti-rabbit antibody was used. In summary, this research comprises several contributions and advances to the broad and multidisciplinary field of nanomaterials-based immunodiagnosis tools, encompassing: (a) the novelty of designing and synthesizing new immunogenic peptides inspired by SARS-CoV-2 virus epitopes using in silico bioinformatics;(b) the peptides induced the immune response in rabbit animal model producing hyperimmune serum;(c) the semi-purified hyperimmune serum rendered effective antibodies to detect SARS-CoV-2 virus in cell suspension;(d) colloidal gold nanoparticles were produced and bioconjugated to the antibodies for qualitative colorimetric detection. As the overall result of this study, it was designed, developed, produced, and validated a new simple, rapid, and sensitive LFA diagnostic test for the SARS-CoV-2 virus using a nanotechnology-based qualitative colorimetric assay, which can be envisioned as promising nanoplatforms for detecting other diseases. The current COVID-19 pandemic presents one of the greatest challenges in human history.

Bibliometric Analysis Of Research on Coronavirus Infection and Patient Safety in Health Care

Objective: The study aimed at analyzing the international scientific publications on coronavirus infection and patient safety in health care. Methods: This research is a bibliometric study carried out by searching published articles in theISIWebofKnowledge/WebofScience database and analyzing the results through bibliometric analysis software HistCite. The selected time frame was between 1970 and 2020, and we used the following descriptors: “coronavirus infection” OR “severe acute respiratory syndrome” OR “COVID-19/SARS-CoV-2”. Results: We found 5,434 publications in 1,491 different journals;they are written by 18,274 authors linked to 4,064 institutions, which are located in 104 countries. In the citations analysis, the h-index was 155, and the average of citations each article received was 30.79. Conclusion: During the studied period, the Web of Science database showed two peaks of publications on coronavirus infections.The first comprised 768 articles published between 2003 and 2004 when a new coronavirus caused an outbreak of severe acute respiratory failure. The second consisted of 576 articles published between 2019 and 2020, during the period of the COVID-19 pandemic COVID-19. The knowledge on coronavirus infection should be widely shared so that new studies can be designed and the world scientific community can contribute to improving patient safety in healthcare and preventing new pandemics of severe acute respiratory infection caused by coronaviruses. © 2021 Nascimento et al.

The social construction of urban climates and its relation to the covid-19 pandemic in Santiago de Chile

Santiago de Chile, like all Latin American cities, registers important socioclimatic differences in its interior that result from the appropriation, privatization, and commoditization of climates due to the lack of adequate urban planning and management and the exercise of power by the real estate market, characterizing a study object proper of critical physical geography. Surface temperature conditions, land covers and uses, urban morphology and ventilation simulations at neighborhood scales represent significant levels of environmental segregation and injustice inside the city. The conditions of origin and diffusion of the Covid-19 pandemic are spatially correlated with such urban climatic differences and with socioeconomic determinants that have been built together with the city that require specific and massive public actions to reverse the current scenario of socioclimatic unsustainability and injustice. © 2021, Universidad Nacional de Colombia. All rights reserved.