A 3D-printed tumor-on-chip: user-friendly platform for the culture of breast cancer spheroids and the evaluation of anti-cancer drugs.

Tumor-on-chips (ToCs) are useful platforms for studying the physiology of tumors and evaluating the efficacy and toxicity of anti-cancer drugs. However, the design and fabrication of a ToC system is not a trivial venture. We introduce a user-friendly, flexible, 3D-printed microfluidic device that can be used to culture cancer cells or cancer-derived spheroids embedded in hydrogels under well-controlled environments. The system consists of two lateral flow compartments (left and right sides), each with two inlets and two outlets to deliver cell culture media as continuous liquid streams. The central compartment was designed to host a hydrogel in which cells and microtissues can be confined and cultured. We performed tracer experiments with colored inks and 40 kDa fluorescein isothiocyanate dextran to characterize the transport/mixing performances of the system. We also cultured homotypic (MCF7) and heterotypic (MCF7-BJ) spheroids embedded in gelatin methacryloyl hydrogels to illustrate the use of this microfluidic device in sustaining long-term micro-tissue culture experiments. We further demonstrated the use of this platform in anticancer drug testing by continuous perfusion of doxorubicin, a commonly used anti-cancer drug for breast cancer. In these experiments, we evaluated drug transport, viability, glucose consumption, cell death (apoptosis), and cytotoxicity. In summary, we introduce a robust and friendly ToC system capable of recapitulating relevant aspects of the tumor microenvironment for the study of cancer physiology, anti-cancer drug transport, efficacy, and safety. We anticipate that this flexible 3D-printed microfluidic device may facilitate cancer research and the development and screening of strategies for personalized medicine.

Self-Diagnosis of SARS-CoV-2 from Saliva Samples at Home: Isothermal Amplification Enabled by Do-It-Yourself Portable Incubators and Laminated Poly-ethyl Sulfonate Membranes.

COVID-19 made explicit the need for rethinking the way in which we conduct testing for epidemic emergencies. During the COVID-19 pandemic, the dependence on centralized lab facilities and resource-intensive methodologies (e.g., RT-qPCR methods) greatly limited the deployment of widespread testing efforts in many developed and underdeveloped countries. Here, we illustrate the development of a simple and portable diagnostic kit that enables self-diagnosis of COVID-19 at home from saliva samples. We describe the development of a do-it-yourself (DIY) incubator for Eppendorf tubes that can be used to conduct SARS-CoV-2 detection with competitive sensitivity and selectivity from saliva at home. In a proof-of-concept experiment, we assembled Eppendorf-tube incubators at our home shop, prepared a single-tube mix of reagents and LAMP primers in our lab, and deployed these COVID-19 detection kits using urban delivery systems (i.e., Rappifavor or Uber) to more than 15 different locations in Monterrey, México. This straightforward strategy enabled rapid and cost-effective at-home molecular diagnostics of SARS-CoV-2 from real saliva samples with a high sensitivity (100%) and high selectivity (87%).

Keratoconus Frequency and Associated Risk Factors Among Patients Younger Than 18 Years With Significant Refractive Errors.

INTRODUCTION: Keratoconus is an ectatic corneal disorder that causes low vision secondary to high myopia, irregular astigmatism, and loss of corneal transparency. In children, the disease behaves aggressively, progresses rapidly, is diagnosed at advanced stages, and presents an increased risk for corneal transplantation; however, only few studies in children have been conducted. PURPOSE: The aims of this study were to determine the frequency of keratoconus in patients younger than 18 years who underwent the Pentacam study because of high myopia or high astigmatism in the oblique axis, analyze topographic criteria and classify them into severity groups, and identify associated risk factors. METHODS: This was a retrospective observational cross-sectional study in which Pentacam examinations were analyzed. Frequency of keratoconus was determined and patients were classified according to visual acuity and severity scales. Medical records were reviewed to identify associated risk factors. RESULTS: Four hundred twenty-six patients younger than 18 years were included, 40 (9.4%) had keratoconus according to Pentacam criteria. The mean age at diagnosis was 14.9 years, with male predilection (75%). Atopy was the only statistically significant risk factor, present in 85%. Family history was present in 7.5%. There were no differences in the distribution in groups according to visual acuity or Amsler-Krumeich scale. Most frequent ABCD classification was A2 (35.6%), B4 (47.9%), and C0 (35.6%), posterior curvature radius being a significant severity criterion. CONCLUSIONS: The study found that frequency of keratoconus in children is higher than previously reported. Atopy has a clear and possible causal association. Early detection should be sought to reduce the risk of progression. Pentacam is a fundamental tool for early diagnosis using simple criteria.

Antecedentes y concepciones actuales del proceso de formación del especialista en dermatología

Introducción: La historia de la dermatología se encuentra estrechamente ligada al desarrollo de la medicina. Objetivo: Exponer una fundamentación teórica de los antecedentes y concepciones actuales del proceso de formación del especialista en dermatología. Métodos: Se realizó una investigación de tipo histórico-descriptiva. Se emplearon métodos del nivel teórico: histórico-lógico y analítico-sintético; métodos del nivel empírico: análisis de documentos y observación. Resultados: El proceso formativo ha transitado desde una concepción basada fundamentalmente en el uso de hospitales-escuelas como escenarios docentes, espontánea y fragmentada, hasta un proceso formativo esencialmente con actividades prácticas, con una vinculación real con los problemas de la profesión, y la estructuración de un programa que expresa los modos de actuación profesional para conformar el perfil ocupacional en los puestos de trabajo. Conclusiones: Las inconsistencias teóricas y metodológicas reveladas en el proceso de formación del especialista en dermatología conllevan a la integración del método clínico; y los procedimientos en la práctica de laboratorio, hacia la interdisciplinariedad, la sistematización de contenidos y la apropiación de métodos investigativos, que, puestos en práctica, desarrollan las habilidades y los conocimientos en ese proceso de formación.

Introduction: The history of dermatology is closely linked to the development of medicine. Objective: To present the theoretical foundations concerning the antecedents and current conceptions of the training process of dermatology specialists. Methods: A historical-descriptive research was carried out. Theoretical methods were used: historical-logical and analytical-synthetic; as well as empirical methods: analysis of documents and observation. Results: The training process has transited from a spontaneous and fragmented conception, based fundamentally on the use of hospitals-schools as teaching scenarios, to a training process essentially with practical activities, with a real link to the problems of the profession, as well as the structuring of a program that expresses the modes of professional performance to make up the occupational profile of respective jobs. Conclusions: The theoretical and methodological inconsistencies revealed in the training process of the dermatology specialist lead to the integration of the clinical method; while the procedures within laboratory practice lead towards interdisciplinarity, systematization of contents and appropriation of research methods, which, put into practice, develop skills and knowledge in that training process.

Sistema de procedimientos para la formación interdisciplinar de la habilidad diagnosticar en residentes de dermatología / A System of Procedures for the Interdisciplinary Training of the Dill To Diagnose in Dermatology Residents

Introducción: En las prácticas de laboratorio se adquiere la habilidad que permite corroborar el diagnóstico de las enfermedades de la piel y anejos después de un diagnóstico presuntivo, con la utilización del método clínico. Esto se respalda en las exigencias establecidas en los documentos normativos de ese proceso formativo. Objetivo: Proponer un sistema de procedimientos para la formación interdisciplinar de la habilidad "diagnosticar enfermedades dermatológicas en los residentes de dermatología, a partir de insuficiencias detectadas en el programa de la especialidad. Métodos: La investigación fue cualitativa, con un estudio descriptivo en el Hospital Provincial General Docente Dr. Antonio Luaces Iraola, de Ciego de Ávila, desde 2018 hasta 2022. Se trabajó con toda la población conformada por 16 residentes de primer año en dermatología. Se utilizaron métodos de nivel teórico, empírico y estadístico. Resultados: En el sistema de procedimientos propuesto, se concretan fortalezas y debilidades, objetivo general, orientaciones metodológicas, precisión de los objetivos específicos y sistema de acciones para cada procedimiento, y sistema de control y evaluación de la efectividad de las acciones realizadas. La demostración de la formación de la habilidad diagnosticar, a través de un caso clínico real, reveló como esencial la consecutividad lógica de las acciones del residente desde la atención médica del caso y la formulación del diagnóstico presuntivo hasta el establecimiento del diagnóstico corroborativo en los laboratorios de anatomía patológica, microbiología y parasitología médica. Conclusiones: Se aporta un sistema de procedimientos que posibilita la formación de la habilidad "diagnosticar enfermedades dermatológicas en los residentes, con carácter secuencial, interdisciplinar e investigativo(AU)

Introduction: Laboratory practices provide the ability that allows corroborating the diagnosis of skin and adnexal diseases after a presumptive diagnosis, with the use of the clinical method. This is supported by the requirements established in the standardization documents of this training process. Objective: To propose a system of procedures for the interdisciplinary training of the skill to diagnose dermatological diseases in Dermatology residents, based on insufficiencies detected in the specialty program. Methods: The research was qualitative and consisted in a descriptive study carried out in Hospital General Docente Dr. Antonio Luaces Iraola, of Ciego de Avila, from 2018 to 2022. The work was done with the entire population made up of 16 first-year residents in Dermatology. Theoretical, empirical and statistical methods were used. Results: In the proposed system of procedures, strengths and weaknesses are specified, together with general objective, methodological guidelines, precision of specific objectives and system of actions for each procedure, as well as system of control and evaluation of the effectiveness of the actions. Demonstrating the received formation for the diagnostic skill, through a real clinical case, revealed as essential the logical consecutivity of the resident's actions from the medical attention of the case and the formulation of the presumptive diagnosis to the establishment of the corroborative diagnosis in the laboratories of pathological anatomy, microbiology and medical parasitology. Conclusions: A system of procedures is provided that makes possible the formation of the skill to diagnose dermatological diseases in residents, with sequential, interdisciplinary and investigative character(AU)

Nitrogen-functionalized graphene quantum dot incorporated GelMA microgels as fluorescent 3D-tissue Constructs.

Biopolymer microgels present many opportunities in biomedicine and tissue engineering. To understand their in vivo behavior in therapeutic interventions, long-term monitoring is critical, which is usually achieved by incorporating fluorescent materials within the hydrogel matrix. Current research is limited due to issues concerning the biocompatibility and instability of the conventional fluorescent species, which also tend to adversely affect the bio-functionality of the hydrogels. Here, we introduce a microfluidic-based approach to generate nitrogen-functionalized graphene quantum dot (NGQD) incorporated gelatin methacryloyl (GelMA) hydrogel microspheres, capable of long-term monitoring while preserving or enhancing the other favorable features of 3D cell encapsulation. A multilayer droplet-based microfluidic device was designed and fabricated to make monodisperse NGQD-loaded GelMA hydrogel microspheres encapsulating skeletal muscle cells (C2C12). Control over the sizes of microspheres could be achieved by tuning the flow rates in the microfluidic device. Skeletal muscle cells encapsulated in these microgels exhibited high cell viability from day 1 (82.9 ± 6.50%) to day 10 (92.1 ± 3.90%). The NGQD-loaded GelMA microgels encapsulating the cells demonstrated higher metabolic activity compared to the GelMA microgels. Presence of sarcomeric α-actin was verified by immunofluorescence staining on day 10. A fluorescence signal was observed from the NGQD-loaded microgels during the entire period of the study. The investigation reveals the advantages of integrating NGQDs in microgels for non-invasive imaging and monitoring of cell-laden microspheres and presents new opportunities for future therapeutic applications.

3D-Printed Tumor-on-Chip for the Culture of Colorectal Cancer Microspheres: Mass Transport Characterization and Anti-Cancer Drug Assays.

Tumor-on-chips have become an effective resource in cancer research. However, their widespread use remains limited due to issues related to their practicality in fabrication and use. To address some of these limitations, we introduce a 3D-printed chip, which is large enough to host ~1 cm3 of tissue and fosters well-mixed conditions in the liquid niche, while still enabling the formation of the concentration profiles that occur in real tissues due to diffusive transport. We compared the mass transport performance in its rhomboidal culture chamber when empty, when filled with GelMA/alginate hydrogel microbeads, or when occupied with a monolithic piece of hydrogel with a central channel, allowing communication between the inlet and outlet. We show that our chip filled with hydrogel microspheres in the culture chamber promotes adequate mixing and enhanced distribution of culture media. In proof-of-concept pharmacological assays, we biofabricated hydrogel microspheres containing embedded Caco2 cells, which developed into microtumors. Microtumors cultured in the device developed throughout the 10-day culture showing >75% of viability. Microtumors subjected to 5-fluorouracil treatment displayed <20% cell survival and lower VEGF-A and E-cadherin expression than untreated controls. Overall, our tumor-on-chip device proved suitable for studying cancer biology and performing drug response assays.

Cuidado de la vida y salud pública / Life care and public health

Entre los días 17 y 19 de noviembre de 2022 se realizó el 18° Coloquio de Investigación en Salud Pública en el Centro de Estudios en Salud de la Universidad de Nariño (CESUN) de la Universidad de Nariño. Este es un evento anual que se lleva a cabo por iniciativa del Doctorado Interfacultades en Salud Pública de la Universidad Nacional de Colombia, pero cada vez más participan escuelas de formación de investigadores(as) en el campo de la salud pública de todo el país y, recientemente, algunas de México.

Concepción didáctica del proceso formativo interdisciplinar de la habilidad diagnosticar enfermedades para residentes de Dermatología / Didactic Concept of the Interdisciplinary Formation Process of the Diagnostic Ability of Dermatology Residents

Fundamento: El estudio teórico, el diagnóstico realizado y la experiencia de los investigadores, posibilitan formular como problema de la presente investigación: limitaciones en el desarrollo de la habilidad diagnosticar enfermedades dermatológicas en los residentes de la especialidad de Dermatología del Hospital General Provincial Docente "Dr. Antonio Luaces Iraola" de Ciego de Ávila. Objetivo: Elaborar una concepción didáctica del proceso de formación interdisciplinar de la habilidad diagnosticar enfermedades dermatológicas en los residentes de la especialidad de Dermatología, a partir de la caracterización del estado actual de esta habilidad. Metodología: Se realizó una investigación educativa con un componente descriptivo en el Hospital General Provincial Docente "Dr. Antonio Luaces Iraola" de Ciego de Ávila, en los cursos escolares desde 2016 al 2020. La población de estudio fueron los 16 residentes de 1.er año que matricularon la especialidad de Dermatología en el período de estudio. Se emplearon métodos del nivel teórico y empírico. Resultados: La caracterización realizada reveló limitaciones en el desarrollo de la habilidad diagnosticar enfermedades dermatológicas en los laboratorios de Anatomía Patológica, Microbiología y Parasitología Médica, por los residentes (100 %). La concepción didáctica del proceso de formación interdisciplinar de la habilidad diagnosticar orienta el proceso desde las actividades docentes-atencionales y prácticas de laboratorio en una consecutividad lógica y sistematización desde las diferentes formas de enseñanza y tipologías de clase. Integra la interdisciplinariedad y la utilización del método investigativo establecido en las ideas rectoras. Conclusiones: La concepción didáctica como aporte de la investigación resuelve la contradicción dialéctica entre la aplicación del método clínico y los procedimientos en la práctica de laboratorio que se da en ese proceso formativo y constituye un soporte didáctico que respalda las actividades prácticas en los laboratorios para cumplir con los objetivos del Plan de estudio de la especialidad.

Background: The theoretical study, the diagnosis conducted and the experience of the researchers make possible to formulate the problem of the present research: limitations in the development of the ability to diagnose dermatological diseases in residents of the Specialty of Dermatology of the General Provincial Teaching Hospital "Dr. Antonio Luaces Iraola" of Ciego de Avila. Objective: To elaborate a didactic conception of the interdisciplinary training process of the ability to diagnose dermatological diseases in residents of the specialty of Dermatology, based on the characterization of the current state of that ability. Methodology: An educational research with a descriptive component was conducted at the Provincial General Teaching Hospital "Dr. Antonio Luaces Iraola" of Ciego de Avila, in the 2016-2020 school years. The study population consisted of the 16 first-year dermatology residents who enrolled in the specialty during the study period. Results: The characterization conducted showed limitations in the development of the ability to diagnose dermatological diseases in anatomic pathology laboratories, Microbiology and Medical Parasitology, by residents (100%). The didactic conception of the interdisciplinary training process of diagnostic ability focuses on teaching and learning activities and laboratory practices in a logical consecutiveness and systematization from the different forms of teaching and class typologies. It integrates the interdisciplinary and the use of the research method that is established in the guiding ideas. Conclusions: The didactic conception, as a research contribution, resolves the dialectic contradiction between the application of the clinical method and the procedures in laboratory practice that occurs in this formative process which is a didactic support that backs up the practical activities in the laboratories in order to achieve the objectives of the study plan of the specialty.

Structural and biological engineering of 3D hydrogels for wound healing.

Chronic wounds have become one of the most important issues for healthcare systems and are a leading cause of death worldwide. Wound dressings are necessary to facilitate wound treatment. Engineering wound dressings may substantially reduce healing time, reduce the risk of recurrent infections, and reduce the disability and costs associated. In the path of engineering of an ideal wound dressing, hydrogels have played a leading role. Hydrogels are 3D hydrophilic polymeric structures that can provide a protective barrier, mimic the native extracellular matrix (ECM), and provide a humid environment. Due to their advantages, hydrogels (with different architectural, physical, mechanical, and biological properties) have been extensively explored as wound dressing platforms. Here we describe recent studies on hydrogels for wound healing applications with a strong focus on the interplay between the fabrication method used and the architectural, mechanical, and biological performance achieved. Moreover, we review different categories of additives which can enhance wound regeneration using 3D hydrogel dressings. Hydrogel engineering for wound healing applications promises the generation of smart solutions to solve this pressing problem, enabling key functionalities such as bacterial growth inhibition, enhanced re-epithelialization, vascularization, improved recovery of the tissue functionality, and overall, accelerated and effective wound healing.

Gelatin-methacryloyl hydrogels containing turnip mosaic virus for fabrication of nanostructured materials for tissue engineering.

Current tissue engineering techniques frequently rely on hydrogels to support cell growth, as these materials strongly mimic the extracellular matrix. However, hydrogels often need ad hoc customization to generate specific tissue constructs. One popular strategy for hydrogel functionalization is to add nanoparticles to them. Here, we present a plant viral nanoparticle the turnip mosaic virus (TuMV), as a promising additive for gelatin methacryloyl (GelMA) hydrogels for the engineering of mammalian tissues. TuMV is a flexuous, elongated, tubular protein nanoparticle (700-750 nm long and 12-15 nm wide) and is incapable of infecting mammalian cells. These flexuous nanoparticles spontaneously form entangled nanomeshes in aqueous environments, and we hypothesized that this nanomesh structure could serve as a nanoscaffold for cells. Human fibroblasts loaded into GelMA-TuMV hydrogels exhibited similar metabolic activity to that of cells loaded in pristine GelMA hydrogels. However, cells cultured in GelMA-TuMV formed clusters and assumed an elongated morphology in contrast to the homogeneous and confluent cultures seen on GelMA surfaces, suggesting that the nanoscaffold material per se did not favor cell adhesion. We also covalently conjugated TuMV particles with epidermal growth factor (EGF) using a straightforward reaction scheme based on a Staudinger reaction. BJ cells cultured on the functionalized scaffolds increased their confluency by approximately 30% compared to growth with unconjugated EGF. We also provide examples of the use of GelMA-TuMV hydrogels in different biofabrication scenarios, include casting, flow-based-manufacture of filaments, and bioprinting. We envision TuMV as a versatile nanobiomaterial that can be useful for tissue engineering.

Polyphenols and Flavonoids Composition, Anti-Inflammatory and Antioxidant Properties of Andean Baccharis macrantha Extracts.

This study examined the leaves of Baccharis macrantha to obtain extracts of Baccharis macrantha (EBM) and to determine the total flavonoid content (TFC) and the total polyphenol content (TPC). The main objective of this work was to quantify TPC and TFC of extracts of B. macrantha from Ecuador and evaluate its antioxidant and anti-inflammatory activities and inhibition of lipid peroxidation. The extraction method was optimized with solvents, ethanol, and methanol, at temperatures of 30-60 °C and extraction times of 5-20 min. The optimal TFC extraction conditions were at EtOH25% at 50 °C for 10 min. The optimal TPC extraction conditions were at EtOH50% at 50 °C for 10 min. EBM was characterized by TLC and HPLC with three standards: gallic acid, catechin, and quercetin. EBM-EtOH25% and EBM-EtOH50% obtained at 50 °C for 10 min were used to identify quercetin and evaluate biologicals activities. Quercetin was detected in EBM (EtOH25% and EtOH50%). EBM anti-inflammatory activity was evaluated with the red blood cell stabilization (RBC) method. The RBC model showed values of 49.72% of protection lysis RBC to EBM-EtOH25% and 50.71% of protection lysis RBC to EBM-EtOH50%. The EBM in vitro inhibition of lipid peroxidation showed a protection of 77.00% (EtOH25%) and 73.11% (EtOH50%) when the TBARs method was used. EBM-EtOH25% and EtOH50% showed high antioxidant activity. EBM-EtOH25% presented values of ABTS (1172 µmol TE/g EBM), DPPH (836 µmol TE/g, EBM), and FRAP (85.70 µmol TE/g, EBM).

nurP28, a New-to-Nature Zein-Derived Peptide, Enhances the Therapeutic Effect of Docetaxel in Breast Cancer Monolayers and Spheroids.

The development of novel cancer therapeutic strategies has garnered increasing interest in cancer research. Among the therapeutic choices, chemosensitizers have shown exciting prospects. Peptides are an attractive alternative among the molecules that may be used as chemosensitizers. We rationally designed a new-to-nature peptide, nurP28, derived from the 22-kDa α-zein protein sequence (entry Q00919_MAIZE). The resultant sequence of the nurP28 peptide after the addition of arginine residues was LALLALLRLRRRATTAFIIP, and we added acetyl and amide groups at the N- and C-terminus, respectively, for capping. We evaluated the cytotoxicity of the nurP28 peptide alone and in combination with docetaxel in fibroblast monolayers and breast cancer monolayers and spheroids. Our results indicated that nurP28 is not cytotoxic to human fibroblasts or cancer cells. Nevertheless, when combined with 1 µM docetaxel, 3 ng/mL nurP28 induced equivalent (in MCF7 monolayers) and higher (in MCF7 spheroids) cytotoxic effects than 10-fold higher doses of docetaxel alone. These findings suggest that nurP28 may act as a chemosensitizer in breast cancer treatment. This study describes the enhancing "anti-cancer" effects of nurP28 in breast cancer 2D and 3D cultures treated with docetaxel. Further studies should explore the mechanisms underlying these effects and assess the clinical potential of our findings using animal models.

Fractured lives in fractured cities: Towards a critical understanding of urban violence in the context of market-driven urban restructuring processes in Bogotá and Rio de Janeiro.

Based on a comparative case study on two neighborhoods in Bogota and Rio de Janeiro (2017-2019) and a comprehensive literature review, this article proposes a critical Public Health approach to urban violence and makes a case for understanding the phenomenon in the context of market-driven urban territorial restructuring processes that assume specific qualities in cities of the Global South. The case studies are based on focus groups and semi-structured interviews with residents, specialists and community leaders. It is argued that urban violence is a key public health challenge, particularly in Latin America, given its dimensions and its impact on the populations' life and health. In this regard it configures "fractured lives" in what urban scholars have termed "fractured cities" - essentially unequal and polarized cities that are not merely sites of urban violence but, as we argue in this article, fundamentally shape urban violence, its qualities, dynamics and dimensions. The study is informed by a unique theoretical articulation between Latin American Social Medicine and Collective Health, critical (Latin American) geographical theory and authoritarian neoliberalism literature and shows how urban violence is directly implied in the territorial making and un-making of the cities, driven by commodification as well as both legal and illegal capitalist market logics, that include but are not limited to drug trade. The cases reflect the violence implied in permanent threats of eviction and displacement, "necropolitical" police/military interventions and what is described as a silent imposition of a "slow death" on infrastructure, the neighborhood and ultimately also its residents, which "fracture" the lives of significant parts of the urban population, produce "ill-being" and bring about health consequences that are rarely considered in relation to urban violence.

Riesgo trombo génico en el aleteo auricular determinado con ecocardiografía transesofágica / Thrombogenic risk in atrial flutter determined by transesophageal echocardiography

Introducción: Los factores de riesgo trombo génico en pacientes con aleteo auricular (AA) no estan todavía claros, hay datos muy variables en trabajos con pocas personas que padecen este mal. Conclusiones: Los principales factores trombo génicos en el AA son la presencia de CE, VV menores a 30 cm/s, VL menores a 20 cm/s y el NR fuera de rango.

Acquired insights from the long-term surveillance of SARS-CoV-2 RNA for COVID-19 monitoring: The case of Monterrey Metropolitan Area (Mexico).

Wastewater-based epidemiology offers a time- and cost-effective way to monitor SARS-CoV-2 spread in communities and therefore represents a complement to clinical testing. WBE applicability has been demonstrated in a number of cases over short-term periods as a method for tracking the prevalence of SARS-CoV-2 and an early-warning tool for predicting outbreaks in the population. This study reports SARS-CoV-2 viral loads from wastewater treatment plants (WWTPs) and hospitals over a 6-month period (June to December 2020). Results show that the overall range of viral load in positive tested samples was between 1.2 × 103 and 3.5 × 106 gene copies/l, unveiling that secondary-treated wastewaters mirrored the viral load of influents. The interpretation suggests that the viral titers found in three out of four WWTPs were associated to clinical COVID-19 surveillance indicators preceding 2-7 days the rise of reported clinical cases. The median wastewater detection rate of SARS-CoV-2 was one out of 14,300 reported new cases. Preliminary model estimates of prevalence ranged from 0.02 to 4.6% for the studied period. This comprehensive statistical and epidemiological analysis demonstrates that the applied wastewater-based approach to COVID-19 surveillance is in general consistent and feasible, although there is room for improvements.

Low-Cost Light-Based GelMA 3D Bioprinting via Retrofitting: Manufacturability Test and Cell Culture Assessment.

Light-based bioprinter manufacturing technology is still prohibitively expensive for organizations that rely on accessing three-dimensional biological constructs for research and tissue engineering endeavors. Currently, most of the bioprinting systems are based on commercial-grade-based systems or modified DIY (do it yourself) extrusion apparatuses. However, to date, few examples of the adoption of low-cost equipment have been found for light-based bioprinters. The requirement of large volumes of bioinks, their associated cost, and the lack of information regarding the parameter selection have undermined the adoption of this technology. This paper showcases the retrofitting and assessing of a low-cost Light-Based 3D printing system for tissue engineering. To evaluate the potential of a proposed design, a manufacturability test for different features, machine parameters, and Gelatin Methacryloyl (GelMA) concentrations for 7.5% and 10% was performed. Furthermore, a case study of a previously seeded hydrogel with C2C12 cells was successfully implemented as a proof of concept. On the manufacturability test, deviational errors were found between 0.7% to 13.3% for layer exposure times of 15 and 20 s. Live/Dead and Actin-Dapi fluorescence assays after 5 days of culture showed promising results in the cell viability, elongation, and alignment of 3D bioprinted structures. The retrofitting of low-cost equipment has the potential to enable researchers to create high-resolution structures and three-dimensional in vitro models.

Portable and Label-Free Quantitative Loop-Mediated Isothermal Amplification (LF-qLamp) for Reliable COVID-19 Diagnostics in Three Minutes of Reaction Time: Arduino-Based Detection System Assisted by a pH Microelectrode.

Loop-mediated isothermal amplification (LAMP) has been recently studied as an alternative method for cost-effective diagnostics in the context of the current COVID-19 pandemic. Recent reports document that LAMP-based diagnostic methods have a comparable sensitivity and specificity to that of RT-qPCR. We report the use of a portable Arduino-based LAMP-based amplification system assisted by pH microelectrodes for the accurate and reliable diagnosis of SARS-CoV-2 during the first 3 min of the amplification reaction. We show that this simple system enables a straightforward discrimination between samples containing or not containing artificial SARS-CoV-2 genetic material in the range of 10 to 10,000 copies per 50 µL of reaction mix. We also spiked saliva samples with SARS-CoV-2 synthetic material and corroborated that the LAMP reaction can be successfully monitored in real time using microelectrodes in saliva samples as well. These results may have profound implications for the design of real-time and portable quantitative systems for the reliable detection of viral pathogens including SARS-CoV-2.

Fabrication of Multilayered Composite Nanofibers Using Continuous Chaotic Printing and Electrospinning: Chaotic Electrospinning.

Multi-material and multilayered micro- and nanostructures are prominently featured in nature and engineering and are recognized by their remarkable properties. Unfortunately, the fabrication of micro- and nanostructured materials through conventional processes is challenging and costly. Herein, we introduce a high-throughput, continuous, and versatile strategy for the fabrication of polymer fibers with complex multilayered nanostructures. Chaotic electrospinning (ChE) is based on the coupling of continuous chaotic printing (CCP) and electrospinning, which produces fibers with an internal multi-material microstructure. When a CCP printhead is used as an electrospinning nozzle, the diameter of the fibers is further scaled down by 3 orders of magnitude while preserving their internal structure. ChE enables the use of various polymer inks for the creation of nanofibers with a customizable number of internal nanolayers. Our results showcase the versatility and tunability of ChE to fabricate multilayered structures at the nanoscale at high throughput. We apply ChE to the synthesis of unique carbon textile electrodes composed of nanofibers with striations carved into their surface at regular intervals. These striated carbon electrodes with high surface areas exhibit 3- to 4-fold increases in specific capacitance compared to regular carbon nanofibers; ChE holds great promise for the cost-effective fabrication of electrodes for supercapacitors and other applications.

Azadirachta indica Leaf Extract as Green Corrosion Inhibitor for Reinforced Concrete Structures: Corrosion Effectiveness against Commercial Corrosion Inhibitors and Concrete Integrity.

The construction industry has extensively demanded novel green inhibition strategies for the conservation and protection of carbon steel-reinforced concrete structures. For the first time, the effect of Azadirachta indica leaf extract (Neem) as a potential corrosion inhibitor of carbon steel in reinforced concrete under corrosion in saline simulated media was evaluated. To assess the corrosion inhibition behavior of the Neem natural organic extract, three inorganic commercial inhibitors were tested to compare following the criteria established by Stratful for half-cell potential under a simulated chloride environment. Moreover, the effect of concrete integrity by the Neem treatment was recorded after different temperature conditions, slump, weight alteration, air content, compressive strength, and chloride-ions penetration. The results suggested that the Neem treatments did not alter the concrete integrity and the physicochemical parameters. We reached a promoted long-term corrosion protection of 95% after 182 days of evaluation. Thus far, our current results open up a new promising "green" road to the conservation of carbon steel in reinforced concrete for the construction industry.