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Enterococcus is a bacterial genus that is strongly associated with nosocomial infections and has a high capacity to transfer and acquire resistance genes. In this study, the main objective was to evaluate the presence of Enterococcus species in ornamental animal feed and characterize their antimicrobial resistance and virulence factors. Antimicrobial susceptibility was determined using 14 antimicrobial agents by the disk diffusion method, complemented by genotypic analysis to identify Enterococcus species and the presence of 14 antimicrobial resistance and 10 virulence genes. From 57 samples of ornamental animal feed, 103 Enterococcus isolates were recovered from 15 bird, 9 fish and 4 reptile feed samples. Enterococcus isolates were highly resistance to rifampicin (78%) and erythromycin (48%), and 48% of isolates were classified as multidrug-resistant. Enterococcus faecalis (36.7%) and E. faecium (31.7%) were the species most frequently identified. Most isolates carried the resistance genes ermB (57%) and tetL (52%) and the virulence genes, cylL (52%) and esp (40%). Enterococcus gallinarum was the species with the highest number of multidrug-resistant isolates (50%) and virulence genes (80%). These results highlight the high levels of antibiotic-resistant Enterococcus spp. present in ornamental animal feed and the growing interaction of these animals with humans as a public health concern.
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Enterococci are considered among the most prevalent global multidrug-resistant microorganisms globally. Their dissemination is a global concern, particularly by food-producing animals for both animals and humans. The aim of this study was to identify the species and investigate the antibiotic resistance and virulence profile of Enterococcus in bovine colostrum. Out of 88 presumptive Enterococcus isolates, species identification and susceptibility to 14 antimicrobials were tested using the disk diffusion method. An analysis of the antibiotic resistance and virulence genes was performed on the most prevalent species, using specific PCR assays. Enterococcus faecalis (54.5%), E. faecium (14.8%) and E. gallinarum (6.8%) were the identified species. To the best of our knowledge, this is the first report of E. gallinarum in bovine colostrum. The majority of the isolates showed resistance to quinupristin-dalfopristin (95.9%), erythromycin (80.7%), tetracycline (80.7%) and streptomycin (58%). Ninety-two percent of isolates were classified as multidrug-resistant. The most frequently detected resistance genes were tet(K) (61.1%), tet(M) (75.9%), tet(L) (90.7%), erm(B) (55.6%) and ant(6)-Ia (46.3%). The most prevalent virulence factors were cpd, esp, agg and cylLL. Enterococcus faecium showed a higher probability of carrying the erm(C), tet(M), ace and gel(E) genes (p < 0.05). These results demonstrated that colostrum can constitute an important reservoir and vehicle for the dissemination of antibiotic resistance and virulence genes to the three niches included in a One Health perspective (humans, animals and the environment), highlighting the importance of hygiene sanitary measures to mitigate colostrum microbial contamination.
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Cytokines play a very important role in our immune system by acting as mediators to put up a coordinated defense against foreign elements in our body. Elevated levels of cytokines in the body can signal to an ongoing response of the immune system to some abnormality. Thus, the quantification of a panel of cytokines can provide valuable information regarding the diagnosis of specific diseases and state of overall health of an individual. Conventional Enzyme Linked Immunosorbent Assay (ELISA) is the gold-standard for quantification of cytokines, however the need for trained personnel and expensive equipment limits its application to centralized laboratories only. In this context, there is a lack of simple, low-cost and portable devices which can allow for quantification of panels of cytokines at point-of-care and/or resource limited settings. Here, we report the development of a versatile, low-cost and portable bead-based centrifugal microfluidic platform allowing for multiplexed detection of cytokines with minimal hands-on time and an integrated colorimetric signal readout without the need for any external equipment. As a model, multiplexed colorimetric quantification of three target cytokines i.e., Tumor necrosis factor alpha (TNF-α), Interferon gamma (IFN-γ) and Interleukin-2 (IL-2) was achieved in less than 30 min with limits of detection in ng/mL range. The developed platform was further evaluated using spiked-in plasma samples to test for matrix interference. The ease of use, low-cost and portability of the developed platform highlight its potential to serve as a sample-to-answer solution for detection of cytokine panels in resource limited settings.
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Colorimetria , Microfluídica , Citocinas , Ensaio de Imunoadsorção Enzimática , BiomarcadoresRESUMO
Emergence of novel zoonotic infections among the human population has increased the burden on global healthcare systems to curb their spread. To meet the evolutionary agility of pathogens, it is essential to revamp the existing diagnostic methods for early detection and characterization of the pathogens at the molecular level. Padlock probes (PLPs), which can leverage the power of isothermal nucleic acid amplification techniques (NAAT) such as rolling circle amplification (RCA), are known for their high sensitivity and specificity in detecting a diverse pathogen panel of interest. However, due to the complexity involved in deciding the target regions for PLP design and the need for optimization of multiple experimental parameters, the applicability of RCA has been limited in point-of-care testing for pathogen detection. To address this gap, we have developed a novel and integrated PLP design pipeline named AutoPLP, which can automate the probe design process for a diverse pathogen panel of interest. The pipeline is composed of three modules which can perform sequence data curation, multiple sequence alignment, conservation analysis, filtration based on experimental parameters (Tm, GC content, and secondary structure formation), and in silico probe validation via potential cross-hybridization check with host genome. The modules can also take into account the backbone and restriction site information, appropriate combinations of which are incorporated along with the probe arms to design a complete probe sequence. The potential applications of AutoPLP are showcased through the design of PLPs for the detection of rabies virus and drug-resistant strains of Mycobacterium tuberculosis.
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Mycobacterium tuberculosis , Humanos , Sequência de Bases , Mycobacterium tuberculosis/genéticaRESUMO
This systematic review aims to present an overview of the current aerosol sampling methods (and equipment) being used to investigate the presence of SARS-CoV-2 in the air, along with the main parameters reported in the studies that are essential to analyze the advantages and disadvantages of each method and perspectives for future research regarding this mode of transmission. A systematic literature review was performed on PubMed/MEDLINE, Web of Science, and Scopus to assess the current air sampling methodologies being applied to SARS-CoV-2. Most of the studies took place in indoor environments and healthcare settings and included air and environmental sampling. The collection mechanisms used were impinger, cyclone, impactor, filters, water-based condensation, and passive sampling. Most of the reviewed studies used RT-PCR to test the presence of SARS-CoV-2 RNA in the collected samples. SARS-CoV-2 RNA was detected with all collection mechanisms. From the studies detecting the presence of SARS-CoV-2 RNA, fourteen assessed infectivity. Five studies detected viable viruses using impactor, water-based condensation, and cyclone collection mechanisms. There is a need for a standardized protocol for sampling SARS-CoV-2 in air, which should also account for other influencing parameters, including air exchange ratio in the room sampled, relative humidity, temperature, and lighting conditions.
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Poluição do Ar em Ambientes Fechados , COVID-19 , Humanos , RNA Viral , Aerossóis e Gotículas Respiratórios , SARS-CoV-2 , ÁguaRESUMO
Microfluidics has emerged rapidly over the past 20 years and has been investigated for a variety of applications from life sciences to environmental monitoring. Although continuous-flow microfluidics is ubiquitous, segmented-flow or droplet microfluidics offers several attractive features. Droplets can be independently manipulated and analyzed with very high throughput. Typically, microfluidics is carried out within planar networks of microchannels, namely, microfluidic chips. We propose that fibers offer an interesting alternative format with key advantages for enhanced optical coupling. Herein, we demonstrate the generation of monodisperse droplets within a uniaxial optofluidic Lab-in-a-Fiber scheme. We combine droplet microfluidics with laser-induced fluorescence (LIF) detection achieved through the development of an optical side-coupling fiber, which we term a periscope fiber. This arrangement provides stable and compact alignment. Laser-induced fluorescence offers high sensitivity and low detection limits with a rapid response time making it an attractive detection method for in situ real-time measurements. We use the well-established fluorophore, fluorescein, to characterize the Lab-in-a-Fiber device and determine the generation of [Formula: see text] 0.9 nL droplets. We present characterization data of a range of fluorescein concentrations, establishing a limit of detection (LOD) of 10 nM fluorescein. Finally, we show that the device operates within a realistic and relevant fluorescence regime by detecting reverse-transcription loop-mediated isothermal amplification (RT-LAMP) products in the context of COVID-19 diagnostics. The device represents a step towards the development of a point-of-care droplet digital RT-LAMP platform.
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Dispositivos Lab-On-A-Chip , Vírus/isolamento & purificação , Fluorescência , LasersRESUMO
As the third wave of the COVID-19 pandemic hit Portugal, it forced the country to reintroduce lockdown measures due to hospitals reaching their full capacities. Under these circumstances, environmental contamination by SARS-CoV-2 in different areas of one of Portugal's major Hospitals was assessed between 21 January and 11 February 2021. Air samples (n = 44) were collected from eleven different areas of the Hospital (four COVID-19 and seven non-COVID-19 areas) using Coriolis® µ and Coriolis® Compact cyclone air sampling devices. Surface sampling was also performed (n = 17) on four areas (one COVID-19 and three non-COVID-19 areas). RNA extraction followed by a one-step RT-qPCR adapted for quantitative purposes were performed. Of the 44 air samples, two were positive for SARS-CoV-2 RNA (6575 copies/m3 and 6662.5 copies/m3, respectively). Of the 17 surface samples, three were positive for SARS-CoV-2 RNA (200.6 copies/cm2, 179.2 copies/cm2, and 201.7 copies/cm2, respectively). SARS-CoV-2 environmental contamination was found both in air and on surfaces in both COVID-19 and non-COVID-19 areas. Moreover, our results suggest that longer collection sessions are needed to detect point contaminations. This reinforces the need to remain cautious at all times, not only when in close contact with infected individuals. Hand hygiene and other standard transmission-prevention guidelines should be continuously followed to avoid nosocomial COVID-19.
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COVID-19 , SARS-CoV-2 , Controle de Doenças Transmissíveis , Hospitais , Humanos , Pandemias , Portugal , RNA ViralRESUMO
Inflammatory bowel disease (IBD) is a term used to describe disorders that involve chronic inflammation in the gastrointestinal tract, affecting more than 6.8 million people worldwide. Biological therapy is used in the most severe cases of IBD where anti-tumour necrosis factor-alpha (TNF-α) antibodies are the first choice for a biological treatment. When administrated to patients, these antibodies interact with TNF-α, usually overexpressed in these diseases, neutralizing its biological activity. Because of the chronic nature of these diseases, a recurring administration of the therapeutic antibodies is required, thus making therapy monitorization essential for the correct management of these diseases. The aim of this work is the development of an enzyme-linked immunosorbent assay (ELISA) microfluidic biosensor to quantify the therapeutic antibodies in IBD patient plasma samples, where the commercial monoclonal antibody Infliximab (IFX) is used as a model target. By providing a faster and more accurate measurement of IFX, the proposed method leads to improved therapy scheduling and a reduced risk of endogenous anti-drug antibodies (ADAs) reducing the efficacy of the treatment. The time needed between sample insertion and result output for the microfluidic ELISA (mELISA) is 24 minutes, drastically shorter than the time required by the conventional ELISA (cELISA). The mELISA presented in this work has a LoD of 0.026 µg mL-1, while commercially available solutions provide a LoD of 0.15 µg mL-1. Results acquired by the mELISA are highly correlated with the results obtained from the cELISA (r = 0.998; R2 = 0.996; p < 0.0001), demonstrating the validity of the microfluidic approach for the quantification of IFX from patient plasma and its potential for use at the point-of-care (POC).
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Doenças Inflamatórias Intestinais , Microfluídica , Anticorpos Monoclonais , Monitoramento de Medicamentos , Ensaio de Imunoadsorção Enzimática , Humanos , Doenças Inflamatórias Intestinais/diagnóstico , Doenças Inflamatórias Intestinais/tratamento farmacológico , Infliximab , Fator de Necrose Tumoral alfaRESUMO
The development of robust methods allowing the precise detection of specific nucleic acid sequences is of major societal relevance, paving the way for significant advances in biotechnology and biomedical engineering. These range from a better understanding of human disease at a molecular level, allowing the discovery and development of novel biopharmaceuticals and vaccines, to the improvement of biotechnological processes providing improved food quality and safety, efficient green fuels, and smart textiles. Among these applications, the significance of pathogen diagnostics as the main focus of this Account has become particularly clear during the recent SARS-CoV-2 pandemic. In this context, while RT-PCR is the gold standard method for unambiguous detection of genetic material from pathogens, other isothermal amplification alternatives circumventing rapid heating-cooling cycles up to â¼95 °C are appealing to facilitate the translation of the assay into point-of-care (PoC) analytical platforms. Furthermore, the possibility of routinely multiplexing the detection of tens to hundreds of target sequences with single base pair specificity, currently not met by state-of-the-art methods available in clinical laboratories, would be instrumental along the path to tackle emergent viral variants and antimicrobial resistance genes. Here, we advocate that padlock probes (PLPs), first reported by Nilsson et al. in 1994, coupled with rolling circle amplification (RCA), termed here as PLP-RCA, is an underexploited technology in current arena of isothermal nucleic acid amplification tests (NAATs) providing an unprecedented degree of multiplexing, specificity, versatility, and amenability to integration in miniaturized PoC platforms. Furthermore, the intrinsically digital amplification of PLP-RCA retains spatial information and opens new avenues in the exploration of pathogenesis with spatial multiomics analysis of infected cells and tissue.The Account starts by introducing PLP-RCA in a nutshell focusing individually on the three main assay steps, namely, (1) PLP design and ligation mechanism, (2) RCA after probe ligation, and (3) detection of the RCA products. Each subject is touched upon succinctly but with sufficient detail for the reader to appreciate some assay intricacies and degree of versatility depending on the analytical challenge at hand. After familiarizing the reader with the method, we discuss specific examples of research in our group and others using PLP-RCA for viral, bacterial, and fungal diagnostics in a variety of clinical contexts, including the genotyping of antibiotic resistance genes and viral subtyping. Then, we dissect key developments in the miniaturization and integration of PLP-RCA to minimize user input, maximize analysis throughput, and expedite the time to results, ultimately aiming at PoC applications. These developments include molecular enrichment for maximum sensitivity, spatial arrays to maximize analytical throughput, automation of liquid handling to streamline the analytical workflow in miniaturized devices, and seamless integration of signal transduction to translate RCA product titers (and ideally spatial information) into a readable output. Finally, we position PLP-RCA in the current landscape of NAATs and furnish a systematic Strengths, Weaknesses, Opportunities and Threats analysis to shine light upon unpolished edges to uncover the gem with potential for ubiquitous, precise, and unbiased pathogen diagnostics.
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Técnicas Biossensoriais , COVID-19/diagnóstico , Técnicas de Amplificação de Ácido Nucleico , SARS-CoV-2/genética , COVID-19/genética , Genótipo , Humanos , Sistemas Automatizados de Assistência Junto ao LeitoRESUMO
With its origin estimated around December 2019 in Wuhan, China, the ongoing SARS-CoV-2 pandemic is a major global health challenge. The demand for scalable, rapid and sensitive viral diagnostics is thus particularly pressing at present to help contain the rapid spread of infection and prevent overwhelming the capacity of health systems. While high-income countries have managed to rapidly expand diagnostic capacities, such is not the case in resource-limited settings of low- to medium-income countries. Aiming at developing cost-effective viral load detection systems for point-of-care COVID-19 diagnostics in resource-limited and resource-rich settings alike, we report the development of an integrated modular centrifugal microfluidic platform to perform loop-mediated isothermal amplification (LAMP) of viral RNA directly from heat-inactivated nasopharyngeal swab samples. The discs were pre-packed with dried n-benzyl-n-methylethanolamine modified agarose beads used to selectively remove primer dimers, inactivate the reaction post-amplification and allowing enhanced fluorescence detection via a smartphone camera. Sample-to-answer analysis within 1 hour from sample collection and a detection limit of approximately 100 RNA copies in 10 µL reaction volume were achieved. The platform was validated with a panel of 162 nasopharyngeal swab samples collected from patients with COVID-19 symptoms, providing a sensitivity of 96.6% (82.2-99.9%, 95% CI) for samples with Ct values below 26 and a specificity of 100% (90-100%, 95% CI), thus being fit-for-purpose to diagnose patients with a high risk of viral transmission. These results show significant promise towards bringing routine point-of-care COVID-19 diagnostics to resource-limited settings.
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COVID-19 , Teste para COVID-19 , Humanos , Microfluídica , Técnicas de Diagnóstico Molecular , Técnicas de Amplificação de Ácido Nucleico , RNA Viral/genética , SARS-CoV-2 , Sensibilidade e Especificidade , SmartphoneRESUMO
The biopharmaceutical market has been rapidly growing in recent years, creating a highly competitive arena where R&D is critical to strike a balance between clinical safety and profitability. Toward process optimization, the recent development and adoption of new process analytical technologies (PAT) highlight the dynamic complexity of mammalian/human cell culture processes, as well as the importance of fine-tuning and modeling key metabolites and proteins. In this context, simple, rapid, and cost-effective devices allowing routine at-line monitoring of specific proteins during process development and production are currently lacking. Here, we report the development of a versatile microfluidic protein analysis cartridge allowing the multiplexed bead-based immunodetection of specific proteins directly from complex mixtures with minimal hands-on time. Colorimetric quantification of Chinese hamster ovary (CHO) host cell proteins as key impurities, monoclonal antibodies as target biopharmaceuticals, and lactate dehydrogenase as a marker of cell viability was achieved with limits of detection in the 1-10 ng/mL range and analysis times as short as 30 min. The device was further demonstrated for the monitoring of a Rituximab-producing CHO cell bioreactor over the course of 8 days, providing comparable recoveries to standard enzyme-linked immunosorbent assay (ELISA) kits. The high sensitivity combined with robustness to matrix interference highlights the potential of the device to perform at-line measurements spanning from the bioreactor to the downstream processing.
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Produtos Biológicos , Microfluídica , Animais , Células CHO , Técnicas de Cultura de Células , Cricetinae , Cricetulus , HumanosRESUMO
Since the COVID-19 outbreak was declared a pandemic by the World Health Organization (WHO) in March 2020, ongoing efforts have been made to develop sensitive diagnostic platforms. Detection of viral RNA provides the highest sensitivity and specificity for detection of early and asymptomatic infections. Thus, this work aimed at developing a label-free genosensor composed of graphene as a working electrode that could be embedded into a flex printed circuit board (FPCB) for the rapid, sensitive, amplification-free and label-free detection of SARS-CoV-2. To facilitate liquid handling and ease of use, the developed biosensor was embedded with a user-friendly reservoir chamber. As a proof-of-concept, detection of a synthetic DNA strand matching the sequence of ORF1ab was performed as a two-step strategy involving the immobilization of a biotinylated complementary sequence on a streptavidin-modified surface, followed by hybridization with the target sequence recorded by the differential pulse voltammetric (DPV) technique in the presence of a ferro/ferricyanide redox couple. The effective design of the sensing platform improved its selectivity and sensitivity and allowed DNA quantification ranging from 100 fg/mL to [Formula: see text]/mL. Combining the electrochemical technique with FPCB enabled rapid detection of the target sequence using a small volume of the sample (5-[Formula: see text]). We achieved a limit-of-detection of 100 fg/mL, whereas the predicted value was ~33 fg/mL, equivalent to approximately [Formula: see text] copies/mL and comparable to sensitivities provided by isothermal nucleic acid amplification tests. We believe that the developed approach proves the ability of an FPCB-implemented DNA sensor to act as a potentially simpler and more affordable diagnostic assay for viral infections in Point-Of-Care (POC) applications.
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BACKGROUND: Although an increasing body of data reports the detection of SARS-CoV-2 RNA in air, this does not correlate to the presence of infectious viruses, thus not evaluating the risk for airborne COVID-19. Hence there is a marked knowledge gap that requires urgent attention. Therefore, in this systematic review, viability/stability of airborne SARS-CoV-2, SARS-CoV and MERS-CoV viruses is discussed. METHODS: A systematic literature review was performed on PubMed/MEDLINE, Web of Science and Scopus to assess the stability and viability of SARS-CoV, MERS-CoV and SARS-CoV-2 on air samples. RESULTS AND DISCUSSION: The initial search identified 27 articles. Following screening of titles and abstracts and removing duplicates, 11 articles were considered relevant. Temperatures ranging from 20 °C to 25 °C and relative humidity ranging from 40% to 50% were reported to have a protective effect on viral viability for airborne SARS-CoV and MERS-CoV. As no data is yet available on the conditions influencing viability for airborne SARS-CoV-2, and given the genetic similarity to SARS-CoV and MERS-CoV, one could extrapolate that the same conditions would apply. Nonetheless, the effect of these conditions seems to be residual considering the increasing number of cases in the south of USA, Brazil and India, where high temperatures and humidities have been observed. CONCLUSION: Higher temperatures and high relative humidity can have a modest effect on SARS-CoV-2 viability in the environment, as reported in previous studies to this date. However, these studies are experimental, and do not support the fact that the virus has efficiently spread in the tropical regions of the globe, with other transmission routes such as the contact and droplet ones probably being responsible for the majority of cases reported in these regions, along with other factors such as human mobility patterns and contact rates. Further studies are needed to investigate the extent of aerosol transmission of SARS-CoV-2 as this would have important implications for public health and infection-control policies.
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COVID-19 , Coronavírus da Síndrome Respiratória do Oriente Médio , Brasil , Humanos , Índia , RNA Viral , SARS-CoV-2RESUMO
According to reports by the World Health Organization (WHO), cancer-related deaths reached almost 10 million in 2018. Nearly 65% of these deaths occurred in low- to middle-income countries, a trend that is bound to increase since cancer diagnostics are not currently considered a priority in resource-limited settings (RLS). Thus, cost-effective and specific cancer screening and diagnostics tools are in high demand, particularly in RLS. The selective isolation and up-concentration of rare cells while maintaining cell viability and preventing phenotypic changes is a powerful tool to allow accurate and sensitive downstream analysis. Here, multi-layer cellulose nanofibril-based coatings functionalized with anti-EpCAM antibodies on the surface of disposable microfluidic devices were optimized for specific capture of target cells, followed by efficient release without significant adverse effects. HCT 116 colon cancer cells were captured in a single step with >97% efficiency at 41.25 µL min-1 and, when spiked in whole blood, an average enrichment factor of â¼200-fold relative to white blood cells was achieved. The release of cells was performed by enzymatic digestion of the cellulose nanofibrils which had a negligible impact on cell viability. In particular, >80% of the cells were recovered with at least 97% viability in less than 30 min. Such performance paves the way to expand and improve clinical diagnostic applications by simplifying the isolation of circulating tumor cells (CTCs) and other rare cells directly from whole blood.
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Dispositivos Lab-On-A-Chip , Técnicas Analíticas Microfluídicas , Células Neoplásicas Circulantes , Contagem de Células , Linhagem Celular Tumoral , Separação Celular , Celulose , HumanosRESUMO
Despite significant progress in diagnostics and disease management during the past decades, human immunodeficiency virus (HIV) infections are still responsible for nearly 1 million deaths every year, mostly in resource-limited settings. Thus, novel, accurate and cost-effective tools for viral load monitoring become crucial to allow specific diagnostics and the effective monitoring of the associated antiviral therapies. Herein, we report an effective combination of a (1) padlock probe (PLP)-mediated rolling circle amplification (RCA) bioassay and an (2) agarose bead-based microfluidic device for the affinity chromatography-based capture and detection of RCA products (RCPs) pre-labelled simultaneously with biotin and an organic fluorophore. This method allowed the efficient capture of ~1 µm-sized RCPs followed by their quantification either as discrete signals or an average fluorescence signal, thus being compatible with both high-resolution imaging for maximum sensitivity as well as simpler optical detection setups. A limit of detection < 30 fM was obtained for HIV-1 synthetic target with just a single round of RCA, comparable to recently reported procedures requiring technically complex amplification strategies such as hyperbranching and/or enzymatic digestion/amplification. Furthermore, targeting a set of five conserved regions in the HIV-1 gag gene, the method could specifically detect HIV-1 in 293T cell culture supernatants, as well as a set of 11 HIV-1 NIH reference samples with four different subtypes. The reported method provides simplicity of operation, unique versatility of signal transduction (i.e. average or discrete signals), and potential coupling with previously reported miniaturized photodetectors. These combined features hold promise for bringing RCA-based molecular diagnostics closer to the point-of-care.
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Técnicas Biossensoriais , HIV-1 , Cromatografia de Afinidade , HIV-1/genética , Humanos , Microfluídica , Técnicas de Amplificação de Ácido NucleicoRESUMO
The optimization of chromatography ligands for the purification of biopharmaceuticals is highly demanded to meet the needs of the pharmaceutical industry. In the case of monoclonal antibodies (mAbs), synthetic ligands comprising multiple types of interactions (multimodal) provide process and economic advantages compared to protein-based affinity ligands. However, optimizing the operation window of these ligands requires the development of effective high-throughput screening platforms. Here, a novel microfluidics-based methodology to perform rapid and multiplexed screening of various multimodal ligands relative to their ability to bind different target molecules is demonstrated. The microfluidic structure comprises three individual chambers (≈8 nL each) packed with different types of chromatography beads in series with the feed flow. An artificial mixture composed of immunoglobulin G (IgG) and bovine serum albumin, labeled with different thiol-reactive neutral fluorescent dyes, is used as a model to quantitatively optimize the performance (yield and purity) of the separation. This approach can potentially be used as a predictive analytical tool in the context of mAb purification, allowing low consumption of molecules and providing results in <3 min. Furthermore, this versatile approach can potentially be extended not only with respect to the number of different resins and target molecules, but also for parallel analysis of multiple conditions.
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Cromatografia/instrumentação , Imunoglobulina G/isolamento & purificação , Microfluídica/instrumentação , Corantes Fluorescentes/química , Ligantes , Soroalbumina Bovina/químicaRESUMO
Background: In Portuguese law, police officers are the link between security and the treatment of people with serious mental disorders who require compulsory admission. The perceptions of police officers are in part based on their individual characteristics, and may influence their capability in managing patients they are transporting. However, little is known about police officers experience of this process. Methods: In-depth semi-structured interviews explored the experiences and per- ceptions of police officers from Porto Police Department in Portugal. All interviews were audio recorded, transcribed and analyzed through thematic analysis. Results: Ten police officers agreed to take part in this study. The interviewed police officers consisted of nine men and one woman, had an average length service of 22.6 years and all had more than 10 years of service. The interviews highlighted that the activity of the police under the Mental Health Law is shaped by whether the person who they are transporting has a mental health disorder and requires psychiatric admission. The police officers reportedly adjusted their behavior to give patients more attention, comfort and empathy. However, they describe these interactions as one of the most time consuming and challenging activities for the police. Importantly, they acknowledged family members as crucial for police officers to be able to gain direct access to patients and knowledge about them. Police officers showed to perceive people with mental illness as unpredictable, dangerous and without discernment, and identified some aspects of the process that could be improved, such as hospital admission waiting times. Police officers felt they required more skilled support to deal with unwell patients. Conclusions: This study highlights the perceptions and experiences of police officers about the process of compulsory admission, and identifies areas of unmet needs. These findings help to raise awareness of their needs, improving this process, and ensuring a more humane and effective approach.
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Aqueous two-phase extraction (ATPE) has been showing significant potential in the biopharmaceutical industry, allowing the selective separation of high-value proteins directly from unclarified cell culture supernatants. In this context, effective high-throughput screening tools are critical to perform a rapid empirical optimization of operating conditions. In particular, microfluidic ATPE screening devices, coupled with fluorescence microscopy to continuously monitor the partition of fluorophore-labeled proteins, have been recently demonstrated to provide short diffusion distances and rapid partition, using minimal reagent volumes. Nevertheless, the currently overlooked influence of the labeling procedure on partition must be carefully evaluated to validate the extrapolation of results to the unlabeled molecule. Here, three fluorophores with different global charge and reactivity selected to label immunoglobulin G (IgG) at degrees of labeling (DoL) ranging from 0.5 to 7.6. Labeling with BODIPY FL maleimide (DoL = 0.5), combined with tris(2-carboxyethyl) phosphine (TCEP) to generate free thiol groups, is the most promising strategy to minimize the influence of the fluorophore on partition. In particular, the partition coefficient (Kp ) measured in polyethylene glycol (PEG) 3350-phosphate systems with and without the addition of NaCl using microtubes (batch) or microfluidic devices (continuous) is comparable to those quantified for the native protein.