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INTRODUCTION: Diagnosis is a key step towards the provision of medical intervention and saving lives. However, in low- and middle-income countries, diagnostic services are mainly centralized in large cities and are costly. Point of care (POC) diagnostic technologies have been developed to fill the diagnostic gap for remote areas. The linkage of POC testing onto smartphones has leveraged the ever-expanding coverage of mobile phones to enhance health services in low- and middle-income countries. Tanzania, like most other middle-income countries, is poised to adopt and deploy the use of mobile phone-enabled diagnostic devices. However, there is limited information on the situation on the ground with regard to readiness and capabilities of the veterinary and medical professionals to make use of this technology. METHODS: In this study we survey awareness, digital literacy and prevalent health condition to focus on in Tanzania to guide development and future implementation of mobile phoned-enable diagnostic tools by veterinary and medical professionals. Data was collected using semi-structured questionnaire with closed and open-ended questions, guided in-depth interviews and focus group discussion administered to the participants after informed consent was obtained. RESULTS: A total of 305 participants from six regions of Tanzania were recruited in the study. The distribution of participants across the six regions was as follows: Kilimanjaro (37), Arusha (31), Tabora (68), Dodoma (61), Mwanza (58), and Iringa (50). Our analysis reveals that only 48.2% (126/255) of participants demonstrated significant awareness of mobile phone-enabled diagnostics. This awareness varies significantly across age groups, professions and geographical locations. Interestingly, while 97.4% of participants own and can operate a smartphone, 62% have never utilized their smartphones for health services, including disease diagnosis. Regarding prevalent health condition to focus on when developing mobile phone -enabled diagnostics tools for Tanzania; there was disparity between medical and veterinary professionals. For medical professionals the top 4 priority diseases were Malaria, Urinary Tract Infections, HIV and Diabetes, while for veterinary professionals they were Brucellosis, Anthrax, Newcastle disease and Rabies. DISCUSSION: Despite the widespread ownership of smartphones among healthcare providers (both human and animal), only a small proportion have utilized these devices for healthcare practices, with none reported for diagnostic purposes. This limited utilization may be attributed to factors such as a lack of awareness, absence of policy guidelines, limited promotion, challenges related to mobile data connectivity, and adherence to cultural practices. CONCLUSION: The majority of medical and veterinary professionals in Tanzania possess the necessary digital literacy to utilize mobile phone-enabled diagnostics and demonstrate readiness to adopt digital technologies and innovations to enhance diagnosis. However, effective implementation will require targeted training and interventions to empower them to effectively apply such innovations for disease diagnosis and other healthcare applications.
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Foot-and-mouth disease (FMD) is a highly contagious viral disease of cloven-hoofed animals responsible for economic losses that amount to >$20 billion annually. Rapid recognition of FMD cases provides vital information to guide control programmes. A range of point-of-need amplification technologies have been developed which allow sensitive detection of the causative virus (FMDV) in the field at locations remote from laboratories. Here we describe a novel system to detect FMDV RNA using loop-mediated isothermal amplification (LAMP). This test was evaluated using a panel of FMDV isolates (n = 79) and RNA standards demonstrating capability to amplify viral genome directly from clinical material in the absence of nucleic acid extraction. This extraction-free RT-LAMP assay was transferred to a bespoke closed-system lateral flow test (LFT) that was used in combination with a low-cost hand-held heater. Our results show that the RT-LAMP-LFT assay retains a high level of diagnostic and analytical sensitivity when using direct clinical material, with a limit of detection under 80 copies per reaction. Together, our data support the potential for the use of this assay at the point-of-need to facilitate rapid feedback on the status of suspect cases.
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BACKGROUND: In countries where malaria is endemic, the use of rapid diagnostic tests(RDTs) has become routine, especially in rural settings. Such regions are characterised by often having other co-endemic infectious diseases, at high levels of prevalence. AIM: To illustrate the potential added-value of "sentinel" screening for patients presenting for a routine diagnostic test for malaria, at healthcare facilities in Uganda. METHODS: We developed an economic model by combining two decision trees, one for malaria and a second for the co-endemic disease schistosomiasis. The integrated model was designed to inform policy strategies for the co-endemic disease in addition to malaria (i.e., whether to test opportunistically for schistosomiasis or use mass drug administration(MDA) as per usual practice).We performed the analysis on three comparators varying testing accuracy and costs. RESULTS: Sentinel screening can provide added value to the testing of patients compared with the status quo: when schistosomiasis prevalence is high then MDA is preferential; if low prevalence, treating no one is preferred. If the disease has average levels of prevalence, then a strategy involving testing is preferred. Prevalence thresholds driving the dominant strategy are dependent upon the model parameters, which are highly context specific. At average levels of prevalence for schistosomiasis and malaria for Uganda, adding a sentinel screening was cost-effective when the accuracy of test was higher than current diagnostics and when economies of scope were generated(Expected value clinical Information = 0.65$ per DALY averted, 137.91$ per correct diagnoses).Protocols using diagnostics with current accuracy levels were preferred only for levels of MDA coverage below 75%. CONCLUSION: The importance of the epidemiological setting is crucial in determining the best cost-effective strategy for detecting endemic disease. Economies of scope can make sentinel screenings cost-effective strategies in specific contexts. Blanket thresholds recommended for MDA may not always be the preferred option for endemic diseases.
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Análisis Costo-Beneficio , Enfermedades Endémicas , Malaria , Esquistosomiasis , Humanos , Esquistosomiasis/diagnóstico , Esquistosomiasis/epidemiología , Esquistosomiasis/economía , Malaria/diagnóstico , Malaria/epidemiología , Uganda/epidemiología , Femenino , Masculino , Adulto , Niño , Adolescente , Pruebas Diagnósticas de Rutina/economía , Pruebas Diagnósticas de Rutina/métodos , Persona de Mediana Edad , Preescolar , Adulto Joven , Prevalencia , Tamizaje Masivo/economía , Tamizaje Masivo/métodos , Vigilancia de Guardia , Modelos Económicos , AncianoRESUMEN
Accurate prediction of the efficacy of immunotherapy for cancer patients through the characterization of both genetic and phenotypic heterogeneity in individual patient cells holds great promise in informing targeted treatments, and ultimately in improving care pathways and clinical outcomes. Here, we describe the nanoplatform for interrogating living cell host-gene and (micro-)environment (NICHE) relationships, that integrates micro- and nanofluidics to enable highly efficient capture of circulating tumor cells (CTCs) from blood samples. The platform uses a unique nanopore-enhanced electrodelivery system that efficiently and rapidly integrates stable multichannel fluorescence probes into living CTCs for in situ quantification of target gene expression, while on-chip coculturing of CTCs with immune cells allows for the real-time correlative quantification of their phenotypic heterogeneities in response to immune checkpoint inhibitors (ICI). The NICHE microfluidic device provides a unique ability to perform both gene expression and phenotypic analysis on the same single cells in situ, allowing us to generate a predictive index for screening patients who could benefit from ICI. This index, which simultaneously integrates the heterogeneity of single cellular responses for both gene expression and phenotype, was validated by clinically tracing 80 non-small cell lung cancer patients, demonstrating significantly higher AUC (area under the curve) (0.906) than current clinical reference for immunotherapy prediction.
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Células Neoplásicas Circulantes , Humanos , Células Neoplásicas Circulantes/patología , Células Neoplásicas Circulantes/metabolismo , Microfluídica/métodos , Análisis de la Célula Individual/métodos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/sangre , Fenotipo , Línea Celular Tumoral , Inmunoterapia/métodos , Perfilación de la Expresión Génica/métodos , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/patología , Carcinoma de Pulmón de Células no Pequeñas/sangre , Técnicas Analíticas Microfluídicas/métodos , Técnicas Analíticas Microfluídicas/instrumentaciónRESUMEN
BACKGROUND: Neisseria meningitidis can cause life-threatening meningococcal meningitis and meningococcemia. Old standard microbiological results from CSF/blood cultures are time consuming. This study aimed to combine the sensitivity of loop-mediated isothermal nucleic acid amplification (LAMP) with the specificity of CRISPR/Cas12a cleavage to demonstrate a reliable diagnostic assay for rapid detection of N. meningitidis. METHODS: A total of n = 139 samples were collected from patients with suspected meningococcal disease and were used for evaluation. The extracted DNA was subjected to qualitative real-time PCR, targeting capsular transporter gene (ctrA) of N. meningitidis. LAMP-specific primer pairs, also targeting the ctrA, were designed and the LAMP products were subjected to CRISPR/Cas12 cleavage reaction. the readout was on a lateral flow strip. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of LAMP-CRISPR/Cas was compared with real-time PCR assays. The limit of detection (LOD) was established with serial dilutions of the target N. meningitidis DNA and calculated by Probit regression analysis. RESULTS: Six LAMP assay-specific primers were developed targeting the ctrA gene of N. meningitidis, which is conserved in all meningococcal serogroups. The LAMP primers did not amplify DNA from other bacterial DNA tested, showing 100% specificity. The use of 0.4 M betaine increased the sensitivity and stability of the reaction. LAMP-CRISPR/Cas detected meningococcal serogroups (B, C, W). The assay showed no cross-reactivity and was specific for N. meningitidis. The LOD was 74 (95% CI: 47-311) N. meningitidis copies. The LAMP-CRISPR/Cas performed well compared to the gold standard. In the 139 samples from suspected patients, the sensitivity and specificity of the test were 91% and 99% respectively. CONCLUSION: This developed and optimized method can complement for the available gold standard for the timely diagnosis of meningococcal meningitis and meningococcemia.
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Meningitis Meningocócica , Infecciones Meningocócicas , Neisseria meningitidis , Sepsis , Humanos , Neisseria meningitidis/genética , Meningitis Meningocócica/diagnóstico , Meningitis Meningocócica/microbiología , Infecciones Meningocócicas/diagnóstico , Infecciones Meningocócicas/microbiología , Sensibilidad y Especificidad , ADN Bacteriano/genéticaRESUMEN
Despite its importance, the functional heterogeneity surrounding the dynamics of interactions between mycobacterium tuberculosis and human immune cells in determining host immune strength and tuberculosis (TB) outcomes, remains far from understood. This work now describes the development of a new technological platform to elucidate the immune function differences in individuals with TB, integrating single-cell RNA sequencing and cell surface antibody sequencing to provide both genomic and phenotypic information from the same samples. Single-cell analysis of 23 990 peripheral blood mononuclear cells from a new cohort of primary TB patients and healthy controls enables to not only show four distinct immune phenotypes (TB, myeloid, and natural killer (NK) cells), but also determine the dynamic changes in cell population abundance, gene expression, developmental trajectory, transcriptomic regulation, and cell-cell signaling. In doing so, TB-related changes in immune cell functions demonstrate that the immune response is mediated through host T cells, myeloid cells, and NK cells, with TB patients showing decreased naive, cytotoxicity, and memory functions of T cells, rather than their immunoregulatory function. The platform also has the potential to identify new targets for immunotherapeutic treatment strategies to restore T cells from dysfunctional or exhausted states.
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Mycobacterium tuberculosis , Tuberculosis , Humanos , Leucocitos Mononucleares , Mycobacterium tuberculosis/fisiología , Linfocitos T , Células Asesinas NaturalesRESUMEN
OBJECTIVE: We previously reported an increased expression of microRNA-155 (miR-155) in the blood monocytes of patients with rheumatoid arthritis (RA) that could be responsible for impaired monocyte polarization to anti-inflammatory M2-like macrophages. In this study, we employed two preclinical models of RA, collagen-induced arthritis and K/BxN serum transfer arthritis, to examine the therapeutic potential of antagomiR-155-5p entrapped within PEGylated (polyethylene glycol [PEG]) liposomes in resolution of arthritis and repolarization of monocytes towards the anti-inflammatory M2 phenotype. METHODS: AntagomiR-155-5p or antagomiR-control were encapsulated in PEG liposomes of 100 nm in size and -10 mV in zeta potential with high antagomiR loading efficiency (above 80%). Mice were injected intravenously with 1.5 nmol/100 µL PEG liposomes containing antagomiR-155-5p or control after the induction of arthritis. RESULTS: We demonstrated the biodistribution of fluorescently tagged PEG liposomes to inflamed joints one hour after the injection of fluorescently tagged PEG liposomes, as well as the liver's subsequent accumulation after 48 hours, indicative of hepatic clearance, in mice with arthritis. The injection of PEG liposomes containing antagomiR-155-5p decreased arthritis score and paw swelling compared with PEG liposomes containing antagomiR-control or the systemic delivery of free antagomiR-155-5p. Moreover, treatment with PEG liposomes containing antagomiR-155-5p led to the restoration of bone marrow monocyte defects in anti-inflammatory macrophage differentiation without any significant functional change in other immune cells, including splenic B and T cells. CONCLUSION: The injection of antagomiR-155-5p encapsulated in PEG liposomes allows the delivery of small RNA to monocytes and macrophages and reduces joint inflammation in murine models of RA, providing a promising strategy in human disease.
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Artritis Experimental , Artritis Reumatoide , MicroARNs , Humanos , Ratones , Animales , Antagomirs/metabolismo , Antagomirs/uso terapéutico , Liposomas/metabolismo , Liposomas/uso terapéutico , Distribución Tisular , Macrófagos , Antiinflamatorios/uso terapéutico , MicroARNs/metabolismoRESUMEN
Haemonchus contortus is a parasitic haematophagous nematode that primarily affects small ruminants and causes significant economic loss to the global livestock industry. Treatment of haemonchosis typically relies on broad-spectrum anthelmintics, resistance to which is an important cause of treatment failure. Resistance to levamisole remains less widespread than to other major anthelmintic classes, prompting the need for more effective and accurate surveillance to maintain its efficacy. Loop-primer endonuclease cleavage loop-mediated isothermal amplification (LEC-LAMP) is a recently developed diagnostic method that facilitates multiplex target detection with single nucleotide polymorphism (SNP) specificity and portable onsite testing. In this study, we designed a new LEC-LAMP assay and applied it to detect the levamisole resistance marker S168T in H. contortus. We explored multiplexing probes for both the resistant S168T and the susceptible S168 alleles in a single-tube assay. We then included a generic probe to detect the acr-8 gene in the multiplex assay, which could facilitate the quantification of both resistance markers and overall genetic material from H. contortus in a single step. Our results showed promising application of these technologies, demonstrating a proof-of-concept assay which is amenable to detection of resistance alleles within the parasite population, with the potential for multiplex detection, and point-of-care application enabled by lateral flow end-point detection. However, further optimisation and validation is necessary.
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Antihelmínticos , Haemonchus , Técnicas de Diagnóstico Molecular , Técnicas de Amplificación de Ácido Nucleico , Animales , Levamisol/farmacología , Haemonchus/genética , Resistencia a Medicamentos/genética , Antihelmínticos/farmacología , Antihelmínticos/uso terapéuticoRESUMEN
Although polydimethylsiloxane (PDMS) is a versatile and easy-to-use material for microfluidics, its inherent hydrophobicity often necessitates specific hydrophilic treatment to fabricate microchip architectures for generating double emulsions. These additional processing steps frequently lead to increased complexity, potentially creating barriers to the wider use of promising microfluidic techniques. Here we describe an alignment-free spatial hydrophilic PDMS patterning technique to produce devices for the creation of double emulsions using combinations of PDMS and PDMS/surfactant bilayers. The technique enables us to achieve selective patterning and alignment-free bonding, producing reliable and reproducible water-in-oil-in-water W/O/W droplet emulsions. Our method involves processing devices in a vertical orientation, with the wetting transition contrast being achieved simply by imaging whilst adjusting the PDMS pouring speed (using a mobile phone, for example). We successfully obtain hydrophilic surfaces without distinguishable hydrophobic recovery using a range of surfactant concentrations. Droplet emulsions were produced with low coefficients of variation aligned with those generated with other, more complex, techniques (e.g. 3.8% and 3.1% for the inner and outer diameters, respectively). As a further example, the methods were also demonstrated for liposome production. In future we anticipate that the technique may be applied to other fields, including e.g. reagent delivery, DNA amplification, and encapsulated cell studies.
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The recent COVID-19 outbreak highlighted the need for lab-on-chip diagnostic technology fit for real-life deployment in the field. Existing bottlenecks in multistep analytical microsystem integration and upscalable, standardized fabrication techniques delayed the large-scale deployment of lab-on-chip solutions during the outbreak, throughout a global diagnostic test shortage. This study presents a technology that has the potential to address these issues by redeploying and repurposing the ubiquitous printed circuit board (PCB) technology and manufacturing infrastructure. We demonstrate the first commercially manufactured, miniaturised lab-on-PCB device for loop-mediated isothermal amplification (LAMP) genetic detection of SARS-CoV-2. The system incorporates a mass-manufactured, continuous-flow PCB chip with ultra-low cost fluorescent detection circuitry, rendering it the only continuous-flow µLAMP platform with off-the-shelf optical detection components. Ultrafast, SARS-CoV-2 RNA amplification in wastewater samples was demonstrated within 2 min analysis, at concentrations as low as 17 gc µL-1. We further demonstrate our device operation by detecting SARS-CoV-2 in 20 human nasopharyngeal swab samples, without the need for any RNA extraction or purification. This renders the presented miniaturised nucleic-acid amplification-based diagnostic test the fastest reported SARS-CoV-2 genetic detection platform, in a practical implementation suitable for deployment in the field. This technology can be readily extended to the detection of alternative pathogens or genetic targets for a very broad range of applications and matrices. LoCKAmp lab-on-PCB chips are currently mass-manufactured in a commercial, ISO-compliant PCB factory, at a small-scale production cost of £2.50 per chip. Thus, with this work, we demonstrate a high technology-readiness-level lab-on-chip-based genetic detection system, successfully benchmarked against standard analytical techniques both for wastewater and nasopharyngeal swab SARS-CoV-2 detection.
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Phage-inducible chromosomal islands (PICIs) are a family of phage satellites that hijack phage components to facilitate their mobility and spread. Recently, these genetic constructs are repurposed as antibacterial drones, enabling a new toolbox for unorthodox applications in biotechnology. To illustrate a new suite of functions, the authors have developed a user-friendly diagnostic system, based upon PICI transduction to selectively enrich bacteria, allowing the detection and sequential recovery of Escherichia coli and Staphylococcus aureus. The system enables high transfer rates and sensitivities in comparison with phages, with detection down to ≈50 CFU mL-1 . In contrast to conventional detection strategies, which often rely on nucleic acid molecular assays, and cannot differentiate between dead and live organisms, this approach enables visual sensing of viable pathogens only, through the expression of a reporter gene encoded in the PICI. The approach extends diagnostic sensing mechanisms beyond cell-free synthetic biology strategies, enabling new synthetic biology/biosensing toolkits.
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Bacteriófagos , Bacteriófagos/genética , Islas , Islas Genómicas/genética , Bacterias , Escherichia coli/genéticaRESUMEN
The detection of changes in nucleic acid sequences at specific sites remains a critical challenge in epigenetics, diagnostics and therapeutics. To date, such assays often require extensive time, expertise and infrastructure for their implementation, limiting their application in clinical settings. Here we demonstrate a generalizable method, named Specific Terminal Mediated Polymerase Chain Reaction (STEM-PCR) for the detection of DNA modifications at specific sites, in a similar way as DNA sequencing techniques, but using simple and widely accessible PCR-based workflows. We apply the technique to both for site-specific methylation and co-methylation analysis, importantly using a bisulfite-free process - so providing an ease of sample processing coupled with a sensitivity 20-fold better than current gold-standard techniques. To demonstrate the clinical applicability through the detection of single base mutations with high sensitivity and no-cross reaction with the wild-type background, we show the bisulfite-free detection of SEPTIN9 and SFRP2 gene methylation in patients (as key biomarkers in the prognosis and diagnosis of tumours).
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Bioensayo , Humanos , Reacción en Cadena de la Polimerasa , Reacciones Cruzadas , MutaciónRESUMEN
Background: Despite its strong growth in many parts of the world, mobile health access is still limited in low- and middle-income countries. Among the many factors restricting implementation are the lack of information security, insufficient evidence base, low sensitization, and user acceptance. Limited evidence has been obtained on current practices, perceptions, and user acceptability in such settings. The aim of this study was therefore to evaluate the knowledge, attitude, and perceptions on mobile health use among health workers and veterinary officers in Uganda. Materials and Methods: A cross-section study was carried out, targeting health practitioners in both hospitals and veterinary laboratories/clinics. A structured questionnaire was used to collect data from the Central, Eastern, Northern, and Western representative regions. Interviews with selected health workers were also conducted as well as a focused group discussion. Results: Of the 120 health practitioners that were targeted, a total of 80 health workers and 7 veterinary practitioners participated in the study of which 46% were men and 54% women. Majority of the health workers had encountered m-health but had never used it, whereas the 15 practitioners who had used it before the survey did not use it for disease diagnosis in hospitals but used it for ordering medicine online, for patient consultations with the doctors, result interpretation, tracking women menstrual cycles, tuberculosis assessment. Discussion and Conclusion: Participants expressed significant interest in mobile health as it addresses key challenges including challenges with management of patient data, and long patient queues, which would ultimately improve service delivery. However, there is some skepticism about access as many rural facilities lack access to smartphones and stable internet.
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Médicos , Telemedicina , Masculino , Humanos , Femenino , Uganda , Conocimientos, Actitudes y Práctica en Salud , Personal de SaludRESUMEN
The current COVID-19 pandemic has shown us that the pulse oximeter is a key medical device for monitoring blood-oxygen levels non-invasively in patients with chronic or acute illness. It has also emphasised limitations in accuracy for individuals with darker skin pigmentation, calling for new methods to provide better measurements. The aim of our study is to identify the impact of skin pigmentation on pulse oximeter measurements. We also explored the benefits of a multi-wavelength approach with an induced change of arterial oxygen saturation. A total of 20 healthy volunteers were recruited. We used time domain diffuse reflectance spectroscopy (TDDRS) from a broad band light source, collecting spectra from the index finger along with three different pulse oximeters used simultaneously for monitoring purposes. Five acute hypoxic events were induced by administering 11% FiO2, produced by a Hypoxico altitude training system, for 120 sec through a face mask with a one-way valve. Our multi-wavelength approach revealed a correlation between the signature of skin pigmentation and the dynamic range of oxygen saturation measurements. Principal component analysis (PCA) showed separation between a range of different pigmented volunteers (PC1 = 56.00%) and oxygen saturation (PC2 = 22.99%). This emphasises the need to take into account skin pigmentation in oximeter measurements. This preliminary study serves to validate the need to better understand the impact of skin pigmentation absorption on optical readings in pulse oximeters. Multi-wavelength approaches have the potential to enable robust and accurate measurements across diverse populations.
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COVID-19 , Pigmentación de la Piel , Humanos , Proyectos Piloto , Altitud , Pandemias , Oximetría/métodos , Hipoxia , OxígenoRESUMEN
Accelerating the design of nucleic acid amplification methods remains a critical challenge in the development of molecular tools to identify biomarkers to diagnose both infectious and non-communicable diseases. Many of the principles that underpin these mechanisms are often complex and can require iterative optimisation. Here we focus on creating a generalisable isothermal nucleic acid amplification methodology, describing the systematic implementation of abstraction-based models for the algorithmic design and application of assays. We demonstrate the simplicity, ease and flexibility of our approach using a software tool that provides amplification schemes de novo, based upon a user-input target sequence. The abstraction of reaction network predicts multiple reaction pathways across different strategies, facilitating assay optimisation for specific applications, including the ready design of multiplexed tests for short nucleic acid sequence miRNAs or for difficult pathogenic targets, such as highly mutating viruses.
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Enfermedades Transmisibles , Ácidos Nucleicos , Virus , Humanos , Técnicas de Amplificación de Ácido Nucleico/métodos , Virus/genéticaRESUMEN
Viral evolution impacts diagnostic test performance through the emergence of variants with sequences affecting the efficiency of primer binding. Such variants that evade detection by nucleic acid-based tests are subject to selective pressure, enabling them to spread more efficiently. Here, we report a variant-tolerant diagnostic test for SARS-CoV-2 using a loop-mediated isothermal nucleic acid-based amplification (LAMP) assay containing high-fidelity DNA polymerase and a high-fidelity DNA polymerase-medicated probe (HFman probe). In addition to demonstrating a high tolerance to variable SARS-CoV-2 viral sequences, the mechanism also overcomes frequently observed limitations of LAMP assays arising from non-specific amplification within multiplexed reactions performed in a single "pot". Results showed excellent clinical performance (sensitivity 94.5%, specificity 100%, n = 190) when compared directly to a commercial gold standard reverse transcription quantitative polymerase chain reaction assay for the extracted RNA from nasopharyngeal samples and the capability of detecting a wide range of sequences containing at least alpha and delta variants. To further validate the test with no sample processing, directly from nasopharyngeal swabs, we also detected SARS-CoV-2 in positive clinical samples (n = 49), opening up the possibility for the assay's use in decentralized testing.
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COVID-19 , SARS-CoV-2 , COVID-19/diagnóstico , Prueba de COVID-19 , Humanos , Técnicas de Diagnóstico Molecular , Técnicas de Amplificación de Ácido Nucleico/métodos , Sistemas de Atención de Punto , ARN Viral/análisis , ARN Viral/genética , SARS-CoV-2/genética , Sensibilidad y EspecificidadRESUMEN
The early diagnosis of active hepatitis C virus (HCV) infection remains a significant barrier to the treatment of the disease and to preventing the associated significant morbidity and mortality seen, worldwide. Current testing is delayed due to the high cost, long turnaround times and high expertise needed in centralised diagnostic laboratories. Here we demonstrate a user-friendly, low-cost pan-genotypic assay, based upon reverse transcriptase loop mediated isothermal amplification (RT-LAMP). We developed a prototype device for point-of-care use, comprising a LAMP amplification chamber and lateral flow nucleic acid detection strips, giving a visually-read, user-friendly result in <40 min. The developed assay fulfils the current guidelines recommended by World Health Organisation and is manufactured at minimal cost using simple, portable equipment. Further development of the diagnostic test will facilitate linkage between disease diagnosis and treatment, greatly improving patient care pathways and reducing loss to follow-up, so assisting in the global elimination strategy.
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Hepatitis C/diagnóstico , Microfluídica/métodos , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificación de Ácido Nucleico/métodos , Ingeniería Biomédica/métodos , Nitrógeno de la Urea Sanguínea , Pruebas Diagnósticas de Rutina , Diagnóstico Precoz , Genotipo , Hepacivirus , Humanos , Laboratorios , Sistemas de Atención de Punto , Carga Viral , Organización Mundial de la SaludRESUMEN
Human immunodeficiency virus (HIV) continues to be a major burden on public health globally with on-going increases in the number of new infections each year. Rapid and sensitive point-of-care tests allow timely interventions and are essential to control the spread of the disease. However the highly variable nature of the virus, resulting in the evolution of many subtypes and inter-subtype recombinants, poses important challenges for its diagnosis. Here we describe a variant-tolerant reverse-transcription RT-LAMP amplification of the virus's INT gene, providing a simple to use, rapid (<30 min) in vitro point-of-care diagnostic test with a limit of detection <18 copies/reaction. The assay was first validated in clinical studies of patient samples, using both established RT-LAMP and RT-qPCR assays for reference, with results showing that this new variant-tolerant HIV-1 RT-LAMP diagnostic test is highly sensitive without compromising its high specificity for HIV-1 subtypes. The diagnostic test was subsequently configured within an easy-to-read paper microfluidic lateral flow test and was validated clinically using patient samples, demonstrating its future potential for use in timely, effective, low cost HIV diagnostics in global regions where healthcare resources may be limited.
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VIH-1 , VIH-1/genética , Humanos , Técnicas de Diagnóstico Molecular , Técnicas de Amplificación de Ácido Nucleico , Sistemas de Atención de Punto , Transcripción Reversa , Sensibilidad y EspecificidadRESUMEN
The emergence of lipid membranes and embedded proteins was essential for the evolution of cells. Translocon complexes mediate cotranslational recruitment and membrane insertion of nascent proteins, but they already contain membrane-integral proteins. Therefore, a simpler mechanism must exist, enabling spontaneous membrane integration while preventing aggregation of unchaperoned protein in the aqueous phase. Here, we used giant unilamellar vesicles encapsulating minimal translation components to systematically interrogate the requirements for insertion of the model protein proteorhodopsin (PR) - a structurally ubiquitous membrane protein. We show that the N-terminal hydrophobic domain of PR is both necessary and sufficient for cotranslational recruitment of ribosomes to the membrane and subsequent membrane insertion of PR. Insertion of N-terminally truncated PR was restored by artificially attaching ribosomes to the membrane. Our findings offer a self-sufficient protein-inherent mechanism as a possible explanation for effective membrane protein biogenesis in a "pretranslocon" era, and they offer new opportunities for generating artificial cells.