5,720 results
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2. A microfluidic paper analytical device using capture aptamers for the detection of PfLDH in blood matrices
- Author
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Ogunmolasuyi, Adewoyin Martin, Fogel, Ronen, Hoppe, Heinrich, Goldring, Dean, and Limson, Janice
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- 2022
- Full Text
- View/download PDF
3. Antibody affinity as a driver of signal generation in a paper-based immunoassay for Ebola virus surveillance
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Murray, Lara P., Govindan, Ramesh, Mora, Andrea C., Munro, James B., and Mace, Charles R.
- Published
- 2021
- Full Text
- View/download PDF
4. A microfluidic paper analytical device using capture aptamers for the detection of PfLDH in blood matrices
- Author
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Adewoyin Martin Ogunmolasuyi, Ronen Fogel, Heinrich Hoppe, Dean Goldring, and Janice Limson
- Subjects
Malaria ,Paper ,Diagnostics ,Aptamer ,Plasmodium falciparum LDH test ,Blood ,Arctic medicine. Tropical medicine ,RC955-962 ,Infectious and parasitic diseases ,RC109-216 - Abstract
Abstract Background The prevalence and death rate arising from malaria infection, and emergence of other diseases showing similar symptoms to malaria require the development of malaria-specific and sensitive devices for its diagnosis. To address this, the design and fabrication of low-cost, rapid, paper-based analytical devices (µPAD) using surface-immobilized aptamers to detect the presence of a recombinant malarial biomarker—Plasmodium falciparum lactate dehydrogenase (rPfLDH)—is reported in this study. Methods Test zones on paper surfaces were created by covalently immobilizing streptavidin to the paper, subsequently attaching biotinylated aptamers to streptavidin. Aptamers selectively bound rPfLDH. The measurement of captured rPfLDH enzyme activity served as the means of detecting this biomarker. Enzyme activity across three replicate sensors was digitally quantified using the colorimetric Malstat assay. Results Screening of several different aptamers reported in the literature showed that aptamers rLDH7 and 2008s immobilized in this manner specifically recognised and captured PfLDH. Using rLDH7, the sensitivity of the µPAD sensor was evaluated and the µPAD sensor was applied for preferential detection of rPfLDH, both in buffered solutions of the protein and in spiked serum and red blood cell lysate samples. In buffered solutions, the test zone of the µPAD sensor exhibited a K D of 24 ± 11 nM and an empirical limit of detection of 17 nM, respectively, a limit similar to commercial antibody-based sensors exposed to rPfLDH. The specific recognition of 133 nM rPfLDH in undiluted serum and blood samples was demonstrated by the µPAD. Conclusion The reported µPAD demonstrates the potential of integrating aptamers into paper-based malarial rapid diagnostic tests. Graphical Abstract The assembly of µPAD sensors using APTEC assay principles for the detection the malarial biomarker, lactate dehydrogenase enzymes from Plasmodium falciparum (PfLDH). The aptamers immobilized at the test zones capture the PfLDH in samples. After washing the unbound sample components from the zones, Malstat assay reagents are added for colour development, proportional to the amount of captured PfLDH.
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- 2022
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5. Paper-based sensors for rapid important biomarkers detection
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Bambang Kuswandi, M. Amrun Hidayat, and Eka Noviana
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Paper-based device ,Chemical sensors ,Biosensors ,Microfluidic ,Diagnostics ,Biomarkers ,Biotechnology ,TP248.13-248.65 - Abstract
Paper-based sensors have received increasing attention in the last decade, their use has spread to various application fields, such as clinical diagnostic, food safety, environmental monitoring, etc. Feature inherent to on-side detection is suitable to be used as point-of-care (POC) testing, including avoided sampling, sample preparation, and laborious procedure in the classical clinical lab, which is undoubtedly driving many developments of this lab-on-paper technology. The detection of biomarkers that are related to human health conditions has to play important role in the indication of the risk of diseases. In this review, the development of paper-based sensors for the detection of important biomarkers is presented. The also emphasis on recognition elements, such as chromophores/fluorophores, plasmonic nanoparticles, metal nanoclusters, etc., used to serve suitable selectivity and sensitivity. The performance of paper-based sensors using various techniques, including optical and electrochemical and other detection techniques are addressed. Furthermore, their limitations and prospects are discussed. The review also highlights cutting-edge technologies for further enhancement in the sensor performances for biomarkers detection.
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- 2022
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6. A Low-Cost Paper-Based Device for the Colorimetric Quantification of Bilirubin in Serum Using Smartphone Technology
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Brittany AuYoung, Akshay Gutha Ravichandran, Divykumar Patel, Nisarg Dave, Achal Shah, Brianna Wronko-Stevens, Franklin Bettencourt, Reshma Rajan, and Nidhi Menon
- Subjects
diagnostics ,paper microfluidics ,object detection ,image processing ,bilirubin ,Chemistry ,QD1-999 - Abstract
Total bilirubin values have been used as a potential marker to pre-screen and diagnose various liver-based diseases such as jaundice, bile obstruction, liver cancer, etc. A device known as KromaHealth Kit, composed of paper and an acrylic backbone, is developed to quantify total bilirubin in human serum using image processing and machine learning technology. The biochemical assays are deposited on absorbent paper pads that act as reaction zones when serum is added. A dedicated smartphone app captures images of the colorimetric changes on the pad and converts them into quantitative values of bilirubin. The range of bilirubin concentration that can be quantified using the device ranges from 0.5 mg/dl to 7.0 mg/dl. The precision, limit of detection, interference analysis, linearity, stability, and comparison with a predicate are studied in this paper in accordance with clinical and laboratory standards institute. The results indicate that the KromaHealth Kit can be used as an inexpensive alternative to conventional bilirubin testing in clinical settings. With its level of precision, ease-of-use, long shelf-life, and short turnaround time, it will prove to be invaluable in limited-resource settings.
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- 2022
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7. Three-Dimensional Microfluidic Devices Fabricated in Layered Paper and Tape
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Martinez, Andres W., Phillips, Scott T., and Whitesides, George M.
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- 2008
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8. Scalable Methods for Device Patterning as an Outstanding Challenge in Translating Paper-Based Microfluidics from the Academic Benchtop to the Point-of-Care
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Brooks, Jessica C. and Mace, Charles R.
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- 2019
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9. Metallic Nanoparticles for Expanding the Point-of-Care Applications of Paper-Based Diagnostic Devices
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Trinh, Jasmine Thanh
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Bioengineering ,Diagnostics ,Gold nanorod ,Lateral-flow immunoassay ,Nanozyme ,Paper-based diagnostics ,Point of care - Abstract
As early diagnosis is essential for improving patient outcomes when treating both communicable and noncommunicable diseases, it is necessary to develop diagnostic tests that are accessible at the point of care. Thus, there is a need for rapid, robust, and inexpensive diagnostic tests, especially in resource-limited areas where access to healthcare is reduced. One such test is the lateral-flow immunoassay (LFA), which has seen a drastic rise in use during the COVID-19 pandemic. However, the conventional LFA suffers from a couple limitations, which this thesis aims to address. First, we address the limited sensitivity of the LFA by incorporating nanozyme signal enhancement to improve detection of the SARS-CoV-2 nucleocapsid protein in serum. By developing dehydrated signal enhancement reagents and an innovative 3D printed casing to store and deliver reagents at the push of a button, we were able to improve the limit of detection of the LFA by at least 10-fold without introducing additional complexity for the user.Next, we shifted our focus to introducing semi-quantitative results to the LFA through the multicolor etching of gold nanorods (GNRs). We demonstrated the first integration of the LFA with GNRs to produce a multicolor readout for the quantification of digoxin levels in serum. We then expanded upon this work by developing a fully paper-based assay to incorporate both the LFA detection and GNR etching steps together, which involved the design of novel color-changing GNR pads. The color hues generated by GNR etching are easily distinguishable by the naked eye, thus allowing for quantification of target biomarker concentrations at the point of care.
- Published
- 2022
10. European Neuroendocrine Tumour Society (ENETS) 2023 guidance paper for nonfunctioning pancreatic neuroendocrine tumours.
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Kos‐Kudła, Beata, Castaño, Justo P., Denecke, Timm, Grande, Enrique, Kjaer, Andreas, Koumarianou, Anna, de Mestier, Louis, Partelli, Stefano, Perren, Aurel, Stättner, Stefan, Valle, Juan W., and Fazio, Nicola
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NEUROENDOCRINE tumors , *PROGNOSIS , *THERAPEUTICS - Abstract
This ENETS guidance paper for well‐differentiated nonfunctioning pancreatic neuroendocrine tumours (NF‐Pan‐NET) has been developed by a multidisciplinary working group, and provides up‐to‐date and practical advice on the management of these tumours. Using the extensive experience of centres treating patients with NF‐Pan‐NEN, the authors of this guidance paper discuss 10 troublesome questions in everyday clinical practice. Our many years of experience in this field are still being verified in the light of the results of new clinical, which set new ways of proceeding in NEN. The treatment of NF‐Pan‐NEN still requires a decision of a multidisciplinary team of specialists in the field of neuroendocrine neoplasms. This ENETS guidance paper provides up‐to‐date practical advice on the NF‐Pan‐NET diagnosis and treatment. Management of NF‐Pan‐NET patients requires a NET‐dedicated MDT decision. ENETS Centres of Excellence should be strongly considered to be involved in the diagnostic‐therapeutic strategy of these patients. Further studies are needed to fulfil the unmet needs in this field focusing on prognostic molecular markers, dilemmas concerning the selection of a therapeutic approach as well as the sequence of their use to achieve success in the management of NF‐Pan‐NETs patients. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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11. (In)Visible Disease: Motions and Emotions Engendered by Papers and Diagnostics of People Accessing Healthcare in Burkina Faso
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Pia Juul Bjertrup
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visibility ,documents ,diagnostics ,access to healthcare ,burkina faso ,Anthropology ,GN1-890 ,Medicine (General) ,R5-920 - Abstract
Within the last decade, challenges of diagnosis have emerged on the global health agenda, accompanied by an expansion in the use of point-of-care and rapid detection devices in low-resource contexts where laboratory facilities are scarce. Few studies have explored how these changes are shaping people’s diagnostic journeys and their modes of accessing such technologies. In this paper I show how sick people and their families in a peri-urban area in Burkina Faso attempt to access diagnostic technologies and make themselves visible to the healthcare system through papers. In this context, I show how referral papers and diagnostic papers take on significance for people as they attempt to access care and diagnostic technologies and ‘carry’ knowledge between different levels of the healthcare system. The use of papers is often an uncertain undertaking, as they remain unintelligible to the sick and the layperson. I highlight how the form of the papers makes a crucial difference to the ways that sick people are able to use them. Papers and diagnostic technologies present both opportunities and challenges, and simultaneously engender hope, uncertainty, disappointment, and despair for the sick seeking a cure. Uncertainties, especially financial ones, arise with the possibility of new referrals and diagnostic tests, and along the way many give up or are immobilised when faced with diagnostic ambiguity.
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- 2021
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12. The Development of an Interface-Locating Extraction Device for the Automated Application of Aqueous Two-Phase Systems to Rapid Paper-Based Assays
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Toubian, Adam Ashkan
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Bioengineering ,automated ,device ,diagnostics ,immunoassay ,lateral-flow ,urine - Abstract
The clinical diagnosis of urinary tract infections (UTIs) faces challenges characterized by prolonged test results, contributing to over-prescription of antibiotics, and missed diagnoses. Point-of-care (POC) tests such as the lateral-flow immunoassay (LFA) attempt to alleviate this issue by providing patients with rapid results; however, their effectiveness is limited by low sensitivity. To improve the performance of the LFA, this thesis focuses on the development of an automated device that enables the addition of a sample preconcentration step at the POC using an aqueous two-phase system (ATPS). The device utilizes a photoresistor-based interface detection algorithm to selectively extract the bottom phase of the ATPS, containing concentrated biomarker, thereby avoiding the dispensing of the undesired top phase onto an LFA. The device incorporates a custom syringe pump module to apply the sample fluid to the LFA, and a gravity-based buffer dispensing module to facilitate the application of running buffer following sample addition. The affordability of the device is ensured through the use of reusable electrical components and cost- effective consumables, making it accessible to physician offices and mobile clinics at the POC. Experimental results demonstrate the successful automation of ATPS application onto the LFA, effectively extracting the bottom phase without any of the top phase. This advancement brings sample preconcentration using an ATPS one step closer to clinical adoption, offering a sensitive, rapid, and user-friendly UTI diagnostic solution.
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- 2023
13. Method for Rating and Analyzing the Combined Effects of Moisture and Temperature on the Oil–Paper Insulation System of Power Transformers by Means of Load Variations
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de Carvalho Sousa, Felipe Resende, de Jesus Ribeiro, Cacilda, Pereira Marques, André, and da Cunha Brito, Leonardo
- Published
- 2020
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14. Progress in Functional Urology Reflected in Recent Papers in the Journal of Clinical Medicine
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Martin C. Michel
- Subjects
benign prostatic hyperplasia ,overactive bladder syndrome ,stress urinary incontinence ,epidemiology ,pathophysiology ,diagnostics ,Medicine - Abstract
Benign conditions of the lower urinary tract, including benign prostatic hyperplasia, overactive bladder syndrome, and stress urinary incontinence, are frequent in the general population. Despite their benign nature, they have major adverse effects on the quality of life of the afflicted patients and their partners. Despite major progress in the diagnosis and treatment of these conditions, improved understanding and management of these patients remain substantial medical needs. This editorial discusses some recent high-quality articles published in the Journal of Clinical Medicine on the understanding of the epidemiology, pathophysiology, diagnostic, and treatment of benign diseases of the lower urinary tract tissues such as the bladder and prostate.
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- 2023
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15. Findings from University of Oklahoma Update Understanding of Helicobacter (Polymerase Chain Reaction On In-cage Filter Paper At Different Time Points To Detect Helicobacter Spp).
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COLONIES (Biology) ,HELICOBACTER diseases ,GRAM-negative bacteria ,BACTERIAL genetics ,FILTER paper - Abstract
A recent report from the University of Oklahoma discusses the challenges of detecting Helicobacter spp. infections in mice. The researchers used polymerase chain reaction (PCR) testing on in-cage filter paper to screen mouse colonies for the presence of Helicobacter species. However, the study found that PCR testing on the filter paper may not be reliable in detecting low levels of Helicobacter spp. nucleic acid in dirty bedding. These findings highlight the need for alternative methods of detecting and monitoring Helicobacter infections in laboratory animals. [Extracted from the article]
- Published
- 2024
16. A review of the use of propensity score diagnostics in papers published in high-ranking medical journals
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Emily Granger, Tim Watkins, Jamie C. Sergeant, and Mark Lunt
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Covariate balance ,Confounding ,Propensity scores ,Diagnostics ,Epidemiology ,Medicine (General) ,R5-920 - Abstract
Abstract Background Propensity scores are widely used to deal with confounding bias in medical research. An incorrectly specified propensity score model may lead to residual confounding bias; therefore it is essential to use diagnostics to assess propensity scores in a propensity score analysis. The current use of propensity score diagnostics in the medical literature is unknown. The objectives of this study are to (1) assess the use of propensity score diagnostics in medical studies published in high-ranking journals, and (2) assess whether the use of propensity score diagnostics differs between studies (a) in different research areas and (b) using different propensity score methods. Methods A PubMed search identified studies published in high-impact journals between Jan 1st 2014 and Dec 31st 2016 using propensity scores to answer an applied medical question. From each study we extracted information regarding how propensity scores were assessed and which propensity score method was used. Research area was defined using the journal categories from the Journal Citations Report. Results A total of 894 papers were included in the review. Of these, 187 (20.9%) failed to report whether the propensity score had been assessed. Commonly reported diagnostics were p-values from hypothesis tests (36.6%) and the standardised mean difference (34.6%). Statistical tests provided marginally stronger evidence for a difference in diagnostic use between studies in different research areas (p = 0.033) than studies using different propensity score methods (p = 0.061). Conclusions The use of diagnostics in the propensity score medical literature is far from optimal, with different diagnostics preferred in different areas of medicine. The propensity score literature may improve with focused efforts to change practice in areas where suboptimal practice is most common.
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- 2020
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17. A review of the use of propensity score diagnostics in papers published in high-ranking medical journals
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Granger, Emily, Watkins, Tim, Sergeant, Jamie C., and Lunt, Mark
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- 2020
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18. Summary Paper on the 2023 European Association of Urology Guidelines on the Management of Non-neurogenic Male Lower Urinary Tract Symptoms.
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Gravas, Stavros, Gacci, Mauro, Gratzke, Christian, Herrmann, Thomas R.W., Karavitakis, Markos, Kyriazis, Iason, Malde, Sachin, Mamoulakis, Charalampos, Rieken, Malte, Sakalis, Vasileios I., Schouten, Natasha, Speakman, Mark J., Tikkinen, Kari A.O., and Cornu, Jean-Nicolas
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URINARY organs , *BEHAVIOR modification , *DELPHI method , *WATCHFUL waiting , *PROSTATE-specific antigen , *MALE infertility , *PROSTATE cancer - Abstract
Male lower urinary tract dysfunction represents a common problem in the community. Physicians should approach these patients based on the best available evidence. This summary provides the up-to-date recommendations for the evaluation and the management of men with lower urinary tract symptoms. Lower urinary tract symptoms (LUTS) are common, often bothersome, and have multifactorial aetiology. To present a summary of the 2023 version of the European Association of Urology guidelines on the management of male LUTS. A structured literature search from 1966 to 2021 selected the articles with the highest certainty evidence. The Delphi technique consensus approach was used to develop the recommendations. The assessment of men with LUTS should be practical. A careful medical history and physical examination are essential. Validated symptom scores, urine test, uroflowmetry, and postvoid urine residual, as well as frequency-volume charts for patients with nocturia or predominately storage symptoms should be used. Prostate-specific antigen should be ordered if a diagnosis of prostate cancer changes the treatment plan. Urodynamics should be performed for selected patients. Men with mild symptoms are candidates for watchful waiting. Behavioural modification should be offered to men with LUTS prior to, or concurrent with, treatment. The choice of medical treatment depends on the assessment findings, predominant type of symptoms, ability of the treatment to change the findings, and the expectations to be met in terms of the speed of onset, efficacy, side effects, and disease progression. Surgery is reserved for men with absolute indications, and for patients who fail or prefer not to receive medical therapy. Surgical management has been divided into five sections: resection, enucleation, vaporisation, and alternative ablative and nonablative techniques. The choice of surgical technique depends on patient's characteristics, expectations, and preferences; surgeon's expertise; and availability of modalities. The guidelines provide an evidence-based approach for the management of male LUTS. A clinical assessment should identify the cause(s) of symptoms and define the clinical profile and patient's expectations. The treatment should aim to ameliorate symptoms and reduce the risk of complications. [ABSTRACT FROM AUTHOR]
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- 2023
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19. Antibody affinity as a driver of signal generation in a paper-based immunoassay for Ebola virus surveillance
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James B. Munro, Andrea C. Mora, Lara P. Murray, Charles R. Mace, and Ramesh Govindan
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Paper analytical devices ,medicine.drug_class ,Microfluidics ,02 engineering and technology ,Biology ,medicine.disease_cause ,Monoclonal antibody ,Antibodies, Viral ,01 natural sciences ,Biochemistry ,Epitope ,Analytical Chemistry ,Serology ,Affinity Reagent ,Viral Envelope Proteins ,medicine ,Humans ,Immunoassays ,Diagnostics ,Immunoassay ,Ebola virus ,medicine.diagnostic_test ,010401 analytical chemistry ,Equipment Design ,Hemorrhagic Fever, Ebola ,Microfluidic Analytical Techniques ,021001 nanoscience & nanotechnology ,Ebolavirus ,Virology ,0104 chemical sciences ,Ectodomain ,Paper-based microfluidics ,Ebola ,biology.protein ,Antibody ,0210 nano-technology ,Research Paper - Abstract
Graphical abstract During epidemics, such as the frequent and devastating Ebola virus outbreaks that have historically plagued regions of Africa, serological surveillance efforts are critical for viral containment and the development of effective antiviral therapeutics. Antibody serology can also be used retrospectively for population-level surveillance to provide a more complete estimate of total infections. Ebola surveillance efforts rely on enzyme-linked immunosorbent assays (ELISAs), which restrict testing to laboratories and are not adaptable for use in resource-limited settings. In this manuscript, we describe a paper-based immunoassay capable of detecting anti-Ebola IgG using Ebola virus envelope glycoprotein ectodomain (GP) as the affinity reagent. We evaluated seven monoclonal antibodies (mAbs) against GP—KZ52, 13C6, 4G7, 2G4, c6D8, 13F6, and 4F3—to elucidate the impact of binding affinity and binding epitope on assay performance and, ultimately, result interpretation. We used biolayer interferometry to characterize the binding of each antibody to GP before assessing their performance in our paper-based device. Binding affinity (KD) and on rate (kon) were major factors influencing the sensitivity of the paper-based immunoassay. mAbs with the best KD (3–25 nM) exhibited the lowest limits of detection (ca. μg mL−1), while mAbs with KD > 25 nM were undetectable in our device. Additionally, and most surprisingly, we determined that observed signals in paper devices were directly proportional to kon. These results highlight the importance of ensuring that the quality of recognition reagents is sufficient to support desired assay performance and suggest that the strength of an individual’s immune response can impact the interpretation of assay results. Supplementary Information The online version contains supplementary material available at 10.1007/s00216-021-03317-4.
- Published
- 2021
20. Strategic reuse of rapid antigen tests for coagulation status assessment: an integrated machine learning approach
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Sun, Allan, Nasser, Arian, Chen, Chaohao, Zhao, Yunduo Charles, Zhao, Haimei, Wang, Zihao, Cheng, Wenlong, Qian, Pierre, and Ju, Lining Arnold
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- 2024
- Full Text
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21. Patterned paper and alternative materials as substrates for low-cost microfluidic diagnostics
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Ballerini, David R., Li, Xu, and Shen, Wei
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- 2012
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22. Most Common Publication Types of Neuroimaging Literature: Papers With High Levels of Evidence Are on the Rise
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Andy Wai Kan Yeung
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publication type ,neuroimaging ,diagnostics ,bibliometric ,citation distribution ,uncitedness ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
Objective: This study evaluated the bibliometric data of the most common publication types of the neuroimaging literature.Methods: PubMed was searched to identify all published papers with “neuroimaging” as their MeSH Major Topics, and they were further searched by the following publication types: case report, clinical trial, comparative study, editorial, evaluation study, guideline, meta-analysis, multicenter study, randomized controlled trial, review, technical report, and validation study. The proportion of papers belonging to each publication type published in neuroimaging journals was calculated. Year-adjusted mean citation counts for each publication type were computed using data from Web of Science. Publication trend and its correlation with citation performance were assessed.Results: Review and comparative study were the most common publication types. Publication types with the highest proportion in neuroimaging journals were guideline, validation study, and technical reports. Since the year 2000, multicenter study, review, and meta-analysis showed the strongest linear increase in annual publication count. These publication types also had the highest year-adjusted citation counts (4.7–10.0). Publication types with the lowest year-adjusted citation counts were editorial and case report (0.5–1.0). It was estimated that 12.5% of the publications labeled as case reports were incorrectly labeled.Conclusions: Neuroimaging literature has been expanding with papers of higher levels of evidence, such as meta-analyses, multicenter studies, and randomized controlled trials.
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- 2020
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23. Chronometric Quantitation of Analytes in Paper-Based Microfluidic Devices (MicroPADs) via Enzymatic Degradation of a Metastable Biomatrix
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Aditya R. Jangid, E. Brandon Strong, Emiliano Escamilla, Brittany A. Lore, Nicholas J. Tod, Robert Thiel, Andres W. Martinez, and Nathaniel W. Martinez
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microfluidic paper-based analytical device ,µPAD ,microPAD ,point-of-care ,diagnostics ,microfluidics ,wax printing ,immunoassays ,analytical chemistry ,Engineering machinery, tools, and implements ,TA213-215 ,Technological innovations. Automation ,HD45-45.2 - Abstract
The following article summarizes United States Patent Application No. US20180052155A1, titled ‘Assay Devices and Methods’ (filed 16 August 2016, published 22 February 2018). While lateral flow assays (LFAs) have revolutionized point-of-care diagnostics by enabling accurate, inexpensive, and rapid detection of biomarkers, they typically do not provide quantitative results. Hence, there is a significant need for quantitative assays at the point of care. This patent summary describes a novel method of chronometric biomarker quantitation via enzymatic degradation of a metastable gelatin-based biomatrix, principally suited for use in paper-based microfluidic devices (microPADs). This new quantitation mechanism was designed to meet the ASSURED criteria for point-of-care diagnostic devices laid forth by the World Health Organization and may ultimately provide increased access to healthcare, at a significantly reduced cost, around the world.
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- 2019
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24. Development and Evaluation of a Paper-Based Microfluidic Device for Detection of Listeria monocytogenes on Food Contact and Non-Food Contact Surfaces
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Codi Jo Broten, John B. Wydallis, Thomas H. Reilly, and Bledar Bisha
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diagnostics ,colorimetric detection ,foodborne pathogens ,PCR ,rapid detection ,environmental sampling ,Chemical technology ,TP1-1185 - Abstract
Listeria monocytogenes is the third most deadly foodborne pathogen in the United States. The bacterium is found in soil and water, contaminating raw food products and the processing environment, where it can persist for an extended period. Currently, testing of food contact and non-food contact surfaces is performed using an array of sampling devices and endpoint technologies, offering various levels of sensitivity, cost, user skill, and time to detection. Paper-based microfluidic devices (µPADs) are a rapid detection platform amenable to low-cost, user-friendly, and portable diagnostics. In this study, we developed and evaluated a µPAD platform specific for the colorimetric detection of the Listeria genus following recovery from food contact and non-food contact surfaces. For detection, four colorimetric substrates specific for the detection of β-glucosidase, two broths selective for the detection of Listeria spp., and a nonselective broth were evaluated to facilitate detection of Listeria spp. The limit of detection and time to detection were determined by using pure bacterial cultures. After 8 h enrichment, L. monocytogenes (102 Colony Forming Units (CFU)/coupon) was detected on every surface. After 18 h enrichment, L. monocytogenes (102 CFU/coupon) was detected on all surfaces with all swabbing devices. This study demonstrated the ability of the µPAD-based method to detect potentially stressed cells at low levels of environmental contamination.
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- 2022
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25. Engineering paper as a substrate for blood typing bio-diagnostics
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Su, Jielong, Al-Tamimi, Mohammad, and Garnier, Gil
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- 2012
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26. Progress in Functional Urology Reflected in Recent Papers in the Journal of Clinical Medicine.
- Author
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Michel, Martin C.
- Subjects
- *
CLINICAL medicine , *URINARY stress incontinence , *BENIGN prostatic hyperplasia , *OVERACTIVE bladder , *UROLOGY , *URINARY organs - Abstract
Benign conditions of the lower urinary tract, including benign prostatic hyperplasia, overactive bladder syndrome, and stress urinary incontinence, are frequent in the general population. Despite their benign nature, they have major adverse effects on the quality of life of the afflicted patients and their partners. Despite major progress in the diagnosis and treatment of these conditions, improved understanding and management of these patients remain substantial medical needs. This editorial discusses some recent high-quality articles published in the Journal of Clinical Medicine on the understanding of the epidemiology, pathophysiology, diagnostic, and treatment of benign diseases of the lower urinary tract tissues such as the bladder and prostate. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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27. Recent Advances in Paper-Based Sensors
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Edith Chow, Burkhard Raguse, Devi D. Liana, and J. Justin Gooding
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paper ,sensor ,device ,microfluidics ,lab-on-a-chip ,diagnostics ,analytical ,Chemical technology ,TP1-1185 - Abstract
Paper-based sensors are a new alternative technology for fabricating simple, low-cost, portable and disposable analytical devices for many application areas including clinical diagnosis, food quality control and environmental monitoring. The unique properties of paper which allow passive liquid transport and compatibility with chemicals/biochemicals are the main advantages of using paper as a sensing platform. Depending on the main goal to be achieved in paper-based sensors, the fabrication methods and the analysis techniques can be tuned to fulfill the needs of the end-user. Current paper-based sensors are focused on microfluidic delivery of solution to the detection site whereas more advanced designs involve complex 3-D geometries based on the same microfluidic principles. Although paper-based sensors are very promising, they still suffer from certain limitations such as accuracy and sensitivity. However, it is anticipated that in the future, with advances in fabrication and analytical techniques, that there will be more new and innovative developments in paper-based sensors. These sensors could better meet the current objectives of a viable low-cost and portable device in addition to offering high sensitivity and selectivity, and multiple analyte discrimination. This paper is a review of recent advances in paper-based sensors and covers the following topics: existing fabrication techniques, analytical methods and application areas. Finally, the present challenges and future outlooks are discussed.
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- 2012
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28. Estimation of state of paper electric insulation based on results of measuring recovered voltage
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Kononenko, A. I. and Khokhryakov, A. V.
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- 2010
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29. Characterization of Reagent Pencils for Deposition of Reagents onto Paper-Based Microfluidic Devices
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Cheyenne H. Liu, Isabelle C. Noxon, Leah E. Cuellar, Amanda L. Thraen, Chad E. Immoos, Andres W. Martinez, and Philip J. Costanzo
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paper ,diagnostics ,microfluidic paper-based analytical devices (microPADs) ,pencil ,wear ,colorimetry ,Mechanical engineering and machinery ,TJ1-1570 - Abstract
Reagent pencils allow for solvent-free deposition of reagents onto paper-based microfluidic devices. The pencils are portable, easy to use, extend the shelf-life of reagents, and offer a platform for customizing diagnostic devices at the point of care. In this work, reagent pencils were characterized by measuring the wear resistance of pencil cores made from polyethylene glycols (PEGs) with different molecular weights and incorporating various concentrations of three different reagents using a standard pin abrasion test, as well as by measuring the efficiency of reagent delivery from the pencils to the test zones of paper-based microfluidic devices using absorption spectroscopy and digital image colorimetry. The molecular weight of the PEG, concentration of the reagent, and the molecular weight of the reagent were all found to have an inverse correlation with the wear of the pencil cores, but the amount of reagent delivered to the test zone of a device correlated most strongly with the concentration of the reagent in the pencil core. Up to 49% of the total reagent deposited on a device with a pencil was released into the test zone, compared to 58% for reagents deposited from a solution. The results suggest that reagent pencils can be prepared for a variety of reagents using PEGs with molecular weights in the range of 2000 to 6000 g/mol.
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- 2017
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30. A Cellulose Paper-Based Fluorescent Lateral Flow Immunoassay for the Quantitative Detection of Cardiac Troponin I
- Author
-
Satheesh Natarajan, Joseph Jayaraj, and Duarte Miguel F. Prazeres
- Subjects
biomarker ,carbon nanofiber ,cellulose ,diagnostics ,immunoassay ,lateral flow assays ,Biotechnology ,TP248.13-248.65 - Abstract
This paper presents a lateral flow assay (LFA) for the quantitative, fluorescence-based detection of the cardiac biomarker troponin I (cTnI) that features an analytical strip made of cellulose filter paper. The results show that the wicking and test time are comparable to those obtained with conventional nitrocellulose (NC)-based LFAs. Further, the cellulose paper provides an excellent background with no auto-fluorescence that is very adequate in detecting fluorescent lines. While fluorescence that was generated with cellulose strips was lower when compared to that generated in NC strips, signals could be improved by layering carbon nanofibers (CNF) on the cellulose. A nonlinear behavior of the concentration–response relationship was observed for the LFA architectures with NC, cellulose, and cellulose-CNF in the 0 to 200 ng/mL cTnI concentration range. The measurements were consistent and characterized by coefficients of variation lower than 2.5%. Detection and quantitation limits that were in the range 1.28–1.40 ng/mL and 2.10–2.75 ng/mL were obtained for LFA with cellulose and cellulose CNF strips that are equivalent to the limits obtained with the standard NC LFA. Overall, we showed that commercially available filter paper can be used in the analytical strip of LFA.
- Published
- 2021
- Full Text
- View/download PDF
31. Nonplanar Three Dimensional Paper Microfluidics And Distance-Based Semi-Quantitative DNA Detection
- Author
-
Kalish, Brent Nathaniel
- Subjects
Mechanical engineering ,Diagnostics ,Microfluidics ,Paper-based ,POC - Abstract
The development of patterning high-resolution microfluidic circuits onto cellulose paper in 2007 initiated widespread research into the use of the paper as a low-cost, easy-to-use alternative substrate over the glass and plastics of traditional microfluidics. Paper, as a porous hydrophilic material, naturally wicks fluid through itself, without the need to external pumps or power sources. The patterning of paper into hydrophobic and hydrophilic regions, now achievable with consumer-grade office printers, allowed the design of new 2D devices, capable of multi-analyte detection. 3D devices, made from multiple stacked layers of paper, offer even more possibilities for complex, multi-fluid routing in smaller overall device footprints. The use of patterned aerosol adhesives are investigated as an improved method of attaching multiple paper layers together rapidly and with minimal interference of interlayer fluid transport. Patterned aerosol adhesives also enable the development of nonplanar 3D devices, which represent a novel platform upon which to develop new microfluidic devices, which would otherwise be impossible to construct or function in a planar device.Much of paper microfluidics research is focused on developing more sophisticated detection methods that provide quantitative data, instead of simple colorimetric qualitative yes/no answers. Frequently quantification is obtained by scanning the device and performing a color intensity analysis to relate a color change to concentrations of a target analyte. This technique suffers due to variations in the quality of imaging equipment and the ambient lighting conditions during image acquisition. To address this, some have proposed a distance-based lateral flow device, where the distance traveled by a colored substance is proportional to the target analyte concentration. The use of a microsphere aggregation-based sandwich assay was investigated for semi-quantitatively determining the concentration of a target ssDNA strand.
- Published
- 2015
32. Spatial neglect in the digital age: Influence of presentation format on patients' test behavior.
- Author
-
Rosenzopf, Hannah, Sperber, Christoph, Wortha, Franz, Wiesen, Daniel, Muth, Annika, Klein, Elise, Möller, Korbinian, and Karnath, Hans-Otto
- Subjects
UNILATERAL neglect ,DIGITAL technology ,ELECTRONIC paper ,STROKE patients ,SEARCHING behavior - Abstract
Objective: Computerized neglect tests could significantly deepen our disorder-specific knowledge by effortlessly providing additional behavioral markers that are hardly or not extractable from existing paper-and-pencil versions. This study investigated how testing format (paper versus digital), and screen size (small, medium, large) affect the Center of cancelation (CoC) in right-hemispheric stroke patients in the Letters and the Bells cancelation task. Our second objective was to determine whether a machine learning approach could reliably classify patients with and without neglect based on their search speed, search distance, and search strategy. Method: We compared the CoC measure of right hemisphere stroke patients with neglect in two cancelation tasks across different formats and display sizes. In addition, we evaluated whether three additional parameters of search behavior that became available through digitization are neglect-specific behavioral markers. Results: Patients' CoC was not affected by test format or screen size. Additional search parameters demonstrated lower search speed, increased search distance, and a more strategic search for neglect patients than for control patients without neglect. Conclusion: The CoC seems robust to both test digitization and display size adaptations. Machine learning classification based on the additional variables derived from computerized tests succeeded in distinguishing stroke patients with spatial neglect from those without. The investigated additional variables have the potential to aid in neglect diagnosis, in particular when the CoC cannot be validly assessed (e.g., when the test is not performed to completion). [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
33. A paper-based assay for detecting hypervirulent Klebsiella pnuemoniae using CRISPR-Cas13a system.
- Author
-
Bhattacharjee, Gargi, Gohil, Nisarg, Khambhati, Khushal, Gajjar, Devarshi, Abusharha, Ali, and Singh, Vijai
- Subjects
- *
MEDICAL personnel , *KLEBSIELLA pneumoniae , *KLEBSIELLA , *DRUG resistance in microorganisms , *POLYSACCHARIDES , *CRISPRS - Abstract
[Display omitted] • A simple and user-friendly diagnostics to detect the hypervirulent K. pneumoniae. • CRISPR-assisted point-of-need tool that stands worthy of the ASSURED criteria. • Species-specific detection of solely the test-strains of K. pneumoniae. • No cross-reactivity observed when tested on different genera besides the test strains. • Instrument-free readout to extend the reach of the technology to remote locations. Klebsiella pneumoniae , a prevalent healthcare-associated pathogen, poses a significant challenge to diagnosis and treatment due to its virulence and antimicrobial resistance. The demand for more efficient, precise and accessible diagnostic methods is imperative, as current approaches are labor-intensive and resource-dependent. In this study, a CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)-based diagnostic tool for rapid detection of hypervirulent K. pneumoniae infections was proposed. We integrated recombinase polymerase amplification (RPA) coupled with a lateral flow assay and Cas13a (CRISPR associated protein 13a) to target the housekeeping rpoB gene for species-specific detection and the capsular polysaccharide regulating gene rmpA for identification of hypervirulent strains of K. pneumoniae. Tested on 18 K. pneumoniae strains, the devised tool successfully detected hypervirulent strains K. pneumoniae M59 and K. pneumoniae KP109 showing presence of rmpA. This study allows to develop an instrument-free platform for routine diagnosis of K. pneumoniae from serum, urine, and saliva samples that would empower healthcare personnel to facilitate proper and timely treatment of infections caused by the K. pneumoniae. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
34. COVID-19 living paper: overview of information available to support the development of medical countermeasures and interventions against COVID-19
- Author
-
Martine DENIS, Valerie VANDEWEERD, Rein VERBEEKE, and Diane VAN DER VLIET
- Subjects
SARS-CoV-2 ,public health ,review ,therapeutics ,diagnostics ,COVID-19 ,epidemiology ,vaccines ,living paper ,clinical ,animal models - Abstract
The living paper on the new coronavirus disease (COVID-19) provides a structured compilation of scientific data about the virus, the disease and its control.Its objective is to help scientists identify the most relevant publications on COVID-19 in the mass of information that appears every day. It is also expected to foster a global understanding of disease control and stimulate transdisciplinary initiatives. This living paper is updated on a weekly basis. It is an initiative of the journal Transciplinary Insights.
- Published
- 2020
- Full Text
- View/download PDF
35. Paper-based smart microfluidics for education and low-cost diagnostics
- Author
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Suzanne Smith, Klariska Moodley, Ureshnie Govender, Hao Chen, Louis Fourie, Sibusiso Ngwenya, Shavon Kumar, Phumlani Mjwana, Hastings Cele, Mesuli B. Mbanjwa, Suretha Potgieter, Trudi-Heleen Joubert, and Kevin Land
- Subjects
diagnostics ,printed electronics ,biosensors ,micro paper-based analytical devices ,μPAD ,Science ,Science (General) ,Q1-390 ,Social Sciences ,Social sciences (General) ,H1-99 - Abstract
Current centralised healthcare models pose many challenges, particularly for developing countries such as South Africa, where travel and time costs make it difficult for patients to seek healthcare, even when urgently needed. To address this issue, point-of-care (PoC) tests, which are performed at or near the site of clinical care, have gained popularity and are actively being developed. Microfluidic systems, in which small volumes of fluids can be processed, provide an ideal platform on which to develop PoC diagnostic solutions. Specifically, the emerging field of paper-based microfluidics, with advantages such as low-cost, disposability and minimal external equipment requirements, provides unique opportunities for addressing healthcare issues in developing countries. This work explores the field of paper-based microfluidics, with step-by-step instructions on the design, manufacture and testing processes to realise paper-based devices towards diagnostic applications. Paper-based microfluidic and electronic components are presented, as well as the integration of these components to provide smart paper-based devices. This serves as an educational tool, enabling both beginners and experts in the field to fast-track development of unique paper-based solutions towards PoC diagnostics, with emphasis on the South African context, where both the need for and impact of these solutions are great.
- Published
- 2015
- Full Text
- View/download PDF
36. Model building for current transformer paper-oil insulation state diagnostics
- Author
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L.S. Skrupskaya, A.O. Oliinyk, and A.A. Sakhno
- Subjects
diagnostics ,transformer equipment ,insulation ,a neural network ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
A feedforward neural network based diagnostic model of oil-impregnated paper insulation of a current transformer has been developed. Its experimental validation as compared with a regression model has been performed.
- Published
- 2014
37. Chronometric Quantitation of Analytes in Paper-Based Microfluidic Devices (MicroPADs) via Enzymatic Degradation of a Metastable Biomatrix
- Author
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Emiliano Escamilla, E. Bradley Strong, Nicholas J. Tod, Robert Thiel, Andres W. Martinez, Brittany A. Lore, Nathaniel W. Martinez, and Aditya Jangid
- Subjects
Analyte ,µPAD ,lcsh:Engineering machinery, tools, and implements ,Computer science ,Microfluidics ,microfluidics ,Nanotechnology ,02 engineering and technology ,01 natural sciences ,Rapid detection ,World health ,microPAD ,wax printing ,analytical chemistry ,diagnostics ,lcsh:Technological innovations. Automation ,Point of care ,lcsh:HD45-45.2 ,010401 analytical chemistry ,microfluidic paper-based analytical device ,General Engineering ,Paper based ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,immunoassays ,point-of-care ,lcsh:TA213-215 ,0210 nano-technology ,Enzymatic degradation - Abstract
The following article summarizes United States Patent Application No. US20180052155A1, titled ‘Assay Devices and Methods’ (filed 16 August 2016, published 22 February 2018). While lateral flow assays (LFAs) have revolutionized point-of-care diagnostics by enabling accurate, inexpensive, and rapid detection of biomarkers, they typically do not provide quantitative results. Hence, there is a significant need for quantitative assays at the point of care. This patent summary describes a novel method of chronometric biomarker quantitation via enzymatic degradation of a metastable gelatin-based biomatrix, principally suited for use in paper-based microfluidic devices (microPADs). This new quantitation mechanism was designed to meet the ASSURED criteria for point-of-care diagnostic devices laid forth by the World Health Organization and may ultimately provide increased access to healthcare, at a significantly reduced cost, around the world.
- Published
- 2019
38. Usability as a guiding principle for the design of paper-based, point-of-care devices – A review.
- Author
-
Murray, Lara P. and Mace, Charles R.
- Subjects
- *
POINT-of-care testing , *SAMPLING (Process) - Abstract
Due to their portability, versatility for supporting multiple assay formats, and potential for resulting in low-cost assays, paper-based analytical devices (PADs) are an increasingly popular format as a platform for the development of point-of-care tests. However, very few PADs have been translated successfully to their intended environments outside of academic settings. Often overlooked as a factor that inhibits translation, usability is a vital characteristic of any successful point-of-care test. Recent advancements in PAD design have demonstrated improved usability by simplifying various aspects of user operation, including sample collection, sample processing, device operation, detection, and readout/interpretation. Field testing at various stages of device design can offer critical feedback about device usability, especially when it involves the proposed end-user or other stakeholders. By highlighting advances in usability, we aim to encourage thoughtful and rigorous design at the academic prototyping stage to address one outstanding hurdle that limits the number of PADs that make it from the benchtop to the point-of-care. Image 1 • Paper-based devices have potential for use at the point-of-care. • Devices that are user-friendly are more likely to be translated to the field. • Additional user steps create additional opportunities for user error. • We discuss ways to streamline user operation of paper-based devices. • We highlight three case studies for devices deployed successfully to the field. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
39. Recent Advances in Paper-Based Sensors.
- Author
-
Liana, Devi D., Raguse, Burkhard, Gooding, J. Justin, and Chow, Edith
- Subjects
APPROPRIATE technology ,ENVIRONMENTAL monitoring ,DETECTORS ,MICROFLUIDIC analytical techniques ,THREE-dimensional display systems ,MICROFABRICATION ,SENSITIVITY analysis - Abstract
Paper-based sensors are a new alternative technology for fabricating simple, low-cost, portable and disposable analytical devices for many application areas including clinical diagnosis, food quality control and environmental monitoring. The unique properties of paper which allow passive liquid transport and compatibility with chemicals/biochemicals are the main advantages of using paper as a sensing platform. Depending on the main goal to be achieved in paper-based sensors, the fabrication methods and the analysis techniques can be tuned to fulfill the needs of the end-user. Current paper-based sensors are focused on microfluidic delivery of solution to the detection site whereas more advanced designs involve complex 3-D geometries based on the same microfluidic principles. Although paper-based sensors are very promising, they still suffer from certain limitations such as accuracy and sensitivity. However, it is anticipated that in the future, with advances in fabrication and analytical techniques, that there will be more new and innovative developments in paper-based sensors. These sensors could better meet the current objectives of a viable low-cost and portable device in addition to offering high sensitivity and selectivity, and multiple analyte discrimination. This paper is a review of recent advances in paper-based sensors and covers the following topics: existing fabrication techniques, analytical methods and application areas. Finally, the present challenges and future outlooks are discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
40. (In)Visible Disease:Motions and Emotions Engendered by Papers and Diagnostics of People Accessing Healthcare in Burkina Faso
- Author
-
Pia Juul Bjertrup
- Subjects
Medicine (General) ,Referral ,media_common.quotation_subject ,Context (language use) ,Disease ,GN1-890 ,Faculty of Social Sciences ,Documents ,access to healthcare ,R5-920 ,Health care ,diagnostics ,Global health ,medicine ,burkina faso ,Sociology ,Diagnostics ,media_common ,Disappointment ,business.industry ,Burkino Faso ,visibility ,Ambiguity ,Access to healthcare ,Public relations ,Layperson ,Anthropology ,Visibility ,medicine.symptom ,business ,documents - Abstract
Within the last decade, challenges of diagnosis have emerged on the global health agenda, accompanied by an expansion in the use of point-of-care and rapid detection devices in low-resource contexts where laboratory facilities are scarce. Few studies have explored how these changes are shaping people’s diagnostic journeys and their modes of accessing such technologies. In this paper I show how sick people and their families in a peri-urban area in Burkina Faso attempt to access diagnostic technologies and make themselves visible to the healthcare system through papers. In this context, I show how referral papers and diagnostic papers take on significance for people as they attempt to access care and diagnostic technologies and ‘carry’ knowledge between different levels of the healthcare system. The use of papers is often an uncertain undertaking, as they remain unintelligible to the sick and the layperson. I highlight how the form of the papers makes a crucial difference to the ways that sick people are able to use them. Papers and diagnostic technologies present both opportunities and challenges, and simultaneously engender hope, uncertainty, disappointment, and despair for the sick seeking a cure. Uncertainties, especially financial ones, arise with the possibility of new referrals and diagnostic tests, and along the way many give up or are immobilised when faced with diagnostic ambiguity.
- Published
- 2021
41. Characterization of Reagent Pencils for Deposition of Reagents onto Paper-Based Microfluidic Devices
- Author
-
Amanda L. Thraen, Leah E. Cuellar, Isabelle C. Noxon, Philip J. Costanzo, Andres W. Martinez, Cheyenne H. Liu, and Chad E. Immoos
- Subjects
wear ,Absorption spectroscopy ,genetic structures ,lcsh:Mechanical engineering and machinery ,Microfluidics ,education ,Analytical chemistry ,microfluidic paper-based analytical devices (microPADs) ,02 engineering and technology ,01 natural sciences ,behavioral disciplines and activities ,Article ,chemistry.chemical_compound ,diagnostics ,lcsh:TJ1-1570 ,Electrical and Electronic Engineering ,Inverse correlation ,Chemistry ,Mechanical Engineering ,paper ,010401 analytical chemistry ,Paper based ,Polyethylene ,021001 nanoscience & nanotechnology ,pencil ,0104 chemical sciences ,Pencil (optics) ,Wear resistance ,colorimetry ,Chemical engineering ,Control and Systems Engineering ,Reagent ,0210 nano-technology - Abstract
Reagent pencils allow for solvent-free deposition of reagents onto paper-based microfluidic devices. The pencils are portable, easy to use, extend the shelf-life of reagents, and offer a platform for customizing diagnostic devices at the point of care. In this work, reagent pencils were characterized by measuring the wear resistance of pencil cores made from polyethylene glycols (PEGs) with different molecular weights and incorporating various concentrations of three different reagents using a standard pin abrasion test, as well as by measuring the efficiency of reagent delivery from the pencils to the test zones of paper-based microfluidic devices using absorption spectroscopy and digital image colorimetry. The molecular weight of the PEG, concentration of the reagent, and the molecular weight of the reagent were all found to have an inverse correlation with the wear of the pencil cores, but the amount of reagent delivered to the test zone of a device correlated most strongly with the concentration of the reagent in the pencil core. Up to 49% of the total reagent deposited on a device with a pencil was released into the test zone, compared to 58% for reagents deposited from a solution. The results suggest that reagent pencils can be prepared for a variety of reagents using PEGs with molecular weights in the range of 2000 to 6000 g/mol.
- Published
- 2017
42. Novel methods for improving rapid paper-based protein assays with gold nanoparticle detection
- Author
-
Lama, Lara
- Subjects
Medical Biotechnology ,diagnostics ,Gold nanoparticles ,ultrasound energy ,signal enhancement ,COMSOL Multiphysics simulations ,Medicinsk bioteknik ,microarrays ,paper-based assays - Abstract
This thesis describes methods for improving sensitivity in rapid singleplex and multiplex microarray assays. The assays utilize the optical characteristics of colloidal gold nanoparticles for the colorimetric detection of proteins. Multiplexed detection in sandwich immunoassays is limited by cross-reactivity between different detection antibodies. The cross-reactivity between antibodies can contribute to increased background noise - decreasing the Limit-of-Detection of the assay - or generate false positive signals. Paper I shows improved assay sensitivity in a multiplexed vertical flow assay by the application of ultrasonic energy to the gold nanoparticles functionalized with detection antibodies. The ultrasonication of the antibody conjugated gold nanoparticles resulted in a 10 000 fold increase in sensitivity in a 3-plex assay. COMSOL Multiphysics was used to simulate the acoustical energy of the probe used in Paper I for obtaining an indication of the size and direction of the forces acting upon the functionalized gold nanoparticles. In Paper II, it was studied if different gold nanoparticle conjugation methods and colorimetric signal enhancement of the gold nanoparticle conjugates could influence the sensitivity of a paper-based lateral flow microarray assay, targeting cardiac troponin T for the rapid diagnostics of acute myocardial infarction. Ultrasonication and signal enhancement of the detection gold nanoparticles has the potential of improving the sensitivity of paper based assays and expanding their potential future applications. QC 20170911
- Published
- 2017
43. Water-based alkyl ketene dimer ink for user-friendly patterning in paper microfluidics
- Author
-
Elisabeth Verpoorte, Gert Ij. Salentijn, Yumiao Hong, Nurul Hamidon, Pharmaceutical Analysis, and Medicinal Chemistry and Bioanalysis (MCB)
- Subjects
BLOOD ,Microfluidics ,Evaporation ,Nanotechnology ,02 engineering and technology ,POLY(DIMETHYLSILOXANE) BARRIERS ,DIAGNOSTICS ,01 natural sciences ,Biochemistry ,Analytical Chemistry ,Contact angle ,Emulsification procedure ,Journal Article ,Environmental Chemistry ,Semipermeable membrane ,Dissolution ,Spectroscopy ,Alkyl ,chemistry.chemical_classification ,SPRAY IONIZATION CARTRIDGE ,Inkwell ,PLASMA ,010401 analytical chemistry ,021001 nanoscience & nanotechnology ,ANALYTICAL DEVICES ,0104 chemical sciences ,chemistry ,SEPARATION ,0210 nano-technology - Abstract
We propose the use of water-based alkyl ketene dimer (AKD) ink for fast and user-friendly patterning of paper microfluidic devices either manually or using an inexpensive XY-plotter. The ink was produced by dissolving hydrophobic AKD in chloroform and emulsifying the solution in water. The emulsification was performed in a warm water bath, which led to an increased rate of the evaporation of chloroform. Subsequent cooling led to the final product, an aqueous suspension of fine AKD particles. The effects of surfactant and AKD concentrations, emulsification procedure, and cooling approach on final ink properties are presented, along with an optimized protocol for its formulation. This hydrophobic agent was applied onto paper using a plotter pen, after which the paper was heated to allow spreading of AKD molecules and chemical bonding with cellulose. A paper surface patterned with the ink (10 g L-1 AKD) yielded a contact angle of 135.6° for water. Unlike organic solvent-based solutions of AKD, this AKD ink does not require a fume hood for its use. Moreover, it is compatible with plastic patterning tools, due to the effective removal of chloroform in the production process to less than 2% of the total volume. Furthermore, this water-based ink is easy to prepare and use. Finally, the AKD ink can also be used for the fabrication of so-called selectively permeable barriers for use in paper microfluidic networks. These are barriers that stop the flow of water through paper, but are permeable to solvents with lower surface energies. We applied the AKD ink to confine and preconcentrate sample on paper, and demonstrated the use of this approach to achieve higher detection sensitivities in paper spray ionization-mass spectrometry (PSI-MS). Our patterning approach can be employed outside of the analytical lab or machine workshop for fast prototyping and small-scale production of paper-based analytical tools, for use in limited-resource labs or in the field.
- Published
- 2018
44. Paper-based smart microfluidics for education and low-cost diagnostics
- Author
-
MB Mbanjwa, Hao Chen, Louis Fourie, Kevin Land, Sibusiso Ngwenya, Ureshnie Govender, Suzanne Smith, Phumlani Mjwana, Shavon Kumar, Trudi-Heleen Joubert, K Moodley, S. Potgieter, and Hastings Cele
- Subjects
Computer science ,μPAD ,Microfluidics ,Context (language use) ,Time cost ,General Biochemistry, Genetics and Molecular Biology ,Field (computer science) ,lcsh:Social Sciences ,Health care ,diagnostics ,lcsh:Social sciences (General) ,lcsh:Science ,lcsh:Science (General) ,Point of care ,business.industry ,uPADs ,Paper based ,biosensors ,lcsh:H ,Work (electrical) ,Risk analysis (engineering) ,micro paper-based analytical devices ,General Earth and Planetary Sciences ,lcsh:Q ,lcsh:H1-99 ,printed electronics ,General Agricultural and Biological Sciences ,business ,lcsh:Q1-390 - Abstract
Current centralised healthcare models pose many challenges, particularly for developing countries such as South Africa, where travel and time costs make it difficult for patients to seek healthcare, even when urgently needed. To address this issue, point-of-care (PoC) tests, which are performed at or near the site of clinical care, have gained popularity and are actively being developed. Microfluidic systems, in which small volumes of fluids can be processed, provide an ideal platform on which to develop PoC diagnostic solutions. Specifically, the emerging field of paper-based microfluidics, with advantages such as low-cost, disposability and minimal external equipment requirements, provides unique opportunities for addressing healthcare issues in developing countries. This work explores the field of paper-based microfluidics, with step-by-step instructions on the design, manufacture and testing processes to realise paper-based devices towards diagnostic applications. Paper-based microfluidic and electronic components are presented, as well as the integration of these components to provide smart paper-based devices. This serves as an educational tool, enabling both beginners and experts in the field to fast-track development of unique paper-based solutions towards PoC diagnostics, with emphasis on the South African context, where both the need for and impact of these solutions are great.
- Published
- 2015
45. New myeloperoxidase detection system based on enzyme-catalysed oxidative synthesis of a dye for paper-based diagnostic devices.
- Author
-
Bassegoda, Arnau, Ferreres, Guillem, Pérez-Rafael, Sílvia, Hinojosa-Caballero, Dolores, Torrent-Burgués, Juan, and Tzanov, Tzanko
- Subjects
- *
WOUND infections , *MYELOPEROXIDASE , *CATALYSIS , *OXIDATION , *DIAGNOSTIC equipment , *BIOSYNTHESIS - Abstract
Abstract The severity and cost of wound infections strongly demands for simple and fast methods for wound infection determination. Point-of-care testing devices play a crucial role in order to achieve a fast diagnosis and early treatment. Myeloperoxidase (MPO) enzyme, detected in fluids of infected wounds has been postulated as a suitable biomarker for wound diagnostics. Here we present a new system for MPO detection, based on enzyme-catalysed oxidative synthesis of a dye that can be incorporated into paper-based point of care devices. Visual MPO detection has been achieved through the use of phenylenediamine, a common colourless hair dye precursor. MPO oxidation of these compounds yielded bright coloured products distinguishable from the colour of the wound environment. Immobilisation of the MPO substrates on paper strips was achieved through in situ interaction of the oxidised coloured product with branched polyethyleneimine. The colour reaction of the immobilized substrates, detectable by naked eye, responds to the MPO levels present in infected wound fluids revealing an easy system for incorporation of MPO detection in paper based diagnostic devices. Graphical abstract fx1 Highlights • A new sensitive MPO detection method for wound infection diagnose. • Fast visual detection of MPO levels corresponding to infected wounds avoiding haemoglobin cross-reaction. • A new detection method easily transferable to paper-based point of care diagnostic devices. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
46. A Hydroalcoholic Gel-Based Disinfection System for Deteriogenic Fungi on the Contemporary Mixed Media Artwork Poesia by Alessandro Kokocinski
- Author
-
Francesca Ambroselli, Fabiana Canini, Luca Lanteri, Martina Marconi, Claudia Mazzuca, Claudia Pelosi, Vittorio Vinciguerra, Elizabeth Wicks, and Laura Zucconi
- Subjects
Gellan gum ,poster paper ,blue-back ,disinfection treatment ,paper conservation ,diagnostics ,Archaeology ,CC1-960 - Abstract
The disinfection of deteriogenic microorganisms and the removal of induced chromatic alterations in artworks are still open challenges in the field of conservation. For this purpose, a new alcoholic hydrogel was tested to remove an extensive fungal attack from a multimaterial collage by the artist Alessandro Kokocinski and to mitigate chromatic changes caused by the contamination of its poster paper and plywood support layers. A Gellan gum-based hydrogel was used, which was modified by adding a high concentration of alcohol (66.7% ethanol), to give the system an effective disinfecting agent in addition to the detergent capacity of the gel for water-sensitive works of art. It was successfully tested on samples mimicking the complex stratigraphy of the artwork under study. To create replica mock-ups, the artwork materials and stratigraphy were investigated through diagnostic and laboratory techniques such as multispectral imaging, X-ray fluorescence spectroscopy, Fourier transform infrared spectroscopy, and pyrolysis coupled with gas-chromatography-mass spectrometry. The treatment was shown to have a disinfecting effect on the test samples and did not alter their structure, allowing us to apply the method to the artwork. Here, the hydrogel successfully removed and inhibited fungal proliferation in addition to mitigating the color changes caused by fungi.
- Published
- 2023
- Full Text
- View/download PDF
47. Laser cleaning of paper using Nd:YAG laser running at 532 nm
- Author
-
Kolar, Jana, Strlič, M., Müller-Hess, D., Gruber, A., Troschke, K., Pentzien, S., and Kautek, W.
- Subjects
- *
INDUSTRIAL lasers , *PAPER , *CELLULOSE , *POLYMERIZATION - Abstract
The paper reports on immediate effects of pulsed laser operating at 532 nm and fluences below 2.5 J cm–2 on soiled cellulose. The degree of polymerisation was determined viscometrically, while diffuse reflectance FTIR was used to gain insight into the changes in the chemical composition. Although no detectable immediate changes were observed after treatment of paper with laser beam at 532 nm, the irradiation of paper containing carbonaceous dirt resulted in significant discoloration of the treated substrate. The possible reasons for the extensive formation of yellow chromophores are discussed. [Copyright &y& Elsevier]
- Published
- 2003
- Full Text
- View/download PDF
48. Implications of identifying the recently defined members of the Staphylococcus aureus complex S. argenteus and S. schweitzeri: a position paper of members of the ESCMID Study Group for Staphylococci and Staphylococcal Diseases (ESGS).
- Author
-
Becker, K., Schaumburg, F., Kearns, A., Larsen, A.R., Lindsay, J.A., Skov, R.L., and Westh, H.
- Subjects
- *
STAPHYLOCOCCUS aureus , *STAPHYLOCOCCAL diseases , *STAPHYLOCOCCUS , *METHICILLIN-resistant staphylococcus aureus , *INFECTION prevention - Abstract
Staphylococcus argenteus and Staphylococcus schweitzeri, previously known as divergent Staphylococcus aureus clonal lineages, have been recently established as novel, difficult-to-delimit, coagulase-positive species within the S. aureus complex. Methicillin-resistant strains of S. argenteus are known from Australia and the UK. Knowledge of their epidemiology, medical significance and transmission risk is limited and partly contradictory, hampering definitive recommendations. There is mounting evidence that the pathogenicity of S. argenteus is similar to that of 'classical' S. aureus , while as yet no S. schweitzeri infections have been reported. To provide decision support on whether and how to distinguish and report both species. PubMed, searched for S. argenteus and S. schweitzeri. This position paper reviews the main characteristics of both species and draws conclusions for microbiological diagnostics and surveillance as well as infection prevention and control measures. We propose not distinguishing within the S. aureus complex for routine reporting purposes until there is evidence that pathogenicity or clinical outcome differ markedly between the different species. Primarily for research purposes, suitably equipped laboratories are encouraged to differentiate between S. argenteus and S. schweitzeri. Caution is urged if these novel species are explicitly reported. In such cases, a specific comment should be added (i.e. 'member of the S.aureus complex') to prevent confusion with less- or non-pathogenic staphylococci. Prioritizing aspects of patient safety, methicillin-resistant isolates should be handled as recommended for methicillin-resistant Staphylococcus aureus (MRSA). In these cases, the clinician responsible should be directly contacted and informed by the diagnosing microbiological laboratory, as they would be for MRSA. Research is warranted to clarify the epidemiology, clinical impact and implications for infection control of such isolates. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
49. Development and Evaluation of a Paper-Based Microfluidic Device for Detection of Listeria monocytogenes on Food Contact and Non-Food Contact Surfaces.
- Author
-
Broten, Codi Jo, Wydallis, John B., Reilly III, Thomas H., and Bisha, Bledar
- Subjects
MICROFLUIDIC devices ,LISTERIA monocytogenes ,FOOD pathogens ,BACTERIAL cultures ,LISTERIA ,FOOD testing - Abstract
Listeria monocytogenes is the third most deadly foodborne pathogen in the United States. The bacterium is found in soil and water, contaminating raw food products and the processing environment, where it can persist for an extended period. Currently, testing of food contact and non-food contact surfaces is performed using an array of sampling devices and endpoint technologies, offering various levels of sensitivity, cost, user skill, and time to detection. Paper-based microfluidic devices (µPADs) are a rapid detection platform amenable to low-cost, user-friendly, and portable diagnostics. In this study, we developed and evaluated a µPAD platform specific for the colorimetric detection of the Listeria genus following recovery from food contact and non-food contact surfaces. For detection, four colorimetric substrates specific for the detection of β-glucosidase, two broths selective for the detection of Listeria spp., and a nonselective broth were evaluated to facilitate detection of Listeria spp. The limit of detection and time to detection were determined by using pure bacterial cultures. After 8 h enrichment, L. monocytogenes (10
2 Colony Forming Units (CFU)/coupon) was detected on every surface. After 18 h enrichment, L. monocytogenes (102 CFU/coupon) was detected on all surfaces with all swabbing devices. This study demonstrated the ability of the µPAD-based method to detect potentially stressed cells at low levels of environmental contamination. [ABSTRACT FROM AUTHOR]- Published
- 2022
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50. Printed paper based glucose sensor manufactured in pilot scale
- Author
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Hakola, Liisa and Lehtinen, Kaisa
- Subjects
flexography ,sensor ,paper ,diagnostics ,inkjet ,glucose - Abstract
VTT has long experience in development of inkjet printable functional inks including printable enzymes. Also a method for controlling liquid flow on paper has been developed by VTT. This method is based on printed channel boundaries that guide flow of liquids such as water, blood, urine or other suitable liquid analyte. This technology can be used to manufacture inexpensive and simple-to-use diagnostic devices and tests that can provide results by visual colour change. This provides possibility for point-of-care or home testing. Use of paper based diagnostics has been proven to work for e.g. glucose indication in laboratory scale. Furthermore, VTT has studied and developed enzymes suitable for use in diagnostic devices. Many of the enzymes can be applied by using different printing technologies. The objective of this study was to demonstrate the feasibility of paper based diagnostics in pilot scale by utilizing roll-to-roll flexography printing and industrial scale inkjet printheads. A successful glucose sensor demonstrator was realized.
- Published
- 2014
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