Displaying publications 21 - 40 of 72 in total

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  1. Hussain A, Via G, Melniker L, Goffi A, Tavazzi G, Neri L, et al.
    Crit Care, 2020 12 24;24(1):702.
    PMID: 33357240 DOI: 10.1186/s13054-020-03369-5
    COVID-19 has caused great devastation in the past year. Multi-organ point-of-care ultrasound (PoCUS) including lung ultrasound (LUS) and focused cardiac ultrasound (FoCUS) as a clinical adjunct has played a significant role in triaging, diagnosis and medical management of COVID-19 patients. The expert panel from 27 countries and 6 continents with considerable experience of direct application of PoCUS on COVID-19 patients presents evidence-based consensus using GRADE methodology for the quality of evidence and an expedited, modified-Delphi process for the strength of expert consensus. The use of ultrasound is suggested in many clinical situations related to respiratory, cardiovascular and thromboembolic aspects of COVID-19, comparing well with other imaging modalities. The limitations due to insufficient data are highlighted as opportunities for future research.
    Matched MeSH terms: Point-of-Care Systems/standards*
  2. Low JSY, Thevarajah TM, Chang SW, Goh BT, Khor SM
    Crit Rev Biotechnol, 2020 Dec;40(8):1191-1209.
    PMID: 32811205 DOI: 10.1080/07388551.2020.1808582
    Cardiovascular disease is a major global health issue. In particular, acute myocardial infarction (AMI) requires urgent attention and early diagnosis. The use of point-of-care diagnostics has resulted in the improved management of cardiovascular disease, but a major drawback is that the performance of POC devices does not rival that of central laboratory tests. Recently, many studies and advances have been made in the field of surface-enhanced Raman scattering (SERS), including the development of POC biosensors that utilize this detection method. Here, we present a review of the strengths and limitations of these emerging SERS-based biosensors for AMI diagnosis. The ability of SERS to multiplex sensing against existing POC detection methods are compared and discussed. Furthermore, SERS calibration-free methods that have recently been explored to minimize the inconvenience and eliminate the limitations caused by the limited linear range and interassay differences found in the calibration curves are outlined. In addition, the incorporation of artificial intelligence (AI) in SERS techniques to promote multivariate analysis and enhance diagnostic accuracy are discussed. The future prospects for SERS-based POC devices that include wearable POC SERS devices toward predictive, personalized medicine following the Fourth Industrial Revolution are proposed.
    Matched MeSH terms: Point-of-Care Systems
  3. Sakulchit T, Ngu L, Chor YK, Ong GY
    Cureus, 2021 Mar 08;13(3):e13760.
    PMID: 33842136 DOI: 10.7759/cureus.13760
    Melioidosis is an infectious disease most commonly found in places with tropical climates. Definitive diagnosis can be confirmed by culture or pathological results of blood or infected organ. However, imaging study is helpful in providing early provisional diagnosis and guiding therapy. Point-of-care ultrasound can be currently performed bedside by non-radiological staff such as emergency physicians or intensivists. We present the case of a pediatric patient who got diagnosed with melioidosis after detection of multiple splenic and hepatic abscesses by point-of-care ultrasound, leading to early diagnosis and appropriate empirical antibiotic selection, resulting in good treatment outcome.
    Matched MeSH terms: Point-of-Care Systems
  4. Bustam A, Noor Azhar M, Singh Veriah R, Arumugam K, Loch A
    Emerg Med J, 2014 May;31(5):369-73.
    PMID: 23428721 DOI: 10.1136/emermed-2012-201789
    OBJECTIVES: The aim of this study was to evaluate if emergency medicine trainees with a short duration of training in echocardiography could perform and interpret bedside-focused echocardiography reliably on emergency department patients.
    METHODS: Following a web-based learning module and 3 h of proctored practical training, emergency medicine trainees were evaluated in technical and interpretative skills in estimating left ventricular function, detection of pericardial effusion and inferior vena cava (IVC) diameter measurements using bedside-focused echocardiography on emergency department patients. An inter-rater agreement analysis was performed between the trainees and a board-certified cardiologist.
    RESULTS: 100 focused echocardiography examinations were performed by nine emergency medicine trainees. Agreement between the trainees and the cardiologist was 93% (K=0.79, 95% CI 0.773 to 0.842) for visual estimation of left ventricular function, 92.9% (K=0.80, 95% CI 0.636 to 0.882) for quantitative left ventricular ejection fraction by M-mode measurements, 98% (K=0.74, 95% CI 0.396 to 1.000) for the detection of pericardial effusion, and 64.2% (K=0.45, 95% CI 0.383 to 0.467) for IVC diameter assessment. The Bland-Altman limits of agreement for left ventricular function was -9.5% to 13.7%, and a Pearson's correlation yielded a value of 0.82 (p<0.0001, 95% CI 0.734 to 0.881). The trainees detected pericardial effusion with a sensitivity of 60%, specificity of 100%, positive predictive value of 100% and negative predictive value of 97.9%.
    CONCLUSIONS: Emergency medicine trainees were found to be able to perform and interpret focused echocardiography reliably after a short duration of training.
    Study site: Trauma and emergency department, University of Malaya Medical Centre, Kuala Lumpur
    Matched MeSH terms: Point-of-Care Systems*
  5. Khan AH, Noordin R
    Eur J Clin Microbiol Infect Dis, 2020 Jan;39(1):19-30.
    PMID: 31428897 DOI: 10.1007/s10096-019-03680-2
    Infection by Toxoplasma gondii is prevalent worldwide. The parasite can infect a broad spectrum of vertebrate hosts, but infection of fetuses and immunocompromised patients is of particular concern. Easy-to-perform, robust, and highly sensitive and specific methods to detect Toxoplasma infection are important for the treatment and management of patients. Rapid diagnostic methods that do not sacrifice the accuracy of the assay and give reproducible results in a short time are highly desirable. In this context, rapid diagnostic tests (RDTs), especially with point-of-care (POC) features, are promising diagnostic methods in clinical microbiology laboratories, especially in areas with minimal laboratory facilities. More advanced methods using microfluidics and sensor technology will be the future trend. In this review, we discuss serological and molecular-based rapid diagnostic tests for detecting Toxoplasma infection in humans as well as animals.
    Matched MeSH terms: Point-of-Care Systems
  6. Szakmany T, Fitzgerald E, Garlant HN, Whitehouse T, Molnar T, Shah S, et al.
    Front Immunol, 2023;14:1308530.
    PMID: 38332914 DOI: 10.3389/fimmu.2023.1308530
    INTRODUCTION: Early diagnosis of sepsis and discrimination from SIRS is crucial for clinicians to provide appropriate care, management and treatment to critically ill patients. We describe identification of mRNA biomarkers from peripheral blood leukocytes, able to identify severe, systemic inflammation (irrespective of origin) and differentiate Sepsis from SIRS, in adult patients within a multi-center clinical study.

    METHODS: Participants were recruited in Intensive Care Units (ICUs) from multiple UK hospitals, including fifty-nine patients with abdominal sepsis, eighty-four patients with pulmonary sepsis, forty-two SIRS patients with Out-of-Hospital Cardiac Arrest (OOHCA), sampled at four time points, in addition to thirty healthy control donors. Multiple clinical parameters were measured, including SOFA score, with many differences observed between SIRS and sepsis groups. Differential gene expression analyses were performed using microarray hybridization and data analyzed using a combination of parametric and non-parametric statistical tools.

    RESULTS: Nineteen high-performance, differentially expressed mRNA biomarkers were identified between control and combined SIRS/Sepsis groups (FC>20.0, p<0.05), termed 'indicators of inflammation' (I°I), including CD177, FAM20A and OLAH. Best-performing minimal signatures e.g. FAM20A/OLAH showed good accuracy for determination of severe, systemic inflammation (AUC>0.99). Twenty entities, termed 'SIRS or Sepsis' (S°S) biomarkers, were differentially expressed between sepsis and SIRS (FC>2·0, p-value<0.05).

    DISCUSSION: The best performing signature for discriminating sepsis from SIRS was CMTM5/CETP/PLA2G7/MIA/MPP3 (AUC=0.9758). The I°I and S°S signatures performed variably in other independent gene expression datasets, this may be due to technical variation in the study/assay platform.

    Matched MeSH terms: Point-of-Care Systems
  7. Teng CL
    MyJurnal
    In the developing world, clinical knowledge management in primary care has a long way to go. Clinical decision support systems, despite its promise to revolutionise healthcare, is slow in its implementation due to the lack of financial investment in information technology. Point-of-care resources, such as comprehensive electronic textbooks delivered via the web or mobile devices, have yet to be fully utilised by the healthcare organisation or individual clinicians. Increasing amount of applicable knowledge of good quality (e.g. clinical practice guidelines and other pre-appraised resources) are now available via the internet. The policy makers and clinicians need to be more informed about the potential benefits and
    limitations of these new tools and resources and make the necessary budgetary provision and learn how best to harness them for patient care.
    Matched MeSH terms: Point-of-Care Systems
  8. Thanimalai S, Shafie AA, Hassali MA, Sinnadurai J
    Int J Clin Pharm, 2013 Oct;35(5):736-43.
    PMID: 23715759 DOI: 10.1007/s11096-013-9796-6
    BACKGROUNDS: Limited evidence is available regarding pharmacist managed anticoagulation clinic in the Southeast Asian region where there is marked difference in terms of care model, genetic composition and patient demographics.

    OBJECTIVES: This study aimed at comparing the anticoagulation clinic managed by the pharmacist with physician advisory and the usual medical care provided in Kuala Lumpur Hospital (KLH) in terms of anticoagulation control and adverse outcomes.

    SETTING: A 2,302 bedded government tertiary referral hospital in Malaysia.

    METHODS: A 6-month retrospective cohort study of the effectiveness of two models of anticoagulation care, the pharmacist managed anticoagulation clinic which is known as warfarin medication therapy adherence clinic (WMTAC) and usual medical clinic (UMC) in KLH was conducted, where a random number generator was used to recruit patients. The UMC patients received standard medical care where they are managed by rotational medical officers in the physicians' clinic. As for the WMTAC with physician advisory, the pharmacist will counsel and review the patients internationalised normalization ratio at each clinic visit and also adjust the patients' warfarin dose accordingly. Patients are referred to physicians if immediate attention is required.

    MAIN OUTCOME MEASURE: The main therapeutic outcome is time in therapeutic range (TTR) both actual and expanded TTR and thromboembolic and bleeding complications.

    RESULTS: Each of the WMTAC and usual medical care recruited 92 patients, which totals to 184 patients. The patient demographics in terms of age, race and indication of treatment were comparable. At the end of the 6 months follow-up, patients in the WMTAC group had significantly higher actual-TTR (65.1 vs. 48.3 %; p < 0.05) compared to those in usual medical care group. Rates of admission were 6.5 versus 28.2 events per 100 person-years for the WMTAC and UMC groups, respectively. Though the bleeding incidences were not significantly different, it was reduced.

    CONCLUSIONS: These findings will impact local warfarin patient management services and policies because there was no available evidence supporting the role of pharmacists in the management of warfarin patients prior to this study.
    Matched MeSH terms: Point-of-Care Systems
  9. Peyman M, Tai LY, Khaw KW, Ng CM, Win MM, Subrayan V
    Int Ophthalmol, 2015 Oct;35(5):651-5.
    PMID: 25189684 DOI: 10.1007/s10792-014-9989-6
    To assess the intra-observer repeatability and inter-observer reproducibility of central corneal thickness (CCT) measurements of PachPen (Accutome, Inc., Pennsylvania, USA), a hand-held, portable ultrasonic pachymeter when used by an ophthalmic nurse compared to an ophthalmologist. Ophthalmology Clinic, University of Malaya Medical Center In this prospective study, CCT was measured in 184 eyes of 92 healthy subjects, first by a corneal surgeon experienced in ultrasound pachymetry (Observer 1) followed by an ophthalmic nurse new to the procedure (Observer 2). Nine measurements were obtained from each eye by each observer, independently. Measurements were compared between the observers. Coefficients of repeatability and reproducibility were calculated. The Bland-Altman plot was used to assess agreement between observers. Mean age of the study population was 54.3 ± 15.2 years old and consisted of 43.5% male. Mean CCT as measured by Observers 1 and 2 were 528.3 ± 32.9 and 530.7 ± 33.3 µm, respectively. Observer 1 showed higher repeatability of measurements compared to that of Observer 2 (coefficient of repeatability 3.46 vs. 5.55%). The measurements by both observers showed high correlation (0.96) and good agreement (mean difference -2.4 µm; 95% limits of agreement -21.4, 16.7 µm). Coefficient of reproducibility of measurements between observers was 5.08%. Accutome PachPen hand-held ultrasound pachymeters gives excellent intra-observer repeatability and inter-observer reproducibility by personnel of different training grades.
    Matched MeSH terms: Point-of-Care Systems*
  10. Che Engku Noramalina Che-Engku-Chik, Siti Sarah Othman, Helmi Wasoh, Nor Azah Yusof, Jaafar Abdullah, Mohd Hazani Mat Zaid
    MyJurnal
    Despite the continued effort globally made to control the growing case of Tuberculosis (TB), it
    continues to be regarded as the second deadliest disease after the HIV. There are various
    methods developed to diagnose TB, most of which having the criteria of sensitive, selective,
    cheap and portable to be used in robust applications. Even with the advancement in medication,
    the important keys including early stage diagnosis is yet to be considered. In diagnosing TB, the
    only technique remained as the gold standard method is the culturing method, which is the Acid
    Fast Bacilli (AFB) staining. On the other hand, molecular technique utilising Polymerase Chain
    Reaction (PCR) assay is preferred as a non-culturing method. Additionally, as molecular
    techniques become advanced, real-time PCR or quantitative PCR (qPCR) using multiple probes
    in one shot has raised interest among researchers, because it can skip the process of gel
    electrophoresis. Recently, researchers have been working on electrochemical DNA sensors
    which are sensitive, selective, rapid, cheap and can meet with point of care (POC) testing
    requirements to diagnose TB.
    Matched MeSH terms: Point-of-Care Systems
  11. Grigg MJ, William T, Barber BE, Parameswaran U, Bird E, Piera K, et al.
    J Clin Microbiol, 2014 Jun;52(6):2053-60.
    PMID: 24696029 DOI: 10.1128/JCM.00181-14
    Plasmodium knowlesi causes severe and fatal malaria in Malaysia. Microscopic misdiagnosis is common and may delay appropriate treatment. P. knowlesi can cross-react with "species-specific" parasite lactate dehydrogenase (pLDH) monoclonal antibodies used in rapid diagnostic tests (RDTs) to detect P. falciparum and P. vivax. At one tertiary-care hospital and two district hospitals in Sabah, we prospectively evaluated two combination RDTs for malaria diagnosis by using both a pan-Plasmodium-pLDH (pan-pLDH)/P. falciparum-specific-pLDH (Pf-pLDH) RDT (OptiMAL-IT) and a non-P. falciparum VOM-pLDH/Pf-HRP2 RDT (CareStart). Differential cross-reactivity among these combinations was hypothesized to differentiate P. knowlesi from other Plasmodium monoinfections. Among 323 patients with PCR-confirmed P. knowlesi (n = 193), P. falciparum (n = 93), and P. vivax (n = 37) monoinfections, the VOM-pLDH individual component had the highest sensitivity for nonsevere (35%; 95% confidence interval [CI], 27 to 43%) and severe (92%; CI, 81 to 100%) P. knowlesi malaria. CareStart demonstrated a P. knowlesi sensitivity of 42% (CI, 34 to 49%) and specificity of 74% (CI, 65 to 82%), a P. vivax sensitivity of 83% (CI, 66 to 93%) and specificity of 71% (CI, 65 to 76%), and a P. falciparum sensitivity of 97% (CI, 90 to 99%) and specificity of 99% (CI, 97 to 100%). OptiMAL-IT demonstrated a P. knowlesi sensitivity of 32% (CI, 25 to 39%) and specificity of 21% (CI, 15 to 29%), a P. vivax sensitivity of 60% (CI, 42 to 75%) and specificity of 97% (CI, 94 to 99%), and a P. falciparum sensitivity of 82% (CI, 72 to 89%) and specificity of 39% (CI, 33 to 46%). The combination of CareStart plus OptiMAL-IT for P. knowlesi using predefined criteria gave a sensitivity of 25% (CI, 19 to 32%) and specificity of 97% (CI, 92 to 99%). Combining two RDT combinations was highly specific for P. knowlesi malaria diagnosis; however, sensitivity was poor. The specificity of pLDH RDTs was decreased for P. vivax and P. falciparum because of P. knowlesi cross-reactivity and cautions against their use alone in areas where P. knowlesi malaria is endemic. Sensitive P. knowlesi-specific RDTs and/or alternative molecular diagnostic tools are needed in areas where P. knowlesi malaria is endemic.
    Matched MeSH terms: Point-of-Care Systems*
  12. Morgan Freiman J, Wang J, Easterbrook PJ, Robert Horsburgh C, Marinucci F, White LF, et al.
    J Hepatol, 2019 Feb 20.
    PMID: 30797050 DOI: 10.1016/j.jhep.2019.02.011
    BACKGROUND & AIMS: Affordable point-of-care (POC) tests for hepatitis C (HCV) viraemia are needed to improve access to treatment in low and middle income countries (LMICs). Our aims were to determine the target limit of detection (LOD) necessary to diagnose the majority of persons with HCV eligible for treatment, and identify characteristics associated with low-level viraemia (LLV) (defined as the lowest 3% of the distribution of HCV RNA) to understand those at risk of being mis-diagnosed.

    METHODS: We established a multi-country cross-sectional dataset of first available quantitative HCV RNA linked to demographic and clinical data. We excluded individuals on HCV treatment. We analyzed the distribution of HCV RNA and determined critical thresholds for detection of HCV viraemia. We then performed logistic regression to evaluate factors associated with LLV, and derived relative sensitivities for significant covariates.

    RESULTS: The dataset included 66,640 individuals with HCV viraemia from Georgia (44.4%), Canada (40.9%), India (8.1%), Cambodia (2.6%), Egypt (1.6%), Pakistan (1.3%), Cameroon (0.4%), Indonesia (0.2%), Thailand (0.2%), Vietnam (0.1%), Malaysia (0.05%), and Mozambique (0.02%). The 97% LOD was 1,318 IU/mL (95% CI 1298.4, 1322.3). Factors associated with LLV were younger age 18-30 vs. 51-64 years (OR 2.56 95% CI 2.19, 2.99), female vs. male sex (OR 1.32, 95% CI 1.18, 1.49), and advanced fibrosis stage F4 vs. F0-1 (OR 1.44, 95%CI 1.21, 1.69). Only the younger age group had a decreased relative sensitivity below 95% at 93.3%.

    CONCLUSIONS: In this global dataset, a test with an LOD of 1,318 IU/mL would identify 97% of viraemic HCV infections among almost all populations. This LOD will help guide manufacturers in the development of affordable POC diagnostics to expand HCV testing and linkage to care in LMICs.

    LAY SUMMARY: We created and analyzed a dataset from 12 countries with 66,640 participants with chronic hepatitis C virus infection. We determined that about 97% of those with viraemic infection had 1300 International Units/mL or more of circulating virus at the time of diagnosis. While current diagnostic tests can detect as little as 12 International Units/mL of virus, our findings suggest that increasing the level of detection closer to 1300 would maintain good test accuracy and will likely allow for more affordable portable tests to be developed for use in low and middle income countries.

    Matched MeSH terms: Point-of-Care Systems
  13. Swathirajan CR, Vignesh R, Boobalan J, Solomon SS, Saravanan S, Balakrishnan P
    J Med Microbiol, 2017 Oct;66(10):1379-1382.
    PMID: 28901908 DOI: 10.1099/jmm.0.000514
    BACKGROUND: Sustainable suppression of HIV replication forms the basis of anti-retroviral therapy (ART) medication. Thus, reliable quantification of HIV viral load has become an essential factor to monitor the effectiveness of the ART. Longer turnaround-time (TAT), batch testing and technical skills are major drawbacks of standard real-time PCR assays.

    METHODS: The performance of the point-of-care Xpert HIV-1 viral load assay was evaluated against the Abbott RealTime PCR m2000rt system. A total of 96 plasma specimens ranging from 2.5 log10 copies ml-1 to 4.99 log10 copies ml-1 and proficiency testing panel specimens were used. Precision and accuracy were checked using the Pearson correlation co-efficient test and Bland-Altman analysis.

    RESULTS: Compared to the Abbott RealTime PCR, the Xpert HIV-1 viral load assay showed a good correlation (Pearson r=0.81; P<0.0001) with a mean difference of 0.27 log10 copies ml-1 (95 % CI, -0.41 to 0.96 log10 copies ml-1; sd, 0.35 log10 copies ml-1).

    CONCLUSION: Reliable and ease of testing individual specimens could make the Xpert HIV-1 viral load assay an efficient alternative method for ART monitoring in clinical management of HIV disease in resource-limited settings. The rapid test results (less than 2 h) could help in making an immediate clinical decision, which further strengthens patient care.

    Matched MeSH terms: Point-of-Care Systems*
  14. Sculthorpe-Petley L, Liu C, Hajra SG, Parvar H, Satel J, Trappenberg TP, et al.
    J Neurosci Methods, 2015 Apr 30;245:64-72.
    PMID: 25701685 DOI: 10.1016/j.jneumeth.2015.02.008
    Event-related potentials (ERPs) may provide a non-invasive index of brain function for a range of clinical applications. However, as a lab-based technique, ERPs are limited by technical challenges that prevent full integration into clinical settings.
    Matched MeSH terms: Point-of-Care Systems*
  15. Srijaya TC, Ramasamy TS, Kasim NH
    J Transl Med, 2014;12:243.
    PMID: 25182194 DOI: 10.1186/s12967-014-0243-9
    The inadequacy of existing therapeutic tools together with the paucity of organ donors have always led medical researchers to innovate the current treatment methods or to discover new ways to cure disease. Emergence of cell-based therapies has provided a new framework through which it has given the human world a new hope. Though relatively a new concept, the pace of advancement clearly reveals the significant role that stem cells will ultimately play in the near future. However, there are numerous uncertainties that are prevailing against the present setting of clinical trials related to stem cells: like the best route of cell administration, appropriate dosage, duration and several other applications. A better knowledge of these factors can substantially improve the effectiveness of disease cure or organ repair using this latest therapeutic tool. From a certain perspective, it could be argued that by considering certain proven clinical concepts and experience from synthetic drug system, we could improve the overall efficacy of cell-based therapies. In the past, studies on synthetic drug therapies and their clinical trials have shown that all the aforementioned factors have critical ascendancy over its therapeutic outcomes. Therefore, based on the knowledge gained from synthetic drug delivery systems, we hypothesize that by employing many of the clinical approaches from synthetic drug therapies to this new regenerative therapeutic tool, the efficacy of stem cell-based therapies can also be improved.
    Matched MeSH terms: Point-of-Care Systems/trends*
  16. Gan RK, Sanchez Martinez A, Abu Hasan MA, Castro Delgado R, Arcos González P
    J Ultrasound, 2023 Jun;26(2):343-353.
    PMID: 36694072 DOI: 10.1007/s40477-022-00761-5
    INTRODUCTION: Necrotizing fasciitis (NF) is a rapidly progressive necrosis of the fascial layer with a high mortality rate. It is a life-threatening medical emergency that requires urgent treatment. Lack of skin finding in NF made diagnosis difficult and required a high clinical index of suspicion. The use of ultrasound may guide clinicians in improving diagnostic speed and accuracy, thus leading to improved management decisions and patient outcomes. This literature search aims to review the use of point-of-care ultrasonography in diagnosing necrotizing fasciitis.

    METHOD: We searched relevant electronic databases, including PUBMED, MEDLINE, and SCOPUS, and performed a systematic review. Keywords used were "necrotizing fasciitis" or "necrotising fasciitis" or "necrotizing soft tissue infections" and "point-of-care ultrasonography" "ultrasonography" or "ultrasound". No temporal limitation was set. An additional search was performed via google scholar, and the top 100 entry was screened.

    RESULTS: Among 540 papers screened, only 21 were related to diagnosing necrotizing fasciitis using ultrasonography. The outcome includes three observational studies, 16 case reports, and two case series, covering the period from 1976 to 2022.

    CONCLUSION: Although the use of ultrasonography in diagnosing NF was published in several papers with promising results, more studies are required to investigate its diagnostic accuracy and potential to reduce time delay before surgical intervention, morbidity, and mortality.

    Matched MeSH terms: Point-of-Care Systems*
  17. Choi JR, Hu J, Tang R, Gong Y, Feng S, Ren H, et al.
    Lab Chip, 2016 Feb 7;16(3):611-21.
    PMID: 26759062 DOI: 10.1039/c5lc01388g
    With advances in point-of-care testing (POCT), lateral flow assays (LFAs) have been explored for nucleic acid detection. However, biological samples generally contain complex compositions and low amounts of target nucleic acids, and currently require laborious off-chip nucleic acid extraction and amplification processes (e.g., tube-based extraction and polymerase chain reaction (PCR)) prior to detection. To the best of our knowledge, even though the integration of DNA extraction and amplification into a paper-based biosensor has been reported, a combination of LFA with the aforementioned steps for simple colorimetric readout has not yet been demonstrated. Here, we demonstrate for the first time an integrated paper-based biosensor incorporating nucleic acid extraction, amplification and visual detection or quantification using a smartphone. A handheld battery-powered heating device was specially developed for nucleic acid amplification in POC settings, which is coupled with this simple assay for rapid target detection. The biosensor can successfully detect Escherichia coli (as a model analyte) in spiked drinking water, milk, blood, and spinach with a detection limit of as low as 10-1000 CFU mL(-1), and Streptococcus pneumonia in clinical blood samples, highlighting its potential use in medical diagnostics, food safety analysis and environmental monitoring. As compared to the lengthy conventional assay, which requires more than 5 hours for the entire sample-to-answer process, it takes about 1 hour for our integrated biosensor. The integrated biosensor holds great potential for detection of various target analytes for wide applications in the near future.
    Matched MeSH terms: Point-of-Care Systems*
  18. Ang KM, Yeo LY, Hung YM, Tan MK
    Lab Chip, 2016 09 21;16(18):3503-14.
    PMID: 27502324 DOI: 10.1039/c6lc00780e
    The deposition of a thin graphene film atop a chip scale piezoelectric substrate on which surface acoustic waves are excited is observed to enhance its performance for fluid transport and manipulation considerably, which can be exploited to achieve further efficiency gains in these devices. Such gains can then enable complete integration and miniaturization for true portability for a variety of microfluidic applications across drug delivery, biosensing and point-of-care diagnostics, among others, where field-use, point-of-collection or point-of-care functionality is desired. In addition to a first demonstration of vibration-induced molecular transport in graphene films, we show that the coupling of the surface acoustic wave gives rise to antisymmetric Lamb waves in the film which enhance molecular diffusion and hence the flow through the interstitial layers that make up the film. Above a critical input power, the strong substrate vibration displacement can also force the molecules out of the graphene film to form a thin fluid layer, which subsequently destabilizes and breaks up to form a mist of micron dimension aerosol droplets. We provide physical insight into this coupling through a simple numerical model, verified through experiments, and show several-fold improvement in the rate of fluid transport through the film, and up to 55% enhancement in the rate of fluid atomization from the film using this simple method.
    Matched MeSH terms: Point-of-Care Systems
  19. Aeinehvand MM, Weber L, Jiménez M, Palermo A, Bauer M, Loeffler FF, et al.
    Lab Chip, 2019 Feb 20.
    PMID: 30785443 DOI: 10.1039/c8lc00849c
    Reversible valves on centrifugal microfluidic platforms facilitate the automation of bioanalytical assays, especially of those requiring a series of steps (such as incubation) in a single reaction chamber. In this study, we present fixed elastic reversible (FER) valves and tunable elastic reversible (TER) valves that are easy to fabricate, implement and control. In the FER valve the compression of an elastic barrier/patch against a microchamber's outlet prevents the release of liquid. The valve sealing pressure was determined by adjusting the engraving depth of the valve-seat at which the elastic patch was located, this allows to set the sealing pressure during disc fabrication. In the TER valve, the patch compression value and sealing pressure is controlled by the penetration depth of a plastic screw into the valve-seat. The ER valves prevent liquid flow until the centrifugal force overcomes their sealing pressure. Moreover, at a constant spin speed, turning the screw of a TER valve reduces its sealing pressure and opens the valve. Therefore, the TER valve allows for controlling of the liquid transfer volume at various spin speeds. The FER and TER valves' behavior is mathematically described and equations for the prediction of their operation under centrifugal forces are provided. As a point-of-care (POC) application of ER valves, we have developed a microfluidic disc with a series of TER valves and peptide microarrays for automated multiplexed detection of five different proteins from a single serum sample.
    Matched MeSH terms: Point-of-Care Systems
  20. Aeinehvand MM, Ibrahim F, Harun SW, Al-Faqheri W, Thio TH, Kazemzadeh A, et al.
    Lab Chip, 2014 Mar 07;14(5):988-97.
    PMID: 24441792 DOI: 10.1039/c3lc51116b
    Centrifugal microfluidic platforms have emerged as point-of-care diagnostic tools. However, the unidirectional nature of the centrifugal force limits the available space for multi-step processes on a single microfluidic disc. To overcome this limitation, a passive pneumatic pumping method actuated at high rotational speeds has been previously proposed to pump liquid against the centrifugal force. In this paper, a novel micro-balloon pumping method that relies on elastic energy stored in a latex membrane is introduced. It operates at low rotational speeds and pumps a larger volume of liquid towards the centre of the disc. Two different micro-balloon pumping mechanisms have been designed to study the pump performance at a range of rotational frequencies from 0 to 1500 rpm. The behaviour of the micro-balloon pump on the centrifugal microfluidic platforms has been theoretically analysed and compared with the experimental data. The experimental data show that the developed pumping method dramatically decreases the required rotational speed to pump liquid compared to the previously developed pneumatic pumping methods. It also shows that within a range of rotational speed, a desirable volume of liquid can be stored and pumped by adjusting the size of the micro-balloon.
    Matched MeSH terms: Point-of-Care Systems
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