scholarly journals Optimization of Saliva Collection and Immunochromatographic Detection of Salivary Pepsin for Point-of-Care Testing of Laryngopharyngeal Reflux

Sensors ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 325
Author(s):  
Young Ju Lee ◽  
Jiyoon Kwon ◽  
Sanggyeong Shin ◽  
Young-Gyu Eun ◽  
Jae Ho Shin ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Laryngopharyngeal Reflux ◽  
Point Of Care ◽  
Storage Conditions ◽  
Solution Temperature ◽  
Point Of Care Testing ◽  
Immunochromatographic Strip ◽  
Non Invasive ◽  
Saliva Collection ◽  
Optimized Conditions

Salivary pepsin is a promising marker for the non-invasive diagnosis of laryngopharyngeal reflux (LPR). For reliable results regarding pepsin in saliva, it is critical to standardize the collection, storage, and pre-processing methods. In this study, we optimized the saliva collection protocols, including storage conditions, i.e., solution, temperature, and time, and the pre-processing filter for pepsin. Moreover, we prepared a simple immunochromatographic strip for the rapid detection of pepsin and evaluated its sensing performance. As a result, we selected a polypropylene (PP) filter as the pre-processing filter for salivary pepsin in low resource settings, such as those where point of care testing (POCT) is conducted. This filter showed a similar efficiency to the centrifuge (standard method). Finally, we detected the pepsin using gold nanoparticles conjugated with monoclonal pepsin antibody. Under optimized conditions, the lower limit of detection for pepsin test strips was determined as 0.01 μg/mL. Furthermore, we successfully detected the salivary pepsin in real saliva samples of LPR patients, which were pre-processed by the PP filter. Therefore, we expect that our saliva collection protocol and pepsin immunochromatographic strip can be utilized as useful tools for a non-invasive diagnosis/screening of LPR in POCT.

scholarly journals A Smartphone Camera Colorimetric Assay of Acetylcholinesterase and Butyrylcholinesterase Activity

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1796
Author(s):  
Miroslav Pohanka ◽  
Jitka Zakova
Keyword(s):  
Limit Of Detection ◽  
Colorimetric Assay ◽  
Point Of Care ◽  
Specific Treatment ◽  
Point Of Care Testing ◽  
Analytical Instruments ◽  
Colorimetric Test ◽  
3D Printed ◽  
Butyrylcholinesterase Activity ◽  
Additional Education

Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) can serve as biochemical markers of various pathologies like liver disfunction and poisonings by nerve agents. Ellman’s assay is the standard spectrophotometric method to measure cholinesterase activity in clinical laboratories. The authors present a new colorimetric test to assess AChE and BChE activity in biological samples using chromogenic reagents, treated 3D-printed measuring pads and a smartphone camera as a signal detector. Multiwell pads treated with reagent substrates 2,6-dichlorophenolindophenyl acetate, indoxylacetate, ethoxyresorufin and methoxyresorufin were prepared and tested for AChE and BChE. In the experiments, 3D-printed pads containing indoxylacetate as a chromogenic substrate were optimal for analytical purposes. The best results were achieved using the red (R) channel, where the limit of detection was 4.05 µkat/mL for BChE and 4.38 µkat/mL for AChE using a 40 µL sample and a 60 min assay. The major advantage of this method is its overall simplicity, as samples are applied directly without any specific treatment or added reagents. The assay was also validated to the standard Ellman’s assay using human plasma samples. In conclusion, this smartphone camera-based colorimetric assay appears to have practical applicability and to be a suitable method for point-of-care testing because it does not require specific manipulation, additional education of staff or use of sophisticated analytical instruments.

Point-of-Care Testing Using Invasive and Non-Invasive Hemoglobinometers: Reliable and Valid Method for Estimation of Hemoglobin among Children 6–59 Months

2020 ◽  
Author(s):  
Gomathi Ramaswamy ◽  
Kashish Vohra ◽  
Kapil Yadav ◽  
Ravneet Kaur ◽  
Tripti Rai ◽  
...  
Keyword(s):  
Point Of Care ◽  
Venous Blood ◽  
Public Health Problem ◽  
Outpatient Department ◽  
Point Of Care Testing ◽  
Adequate Treatment ◽  
Non Invasive ◽  
Hematology Analyzer ◽  
The Mean ◽  
Study Participants

Abstract Introduction Globally around 47.4% of children and in India, 58% of children aged 6–59 months are anemic. Diagnosis of anemia in children using accurate technologies and providing adequate treatment is essential to reduce the burden of anemia. Point-of-care testing (POCT) devices is a potential option for estimation of hemoglobin in peripheral and field settings were the hematology analyzer and laboratory services are not available. Objectives To access the validity of the POCTs (invasive and non-invasive devices) for estimation of hemoglobin among children aged 6–59 months compared with hematology analyzer. Methods The study participants were enrolled from the pediatric outpatient department in Haryana, India, from November 2019 to January 2020. Hemoglobin levels of the study participants were estimated in Sahli’s hemoglobinometer and invasive digital hemoglobinometers (DHs) using capillary blood samples. Hemoglobin levels in non-invasive DH were assessed from the finger/toe of the children. Hemoglobin levels measured in POCTs were compared against the venous blood hemoglobin estimated in the hematology analyzer. Results A total of 120 children were enrolled. The mean (SD) of hemoglobin (g/dl) estimated in auto-analyzer was 9.4 (1.8), Sahli’s hemoglobinometer was 9.2 (1.9), invasive DH was 9.7 (1.9), and non-invasive DH was 11.9 (1.5). Sahli’s hemoglobinometer (95.5%) and invasive DH (92.2%) had high sensitivity for the diagnosis of anemia compared with non-invasive DH (24.4%). In contrast, non-invasive DH had higher specificity (96.7%) compared with invasive DH (83.3%) and Sahli’s hemoglobinometer (70%). Invasive DH took the least time (2–3 min) for estimation of hemoglobin per participant, followed by Sahli’s (4–5 min) and non-invasive DH (5–7 min). Conclusion All three POCT devices used in this study are reasonable and feasible for estimating hemoglobin in under-5 children. Invasive DHs are potential POCT devices for diagnosis of anemia among under-5 children, while Sahli’s can be considered as a possible option, where trained and skilled technicians are available. Further research and development are required in non-invasive DH to improve accuracy. Lay summary In India, anemia is a serious public health problem, where 58% of the children aged 6–59 months are anemic. Point-of-care testing (POCT) using digital hemoglobinometers (DHs) has been recommended as one of the key interventions by the Anemia Mukt Bharat program since 2018 in India. These POCT devices are easy to use, less invasive, can be carried to field, require minimal training and results are available immediately. Therefore this study assessed the validity of POCT devices—invasive DH, non-invasive DH and Sahli’s hemoglobinometer among 6–59 months children in facility setting compared with the gold standard hematology analyzer. A total of 120 children under 6–59 months of age were enrolled from the pediatric outpatient department in Haryana, India, from November 2019 to January 2020. The (mean hemoglobin in g/dl) invasive (9.7) and non-invasive DH (11.9) overestimated hemoglobin value, while Sahli’s (9.2) underestimated hemoglobin compared with hematology analyzer (9.4). Invasive DH (92.2%) and Sahli’s hemoglobinometer (95.5%) reported high ability to correctly identify those with anemia compared with non-invasive DH (24.4%). In contrast, non-invasive DH (96.73%) had higher ability to correctly identify those without the anemia compared with invasive DH (83.3%) and Sahli’s (70%).

scholarly journals Wave-shaped microfluidic chip assisted point-of-care testing for accurate and rapid diagnosis of infections

2021 ◽  
Author(s):  
Binfeng Yin ◽  
Xinhua Wan ◽  
Mingzhu Yang ◽  
Changcheng Qian ◽  
A S M Muhtasim Fuad Sohan
Keyword(s):  
Microfluidic Chip ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Simultaneous Detection ◽  
Accurate Diagnosis ◽  
Point Of Care Testing ◽  
Promising Alternative ◽  
Reactive Protein ◽  
Linear Relationships ◽  
Multiple Biomarkers

Abstract Background: Simultaneous and timely detection of C-reactive protein (CRP), procalcitonin (PCT), and interleukin-6 (IL-6) provides effective information for the accurate diagnosis of infections. Early diagnosis and classification of infections increase the cure rate while decreasing complications, which is significant for severe infections, especially for war surgery. However, traditional methods rely on laborious operations and bulky devices. On the other hand, point-of-care (POC) methods suffer from limited robustness and accuracy. Therefore, it is of urgent demand to develop POC devices for rapid and accurate diagnosis of infections to fulfill on-site militarized requirements.Methods: We developed a wave-shaped microfluidic chip (WMC) assisted multiplexed detection platform (WMC-MDP). WMC-MDP reduces detection time and improves repeatability through premixing of the samples and reaction of the reagents. We further combined the detection platform with the streptavidin-biotin (SA-B) amplified system to enhance the sensitivity while using chemiluminescence (CL) intensity as signal readout. We realized simultaneous detection of CRP, PCT, and IL-6 on the detection platform and evaluated the sensitivity, linear range, selectivity, and repeatability. Finally, we finished detecting 15 samples from volunteers and compared the results with commercial ELISA kits.Results: Detection of CRP, PCT, and IL-6 exhibited good linear relationships between CL intensities and concentrations in the range of 1.25-40 μg/mL, 0.4-12.8 ng/mL, and 50-1600 pg/mL. The limit of detection (LOD) of CRP, PCT, and IL-6 were 0.54 μg/mL, 0.11 ng/mL, and 16.25 pg/mL, respectively. WMC-MDP is capable of good adequate selectivity and repeatability. The whole detection procedure takes only 22 minutes that meets the requirements of a POC device. Results of 15 samples from volunteers were consistent with the results detected by commercial ELISA kits.Conclusion: WMC-MDP allows simultaneous, rapid, and sensitive detection of CRP, PCT, and IL-6 with satisfactory selectivity and repeatability, requiring minimal manipulation. However, WMC-MDP takes advantage of being a microfluidic device showing the coefficients of variation less than 10% enabling WMC-MDP to be a type of POCT. Therefore, WMC-MDP provides a promising alternative to point-of-care testing (POCT) of multiple biomarkers. We believe the practical application of WMC-MDP in militarized fields will revolutionize infection diagnosis for soldiers.

Development of Lateral Flow Immunochromatographic Strips for Micropollutants Screening Using Colorants of Aptamer Functionalized Nanogold Particles Part I Methodology and Optimization

2018 ◽  
Vol 101 (5) ◽  
pp. 1402-1407 ◽  
Author(s):  
Shuai Zhao ◽  
Shan Zhang ◽  
Sai Wang ◽  
Jiahui Liu ◽  
Yiyang Dong
Keyword(s):  
Reading Time ◽  
Limit Of Detection ◽  
Blocking Agent ◽  
Rapid Identification ◽  
Lateral Flow ◽  
Immunochromatographic Strip ◽  
Assay Performance ◽  
Nanogold Particles ◽  
Visual Limit ◽  
Optimized Conditions

Abstract A methodology of lateral flow immunochromatographic strip based on aptamer was developed for on-site detection of the small molecule micropollutants. In the present study, we try for the first time to investigate the feasibility of developing a strip assay for the analysis of micropollutants as methodological prototypes by combining the high selectivity and affinity of aptamers with the unique optical properties of nanogolds. This quantitative method was based on the competition for the aptamer between targets and DNA probes. Crucial parameters that might influence the sensitivity, such as the size of nanogolds, amount of aptamer, type and pH of streptavidin, type of nitrocellulose (NC) membrane, blocking procedure, and reading time, were systematically investigated to obtain the optimum assay performance. With the optimized conditions [nanogolds 25 nm, 50 μM aptamer, pH 8 of GSA (a type of streptavidin named “SA Gold,” which is a sulfhydrylization streptavidin), Millipore HFC 135 NC membrane, 1% bovine serum albumin as the blocking agent and added in the running buffer and sample pad soakage agents, and 20 min reading time] the aptamer-based lateral flow assay will show a low visual limit of detection and scanning reader LOD. The strip for on-site screening using colorants of aptamer functionalized nanogold particles did not require any complicated equipment and was a potential portable tool for rapid identification of micropollutants.

Smartphone-based point-of-care testing of salivary α-amylase for personal psychological measurement

The Analyst ◽  
2015 ◽  
Vol 140 (21) ◽  
pp. 7399-7406 ◽  
Author(s):  
Lin Zhang ◽  
Wentao Yang ◽  
Yuankui Yang ◽  
Hong Liu ◽  
Zhongze Gu
Keyword(s):  
Mental Health ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Point Of Care ◽  
Point Of Care Testing ◽  
Psychological Measurement ◽  
Autonomic Nervous System Activity ◽  
System Activity ◽  
Non Invasive ◽  
Nervous System Activity

Here we report a smartphone-based potentiometric biosensor for point-of-care testing of salivary α-amylase (sAA), which is one of the most sensitive indices of autonomic nervous system activity, and therefore a promising non-invasive biomarker for mental health.

scholarly journals Performance evaluation of the point-of-care SAMBA II SARS-CoV-2 Test for detection of SARS-CoV-2

2020 ◽  
Author(s):  
Sonny M Assennato ◽  
Allyson V Ritchie ◽  
Cesar Nadala ◽  
Neha Goel ◽  
Hongyi Zhang ◽  
...  
Keyword(s):  
Public Health ◽  
Infection Control ◽  
Sensitivity And Specificity ◽  
Patient Management ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Clinical Samples ◽  
Analytical Sensitivity ◽  
Point Of Care Testing ◽  
Clinical Sensitivity

AbstractNucleic acid amplification for the detection of SARS-CoV-2 RNA in respiratory samples is the standard method for diagnosis. These tests are centralised and therefore turnaround times can be 2-5 days. Point-of-care testing with rapid turnaround times would allow more effective triage in settings where patient management and infection control decisions need to be made rapidly.Inclusivity and specificity of the SAMBA II SARS-CoV-2 assay was determined by in silico analyses of the primers and probes. Analytical and clinical sensitivity and specificity of the SAMBA II SARS-CoV-2 Test was evaluated for analytical sensitivity and specificity. Clinical performance was evaluated in residual clinical samples compared to the Public Health England reference tests.The limit of detection of the SAMBA II SARS-CoV-2 Test is 250 cp/mL and is specific for detection of 2 regions of the SARS-CoV-2 genome. The clinical sensitivity was evaluated in 172 clinical samples provided by the Clinical Microbiology and Public Health Laboratory, Addenbrooke’s Hospital, Cambridge (CMPHL), which showed a sensitivity of 98.9% (95% CI 94.03-99.97%), specificity of 100% (95% CI 95.55-100%), PPV of 100% and NPV of 98.78% (92.02-99.82%) compared to testing by CMPHLSAMBA detected 3 positive samples that were initially negative by PHE Test. The data shows that the SAMBA II SARS-CoV-2 Test performs equivalently to the centralised testing methods with a much quicker turnaround time. Point of care testing, such as SAMBA, should enable rapid patient management and effective implementation of infection control measures.

Occult blood fecal tests for self-control and point of care testing

2017 ◽  
Vol 53 (2) ◽  
pp. 101-106
Author(s):  
Aleksandra Charchut ◽  
Magdalena Wójcik ◽  
Barbara K. Kościelniak ◽  
Przemysław J. Tomasik
Keyword(s):  
Point Of Care ◽  
Occult Blood ◽  
Gastrointestinal Diseases ◽  
Fecal Occult Blood Testing ◽  
Self Control ◽  
Fecal Occult Blood ◽  
Point Of Care Testing ◽  
Non Invasive ◽  
Fecal Occult ◽  
Fecal Tests

Fecal occult blood testing (FOBT) is a non-invasive and easy-to-carry, self-performed assay. It is often conducted in the diagnosis of various gastrointestinal diseases, especially as a screening test for colorectal cancer. This test is aimed at detecting blood which is not visible macroscopically in a stool sample. The purpose of this paper is to discuss various types of FOB tests: chemical, immunochroma- tographic and DNA tests. Despite the similarity in their performance, these tests use different methods and thus differ in their ability to detect blood from different parts of the gastrointestinal tract. In addition, the interfering factors in the various assays and the proper preparation of the patient before the test are discussed in detail. The knowledge of the differences between these tests will allow to correct performance and interpretation of the results obtained with each tests.

scholarly journals Flexible Enzymatic Glucose Electrochemical Sensor Based on Polystyrene-Gold Electrodes

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 805
Author(s):  
Annika Müsse ◽  
Francesco La Malfa ◽  
Virgilio Brunetti ◽  
Francesco Rizzi ◽  
Massimo De Vittorio
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Glucose Biosensor ◽  
Body Fluids ◽  
Linear Range ◽  
Glucose Levels ◽  
Non Invasive ◽  
Prevalent Disease ◽  
Operational Range ◽  
Menten Constant

Metabolic disorders such as the highly prevalent disease diabetes require constant monitoring. The health status of patients is linked to glucose levels in blood, which are typically measured invasively, but can also be correlated to other body fluids such as sweat. Aiming at a reliable glucose biosensor, an enzymatic sensing layer was fabricated on flexible polystyrene foil, for which a versatile nanoimprinting process for microfluidics was presented. For the sensing layer, a gold electrode was modified with a cysteine layer and glutaraldehyde cross-linker for enzyme conformal immobilization. Chronoamperometric measurements were conducted in PBS buffered glucose solution at two potentials (0.65 V and 0.7 V) and demonstrated a linear range between 0.025 mM to 2mM and an operational range of 0.025 mM to 25 mM. The sensitivity was calculated as 1.76µA/mM/cm2 and the limit of detection (LOD) was calculated as 0.055 mM at 0.7 V. An apparent Michaelis–Menten constant of 3.34 mM (0.7 V) and 0.445 mM (0.65 V) was computed. The wide operational range allows the application for point-of-care testing for a variety of body fluids. Yet, the linear range and low LOD make this biosensor especially suitable for non-invasive sweat sensing wearables.

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