scholarly journals A lateral flow strip based on gold nanoparticles to detect 6-monoacetylmorphine in oral fluid

2018 ◽  
Vol 5 (6) ◽  
pp. 180288 ◽  
Author(s):  
Jia Liu ◽  
Xiaolong Hu ◽  
Fangqi Cao ◽  
Yurong Zhang ◽  
Jianzhong Lu ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Oral Fluid ◽  
Colour Change ◽  
Cross Reactivity ◽  
Lateral Flow ◽  
Driving Under The Influence ◽  
Test Time ◽  
Lateral Flow Strip ◽  
Total Test Time ◽  
Total Test

We used lateral flow strips based on gold nanoparticles to detect 6-monoacetylmorphine (6-MAM; heroin's unique metabolite) in oral fluid samples. In this competitive lateral chromatographic immunoassay, the 6-MAM was chemically synthesized and conjugated to bovine serum albumin. The results were qualitatively detected via the colour change of the test line. By using a proper sample pad, a suitable nitrocellulose membrane and a customized sponge device adsorbed the oral fluid directly from the mouth; the total test time was 3 min. The sensitivity of the assay was 4.0 ng ml −1 without any cross-reactivity with 10 normal drugs, which are widely subject to abuse, including morphine and codeine. This test could be easily used on site to detect heroin in oral fluid, and it could be a promising product in the future including for driving under the influence.

Repeated Measures Battery for the Aged

1987 ◽  
Vol 31 (8) ◽  
pp. 852-856
Author(s):  
Richard H. Shannon
Keyword(s):  
Repeated Measures ◽  
Age Groups ◽  
Test Time ◽  
Control Group ◽  
Men And Women ◽  
Males And Females ◽  
Basic Ability ◽  
Older Males ◽  
Total Test Time ◽  
Total Test

A battery of 29 reliable, valid and repeatable cognitive and psychomotor paper-and-pencil tests, with each test measuring a specific construct, was used to assess the performance of 48 older males and females. These subjects were divided into three separate age groups: 55–60, 65–70, and 75–80 years. In addition, a group of 16 men and women aged 25–35 served as a control group. This battery is divided into three sub-batteries (A, B and C) which were given on three separate weeks. The emphasis of this paper will be to describe the results of the nine tests contained in sub-battery C. Each test of a basic ability was analyzed separately across a total of five days and fifteen trials, with three trials being given each day. Total test time for each trial was approximately 35 minutes.

scholarly journals Fluid elements—a concept for automation of diagnostic tests

1997 ◽  
Vol 43 (2) ◽  
pp. 369-378 ◽  
Author(s):  
Henk Van Damme ◽  
Thea Van Velthoven ◽  
Erik Kaelen ◽  
Eduard Pelssers
Keyword(s):  
Detection Limit ◽  
Hepatitis B ◽  
Diagnostic Tests ◽  
State Of The Art ◽  
Hepatitis B Surface Antigen ◽  
Test Time ◽  
Liquid Handling ◽  
Set Up ◽  
Total Test Time ◽  
Total Test

Abstract Constructs consisting of a channel, a membrane, and an absorber are designed for autonomously carrying out various liquid-handling functions of analytical tests. These so-called fluid elements can be used to set up various circuits for conducting several kinds of analytical tests. To demonstrate the feasibility of this concept, we constructed such a circuit and used it to perform, with two handling steps, an ELISA of hepatitis B surface antigen. The detection limit of the assay was comparable with those of state-of-the-art ELISAs for screening blood, and results could be obtained within a total test time of 20 min. We anticipate that this concept of automation may also serve as a basis for new, highly simplified immunoanalyzers.

scholarly journals Applicability of duplex real time and lateral flow strip reverse-transcription recombinase aided amplification assays for the detection of Enterovirus 71 and Coxsackievirus A16

2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Xin-na Li ◽  
Xin-xin Shen ◽  
Ming-hui Li ◽  
Ju-ju Qi ◽  
Rui-huan Wang ◽  
...  
Keyword(s):  
Real Time ◽  
Reverse Transcription ◽  
Limit Of Detection ◽  
Enterovirus 71 ◽  
Cross Reactivity ◽  
Lateral Flow ◽  
Coxsackievirus A16 ◽  
Fluorescence Detector ◽  
Lateral Flow Strip ◽  
Clinical Diagnostic

Abstract Background Enterovirus 71 (EV71) and coxsackievirus A16 (CA16) are the two main etiological agents of Hand, Foot and Mouth Disease (HFMD). Simple and rapid detection of EV71 and CA16 is critical in resource-limited settings. Methods Duplex real time reverse-transcription recombinase aided amplification (RT-RAA) assays incorporating competitive internal amplification controls (IAC) and visible RT-RAA assays combined with lateral flow strip (LFS) for detection of EV71 and CA16 were developed respectively. Duplex real time RT-RAA assays were performed at 42 °C within 30 min using a portable real-time fluorescence detector, while LFS RT-RAA assays were performed at 42 °C within 30 min in an incubator. Recombinant plasmids containing conserved VP1 genes were used to analyze the sensitivities of these two methods. A total of 445 clinical specimens from patients who were suspected of being infected with HFMD were used to evaluate the performance of the assays. Results The limit of detection (LoD) of the duplex real time RT-RAA for EV71 and CA16 was 47 copies and 38 copies per reaction, respectively. The LoD of the LFS RT-RAA for EV71 and CA16 were both 91 copies per reaction. There was no cross reactivity with other enteroviruses. Compared to reverse transcription-quantitative PCR (RT-qPCR), the clinical diagnostic sensitivities of the duplex real time RT-RAA assay were 92.3% for EV71 and 99.0% for CA16, and the clinical diagnostic specificities were 99.7 and 100%, respectively. The clinical diagnostic sensitivities of the LFS RT-RAA assay were 90.1% for EV71 and 94.9% for CA16, and the clinical diagnostic specificities were 99.7 and 100%, respectively. Conclusions The developed duplex real time RT-RAA and LFS RT-RAA assays for detection of EV71 and CA16 are potentially suitable in primary clinical settings.

scholarly journals Validation of an Enzyme Immunoassay for Detection and Semiquantification of Cannabinoids in Oral Fluid

2010 ◽  
Vol 56 (6) ◽  
pp. 1007-1014 ◽  
Author(s):  
David M Schwope ◽  
Garry Milman ◽  
Marilyn A Huestis
Keyword(s):  
Oral Fluid ◽  
Drugs Of Abuse ◽  
Limit Of Detection ◽  
Cross Reactivity ◽  
Driving Under The Influence ◽  
Diagnostic Efficiency ◽  
Diagnostic Specificity ◽  
Collection Device ◽  
Assay Performance ◽  
Direct Elisa

Abstract Background: Oral fluid (OF) is gaining prominence as an alternative matrix for monitoring drugs of abuse in the workplace, criminal justice, and driving under the influence of drugs programs. It is important to characterize assay performance and limitations of screening techniques for Δ9-tetrahydrocannabinol (THC) in OF. Methods: We collected OF specimens by use of the Quantisal™ OF collection device from 13 daily cannabis users after controlled oral cannabinoid administration. All specimens were tested with the Immunalysis Sweat/OF THC Direct ELISA and confirmed by 2-dimensional GC-MS. Results: The limit of detection was <1 μg/L THC equivalent, and the assay demonstrated linearity from 1 to 50 μg/L, with semiquantification to 200 μg/L. Intraplate imprecision (n = 7) ranged from 2.9% to 7.7% CV, and interplate imprecision (n = 20) was 3.0%–9.1%. Cross-reactivities at 4 μg/L were as follows: 11-hydroxy-THC, 198%; Δ8-tetrahydrocannabinol (Δ8-THC), 128%; 11-nor-9-carboxy-THC (THCCOOH), 121%; THC (target), 98%; cannabinol, 87%; THCCOOH-glucuronide, 11%; THC-glucuronide, 10%; and cannabidiol, 2.4%. Of 499 tested OF specimens, 52 confirmed positive (THC 2.0–290 μg/L), with 100% diagnostic sensitivity at the proposed Substance Abuse and Mental Health Services Administration screening cutoff of 4 μg/L cannabinoids and GC-MS cutoff of 2 μg/L THC. Forty-seven specimens screened positive but were not confirmed by 2D-GC-MS, yielding 89.5% diagnostic specificity and 90.6% diagnostic efficiency. Thirty-one of 47 unconfirmed immunoassay positive specimens were from 1 individual and contained >400 ng/L THCCOOH, potentially contributing to cross-reactivity. Conclusions: The Immunalysis Sweat/OF THC Direct ELISA is an effective screening procedure for detecting cannabinoids in OF.

scholarly journals Novel SH-SAW Biosensors for Ultra-Fast Recognition of Growth Factors

Biosensors ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 17
Author(s):  
Daniel Matatagui ◽  
Ágatha Bastida ◽  
M. Carmen Horrillo
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Test Time ◽  
Dynamic Mode ◽  
Label Free ◽  
Fast Recognition ◽  
Short Period ◽  
Wide Range ◽  
Total Test Time ◽  
Total Test

In this study, we investigated a label-free time efficient biosensor to recognize growth factors (GF) in real time, which are of gran interesting in the regulation of cell division and tissue proliferation. The sensor is based on a system of shear horizontal surface acoustic wave (SH-SAW) immunosensor combined with a microfluidic chip, which detects GF samples in a dynamic mode. In order to prove this method, to our knowledge not previously used for this type of compounds, two different GFs were tested by two immunoreactions: neurotrophin-3 and fibroblast growth factor-2 using its polyclonal antibodies. GF detection was conducted via an enhanced sequential workflow to improve total test time of the immunoassay, which shows that this type of biosensor is a very promising method for ultra-fast recognition of these biomolecules due to its great advantages: portability, simplicity of use, reusability, low cost, and detection within a relatively short period of time. Finally, the biosensor is able to detect FGF-2 growth factor in a concentration wide range, from 1–25 µg/mL, for a total test time of ~15 min with a LOD of 130 ng/mL.

scholarly journals DETERMINATION OF GLYCOGEN IN BEE ORGAN TISSUES AS AN ENERGY METABOLISM PARAMETER

2018 ◽  
pp. 61-63
Author(s):  
I. V. Serduchenko ◽  
N. N. Gugushvili
Keyword(s):  
Cost Effectiveness ◽  
Energy Metabolism ◽  
Colorimetric Method ◽  
Weather Conditions ◽  
Test Time ◽  
Glycogen Level ◽  
Unfavorable Weather ◽  
Total Test Time ◽  
Total Test

New method of glycogen determination in bee organ tissues, considerably different from the existing ones, was suggested. Ghoreishi’s colorimetric method used today is time-, labor- and cost-consuming as the major reagent – orcin – is quite expensive. Comparison of cost-effectiveness of the two methods demonstrated that the proposed technique makes it possible to reduce expenses by using a more available and less expensive resorcin instead of orcin and reducing total test time from 4 to 3 hours 5 minutes. Glycogen contents determination using the updated method was performed in bees of four breeds: Italian-Carpathian, Carpathian, Oka, gray Caucasus mountain honeybees. It was determined that the Oka honeybees demonstrated the highest glycogen level. It is known that the higher is glycogen contents in organs and tissues the better is energy metabolism in insects. Consequently, honeybees of Oka breeds have higher resistance to unfavorable weather conditions and can produce progeny with a higher level of immunity. So, the specified method of glycogen determination in bee organ tissues increases the accuracy of diagnosis and plays a very important role in determining the level of energy metabolism in insects and will be useful for apiculture.

Magnetic orientation of four-ball test specimens and the effect on total test time

Nature ◽  
1978 ◽  
Vol 274 (5670) ◽  
pp. 459-460 ◽  
Author(s):  
J. B. JONES ◽  
G. POCOCK
Keyword(s):  
Test Time ◽  
Magnetic Orientation ◽  
Ball Test ◽  
Total Test Time ◽  
Total Test
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