Integrating nucleic acid sequence-based amplification and microlensing for high-sensitivity self-reporting detection

The Analyst ◽  
2020 ◽  
Vol 145 (23) ◽  
pp. 7528-7533
Author(s):  
Feiyue Teng ◽  
Xinpei Wu ◽  
Tao Hong ◽  
Gary B. Munk ◽  
Matthew Libera

We use electron-beam patterned functional microgels to integrate self-reporting molecular beacons, dielectric microlenses, and solid-phase and/or solution-phase nucleic acid amplification in a viral-detection microarray model.

Biosensors ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 479
Author(s):  
Soumi Sukla ◽  
Prasenjit Mondal ◽  
Subhajit Biswas ◽  
Surajit Ghosh

Detecting dengue virus (DENV) infection in patients as early as possible makes the disease management convenient. Conventionally, DENV infection is diagnosed by ELISA-based methods, but sensitivity and specificity are major concerns. Reverse-transcription-PCR (RT-PCR)-based detection confirms the presence of DENV RNA; however, it is expensive, time-consuming, and skilled personnel are required. A fluorescence-based detection system that detects DENV RNA in patient’s serum directly, without any nucleic acid amplification step, has been developed. The method uses target-specific complementary sequence in the molecular beacon, which would specifically bind to the DENV RNA. The molecular beacons are approximately 40 bases long hairpin structures, with a fluorophore-quencher system attached at the terminal ends of the stem. These probes are biotinylated in the stem region, so that they can be immobilized on the streptavidin-tagged magnetic beads. These magnetic beads, coupled with biotinylated molecular beacons, are used for the detection of the target RNA in the serum by incubating the mixture. After incubation, beads are separated and re-suspended in a buffer. The measurement of fluorescence is taken in fluorometer after 15 min incubation at 50 °C. The whole work is carried out in a single tube. This rapid method can precisely detect dengue RNA within two hours, confirming ongoing DENV replication in the patient.


Author(s):  
Isao Yokota ◽  
Peter Y Shane ◽  
Kazufumi Okada ◽  
Yoko Unoki ◽  
Yichi Yang ◽  
...  

Abstract Background COVID-19 has rapidly evolved to become a global pandemic due largely to the transmission of its causative virus through asymptomatic carriers. Detection of SARS-CoV-2 in asymptomatic people is an urgent priority for the prevention and containment of disease outbreaks in communities. However, few data are available in asymptomatic persons regarding the accuracy of PCR testing. Additionally, although self-collected saliva has significant logistical advantages in mass screening, its utility as an alternative specimen in asymptomatic persons is yet to be determined. Methods We conducted a mass-screening study to compare the utility of nucleic acid amplification, such as reverse transcriptase polymerase chain reaction (RT-PCR) testing, using nasopharyngeal swabs (NPS) and saliva samples from each individual in two cohorts of asymptomatic persons: the contact tracing cohort and the airport quarantine cohort. Results In this mass-screening study including 1,924 individuals, the sensitivity of nucleic acid amplification testing with nasopharyngeal and saliva specimens were 86% (90%CI:77-93%) and 92% (90%CI:83-97%), respectively, with specificities greater than 99.9%. The true concordance probability between the nasopharyngeal and saliva tests was estimated at 0.998 (90%CI:0.996-0.999) on the estimated airport prevalence at 0.3%. In positive individuals, viral load was highly correlated between NPS and saliva. Conclusion Both nasopharyngeal and saliva specimens had high sensitivity and specificity. Self-collected saliva is a valuable specimen to detect SARS-CoV-2 in mass screening of asymptomatic persons.


Author(s):  
Shinnosuke Inoue ◽  
Woon-Hong Yeo ◽  
Jong-Hoon Kim ◽  
Jae-Hyun Chung ◽  
Kyong-Hoon Lee ◽  
...  

Tuberculosis (TB) is an epidemic affecting one-third of the world’s population, mostly in developing and low-resource settings. People having active pulmonary TB are considered highly infectious; therefore, it is critical to identify and treat these patients rapidly before spreading to others. However, the most reliable TB diagnostic methods of bacterial culture or nucleic acid amplification are time-consuming and expensive. The challenge of TB diagnosis lies in highly sensitive and specific screening with low cost. Here, we present an LNA-modified microtip-sensor, which is capable of selectively detecting low-abundance DNA from bacteria. When genomic DNA of Bacillus Calmette-Gue´rin (BCG, a surrogate marker of Mycobacterium bovis), and genomic DNA of Staphylococcus epidermidis (S. epi) are used, the microtip-sensor yields the detection limit of 1,000 copies/mL within 20 minutes. The high sensitivity and specificity approaching nucleic acid amplification methods can potentially overcome the current challenges for rapid TB screening.


2011 ◽  
Vol 26 (2) ◽  
Author(s):  
Francesca Sidoti ◽  
Massimiliano Bergallo ◽  
Maria Elena Terlizzi ◽  
Sara Astegiano ◽  
Cristina Costa ◽  
...  

2015 ◽  
Vol 53 (11) ◽  
pp. 3606-3608 ◽  
Author(s):  
S. W. Peterson ◽  
I. Martin ◽  
W. Demczuk ◽  
A. Bharat ◽  
L. Hoang ◽  
...  

We developed a real-time PCR assay to detect single nucleotide polymorphisms associated with ciprofloxacin resistance in specimens submitted for nucleic acid amplification testing (NAAT). All three single nucleotide polymorphism (SNP) targets produced high sensitivity and specificity values. The presence of ≥2 SNPs was sufficient to predict ciprofloxacin resistance in an organism.


2021 ◽  
Author(s):  
Fei Ma ◽  
Chen-Chen Li ◽  
Chun-Yang Zhang

Single-molecule fluorescence imaging is among the most advanced analytical technologies and has been widely adopted for biosensing due to its distinct advantages of simplicity, rapidity, high sensitivity, low sample consumption,...


2019 ◽  
Vol 57 (6) ◽  
Author(s):  
Johanna Sandlund ◽  
Mark H. Wilcox

ABSTRACT The use of nucleic acid amplification tests (NAATs) for the diagnosis of Clostridium (Clostridioides) difficile infection (CDI) leads to overdiagnosis. To improve the clinical specificity of NAATs, there has been a recent interest in using toxin gene cycle thresholds (CTs) to predict the presence and absence of toxins. Although there is an association between CT values and fecal toxin concentrations, the predictive accuracy of the former is suboptimal for use in clinical practice. Ultrasensitive toxin immunoassays to quantify free toxins in stool offer a novel option for high-sensitivity fecal toxin detection rather than using surrogate markers for prediction.


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