We use cookies to understand how you use our site and to improve your experience. This includes personalizing content and advertising. To learn more, click here. By continuing to use our site, you accept our use of cookies. Cookie Policy.

Features Partner Sites Information LinkXpress hp
Sign In
Advertise with Us
PURITAN MEDICAL

Download Mobile App




Handheld Device Developed for DNA Amplification and Detection

By LabMedica International staff writers
Posted on 23 Jan 2018
A method has been developed that combines electrochemical detection with recombinase polymerase amplification (RPA) on a portable device to improve detection of genetic material from multiple tuberculosis strains.

The RPA reaction uses enzymes called recombinases that form complexes with oligonucleotide primers and pair the primers with homologous sequences in DNA. More...
A single-stranded DNA binding protein binds to the displaced DNA strand and stabilizes the resulting loop. The primer then initiates DNA amplification by a polymerase, but only if the target DNA sequence is present.

Scientists from Harvard University (Boston, MA, USA) and Diagnostics for All (Salem, MA, USA) used disposable, paper-based strips that integrate three screen-printed carbon electrodes and accomplish thermoregulation with +/-0.1 ºC temperature accuracy. To detect DNA, the team first prepares the paper test strip that includes the blood sample and primers, in addition to integrated electrodes that contain the reagents for RPA. The test strips allows the team to cut down on reaction volume, reducing reagent cost and blood sample size. After identifying a 213-bp region common to both Mycobacterium tuberculosis and Mycobacterium smegmatis, the team designed appropriate primers for the RPA assay to amplify the specific sequence. Performed at 65 ºC, the assay combined isothermal amplification with electrochemical readout of redox-active hexa-amine ruthenium (III) (Ru(NH3)6]3+) as an electroactive mediator for the electrochemical detection of DNA.

The team also performed the reaction with varying levels of initial concentrations of the M. smegmatis target DNA in order to demonstrate the assay's sensitivity. According to the study, the assay's limit of detection is 0.04 ng/µL, equating to 11 colony forming units (CFU)/mL of M. tuberculosis. Because RPA assays do not need additional sample preparation time, the assay in the study required 20 minutes to identify the biosignal.

The scientists emphasized that the RPA assay could potentially identify the signal faster depending on the type of primer and target sequence. While the team used M. smegmatis as a surrogate strain for M. tuberculosis, the benchtop RPA assay they developed can detect up to 19 Mycobacterium species. In addition, the team also carried out experiments using samples spiked with M. tuberculosis DNA that highlights that the electrochemical method also works with the specific bacterial strain.

Data collected by the device, called uMEDNA, can be transmitted by plugging it into a cell phone's headphone jack. The uMEDNA device also communicates with any bluetooth-enabled device and can link to any computer, tablet, or smartphone. At the moment, scientists have developed software for Apple devices and are currently working on adapting the program for Android devices. Maria-Nefeli Tsaloglou, PhD, the lead author of the study, said, “The uMEDNA device will only cost the end user about USD 30. Introducing the DNA detection paper-based strips will keep the assay price relatively low, as well. Electrochemical analyzers in the lab are bulky, expensive, almost in the range of USD 300,000 to USD 1 million. In this study, we proved that the size and electronics within the analyzer can be cheaper.” The study was published in the February 2018 issue of the journal Analytical Biochemistry.

Related Links:
Harvard University
Diagnostics for All

Gold Member
Antipsychotic TDM Assays
Saladax Antipsychotic Assays
3-Part Differential Hematology Analyzer
Swelab Alfa Plus Sampler
New
Specimen Radiography System
TrueView 200 Pro
New
Silver Member
Autoimmune Hepatitis Test
LKM-1-Ab ELISA
Read the full article by registering today, it's FREE! It's Free!
Register now for FREE to LabMedica.com and get access to news and events that shape the world of Clinical Laboratory Medicine.
  • Free digital version edition of LabMedica International sent by email on regular basis
  • Free print version of LabMedica International magazine (available only outside USA and Canada).
  • Free and unlimited access to back issues of LabMedica International in digital format
  • Free LabMedica International Newsletter sent every week containing the latest news
  • Free breaking news sent via email
  • Free access to Events Calendar
  • Free access to LinkXpress new product services
  • REGISTRATION IS FREE AND EASY!
Click here to Register








DIASOURCE (A Biovendor Company)

Channels

Hematology

view channel
Image: CitoCBC is the world first cartridge-based CBC to be granted CLIA Waived status by FDA (Photo courtesy of CytoChip)

Disposable Cartridge-Based Test Delivers Rapid and Accurate CBC Results

Complete Blood Count (CBC) is one of the most commonly ordered lab tests, crucial for diagnosing diseases, monitoring therapies, and conducting routine health screenings. However, more than 90% of physician... Read more

Immunology

view channel
Image: An “evolutionary” approach to treating metastatic breast cancer could allow therapy choices to be adapted as patients’ cancer changes (Photo courtesy of 123RF)

Evolutionary Clinical Trial to Identify Novel Biomarker-Driven Therapies for Metastatic Breast Cancer

Metastatic breast cancer, which occurs when cancer spreads from the breast to other parts of the body, is one of the most difficult cancers to treat. Nearly 90% of patients with metastatic cancer will... Read more

Pathology

view channel
Image: A real-time trial has shown that AI could speed cancer care (Photo courtesy of Campanella, et al., Nature Medicine)

AI Accurately Predicts Genetic Mutations from Routine Pathology Slides for Faster Cancer Care

Current cancer treatment decisions are often guided by genetic testing, which can be expensive, time-consuming, and not always available at leading hospitals. For patients with lung adenocarcinoma, a critical... Read more

Technology

view channel
Image: Researchers Dr. Lee Eun Sook and Dr. Lee Jinhyung examine the imprinting equipment used for nanodisk synthesis (Photo courtesy of KRISS)

Multifunctional Nanomaterial Simultaneously Performs Cancer Diagnosis, Treatment, and Immune Activation

Cancer treatments, including surgery, radiation therapy, and chemotherapy, have significant limitations. These treatments not only target cancerous areas but also damage healthy tissues, causing side effects... Read more
Copyright © 2000-2025 Globetech Media. All rights reserved.