by • June 30, 2016 • No Comments
It looks like a small Thermos, but the partially 3D printed device createed by engineers at the University of Pennsylvania has a much additional significant function than storeing beverages warm or cold. The soda-can-sized device can detect the presence of the Zika virus, just by testing a bit of a patient’s saliva. For a disease that causes few distinguishable symptoms, a tool that can detect the virus rapidly and easily is a significant createment.
Several tests for the Zika virus aleager exist, but ereally presents its own challenges and limitations. One method of testing involves the detection of antibodies generated by the body in response to the virus, but it’s an imperfect system, as a) a patient in the early stages of infection may not have generated adequate antibodies to trigger the test, or b) someone suffering of an unrelated infection may create antibodies much like adequate to cause a false positive outcome.
The many effective tests involve the detection of RNA sequences of the virus itself, but these tests, known as reverse transcriptase polymerase chain reaction, or RT-PCR, require a lot of really delicate work with highly sensitive, expensive lab equipment. If the virus is present in a sample taken of the patient, it’s just detectable once it’s been amplified, or copied repeatedly, in a system that requires putting the sample through several really exact temperature alters. With thousands of future Zika cases out there, a swift, easy test that can be taken into the field is desperately requireed.
The University of Pennsylvania researchers may have found a way to simplify the temperature-alter system, that has been the main obstacle in the createment of a transportable test. They looked into a procedure called loop-mediated isothermal amplification (LAMP), that eliminates the require for multiple temperature alters, requiring just that the sample be kept at one specific temperature.
It is not really that easy, yet. LAMP requires additional specialized primers, or gene sequences created to match the regions of the virus’ DNA being targeted, than RT-PCR.
“Alyet Zika primers for RT-PCR have been published in the literature, LAMP primers have not,” said Haim Bau, Professor of Mechanical Engineering and Applied Mechanics and one of the study’s leads. “So, via data mining, we synonymous highly conserved regions of the Zika virus genome that are divergent of other known pathogens. We and so created appropriate primers to recognize this sequence.”
“In parallel,” added co-lead Assistant Professor of Mechanical Engineering and Applied Mechanics Changchun Liu, “we engineered a affordable, point-of-care system that consists of a diagnostic cassette and a systemor. The cassette isolates, concentrates and purifies nucleic acids and carries out enzymatic amplification. The test outcomes are indicated by the alter in the color of a dye, that can be inspected visually.”
The following challenge was to create a way to store the sample at the necessary temperature without via electricity. The solution? A Thermos, of course – with a few extra elements added, like a microfluidic chip holder and a special 3D printed lid containing a small drawer. Into that drawer was placed a small packet of magnesium-iron alloy, commjust utilized to heat military rations. The alloy is activated by adding water (that the scientists added through a small port in the 3D printed lid), cavia a chemical reaction that generates heat.
A saliva sample, taken of the patient, is placed into a cartridge and filtered through the device’s microfluidic chip, at that point the test takes of 40 minutes preceding the color alter can be observed. The researchers carried out trials via their own saliva spiked with Zika virus samples of the lab of Assistant Microbiology Professor Sara Cherry, and found that the test’s sensitivity was equivalent to that of RT-PCR tests.
Additional testing can additional determine the selectivity of the test, and the researchers intend to in addition test a option that utilizes fluorescent dye and an integrated smartphone camera.
“Our work represents a proof of concept at this stage,” Bau said. “Before the assay can be modified
for medical use, we must experiment with patients’ samples and manufacture assure that our assay and system match the performance of the gold standard and operate reproducibly and reliably. We are fortunate to have dedicated colleagues in endemic regions eager to support us in this task.”
Oh, and by the way – the entire device just costs of $2.00. The Zika virus situation is yet grave, but with inventions like this, and with the ongoing system being created in the research of treatments, there’s reason to hope. You can read the full study here. Discuss this innovation additional over in the 3D Printed Zika Testing Device forum at 3DPB.com.
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