Express diagnosis of a heart attack: spit on the biochip!
Currently, the diagnosis of myocardial infarction involves an electrocardiogram (ECG) and the detection of marker proteins in the blood. According to US statistics, in an ambulance, approximately 25% of heart attacks (usually with atypical symptoms) are not recorded using an ECG. The blood test carried out in the hospital increases the accuracy of diagnosis, but it takes precious time to take a blood sample and analyze it.
Scientists at the University of Texas, working under the guidance of Professor John McDevitt, have developed a silicon oxide biochip to assess the levels of protein markers of myocardial infarction in saliva samples.
The black recesses in the center of the chip are a kind of micro-samples for analysis. In the future, researchers will switch to using cheaper stainless steel chips (mugs in the background).
The biochip is a panel the size of a dime embedded inside a larger card. The card is inserted into an analyzer the size of a toaster, inside which the liquid penetrates under pressure into cells coated with antibodies connected to fluorescent labels.
When interacting with marker proteins, the tags begin to emit a glow of different wavelengths, the intensity of which is recorded by a video chip built into the analyzer - the same as those used in digital cameras. As a result, a protein profile is displayed on the analyzer display, suggesting the absence or presence of a heart attack.
To identify biomarker proteins in saliva, the developers had to create more sensitive tests, which, however, are easier to use and provide quick results, which is extremely important to prevent the consequences of a heart attack. In total, during the development of the biochip, scientists identified 32 proteins whose content in the body changes during myocardial infarction, of which they selected 4 of the most indicative.
The authors tested the effectiveness of the new biochip on 59 patients, 29 of whom had a myocardial infarction. ECG analysis alone revealed only 67% of cases of heart attack, and in combination with a new biochip for saliva analysis – 97%. There is no mention of false positive results – obviously there were none.
McDevitt is a scientific expert at LabNow, whose specialists are working on a commercial version of one-time rapid tests and hope to reduce their price to $20 per chip. The analyzers needed to read them will essentially be advanced digital cameras. The start of testing of the new test in the conditions of ambulances is scheduled for the summer of this year.
Some experts doubt the effectiveness of biochips from the point of view of clinical practice, motivating this by the fact that, just like in blood, biomarkers appear in the patient's saliva with a certain time lag. However, the developers claim that low levels of biomarkers are registered in saliva even earlier than in blood. They suggest that this is due to the rapid and constant renewal of saliva.
Portal "Eternal youth" www.vechnayamolodost.ru based on the materials of TechnologyReview
13.05.2008