A new type of membrane test strip for the quantitative immunochromatographic rapid-test has been developed that will be able to accurately and quickly make an early diagnosis of an acute myocardial infarction through the presence of disease markers in blood, as well as to identify various things such as sepsis, a pregnancy's duration, and viral & bacterial infections.

Tests based on immunochromatography (the most popular of which is a pregnancy test) are extremely easy to use. They are based on the detection of individual substances in biological liquids and the visualization of their presence in the form of colouring or fluorescence on the test-strip, on the yes-no principle.

The diagnosis's speed is vital to start treatment immediately in cases of acute myocardial infarction (a serious heart attack), sepsis, and malignant transformations. The science team has managed to combine qualitative and quantitative immunochromatographic test principles in a simple and effective bioanalytical system, thus improving the quality and accuracy of their results.

It is now possible to not only identify the presence of certain substances in the body but also to determine their critical number visually. To get a quantitative result, it is necessary to apply one or several drops of a biosample to the test strip and count the number of coloured test lines appearing in the device's analytical area.

Biological fluid flows on the b segment that contains a conjugate labelled with gold nanoparticles or quantum dots of antibodies, and then the test strip captures it and moves with it along an analytical membrane. The resulting immunocomplexes move along several cross lines containing a second set of antibodies against the defined antigens in increasing concentrations.

The binding of labelled immunocomplexes on the carrier, which is visually registered as forms of coloured cross lines on the test strip, takes place due to the specific interactions of & laquoantibodyantigen. The higher the content of the determining substance in the sample, the greater the number of lines that will appear in the analytical area.

The use of new types of nanosize gold particles or quantum dots in conjugate with antibodies in the form of so-called laquonanoclouds, laquostars, laquopopcorn, and laquoflowers allows us to significantly increase the detection limit of analyzed substances in biological fluids. This is fundamentally important in the analysis of the markers of a number of deadly diseases

Monitoring fatty-acid-binding proteins (FABP) is the most promising way to diagnose early heart attacks. When myocardium is damaged, the concentration of FABPs in the blood increases significantly in the first hours after feeling pain. The simultaneous determination of early FABP and late tropotin I cardiac markers with the use of our new type of rapid-test increases the efficiency of diagnoses and allows doctors to identify hidden forms of heart attacks, the researchers concluded.