Oncological diseases belong to the most serious diseases with high mortality. The most common cancer in children is acute lymphoblastic leukemia (ALL). It is a cancer of the blood-forming tissues characterized by a large increase in the numbers of leukocytes in the circulation or bone marrow. The prognosis of positive treatment increases with early diagnosis of this disease. It is therefore important to develop diagnostic methods that will be able to detect this disease in early stage. One of the option can be non-invasive diagnostics using the biosensors based on nucleic acid - aptamers. Aptamers are characterised by unique properties such as high specificity and nonimmunogenicity. Aptamer recognizes the surface markers on the membrane of cancer cells with the high binding affinity. Biosensors based on aptamers with redox markers are among the most sensitive experimental tools of this type.

In this contribution, we report the development of optimizing redox-labeled electrochemical aptasensor for the detection of Jurkat leukemia cells. The aptamers specific to the protein tyrosine kinase 7 (PTK7), the important membrane protein cancer marker that is overexpressed in Jurkat cells were used. We compared the sensitivity of aptasensors for aptamers modified either by methylene blue (MB) and ferrocene (Fc), respectively. Both aptasensors were tested in the presence of Jurkat cells at concentration range 50-5000 cells/ml using differential pulse voltammetry. In both cases the comparable sensitivity was obtained with limit of detection of approx. 200 cells/mL according to 3S/N rule.

Acknowledgement

This work was funded by Science Agency VEGA, project No. 1/0419/20.