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Sensor to detect drug resistant leukaemia

Date: 22 September 2019 Tags: Biotechnology

Issue

A highly sensitive carbon nanotube based sensor capable of detecting multidrug-resistant myeloid leukaemia cells even when present at very low concentration of has been fabricated by researchers.

 

Background

Compared with drug-sensitive leukemic cells, multidrug-resistant leukaemia cells have better ability to bind to the antibody found on the nanotubes.

The expression of P-glycoprotein transporter present on leukaemia cell surface gets enhanced when the cell becomes multidrug-resistant.

 

Details

  • The scientists used chemotherapy drug doxorubicin to make the leukaemia cells drug resistant and work in the research.

  • Using chemical vapour deposition technique, the sensor produced vertically aligned multi-walled carbon nanotubes. The carbon nanotubes were grown on a silicon wafer substrate.

  • To miniaturise the sensor and make it flexible, moisture-resistant and stable even at 180 degree C, the researchers transferred the carbon nanotubes to a flexible substrate made of polyethylene terephthalate (PET).

  • To convert the carbon nanotubes into a sensor, the researchers functionalised the nanotubes. Nanotubes that are functionalised have better ability to bind to a leukaemia antibody, which in turn binds to the leukaemia cells present in the sample. As more antibodies get bound to carbon nanotubes, the sensitivity improves.

  • The presence of leukaemia cells bound to the antibody is determined by measuring a drop in the conductivity of the carbon nanotubes. To measure changes in conductivity, three electrodes , carbon nanotubes as a working electrode, a counter electrode made of platinum and a reference electrode are immersed in a electrolyte and a constant voltage is applied and a change in current is measured.

  • Leukaemia cells are insulating in nature. So the conductivity of carbon nanotubes reduces as the cells bind to the antibody. The more the concentration of cells bound to the antibody the greater is the reduction in the current flow.