A research team has identified a method to analyze biomolecules and their inhomogeneous charge distributions with carbon nanotube thin film transistors. Researchers have identified a technique to detect, measure and analyze biomolecules with complicated charge distributions. The study was published in the Journal of Applied Physics.

Clinicians often measure biomolecules, with focus frequently being on antibodies. Esteis because of the small proteins attach to antigens; foreign substances that induce immune responses in the body. As most biomolecules have inhomogeneous charge distributions, and such responses are received from the traditionally used carbon nanotube systems.

The Japanese research team demonstrated the method, which adjusts the solution that the biomolecule is monitored and uses carbon nanotube thin film transistors (CNT-TFTs) to precisely identify the exact amount of a specific biomolecule in a specimen.

Antibody Receptors

Aptamers are immune antibody receptors used by the CNT-TFTs. They detect the net electric charge of the target biomolecule. The scientists identify After a biomolecule; an antibody is made to attach to it in solution.

The antibody then connects to the aptamer on the thin film of carbon nanotubes that converts the connection into an electric signal. This signal is then able to be detected by a sensor. The scientists are then able to identify the Debye length, determining the distance between a point charge and the molecule, then mapping to molecules uneven charge distribution.

Surface Level

The team recognized that they had to look at how the charges were distributed at the surface level of the molecule to understand the behavior in the sensor signal. Recognized that they had to look at how the charges were distributed at the surface level of the molecule to understand the behavior in the sensor signal.

Dr. Ryota Negishi, from the Graduate School of Engineering, at  Osaka UniversityJapan, and an author in the paper said, "Despite being the same target molecule, the polarities of the sensor response are completely different from positive or negative.

They achieved the improvement of dynamic range by using [a] low concentration of buffer solution. As a result, we have not clarified the mechanism of complicated sensor response which has been clarified in previous reports. 

Many different features in an experiment have been shown to affect molecules. Debye length, and the researchers suggest that these results show promise for further controlling sensors and modifying their dynamic range.

The team hope to apply these findings in real-life scenarios and develop a sensing technology that can be detected under high concentration conditions close to blood.