Aptamer-field-effect transistors overcome Debye length limitations for small-molecule sensing.

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• Field-effect transistors (FETs) are limited in detecting analytes due to the electrical double layer (Debye length).
• Existing biosensing methods struggle with sensitivity in high-ionic strength physiological conditions.

Purpose of the Study:

• To develop a novel FET-based sensing platform overcoming Debye length limitations.
• To achieve sensitive detection of small molecules under physiological conditions.

Main Methods:

• Modification of printed ultrathin metal-oxide FET arrays with deoxyribonucleotide aptamers.
• Utilizing target-induced aptamer conformational changes to gate semiconductor channel conductance.
• Employing specifically isolated aptameric stem-loop receptors for target recognition.

Main Results:

• Demonstrated sensitive detection of small molecules (serotonin, dopamine, glucose, sphingosine-1-phosphate) in high-ionic strength buffers.
• Overcame the fundamental Debye length limitation in FET-based sensing.
• Achieved detection of both charged and electroneutral analytes.

Conclusions:

• Adaptive aptamer modification of FETs provides a viable strategy for sensitive biosensing.
• This approach enables robust analyte detection in complex physiological environments.
• The developed platform holds potential for various diagnostic and monitoring applications.