Part per trillion label-free electronic bioanalytical detection.

Area of Science:

• Materials Science
• Biotechnology
• Sensor Technology

Background:

• Label-free electronic detection methods are crucial for sensitive biomolecule analysis.
• Organic Field-Effect Transistors (OFETs) offer potential for low-cost, flexible biosensors.
• Achieving high sensitivity and selectivity in biosensing remains a key challenge.

Purpose of the Study:

• To develop a Functional Bio-Interlayer Organic Field-Effect Transistor (FBI-OFET) sensor for label-free biotin detection.
• To optimize the sensor's performance using controllable deposition techniques.
• To explore the potential of FBI-OFETs as disposable electronic strip-tests.

Main Methods:

• Fabrication of FBI-OFETs with a streptavidin-functionalized bio-interlayer.
• Utilizing Layer-by-Layer (LbL) assembly and spin-coating for capturing layer deposition.
• Characterization of sensor response to varying biotin concentrations.
• Modeling analyte binding using a Langmuirian adsorption model.

Main Results:

• Demonstrated label-free electronic detection of biotin with a limit of 3 parts per trillion (15 pM).
• Observed a logarithmic response spanning over 5 orders of magnitude of analyte concentration.
• Showcased sensor functionality with both streptavidin and antibody interlayers, and with a microfluidic system.

Conclusions:

• FBI-OFETs exhibit exceptional sensitivity and selectivity for biotin detection.
• Controllable LbL assembly and spin-coating enable high-performance, potentially low-cost sensor production.
• FBI-OFETs are promising for disposable electronic strip-tests in biological fluid assays requiring ultra-low detection limits.