Highly Effective and Efficient Self-Assembled Multilayer-Based Electrode Passivation for Operationally Stable and...

Area of Science:

• Materials Science
• Biotechnology
• Electrical Engineering

Background:

• Transistor-based biosensors require stable electrode passivation for reliable performance in aqueous electrolytes.
• Electrolyte-gated transistors (EGTs) are promising for biosensing but susceptible to short-circuiting in liquid environments.

Purpose of the Study:

• To develop and validate a self-assembled multilayer (SAML) passivation technique for enhancing the operational stability and reproducibility of EGT biosensors.
• To demonstrate the efficacy of SAML passivation in an EGT biosensor designed for detecting Alzheimer's disease biomarker, Tau protein.

Main Methods:

• Fabrication of a SAML using sequential self-assembly of 1,10-decanedithiol, vinyl-polyhedral oligomeric silsesquioxane, and 1-octadecanethiol.
• Integration of the SAML with an indium oxide (In2O3) thin film as the semiconductor channel and biological interface in an EGT biosensor.
• Functionalization of the SAML-passivated EGT with a Tau-specific DNA aptamer for biomarker detection in phosphate-buffered saline (PBS).

Main Results:

• The SAML passivation effectively prevented short-circuiting in EGTs operating in PBS over multiple measurement cycles.
• The SAML-passivated EGT biosensor demonstrated stable and reproducible performance.
• Ultrasensitive and quantitative detection of Tau protein from 1 x 10^-15 to 1 x 10^-10 M was achieved, exceeding clinical requirements.

Conclusions:

• The facile solution-processed SAML method provides effective electrode passivation for stable and reproducible EGT biosensor operation in aqueous environments.
• This passivation strategy is adaptable for various advanced biomedical devices and bioelectronics operating in physiological conditions.
• The developed EGT biosensor shows significant potential for early and reliable diagnosis of Alzheimer's disease.