Related Experiment Video
Updated: May 5, 2026
07:58
Highly Sensitive and Quantitative Detection of Proteins and Their Isoforms by Capillary Isoelectric Focusing Method
Published on: September 19, 2018
6.3K
Interface Quality Control of Self-Assembled Monolayer for Highly Sensitive Protein Detection Based on EGOFETs
Xinyu Dong1, Xingyu Jiang1, Jiaqi Su2
1State Key Laboratory of Bioinspired Interfacial Materials Science, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou 215123, China.
Sensors (Basel, Switzerland)
|May 4, 2026
Summary
Optimizing self-assembled monolayers (SAMs) on EGOFET biosensors enhances human IgG detection. A 50 mM mixed SAM concentration achieved a 2.82 fM limit of detection, demonstrating high sensitivity and selectivity for disease biomarker applications.
Area of Science:
- Biosensor technology
- Organic electronics
- Surface chemistry
Background:
- Electrolyte-gated organic field-effect transistors (EGOFETs) offer low-cost, low-voltage biosensing with signal amplification.
- Effective receptor immobilization on device surfaces is crucial for biosensor performance.
- Thiol chemistry-based covalent immobilization on gold surfaces is a common strategy for bioreceptor attachment.
Purpose of the Study:
- To optimize a mixed self-assembled monolayer (SAM) for enhanced label-free detection of human IgG using EGOFETs.
- To systematically investigate the effect of SAM concentration on surface quality and biosensor performance.
- To establish a versatile strategy for engineering high-performance EGOFET biosensors for disease biomarker detection.
Main Methods:
- Fabrication and characterization of EGOFET biosensors using mixed SAMs of 11-mercaptoundecanoic acid (11-MUA) and 3-mercaptopropionic acid (3-MPA).
- Systematic variation of total SAM concentration (10-400 mM) and characterization using XPS, EIS, CV, and AFM.
- Immobilization of anti-IgG antibodies via EDC/NHS chemistry and blocking with ethanolamine/BSA, followed by electrical measurements.
Main Results:
- A SAM concentration of 50 mM resulted in a densely packed, well-ordered monolayer, confirmed by surface characterization techniques.
- EGOFET biosensors functionalized with the optimized 50 mM SAM exhibited superior sensing performance.
- The optimized devices demonstrated a highly linear response (R² = 0.998) from 1 fM to 10 nM, with a limit of detection (LOD) of 2.82 fM and excellent selectivity against IgA and IgM.
Conclusions:
- The optimization of mixed SAM concentration is critical for achieving high-performance EGOFET biosensors.
- The developed SAM strategy provides a versatile platform for label-free detection of various disease biomarkers.
- This work advances the development of sensitive and selective EGOFET-based diagnostic tools.
