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Bilirubin Sensing Using Organic Electrochemical Transistors: Role of Gate Materials and Operational Parameters
Yunjia Song1,2, Sihui Xu1,2, Onur Parlak1,2,3
1Department of Medicine, Solna, Division of Dermatology and Venereology, Karolinska Institutet, Stockholm, 17177, Sweden.
Insights
This study introduces organic electrochemical transistors for detecting bilirubin, a key biomarker for neonatal jaundice. The devices show sensitivity to bilirubin when using specific gate electrodes, enabling better diagnostics.
Area of Science:
- Biomedical Engineering
- Materials Science
- Analytical Chemistry
Background:
- Bilirubin is a critical biomarker for neonatal jaundice and liver dysfunction.
- Elevated bilirubin levels pose neurotoxicity risks, especially in neonates.
- Current point-of-care diagnostics for bilirubin face limitations in timely detection.
Purpose of the Study:
- To develop novel organic electrochemical transistors (OECTs) for sensitive bilirubin detection.
- To investigate the role of gate electrode material and polarizability in OECT performance for bilirubin sensing.
- To establish a foundational framework for high-precision bilirubin sensors for neonatal care.
Main Methods:
- Fabrication of OECTs utilizing PEDOT:PSS as the channel material.
- Testing OECT sensitivity to free bilirubin using various polarizable (Au, Pt, glassy carbon) and non-polarizable (Ag/AgCl) gate electrodes.
- Electrochemical characterization including cyclic voltammetry to elucidate redox mechanisms.
- Evaluation of sensor performance with clinically relevant human serum albumin-bound bilirubin.
Main Results:
- OECTs with PEDOT:PSS channels exhibit inherent sensitivity to free bilirubin when paired with polarizable gate electrodes.
- Bilirubin detection sensitivity is abolished with non-polarizable Ag/AgCl gates, emphasizing the importance of electrode polarizability.
- The direction of drain-source current change is modulated by operational parameters, indicating complex interfacial dynamics.
- The sensor demonstrates sensitivity to human serum albumin-bound bilirubin, a clinically relevant form.
Conclusions:
- Gate electrode polarizability is crucial for OECT-based bilirubin detection.
- The developed OECT platform provides a foundational framework for high-precision bilirubin sensors.
- This technology has the potential for transformative diagnostic devices for real-time bilirubin monitoring in neonatal care, especially in resource-limited settings.
Abstract:
Bilirubin, a critical yellow-orange bile pigment and heme degradation product, serves as a key biomarker for neonatal jaundice and liver dysfunction, with elevated concentrations posing significant neurotoxicity risks particularly in neonates. However, timely detection remains challenging due to limitations in current point-of-care technologies. This study reveals that organic electrochemical transistors that include PEDOT:PSS as the channel material exhibit inherent sensitivity to free bilirubin - but only when paired with polarizable gate electrodes (Au, Pt, glassy carbon). Intriguingly, this response is abolished with non-polarizable Ag/AgCl gates, highlighting the pivotal role of electrode polarizability in bilirubin detection. Furthermore, the drain-source current changing direction is modulated by operational parameters, suggesting complex interfacial dynamics between bilirubin and channel material. Through systematic investigation, we demonstrate that this sensitivity persists for human serum albumin-bound bilirubin, a clinically relevant complex, and elucidate the redox mechanisms underlying signal transduction via cyclic voltammetry. Our work not only decouples the influence of gate materials and measurement conditions on device performance but also establishes a foundational framework for designing high-precision bilirubin sensors, paving the way for transformative diagnostic devices that address critical gaps in neonatal care through miniaturized, low-power platforms capable of real-time bilirubin monitoring in both clinical and resource-limited settings.
