In a recent article published in the journal Nature Materials, researchers designed a novel electrochemical biosensor for the detection of cancer biomarkers, specifically focusing on the epidermal growth factor receptor (EGFR). This biosensor is notable for its reusability, capable of undergoing over 200 regeneration cycles without compromising its sensitivity and accuracy. The development of such point-of-care (POC) devices is particularly significant in the context of modern medical diagnostics, where rapid and reliable detection of biomarkers can facilitate timely treatment decisions.
Study: A refresh-in-sensing reusable biosensor. Image Credit: joel bubble ben/Shutterstock.com
Background
Point-of-care devices have emerged as essential tools in medical diagnostics, offering advantages such as rapid response times, high sensitivity, and ease of use. These devices are designed to overcome the limitations of conventional diagnostic techniques, including polymerase chain reaction (PCR) and enzyme-linked immunosorbent assays (ELISA), which can be costly and resource-intensive.
The coronavirus disease 2019 (COVID-19) pandemic highlighted the critical need for efficient diagnostic solutions, further accelerating the development and adoption of POC technologies. Among these, organic electrochemical transistors (OECTs) have gained attention due to their exceptional sensitivity and ability to detect various biomarkers and physicochemical parameters. The architecture of OECTs typically includes a gate, source, and drain, with an organic semiconductor layer that responds to electrochemical reactions, allowing for precise measurements of electrical conductivity changes.
The Current Study
The authors describe the design and operation of the biosensor, which utilizes a refresh-in-sensing mechanism to enhance its performance. The key component of the biosensor is the interaction between gefitinib, a drug that targets EGFR, and the organic semiconductor PEDOT:PSS. Upon exposure to gefitinib, the binding energy of the EGFR-gefitinib complex is stronger than that of the gefitinib-PEDOT:PSS interaction.
This results in gefitinib being displaced from the semiconductor surface, leading to alterations in the surface potential and a decrease in the oxidation level of the PEDOT:PSS layer. Consequently, this shift affects the electrical conductivity between the source and drain of the OECT. The biosensor's regeneration is achieved by adding protonated gefitinib, which restores the surface to its original state, allowing for repeated use.
The authors conducted extensive testing to evaluate the performance of the biosensor, including its selectivity and sensitivity in detecting EGFR. They also assessed the device's durability by testing it with various samples, including peripheral blood, to ensure consistent performance over time. The biosensor's ability to maintain low noise levels and minimal interference from other ions or biosubstances was also a critical aspect of the evaluation.
Results and Discussion
The results demonstrated that the proposed biosensor exhibited exceptional performance in detecting EGFR, with a high degree of selectivity and sensitivity. The authors reported that the device maintained its efficacy even after regeneration cycles, showcasing its potential for long-term use in clinical settings. The low noise recording quality and minimal interference from other substances further underscored the biosensor's reliability.
In addition to EGFR, the authors explored the biosensor's capability to detect other biomarkers. However, they noted that the successful application of this technology to additional biomarkers would depend on specific criteria. For instance, the sensing probe must undergo chemical protonation, and the complex formed between the sensing probe and the target analyte must exhibit strong and selective binding. These requirements may limit the technology's applicability to a broader range of biomarkers, posing challenges for its widespread adoption in POC diagnostics.
The study also addressed potential limitations related to the stability of organic materials like PEDOT:PSS, which can degrade over time due to environmental factors. This degradation could impact the long-term performance and lifespan of the biosensor. Furthermore, the article highlights the need for future POC devices to address emerging challenges, such as sustainability, power supply, and mass fabrication. The authors suggest that self-powered devices represent a significant advancement in the field, paving the way for innovative and cost-effective diagnostic solutions.
Conclusion
In conclusion, the article presents a significant advancement in the development of reusable electrochemical biosensors for cancer biomarker detection. The innovative refresh-in-sensing mechanism allows the biosensor to maintain its sensitivity and accuracy over numerous regeneration cycles, making it a promising tool for point-of-care diagnostics.
The findings underscore the potential of OECTs in revolutionizing medical diagnostics by providing rapid, reliable, and cost-effective solutions. However, the authors also caution that the technology's applicability may be limited to specific biomarkers due to the stringent requirements for successful protein-receptor interactions.
As the field of biosensing continues to evolve, addressing challenges related to material stability, sustainability, and device fabrication will be crucial for the widespread adoption of these technologies in clinical practice. The work of Jiang et al. serves as a foundation for future research aimed at expanding the capabilities of POC devices and enhancing their role in personalized healthcare solutions.
Journal Reference
Gallegos-Martinez, S., & Zhang, Y. S. (2024). A refresh-in-sensing reusable biosensor. Nature Materials. DOI: 10.1038/s41563-024-02001-z, https://www.nature.com/articles/s41563-024-02001-z