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The value of electrochemical ratiometry in immunosensing: A systematic study
Jin Song1, Rui Gong2, Shibo Song3
1Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250103, China.
Insights
Electrochemical immunosensors achieve improved accuracy and reproducibility using ratiometry, overcoming limitations for reliable diagnostics. This method enhances stability, making them a promising alternative to traditional methods like PCR for point-of-care testing.
Area of Science:
- Electrochemistry
- Biosensing
- Nanomaterials
Background:
- Electrochemical immunosensors face challenges in reproducibility and accuracy, leading to false results and hindering adoption.
- Ratiometry has shown potential in addressing these limitations, but its full benefits and mechanisms remain underexplored.
Purpose of the Study:
- To comprehensively investigate the benefits and mechanisms of ratiometry in electrochemical immunosensors.
- To establish electrochemical immunosensors as a viable alternative to gold-standard diagnostic methods.
Main Methods:
- Construction of labeled and label-free electrochemical immunosensors for SARS-CoV-2 pseudovirus quantification.
- Utilizing electrochemically synthesized graphene modified electrodes with various electrochemical probe pairs.
- Comparison of conventional and ratiometric immunosensor designs.
Main Results:
- Electrocatalyst modification significantly enhances immunosensor sensitivity.
- Ratiometry substantially improves reproducibility, accuracy, and stability of electrochemical immunosensors.
- Ratiometry effectively compensates for inherent errors and dynamic variations in the base electrode.
Conclusions:
- Ratiometry is a key strategy for enhancing electrochemical immunosensor performance, addressing critical limitations.
- Electrochemical immunosensors utilizing ratiometry can rival the performance of PCR for immunoassay diagnosis.
- Electrochemical ratiometry holds great promise for developing nucleic acid detection methods for point-of-care testing (POCT).
Abstract:
Reluctant reproducibility and accuracy make electrochemical immunosensors suffering from high possibility of false negative/positive results, and it is the main obstacle that hinders them into an eligible alternative technology to the gold-standard method. It has been demonstrated sporadically previously that ratiometry helps deal with this issue but to what extent this could be beneficial and why it could fulfill is yet to be explored. In this study, to the best of our knowledge, for the first time, we have attempted to answer these questions through comprehensive experiments. For this purpose, labeled and label-free electrochemical immunosensors for SARS-CoV-2 pseudovirus quantification are constructed as a model electrochemical immunosensor. Conventional and ratiometric immunosensors are prepared by using electrochemically synthesized graphene modified electrodes coupled with various electrochemical probe pairs. It was found that the electrocatalyst modification at the electrode interface makes the predominant contribution to immunosensor sensitivity, while appropriate ratiometry provided electrochemical immunosensors with significantly enhanced reproducibility, accuracy, as well as sensing stability. Further, the experiments confirmed that the improvement in sensor performance achieved by ratiometry is primarily through overcoming the inherent errors and dynamic variations of the base electrode. It is also demonstrated electrochemical immunosensors made thereof could easily rival the performances of the gold-standard PCR method, in the view of immunoassay diagnosis. Therefore, it is of great promise to evolve electrochemical immunosensors into an eligible substitute technique towards the prevalent nucleic acid detection method in point-of-care testing (POCT), with the aid of electrochemical ratiometry.
