A Novel Electrochemical DNA Sensor Based on Redox Modulated Fluorescence Intensity
Bibliographic record
Abstract
In clinical applications, a highly sensitive and specific biosensor is required for detecting the trace amount of genetic analyte1. There have been numerous techniques developed for improving the sensitivity and selectivity of the DNA biosensor. Many PCR-based techniques including gene sequencing and fluorescence quantitative polymerase chain reaction have shown advantages such as high accuracy and sensitivity2. However, these techniques are complicated to use and require professionally trained personal. On the other hand, electrochemistry-based measurements such as Square-wave Voltammetry and Cyclic Voltammetry usually assume the electron transfer kinetics of the redox-active monolayer assemblies are uniform. The signal generated is an average and the detailed information about the modified surface is difficult to obtain. Here we show a novel detection method using electrochemistry coupled with fluorescence microscopy. A mixed SAM composed of Methylene Blue (MB) or AlexaFluor488 (AF488) labeled single stranded DNA were electro-deposited on a single crystal gold bead electrode3. We observed a unique profile of fluorescence signal (AF488) modulated by the redox probe (MB) upon DNA hybridization events. In addition, we have found that different surface crystallographies exhibit different sensitivities to the complementary strand (e.g. target) which can be explained by differences in surface coverages4. We demonstrate a coupled electrochemical and fluorescence DNA sensor. References: Pheeney, C. G.; Barton, J. K. DNA Electrochemistry with Tethered Methylene Blue. Langmuir 2012, 28(17), 7063–7070. Santhanam, M.; Algov, I.; Alfonta, L. DNA/RNA Electrochemical Biosensing Devices a Future Replacement of PCR Methods for a Fast Epidemic Containment. Sensors (Switzerland) 2020, 20 (16), 1–15. Ma, T.; Bizzotto, D. Improved Thermal Stability and Homogeneity of Low Probe Density DNA SAMs Using Potential-Assisted Thiol-Exchange Assembly Methods. Chem. 2021. 93 (48), 15973–15981. Mirmomtaz, E.; M. Castronovo.; L. Casalis. Quantitative study of the effect of coverage on the hybridization efficiency of surface- bound DNA nanostructures. Nano Lett. 2008, 8 (12), 4134–4139. Figure 1
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".