An EIS study of the heterogeneity of redox labeled DNA SAMs on gold before and after hybridization
Notice bibliographique
Résumé
Redox active labels on DNA SAMs are used for transducing hybridization via the change in the rate of contact-mediated redox with the electrode surface. This change in the fraction hybridized can be measured using CV or SWV. Here, we detail the use of EIS to quantify the change in the redox rate and thereby assess the hybridization characteristics for DNA SAMs. EIS of methylene blue (MB) labeled DNA SAMs on smooth single crystal bead electrodes were measured and the results fit to a series of equivalent circuits representing one redox rate, two redox rates or a distribution of redox rates. The rate of MB redox decreased with increasing complementary strand (cDNA) concentration, interpreted as an increase in the amount of hybridized dsDNA in the SAM. The EIS method was able to accurately measure the average rate of MB redox, but EIS was unable to independently measure the ssDNA and dsDNA populations as the redox rates were not sufficiently distinct. A majority of the redox active MB was one average time constant, but a consistent 10% of the MB had much faster redox rates which were interpreted as due to non-specifically adsorbed MB-labeled DNA. The EIS fits were not improved by using a CPE in place of C d l . However, the EIS fits were improved by replacing the RC circuit element with a distributed circuit element based on the Cole-Cole model, replacing a R with a CPE in one RC branch of the equivalent circuit. This distributed model better explained the EIS results giving the most probable redox rate and a distribution of rates. The EIS measurement approach was verified with a higher coverage DNA SAM which showed slower redox rates as expected. Interestingly, in all cases the amount of redox active MB ( Γ M B ) decreased with an increase in the [cDNA], suggesting that some MB was in an environment that prevented it from reaching the surface. This decrease in Γ M B with [cDNA] was reflected in the SWV results since it was sensitive to both the change in redox rate and the amount of redox active MB. In contrast, the EIS results were found to measure the k E T independent of the amount of redox active MB. Hybridization isotherms produced using either SWV or EIS results showed a significant difference between SWV (50 Hz) and k E T when fit to a Langmuir-Hill isotherm. These results suggested the SWV results must be interpreted with caution as the K A and Hill co-operativity coefficient ( n ) were different than the EIS measurements, but in a way that strongly depended on the coverage and the SWV frequency chosen. Overall, EIS of the redox labeled DNA SAM was successfully interpreted using a distributed redox rate expression based on the Cole-Cole model. EIS measured k E T provided a hybridization isotherm that was not convoluted with the amount of redox active MB, enabling an accurate assessment of the DNA SAM interface. • EIS was used to characterize redox(MB)-labelled DNA SAMs prepared on a gold electrode. • EIS results suggest the presence of at least two populations of redox active MB • The slow redox process represented contact-mediated electron transfer • The fast redox process may be due to non-specifically adsorbed MB-labelled DNA. • Fitting was improved with a Cole-Cole model using a distribution of redox rates. • Hybridization isotherms from SWV and the redox rate constant from EIS were compared
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».