@article {39699,
	title = {Redox active DNA SAMs investigated using a probabilistic approach for estimating distribution of differential capacity},
	journal = {Electrochimica Acta},
	volume = {575},
	year = {2026},
	pages = {149451},
	abstract = {<p>Characterization of redox-active self-assembled monolayers (SAM) with electrochemical impedance spectroscopy (EIS) analyzed using the distribution of differential capacity (DDC) approach and equivalent circuit models (ECMs) are described and compared. SAMs prepared from a thiol-modified DNA with a distal methylene blue (MB) redox label on a single crystal gold bead electrode were studied. SAMs with two different surface coverages of single-stranded DNA SAM were characterized before and after equilibration with the complementary sequence (cDNA). The DDC approach was first validated using simulated data that represented an interface with a monolayer that had two different redox rates ( k ET ). The experimental EIS spectra were analyzed using the DDC model, which leveraged Gaussian processes to recover the DDC, yielding a distribution of time constants representing different redox rates and capacitances. From this distribution, the k ET and amount of redox active MB were determined for each population of MB. For low coverage DNA SAMs (2 pmol/cm2), the k ET for the dominant MB population determined using ECM or DDC showed the same decrease from k ET = 20 s \&minus; 1 to 2 s \&minus; 1 with the extent of hybridization. In addition, the DDC was able to identify the presence of faster MB redox processes, which were thought to represent MB that were close to the electrode surface and were not hybridized until high cDNA concentrations. The DDC analysis gave a similar result as the ECM approach, but without the need of an a priori circuit model. Other electrodes with higher coverage DNA SAMs (16 pmol/cm2) exhibited a much slower k ET = 5 s \&minus; 1 to 0.5 s \&minus; 1 , which also confirmed that DDC and ECM analyses gave similar results for the main redox process. Crucially, the DDC approach was able to provide more details about other distributed fast and slow k ET processes, which were otherwise not reliably modeled with the ECM. In , the DDC approach for analyzing EIS data from redox-active SAMs is shown to provide meaningful results that are reliable and not based on equivalent circuits, which is expected to pave the way for advanced investigations of impedance data from biosensors.</p>},
	issn = {0013-4686},
	doi = {10.1016/j.electacta.2026.149451},
	url = {https://kwnsfk27.r.eu-west-1.awstrack.me/L0/https:\%2F\%2Fauthors.elsevier.com\%2Fsd\%2Farticle\%2FS0013-4686(26)01340-X/1/0102019f5c36ff08-103adb56-700d-489b-a1c2-555feeb9d01c-000000/8qkZvi8B0oXAMeOt_86Sj6Nm9oM=473},
	author = {Martinez-Blanco, Gilberto and Baker, Daina V. and Py, Baptiste and Rassachack, Enoch and Ciucci, Francesco and Bizzotto, Dan}
}
