{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T01:38:42Z","timestamp":1760060322801,"version":"build-2065373602"},"reference-count":43,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2025,8,21]],"date-time":"2025-08-21T00:00:00Z","timestamp":1755734400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Secretar\u00eda de Ciencia, Humanidades, Tecnolog\u00eda e Innovaci\u00f3n through the project \u201cDesarrollo de dispositivos oft\u00e1lmicos de \u00faltima generaci\u00f3n en el laboratorio Nacional de \u00d3ptica de Vis\u00f3n, LANOV\u201d","award":["LCN-2023-121"],"award-info":[{"award-number":["LCN-2023-121"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Transcorneal electrical stimulation (TES) is a promising treatment for several retinal degenerative diseases (RDDs). TES involves the application of a controlled electrical current to the anterior surface of the cornea, aimed at activating the retina and posterior ocular structures. Dawson\u2013Trick\u2013Litzkow (DTL) and ERG-JET electrodes are among the most widely used for TES. However, their continuous metallic surface design limits spatial resolution and the ability to perform selective ES. In this work, we present the development of a transcorneal electrical stimulation (TES) electrode that, unlike conventional electrodes, enables spatially selective TES. The proposed electrode design consists of an array of 20 independent microelectrodes distributed across the central and paracentral regions of the cornea. The fabrication process combines surface micromachining and flexible electronics technologies, employing only three structural materials: aluminum (Al), titanium (Ti), and polyimide (PI). This material selection is critical for achieving a simplified, reproducible, and low-cost fabrication process. The fabricated electrode was validated through electrical and electrochemical testing. The results show a relatively high electrical conductivity of Al\/Ti structures, low electrochemical impedance values\u2014ranging from 791 k\u03a9 to 1.75 M\u03a9 for the clinically relevant frequency range (11 to 30 Hz)\u2014and a high charge storage capacity of 1437 mC\/cm2. The electrode capacity for electrical signal transmission was demonstrated through in vitro testing. Finally, the applicability of the TES electrode for electroretinogram (ERG) recording was evaluated by measuring its optical transmittance across the visible wavelength range.<\/jats:p>","DOI":"10.3390\/s25165198","type":"journal-article","created":{"date-parts":[[2025,8,21]],"date-time":"2025-08-21T15:19:02Z","timestamp":1755789542000},"page":"5198","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Polyimide-Based Flexible Microelectrode Array for Non-Invasive Transcorneal Electrical Stimulation"],"prefix":"10.3390","volume":"25","author":[{"ORCID":"https:\/\/orcid.org\/0009-0009-9824-8701","authenticated-orcid":false,"given":"V\u00edctor Manuel","family":"Carpio-Verd\u00edn","sequence":"first","affiliation":[{"name":"Centro de Investigaciones en \u00d3ptica, A.C. Loma del Bosque 115, Le\u00f3n 37150, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3800-9003","authenticated-orcid":false,"given":"Natiely","family":"Hern\u00e1ndez-Sebasti\u00e1n","sequence":"additional","affiliation":[{"name":"Centro de Investigaciones en \u00d3ptica, A.C. Loma del Bosque 115, Le\u00f3n 37150, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2318-969X","authenticated-orcid":false,"given":"Bernardino","family":"Barrientos-Garc\u00eda","sequence":"additional","affiliation":[{"name":"Centro de Investigaciones en \u00d3ptica, A.C. Loma del Bosque 115, Le\u00f3n 37150, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Silvia","family":"Solis-Ortiz","sequence":"additional","affiliation":[{"name":"Departamento de Ciencias M\u00e9dicas, Divisi\u00f3n de Ciencias de la Salud, Universidad de Guanajuato, 20 de enero 929, Le\u00f3n 37320, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9986-0611","authenticated-orcid":false,"given":"Erik R.","family":"Bojorges-Valdez","sequence":"additional","affiliation":[{"name":"Departamento de Estudios en Ingenier\u00eda para la Innovaci\u00f3n (DEII), Universidad Iberoamericana Ciudad de M\u00e9xico, Ciudad de M\u00e9xico 01219, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3332-846X","authenticated-orcid":false,"given":"Francisco","family":"L\u00f3pez-Huerta","sequence":"additional","affiliation":[{"name":"Facultad de Ingenier\u00eda El\u00e9ctrica y Electr\u00f3nica, Universidad Veracruzana, Boca del rio, Veracruz 94294, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Carlos Ismael","family":"Mares-Castro","sequence":"additional","affiliation":[{"name":"Centro de Investigaciones en \u00d3ptica, A.C. Loma del Bosque 115, Le\u00f3n 37150, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5485-1597","authenticated-orcid":false,"given":"Wilfrido","family":"Calleja-Arriaga","sequence":"additional","affiliation":[{"name":"Instituto Nacional de Astrof\u00edsica, \u00d3ptica y Electr\u00f3nica\u2014INAOE, Puebla 72840, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,8,21]]},"reference":[{"key":"ref_1","unstructured":"Ruiz, J., and Arias, L. (2019). Manual de la Retina SERV, Elsevier. [2nd ed.]."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"124001","DOI":"10.1088\/1361-6439\/abbb7d","article-title":"An implantable microelectrode array for chronic in vivo epiretinal stimulation of the rat retina","volume":"30","author":"Yoon","year":"2020","journal-title":"J. Micromech. 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