{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,13]],"date-time":"2026-05-13T05:14:15Z","timestamp":1778649255927,"version":"3.51.4"},"reference-count":45,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2019,11,1]],"date-time":"2019-11-01T00:00:00Z","timestamp":1572566400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100006280","name":"Ministerio de Ciencia y Tecnolog\u00eda","doi-asserted-by":"publisher","award":["CTQ2015-69802-C2-1-R"],"award-info":[{"award-number":["CTQ2015-69802-C2-1-R"]}],"id":[{"id":"10.13039\/501100006280","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>A novel sensing device for simultaneous dissolved oxygen (DO) and pH monitoring specially designed for biofilm profiling is presented in this work. This device enabled the recording of instantaneous DO and pH dynamic profiles within biofilms, improving the tools available for the study and the characterization of biological systems. The microsensor consisted of two parallel arrays of microelectrodes. Microelectrodes used for DO sensing were bare gold electrodes, while microelectrodes used for pH sensing were platinum-based electrodes modified using electrodeposited iridium oxide. The device was fabricated with a polyimide (Kapton\u00ae) film of 127 \u00b5m as a substrate for minimizing the damage caused on the biofilm structure during its insertion. The electrodes were covered with a Nafion\u00ae layer to increase sensor stability and repeatability and to avoid electrode surface fouling. DO microelectrodes showed a linear response in the range 0\u20138 mg L\u22121, a detection limit of 0.05 mg L\u22121, and a sensitivity of 2.06 nA L mg\u22121. pH electrodes showed a linear super-Nernstian response (74.2 \u00b1 0.7 mV\/pH unit) in a wide pH range (pH 4\u22129). The multi-analyte sensor array was validated in a flat plate bioreactor where simultaneous and instantaneous pH and DO profiles within a sulfide oxidizing biofilm were recorded. The electrodes spatial resolution, the monitoring sensitivity, and the minimally invasive features exhibited by the proposed microsensor improved biofilm monitoring performance, enabling the quantification of mass transfer resistances and the assessment of biological activity.<\/jats:p>","DOI":"10.3390\/s19214747","type":"journal-article","created":{"date-parts":[[2019,11,1]],"date-time":"2019-11-01T12:30:50Z","timestamp":1572611450000},"page":"4747","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":14,"title":["A Minimally Invasive Microsensor Specially Designed for Simultaneous Dissolved Oxygen and pH Biofilm Profiling"],"prefix":"10.3390","volume":"19","author":[{"given":"Xavier","family":"Guimer\u00e0","sequence":"first","affiliation":[{"name":"Department of Mining Industrial and ICT Engineering, Universitat Polit\u00e8cnica de Catalunya, Avinguda de les Bases de Manresa 61-73, 08242 Manresa, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ana","family":"Moya","sequence":"additional","affiliation":[{"name":"Instituto de Microelectr\u00f3nica de Barcelona IMB-CNM (CSIC), Esfera UAB, Campus Universitat Aut\u00f2noma de Barcelona, 08193 Bellaterra, Spain"},{"name":"CIBER de Bioingenier\u00eda, Biomateriales y Nanomedicina (CIBER-BBN), Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Antonio David","family":"Dorado","sequence":"additional","affiliation":[{"name":"Department of Mining Industrial and ICT Engineering, Universitat Polit\u00e8cnica de Catalunya, Avinguda de les Bases de Manresa 61-73, 08242 Manresa, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3212-1128","authenticated-orcid":false,"given":"Xavi","family":"Illa","sequence":"additional","affiliation":[{"name":"Instituto de Microelectr\u00f3nica de Barcelona IMB-CNM (CSIC), Esfera UAB, Campus Universitat Aut\u00f2noma de Barcelona, 08193 Bellaterra, Spain"},{"name":"CIBER de Bioingenier\u00eda, Biomateriales y Nanomedicina (CIBER-BBN), Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2735-3204","authenticated-orcid":false,"given":"Rosa","family":"Villa","sequence":"additional","affiliation":[{"name":"Instituto de Microelectr\u00f3nica de Barcelona IMB-CNM (CSIC), Esfera UAB, Campus Universitat Aut\u00f2noma de Barcelona, 08193 Bellaterra, Spain"},{"name":"CIBER de Bioingenier\u00eda, Biomateriales y Nanomedicina (CIBER-BBN), Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7713-4192","authenticated-orcid":false,"given":"David","family":"Gabriel","sequence":"additional","affiliation":[{"name":"GENOCOV Research Group, Department of Chemical, Biological and Environmental Engineering, Universitat Aut\u00f2noma de Barcelona, 08193 Bellaterra, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1856-8692","authenticated-orcid":false,"given":"Xavier","family":"Gamisans","sequence":"additional","affiliation":[{"name":"Department of Mining Industrial and ICT Engineering, Universitat Polit\u00e8cnica de Catalunya, Avinguda de les Bases de Manresa 61-73, 08242 Manresa, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gemma","family":"Gabriel","sequence":"additional","affiliation":[{"name":"Instituto de Microelectr\u00f3nica de Barcelona IMB-CNM (CSIC), Esfera UAB, Campus Universitat Aut\u00f2noma de Barcelona, 08193 Bellaterra, Spain"},{"name":"CIBER de Bioingenier\u00eda, Biomateriales y Nanomedicina (CIBER-BBN), Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,11,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1080\/07388550590935814","article-title":"Biofiltration of air: A review","volume":"25","author":"Heitz","year":"2005","journal-title":"Crit. 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