{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,24]],"date-time":"2026-06-24T03:52:49Z","timestamp":1782273169761,"version":"3.54.5"},"reference-count":44,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2020,3,18]],"date-time":"2020-03-18T00:00:00Z","timestamp":1584489600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this paper, we implement a Whispering Gallery mode microbubble resonator (MBR) as an optical transducer to detect the photoacoustic (PA) signal generated by plasmonic nanoparticles. We simulate a flow cytometry experiment by letting the nanoparticles run through the MBR during measurements and we estimate PA intensity by a Fourier analysis of the read-out signal. This method exploits the peaks associated with the MBR mechanical eigenmodes, allowing the PA response of the nanoparticles to be decoupled from the noise associated with the particle flow whilst also increasing the signal-to-noise ratio. The photostability curve of a known contrast agent is correctly reconstructed, validating the proposed analysis and proving quantitative PA detection. The experiment was run to demonstrate the feasible implementation of the MBR system in a flow cytometry application (e.g., the detection of venous thrombi or circulating tumor cells), particularly regarding wearable appliances. Indeed, these devices could also benefit from other MBR features, such as the extreme compactness, the direct implementation in a microfluidic circuit, and the absence of impedance-matching material.<\/jats:p>","DOI":"10.3390\/s20061696","type":"journal-article","created":{"date-parts":[[2020,3,19]],"date-time":"2020-03-19T03:54:14Z","timestamp":1584590054000},"page":"1696","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":17,"title":["Microbubble Resonators for All-Optical Photoacoustics of Flowing Contrast Agents"],"prefix":"10.3390","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4290-3158","authenticated-orcid":false,"given":"Gabriele","family":"Frigenti","sequence":"first","affiliation":[{"name":"Centro Fermi\u2014Museo Storico della Fisica e Centro Studi e Ricerche \u201cEnrico Fermi\u201d, Compendio del Viminale, Piazza del Viminale 1, 00184 Rome, Italy"},{"name":"CNR-IFAC, Istituto di Fisica Applicata \u201cNello Carrara\u201d, Consiglio Nazionale delle Ricerche, via Madonna del Piano 10, I50019 Sesto Fiorentino (FI), Italy"},{"name":"Laboratorio Europeo di Spettroscopia Nonlineare (LENS)\u2014Universit\u00e0 degli Studi di Firenze, via Nello Carrara 1, I50019 Sesto Fiorentino (FI), Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6279-8869","authenticated-orcid":false,"given":"Lucia","family":"Cavigli","sequence":"additional","affiliation":[{"name":"CNR-IFAC, Istituto di Fisica Applicata \u201cNello Carrara\u201d, Consiglio Nazionale delle Ricerche, via Madonna del Piano 10, I50019 Sesto Fiorentino (FI), Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alberto","family":"Fern\u00e1ndez-Bienes","sequence":"additional","affiliation":[{"name":"Facultad de Ingenier\u00eda, Universidad Nacional Aut\u00f3noma de M\u00e9xico (UNAM), Ciudad de M\u00e9xico C.P. 04510, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6721-9486","authenticated-orcid":false,"given":"Fulvio","family":"Ratto","sequence":"additional","affiliation":[{"name":"CNR-IFAC, Istituto di Fisica Applicata \u201cNello Carrara\u201d, Consiglio Nazionale delle Ricerche, via Madonna del Piano 10, I50019 Sesto Fiorentino (FI), Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5432-5589","authenticated-orcid":false,"given":"Sonia","family":"Centi","sequence":"additional","affiliation":[{"name":"CNR-IFAC, Istituto di Fisica Applicata \u201cNello Carrara\u201d, Consiglio Nazionale delle Ricerche, via Madonna del Piano 10, I50019 Sesto Fiorentino (FI), Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5535-3845","authenticated-orcid":false,"given":"Tupak","family":"Garc\u00eda-Fern\u00e1ndez","sequence":"additional","affiliation":[{"name":"Universidad Aut\u00f3noma de la Ciudad de M\u00e9xico (UACM), Prolongaci\u00f3n San Isidro 151, Col. 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C.P. 09790, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2239-7622","authenticated-orcid":false,"given":"Gualtiero","family":"Nunzi Conti","sequence":"additional","affiliation":[{"name":"Centro Fermi\u2014Museo Storico della Fisica e Centro Studi e Ricerche \u201cEnrico Fermi\u201d, Compendio del Viminale, Piazza del Viminale 1, 00184 Rome, Italy"},{"name":"CNR-IFAC, Istituto di Fisica Applicata \u201cNello Carrara\u201d, Consiglio Nazionale delle Ricerche, via Madonna del Piano 10, I50019 Sesto Fiorentino (FI), Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4838-2197","authenticated-orcid":false,"given":"Silvia","family":"Soria","sequence":"additional","affiliation":[{"name":"CNR-IFAC, Istituto di Fisica Applicata \u201cNello Carrara\u201d, Consiglio Nazionale delle Ricerche, via Madonna del Piano 10, I50019 Sesto Fiorentino (FI), Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,3,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"602","DOI":"10.1098\/rsfs.2011.0028","article-title":"Biomedical photoacoustic imaging","volume":"1","author":"Beard","year":"2011","journal-title":"Interface Focus"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1458","DOI":"10.1126\/science.1216210","article-title":"Photoacoustic Tomography: In Vivo Imaging from Organelles to Organs","volume":"335","author":"Wang","year":"2012","journal-title":"Science"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1016\/j.pacs.2018.05.001","article-title":"Photoacoustic tomography of blood oxygenation: A mini review","volume":"10","author":"Li","year":"2018","journal-title":"Photoacoustics"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"137","DOI":"10.1109\/JSTQE.2015.2497323","article-title":"Single Cell Photoacoustic Microscopy: A Review","volume":"22","author":"Strohm","year":"2016","journal-title":"IEEE J. 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