{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,14]],"date-time":"2026-04-14T21:20:55Z","timestamp":1776201655199,"version":"3.50.1"},"reference-count":38,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2021,9,15]],"date-time":"2021-09-15T00:00:00Z","timestamp":1631664000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["UIDB\/50014\/2020"],"award-info":[{"award-number":["UIDB\/50014\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["68873216218"],"award-info":[{"award-number":["68873216218"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["CEECIND\/00471\/2017"],"award-info":[{"award-number":["CEECIND\/00471\/2017"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The ability to select, isolate, and manipulate micron-sized particles or small clusters has made optical tweezers one of the emergent tools for modern biotechnology. In conventional setups, the classification of the trapped specimen is usually achieved through the acquired image, the scattered signal, or additional information such as Raman spectroscopy. In this work, we propose a solution that uses the temporal data signal from the scattering process of the trapping laser, acquired with a quadrant photodetector. Our methodology rests on a pre-processing strategy that combines Fourier transform and principal component analysis to reduce the dimension of the data and perform relevant feature extraction. Testing a wide range of standard machine learning algorithms, it is shown that this methodology allows achieving accuracy performances around 90%, validating the concept of using the temporal dynamics of the scattering signal for the classification task. Achieved with 500 millisecond signals and leveraging on methods of low computational footprint, the results presented pave the way for the deployment of alternative and faster classification methodologies in optical trapping technologies.<\/jats:p>","DOI":"10.3390\/s21186181","type":"journal-article","created":{"date-parts":[[2021,9,15]],"date-time":"2021-09-15T12:00:44Z","timestamp":1631707244000},"page":"6181","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":14,"title":["Particle Classification through the Analysis of the Forward Scattered Signal in Optical Tweezers"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3092-3378","authenticated-orcid":false,"given":"In\u00eas Alves","family":"Carvalho","sequence":"first","affiliation":[{"name":"Centre for Applied Photonics, INESC TEC, Rua do Campo Alegre 687, 4169-007 Porto, Portugal"},{"name":"Departamento de F\u00edsica e Astronomia, Faculdade de Ci\u00eancias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8467-4357","authenticated-orcid":false,"given":"Nuno Azevedo","family":"Silva","sequence":"additional","affiliation":[{"name":"Centre for Applied Photonics, INESC TEC, Rua do Campo Alegre 687, 4169-007 Porto, Portugal"}]},{"given":"Carla C.","family":"Rosa","sequence":"additional","affiliation":[{"name":"Centre for Applied Photonics, INESC TEC, Rua do Campo Alegre 687, 4169-007 Porto, Portugal"},{"name":"Departamento de F\u00edsica e Astronomia, Faculdade de Ci\u00eancias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6205-9479","authenticated-orcid":false,"given":"Lu\u00eds C. C.","family":"Coelho","sequence":"additional","affiliation":[{"name":"Centre for Applied Photonics, INESC TEC, Rua do Campo Alegre 687, 4169-007 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1484-2068","authenticated-orcid":false,"given":"Pedro A. S.","family":"Jorge","sequence":"additional","affiliation":[{"name":"Centre for Applied Photonics, INESC TEC, Rua do Campo Alegre 687, 4169-007 Porto, Portugal"},{"name":"Departamento de F\u00edsica e Astronomia, Faculdade de Ci\u00eancias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2021,9,15]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"288","DOI":"10.1364\/OL.11.000288","article-title":"Observation of a single-beam gradient force optical trap for dielectric particles","volume":"11","author":"Ashkin","year":"1986","journal-title":"Opt. 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