{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,12]],"date-time":"2025-11-12T03:23:31Z","timestamp":1762917811810,"version":"build-2065373602"},"reference-count":39,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2017,10,20]],"date-time":"2017-10-20T00:00:00Z","timestamp":1508457600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"German Research Foundation (DFG)","award":["GU 1686\/1-1"],"award-info":[{"award-number":["GU 1686\/1-1"]}]},{"name":"German Federal Ministry of Education and Research (BMBF)","award":["FKZ 13N13691"],"award-info":[{"award-number":["FKZ 13N13691"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Surface-enhanced Raman spectroscopy (SERS) combines the high speci\ufb01city of Raman scattering with high sensitivity due to an enhancement of the electromagnetic \ufb01eld by metallic nanostructures. However, the tyical fabrication methods of SERS substrates suffer from low throughput and therefore high costs. Furthermore, point-of-care applications require the investigation of liquid solutions and thus the integration of the SERS substrate in a microfluidic chip. We present a roll-to-roll fabrication approach for microfluidics with integrated, highly efficient, surface-enhanced Raman scattering structures. Microfluidic channels are formed using roll-to-roll hot embossing in polystyrene foil. Aerosol jet printing of a gold nanoparticle ink is utilized to manufacture highly efficient, homogeneous, and reproducible SERS structures. The modified channels are sealed with a solvent-free, roll-to-roll, thermal bonding process. In continuous flow measurements, these chips overcome time-consuming incubation protocols and the poor reproducibility of SERS experiments often caused by inhomogeneous drying of the analyte. In the present study, we explore the influence of the printing process on the homogeneity and the enhancement of the SERS structures. The feasibility of aerosol-jet-modified microfluidic channels for highly sensitive SERS detection is demonstrated by using solutions with different concentrations of Rhodamine 6G and adenosine. The printed areas provide homogeneous enhancement factors of ~4 \u00d7 106. Our work shows a way towards the low-cost production of tailor-made, SERS-enabled, label-free, lab-on- chip systems for bioanalysis.<\/jats:p>","DOI":"10.3390\/s17102401","type":"journal-article","created":{"date-parts":[[2017,10,23]],"date-time":"2017-10-23T04:32:19Z","timestamp":1508733139000},"page":"2401","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":22,"title":["Lab-on-Chip, Surface-Enhanced Raman Analysis by Aerosol Jet Printing and Roll-to-Roll Hot Embossing"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9931-2105","authenticated-orcid":false,"given":"Anne","family":"Habermehl","sequence":"first","affiliation":[{"name":"Light Technology Institute, Karlsruhe Institute of Technology (KIT), Engesserstra\u00dfe 13, 76131 Karlsruhe, Germany"}]},{"given":"Noah","family":"Strobel","sequence":"additional","affiliation":[{"name":"Light Technology Institute, Karlsruhe Institute of Technology (KIT), Engesserstra\u00dfe 13, 76131 Karlsruhe, Germany"},{"name":"InnovationLab GmbH, Speyerer Stra\u00dfe 4, 69115 Heidelberg, Germany"}]},{"given":"Ralph","family":"Eckstein","sequence":"additional","affiliation":[{"name":"Light Technology Institute, Karlsruhe Institute of Technology (KIT), Engesserstra\u00dfe 13, 76131 Karlsruhe, Germany"},{"name":"InnovationLab GmbH, Speyerer Stra\u00dfe 4, 69115 Heidelberg, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7893-2743","authenticated-orcid":false,"given":"Nico","family":"Bolse","sequence":"additional","affiliation":[{"name":"Light Technology Institute, Karlsruhe Institute of Technology (KIT), Engesserstra\u00dfe 13, 76131 Karlsruhe, Germany"}]},{"given":"Adrian","family":"Mertens","sequence":"additional","affiliation":[{"name":"Light Technology Institute, Karlsruhe Institute of Technology (KIT), Engesserstra\u00dfe 13, 76131 Karlsruhe, Germany"}]},{"given":"Gerardo","family":"Hernandez-Sosa","sequence":"additional","affiliation":[{"name":"Light Technology Institute, Karlsruhe Institute of Technology (KIT), Engesserstra\u00dfe 13, 76131 Karlsruhe, Germany"},{"name":"InnovationLab GmbH, Speyerer Stra\u00dfe 4, 69115 Heidelberg, Germany"}]},{"given":"Carsten","family":"Eschenbaum","sequence":"additional","affiliation":[{"name":"Light Technology Institute, Karlsruhe Institute of Technology (KIT), Engesserstra\u00dfe 13, 76131 Karlsruhe, Germany"},{"name":"InnovationLab GmbH, Speyerer Stra\u00dfe 4, 69115 Heidelberg, Germany"},{"name":"Institute of Microstructure Technology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany"}]},{"given":"Uli","family":"Lemmer","sequence":"additional","affiliation":[{"name":"Light Technology Institute, Karlsruhe Institute of Technology (KIT), Engesserstra\u00dfe 13, 76131 Karlsruhe, Germany"},{"name":"InnovationLab GmbH, Speyerer Stra\u00dfe 4, 69115 Heidelberg, Germany"},{"name":"Institute of Microstructure Technology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany"}]}],"member":"1968","published-online":{"date-parts":[[2017,10,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1168","DOI":"10.1039\/c2an15947c","article-title":"A simple filter-based approach to surface enhanced Raman spectroscopy for trace chemical detection","volume":"137","author":"Yu","year":"2012","journal-title":"Analyst"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"074101","DOI":"10.1063\/1.2031935","article-title":"Nanowell surface enhanced Raman scattering arrays fabricated by soft-lithography for label-free biomolecular detections in integrated microfluidics","volume":"87","author":"Liu","year":"2005","journal-title":"Appl. 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