{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,29]],"date-time":"2026-10-29T06:42:16Z","timestamp":1793256136108,"version":"4.5.0"},"reference-count":78,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2022,9,7]],"date-time":"2022-09-07T00:00:00Z","timestamp":1662508800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Bioeng. Biotechnol."],"abstract":"<jats:p>The miniaturization of laboratory procedures for Lab-on-Chip (LoC) devices and translation to various platforms such as single cell analysis or Organ-on-Chip (OoC) systems are revolutionizing the life sciences and biomedical fields. As a result, microfluidics is becoming a viable technology for improving the quality and sensitivity of critical processes. Yet, standard test methods have not yet been established to validate basic manufacturing steps, performance, and safety of microfluidic devices. The successful development and widespread use of microfluidic technologies are greatly dependent on the community\u2019s success in establishing widely supported test protocols. A key area that requires consensus guidelines is leakage testing. There are unique challenges in preventing and detecting leaks in microfluidic systems because of their small dimensions, high surface-area to volume ratios, low flow rates, limited volumes, and relatively high-pressure differentials over short distances. Also, microfluidic devices often employ heterogenous components, including unique connectors and fluid-contacting materials, which potentially make them more susceptible to mechanical integrity failures. The differences between microfluidic systems and traditional macroscale technologies can exacerbate the impact of a leak on the performance and safety on the microscale. To support the microfluidics community efforts in product development and commercialization, it is critical to identify common aspects of leakage in microfluidic devices and standardize the corresponding safety and performance metrics. There is a need for quantitative metrics to provide quality assurance during or after the manufacturing process. It is also necessary to implement application-specific test methods to effectively characterize leakage in microfluidic systems. In this review, different methods for assessing microfluidics leaks, the benefits of using different test media and materials, and the utility of leakage testing throughout the product life cycle are discussed. Current leakage testing protocols and standard test methods that can be leveraged for characterizing leaks in microfluidic devices and potential classification strategies are also discussed. We hope that this review article will stimulate more discussions around the development of gas and liquid leakage test standards in academia and industry to facilitate device commercialization in the emerging field of microfluidics.<\/jats:p>","DOI":"10.3389\/fbioe.2022.958582","type":"journal-article","created":{"date-parts":[[2022,9,7]],"date-time":"2022-09-07T06:26:02Z","timestamp":1662531962000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":45,"title":["Overcoming technological barriers in microfluidics: Leakage testing"],"prefix":"10.3389","volume":"10","author":[{"given":"Vania","family":"Silverio","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Suvajyoti","family":"Guha","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Armelle","family":"Keiser","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rucha","family":"Natu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Darwin R.","family":"Reyes","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Henne","family":"van Heeren","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nicolas","family":"Verplanck","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Luke H.","family":"Herbertson","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2022,9,7]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"2548","DOI":"10.3390\/s19112548","article-title":"Recent advances in pipeline monitoring and oil leakage detection technologies: Principles and approaches","volume":"19","author":"Adegboye","year":"2019","journal-title":"Sensors"},{"key":"B2","unstructured":"API 598:2009. Valve inspection and testing2009"},{"key":"B3","first-page":"33455","article-title":"Conversion of leak flow-rates for various fluids and different pressure conditions. EUR 2982","volume":"20","author":"Amesz","year":"1966","journal-title":"Eur. At. Energy Community"},{"key":"B4","first-page":"356","article-title":"Hermetic integration of liquids in MEMS by room temperature, high-speed plugging of liquid-filled cavities at wafer level","author":"Antelius","year":"2011"},{"key":"B5","doi-asserted-by":"publisher","first-page":"1074","DOI":"10.1038\/nm.3621","article-title":"An implantable microfluidic device for self-monitoring of intraocular pressure","volume":"20","author":"Araci","year":"2014","journal-title":"Nat. Med."},{"key":"B6","doi-asserted-by":"publisher","first-page":"548","DOI":"10.1039\/b924816a","article-title":"Irreversible, direct bonding of nanoporous polymer membranes to PDMS or glass microdevices","volume":"10","author":"Aran","year":"2010","journal-title":"Lab. Chip"},{"key":"B7","unstructured":"Astm E2930-13(2021) - standard practice for pressure decay leak test method2021"},{"key":"B8","unstructured":"Astm F2095-07(2021) - standard test methods for pressure decay leak test for flexible packages with and without restraining plates"},{"key":"B9","unstructured":"Air leak testing methods - air decay, differential, mass flow2020"},{"key":"B10","doi-asserted-by":"publisher","first-page":"125003","DOI":"10.1088\/1361-6439\/abb991","article-title":"Leak-free integrated microfluidic channel fabrication for surface plasmon resonance applications","volume":"30","author":"Bakouche","year":"2020","journal-title":"J. Micromech. Microeng."},{"key":"B11","doi-asserted-by":"publisher","first-page":"100155","DOI":"10.1016\/j.measen.2021.100155","article-title":"Uncertainty calculations in optical methods used for micro flow measurement","volume":"18","author":"Batista","year":"2021","journal-title":"Meas. Sensors"},{"key":"B12","doi-asserted-by":"publisher","first-page":"42","DOI":"10.1088\/0960-1317\/17\/1\/006","article-title":"Re-usable quick-release interconnect for characterization of microfluidic systems","volume":"17","author":"Bhagat","year":"2007","journal-title":"J. Micromech. Microeng."},{"key":"B13","unstructured":"How does the leak test work?2022"},{"key":"B14","doi-asserted-by":"publisher","first-page":"292","DOI":"10.3390\/bios11080292","article-title":"PDMS bonding technologies for microfluidic applications: A review","volume":"11","author":"Bor\u00f3k","year":"2021","journal-title":"Biosensors"},{"key":"B15","doi-asserted-by":"publisher","first-page":"904","DOI":"10.1016\/j.snb.2017.02.109","article-title":"Fabricating devices with improved adhesion between PDMS and gold-patterned glass","volume":"246","author":"Casanova-Moreno","year":"2017","journal-title":"Sensors Actuators B Chem."},{"key":"B16","doi-asserted-by":"publisher","first-page":"3504","DOI":"10.1021\/ac062118p","article-title":"Leakage-free bonding of porous membranes into layered microfluidic array systems","volume":"79","author":"Chueh","year":"2007","journal-title":"Anal. Chem."},{"key":"B17","unstructured":"How to establish an acceptable leak rate. Application bulletin: #1202014"},{"key":"B18","unstructured":"How to leak and blockage test microfluidic chips or cassettes. Application note \u25aa medical2020"},{"key":"B19","doi-asserted-by":"publisher","first-page":"1473","DOI":"10.1016\/j.snb.2011.07.040","article-title":"Characterisation of an irreversible bonding process for COC\u2013COC and COC\u2013PDMS\u2013COC sandwich structures and application to microvalves","volume":"160","author":"Cortese","year":"2011","journal-title":"Sensors Actuators B Chem."},{"key":"B20","unstructured":"Setting an air leak testing - quality control specification. Leak Testing Academy\n            DewaillyA.-M.\n          2020"},{"key":"B21","unstructured":"Linear connector2022"},{"key":"B22","article-title":"Pressure decay testing methodology for quantifying leak rates of full-scale docking system seals. Technical memorandum","author":"Dunlap","year":"2009"},{"key":"B23","doi-asserted-by":"publisher","first-page":"067001","DOI":"10.1088\/0960-1317\/18\/6\/067001","article-title":"Determining the optimal PDMS\u2013PDMS bonding technique for microfluidic devices","volume":"18","author":"Eddings","year":"2008","journal-title":"J. Micromech. Microeng."},{"key":"B24","unstructured":"DIN EN 12266-1 Industrial valves - testing of metallic valves - Part 1: Pressure tests, test procedures and acceptance criteria - mandatory requirements2012"},{"key":"B25","unstructured":"DIN EN 1779 Non-destructive testing - leak testing - criteria for method and technique selection1999"},{"key":"B26","unstructured":"DIN EN 1779:1999. Non-destructive testing - leak testing - criteria for method and technique selection1999"},{"key":"B27","doi-asserted-by":"publisher","first-page":"20","DOI":"10.1007\/s10404-021-02420-3","article-title":"Improving plasma bonding of PDMS to gold-patterned glass for electrochemical microfluidic applications","volume":"25","author":"Gonzalez-Gallardo","year":"2021","journal-title":"Microfluid. Nanofluidics"},{"key":"B28","volume-title":"Control of substances hazardous to health","author":"Health","year":"2013"},{"key":"B29","unstructured":"Leak testing2021"},{"key":"B30","volume-title":"Leak testing 101 - Part 1","author":"Hoffmann","year":"2012"},{"key":"B31","doi-asserted-by":"publisher","first-page":"1463","DOI":"10.1109\/TCAD.2014.2336215","article-title":"Testing of flow-based microfluidic biochips: Fault modeling, test generation, and experimental demonstration","volume":"33","author":"Hu","year":"2014","journal-title":"IEEE Trans. Comput. -Aided. Des. Integr. Circuits Syst."},{"key":"B32","unstructured":"ISO 10555-1:2013+A1:2017 Intravascular catheters. Sterile and single-use catheters \u2013 Part 1: General requirements2013"},{"key":"B33","unstructured":"ISO 18081:2016 Non-destructive testing \u2014 acoustic emission testing (AT) \u2014 leak detection by means of acoustic emission2016"},{"key":"B34","unstructured":"ISO 20484:2017 non-destructive testing \u2014 leak testing \u2014 vocabulary2017"},{"key":"B35","unstructured":"ISO 22916:2022 Microfluidic devices \u2014 interoperability requirements for dimensions, connections and initial device classification2022"},{"key":"B36","unstructured":"ISO 5208:2015 Industrial valves \u2014 pressure testing of metallic valves2015"},{"key":"B37","unstructured":"Jis Z 2329:2019 - non-destructive testing - methods for bubble leak testing2019"},{"key":"B38","doi-asserted-by":"publisher","first-page":"2614","DOI":"10.1039\/C004766J","article-title":"Visualization and measurement of flow in two-dimensional paper networks","volume":"10","author":"Kauffman","year":"2010","journal-title":"Lab. Chip"},{"key":"B40","unstructured":"Gas permeable PDMS membranes2020"},{"key":"B41","doi-asserted-by":"publisher","first-page":"444","DOI":"10.1177\/2211068214531760","article-title":"An electromagnetic microvalve for pneumatic control of microfluidic systems","volume":"19","author":"Liu","year":"2014","journal-title":"SLAS Technol."},{"key":"B43","doi-asserted-by":"publisher","first-page":"11310","DOI":"10.1021\/ie101346u","article-title":"Design and packaging of microreactors for high pressure and high temperature applications","volume":"49","author":"Marre","year":"2010","journal-title":"Ind. Eng. Chem. Res."},{"key":"B44","volume-title":"Risk: Theory and application. Pipeline risk management manual","author":"Muhlbauer","year":"2004"},{"key":"B45","doi-asserted-by":"publisher","first-page":"3248","DOI":"10.1021\/ac071903e","article-title":"When PDMS isn\u2019t the best","volume":"79","author":"Mukhopadhyay","year":"2007","journal-title":"Anal. Chem."},{"key":"B47","doi-asserted-by":"publisher","first-page":"101746","DOI":"10.1016\/j.flowmeasinst.2020.101746","article-title":"Development of an optical measurement method for \u201csampled\u201d micro-volumes and nano-flow rates","volume":"73","author":"Ogheard","year":"2020","journal-title":"Flow Meas. Instrum."},{"key":"B48","doi-asserted-by":"publisher","first-page":"450","DOI":"10.1007\/s00542-005-0043-5","article-title":"Fabrication and mechanical testing of glass chips for high-pressure synthetic or analytical chemistry","volume":"12","author":"Oosterbroek","year":"2005","journal-title":"Microsyst. Technol."},{"key":"B49","doi-asserted-by":"publisher","first-page":"11609","DOI":"10.1021\/la1012582","article-title":"Novel carboxyl-amine bonding methods for poly (dimethylsiloxane)-based devices","volume":"26","author":"Ouellet","year":"2010","journal-title":"Langmuir"},{"key":"B50","unstructured":"Guide to good leak testing. Refrigerant emissions and leakage ZERO project2009"},{"key":"B51","doi-asserted-by":"publisher","first-page":"2396","DOI":"10.1021\/ar300314s","article-title":"Materials for microfluidic chip fabrication","volume":"46","author":"Ren","year":"2013","journal-title":"Acc. Chem. Res."},{"key":"B52","doi-asserted-by":"publisher","first-page":"1923","DOI":"10.3390\/mi6121465","article-title":"A simple and reliable PDMS and SU-8 irreversible bonding method and its application on a microfluidic-MEA device for neuroscience research","volume":"6","author":"Ren","year":"2015","journal-title":"Micromachines"},{"key":"B53","doi-asserted-by":"publisher","first-page":"9","DOI":"10.1039\/D0LC00963F","article-title":"Accelerating innovation and commercialization through standardization of microfluidic-based medical devices","volume":"21","author":"Reyes","year":"2020","journal-title":"Lab. Chip"},{"key":"B54","unstructured":"Advanced leak test methods\n            SagiH.\n          2001"},{"key":"B55","volume-title":"Wireless medical systems and algorithms: Design and applications","author":"Salvo","year":"2016"},{"key":"B56","unstructured":"New European standard for the selection of a suitable method for leak detection and leak tightness testing\n            SchroderG.\n          2001"},{"key":"B57","doi-asserted-by":"publisher","first-page":"789","DOI":"10.1016\/j.snb.2009.02.002","article-title":"Design, fabrication and test of a microfluidic nebulizer chip for desorption electrospray ionization mass spectrometry","volume":"137","author":"Sen","year":"2009","journal-title":"Sensors Actuators B Chem."},{"key":"B58","doi-asserted-by":"publisher","first-page":"914","DOI":"10.3390\/mi11100914","article-title":"An easy method for pressure measurement in microchannels using trapped air compression in a one-end-sealed capillary","volume":"11","author":"Shen","year":"2020","journal-title":"Micromachines"},{"key":"B59","doi-asserted-by":"publisher","first-page":"26032","DOI":"10.1038\/srep26032","article-title":"Self-regenerating and hybrid irreversible\/reversible PDMS microfluidic devices","volume":"6","author":"Shiroma","year":"2016","journal-title":"Sci. Rep."},{"key":"B60","doi-asserted-by":"crossref","DOI":"10.1016\/B978-0-12-819838-4.00020-1","article-title":"Lab-on-a-chip: Systems integration at the microscale","volume-title":"Drug delivery devices and therapeutic systems","author":"Silverio","year":"2021"},{"key":"B61","doi-asserted-by":"publisher","first-page":"22","DOI":"10.3390\/mi4010022","article-title":"Compact mass flow meter based on a micro coriolis flow sensor","volume":"4","author":"Sparreboom","year":"2013","journal-title":"Micromachines"},{"key":"B62","unstructured":"Pressure decay method for postinstallation single-use bioreactor bag testing\n            SteringM.\n            DahlbergM.\n            AdamsT.\n            de WildeD.\n            FengeC.\n          2014"},{"key":"B63","doi-asserted-by":"publisher","first-page":"155","DOI":"10.1088\/1742-6596\/34\/1\/026","article-title":"Evaluation of bonding between oxygen plasma treated polydimethyl siloxane and passivated silicon","volume":"34","author":"Tang","year":"2006","journal-title":"J. Phys. Conf. Ser."},{"key":"B64","unstructured":"Results from a leakage survey2021"},{"key":"B65","unstructured":"Survey on Microfluidic test guidelines2016"},{"key":"B66","unstructured":"Survey on reliability of microfluidics-based devices and components2015"},{"key":"B67","doi-asserted-by":"publisher","first-page":"163","DOI":"10.1016\/j.cej.2006.12.036","article-title":"Fabrication, mechanical testing and application of high-pressure glass microreactor chips","volume":"131","author":"Tiggelaar","year":"2007","journal-title":"Chem. Eng. J."},{"key":"B68","unstructured":"Leak testing2022"},{"key":"B69","doi-asserted-by":"publisher","first-page":"262","DOI":"10.1038\/s41467-017-00259-3","article-title":"Membrane-free culture and real-time barrier integrity assessment of perfused intestinal epithelium tubes","volume":"8","author":"Trietsch","year":"2017","journal-title":"Nat. Commun."},{"key":"B70","unstructured":"Micro-flow leak testing\n            VacuumPfeiffer\n          2018"},{"key":"B71","unstructured":"Protocols for leakage testing [White paper]\n            van HeerenH.\n            DaviesM.\n            KeiserA.\n            LagrauwR.\n            ReyesD. R.\n            SilverioV.\n          10.5281\/zenodo.66021612022"},{"key":"B72","unstructured":"Metrology challenges for microfluidics. Commercial micro manufacturing magazine\n            van HeerenH.\n            SilverioV.\n            PecnikC.\n            BatistaE."},{"key":"B73","unstructured":"Microfluidics: The effects of surface tension\n            VowellS.\n          2009"},{"key":"B74","unstructured":"Leak detection theory and practice - comparison among leak testing techniques2006"},{"key":"B75","unstructured":"Optimal protocol for molding PDMS with a PDMS master \u2013 chips and Tips\n            WangJ.\n            ZhengM.\n            WangW.\n            LiZ.\n          2010"},{"key":"B76","doi-asserted-by":"publisher","first-page":"16507","DOI":"10.1063\/1.3694251","article-title":"One step high quality poly (dimethylsiloxane)-hydrocarbon plastics bonding","volume":"6","author":"Xu","year":"2012","journal-title":"Biomicrofluidics"},{"key":"B77","article-title":"Gas permeation in PDMS monitored by on-site pressure sensors","author":"Yang","year":"2010"},{"key":"B78","doi-asserted-by":"publisher","first-page":"1427","DOI":"10.1002\/jssc.200600454","article-title":"The fundamental aspects and applications of Agilent HPLC-Chip","volume":"30","author":"Yin","year":"2007","journal-title":"J. Sep. Sci."},{"key":"B79","doi-asserted-by":"publisher","first-page":"72","DOI":"10.1515\/jee-2018-0010","article-title":"A fast and simple bonding method for low cost microfluidic chip fabrication","volume":"69","author":"Yin","year":"2018","journal-title":"J. Electr. Eng."},{"key":"B80","doi-asserted-by":"publisher","first-page":"104264","DOI":"10.1016\/j.engfailanal.2019.104264","article-title":"A review of leakage detection strategies for pressurised pipeline in steady-state","volume":"109","author":"Zaman","year":"2019","journal-title":"Eng. Fail. Anal."},{"key":"B81","unstructured":"Overview of pipeline leak detection technologies\n            ZhangJ.\n            HanP.\n            TwomeyM.\n          2019"}],"container-title":["Frontiers in Bioengineering and Biotechnology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fbioe.2022.958582\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,9,7]],"date-time":"2022-09-07T06:26:25Z","timestamp":1662531985000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fbioe.2022.958582\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,9,7]]},"references-count":78,"alternative-id":["10.3389\/fbioe.2022.958582"],"URL":"https:\/\/doi.org\/10.3389\/fbioe.2022.958582","relation":{},"ISSN":["2296-4185"],"issn-type":[{"value":"2296-4185","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,9,7]]},"article-number":"958582"}}