{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,29]],"date-time":"2026-09-29T19:36:17Z","timestamp":1790710577272,"version":"4.1.0"},"reference-count":18,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2022,2,14]],"date-time":"2022-02-14T00:00:00Z","timestamp":1644796800000},"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>Lactate measurement is important in the fields of sports and medicine. Lactate accumulation can seriously affect an athlete\u2019s performance. The most common problem caused by lactate accumulation in athletes is muscle soreness due to excessive exercise. Moreover, from a medical viewpoint, lactate is one of the main prognostic factors of sepsis. Currently, blood sampling is the most common approach to lactate measurement for lactate sensing, and continuous measurement is not available. In this study, a low-cost continuous lactate monitoring system (CLMS) is developed based on a percutaneous microneedle array that uses a three-electrode lactate sensor. The working electrode has an area of 10 mm \u00d7 6 mm, including a 3 \u00d7 3 array of stainless-steel microneedles. The length, width, and thickness of each needle are 1 mm, 0.44 mm, and 0.03 mm, respectively. The working electrode is then plated with gold, polyaniline, lactate enzyme, Nafion, and Poly(2-hydroxyethyl methacrylate) (poly HEMA). The reference electrode is a 2 \u00d7 1 array covered with AgCl, and the counter electrode is a 2 \u00d7 1 array plated with gold. The sensor is incorporated into the CLMS and connected to a smartphone application and the cloud. The CLMS was tested on 40 human subjects who rode indoor bicycles, starting at 100 W and increasing in steps of 25 W at intervals of 5 min until exhaustion. The data acquired from the app connected to the CLMS were analyzed to determine the subjects\u2019 lactate response to exercise and the feasibility of assessing exercise performance and training exercise intensity by using the proposed system.<\/jats:p>","DOI":"10.3390\/s22041468","type":"journal-article","created":{"date-parts":[[2022,2,14]],"date-time":"2022-02-14T20:58:03Z","timestamp":1644872283000},"page":"1468","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":33,"title":["Continuous Lactate Monitoring System Based on Percutaneous Microneedle Array"],"prefix":"10.3390","volume":"22","author":[{"given":"Ming-Nan","family":"Chien","sequence":"first","affiliation":[{"name":"Department of Mechanical Engineering, National Taipei University of Technology, No. 1, Sec. 3, Zhongxiao E. Rd., Da\u2019an Dist., Taipei City 10608, Taiwan"},{"name":"Division of Endocrinology and Metabolism, Department of Internal Medicine, MacKay Memorial Hospital, Mackay Medical College, Taipei City 25245, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shih-Hao","family":"Fan","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, National Taipei University of Technology, No. 1, Sec. 3, Zhongxiao E. Rd., Da\u2019an Dist., Taipei City 10608, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chi-Huang","family":"Huang","sequence":"additional","affiliation":[{"name":"Graduate Institute of Sports Science, National Taiwan Sport University, No. 250, Wenhua 1st Rd., Guishan Dist., Taoyuan City 33301, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chien-Chen","family":"Wu","sequence":"additional","affiliation":[{"name":"AREDOT Smart Kinetic Energy Co., Ltd., 3rd Floor, No. 82, Chang\u2019an W. Rd., Datong Dist., Taipei City 10355, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jung-Tung","family":"Huang","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, National Taipei University of Technology, No. 1, Sec. 3, Zhongxiao E. Rd., Da\u2019an Dist., Taipei City 10608, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,2,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"112","DOI":"10.1007\/s004210050659","article-title":"Evaluation of the lactate pro blood lactate analyser","volume":"82","author":"David","year":"2000","journal-title":"Eur. J. Appl. Physiol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1016\/S1440-2440(01)80014-1","article-title":"Examination of the validity and reliability of the accusport blood lactate analyser","volume":"4","author":"Hugh","year":"2001","journal-title":"J. Sci. Med. Sport"},{"key":"ref_3","first-page":"520","article-title":"Study of clinical course and prognostic factors affecting the course of septicemia","volume":"8","author":"Amol","year":"2019","journal-title":"Ind. J. Basic Appl. Med. Res."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Xie, L., Zeng, Z., Sun, J., and Qian, W. (2020). Engineering microneedles for therapy and diagnosis: A survey. Micromachines, 11.","DOI":"10.3390\/mi11030271"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"321","DOI":"10.1039\/C9AN01609K","article-title":"Glutamate sensing in biofluids: Recent advances and research challenges of electrochemical sensors","volume":"145","author":"Schultz","year":"2020","journal-title":"Analyst"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"137691","DOI":"10.1016\/j.electacta.2020.137691","article-title":"Minimally invasive and continuous glucose monitoring sensor based on non-enzymatic porous platinum black-coated gold microneedles","volume":"369","author":"Somasekhar","year":"2021","journal-title":"Eletrochim. Acta"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Chinnadayyala, S.R., Park, J., Kim, Y.H., Choi, S.H., Lee, S.M., Cho, W.W., Lee, G.Y., Pyun, J.C., and Cho, S. (2019). Electrochemical detection of C-reactive protein in human serum based on self-assembled monolayer-modified interdigitated wave-shaped electrode. Sensors, 19.","DOI":"10.3390\/s19245560"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"161","DOI":"10.1007\/s00604-012-0923-1","article-title":"Non-enzymatic electrochemical sensing of glucose","volume":"180","author":"Wang","year":"2013","journal-title":"Microchim. Acta"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"374","DOI":"10.1002\/elan.201800630","article-title":"Minimally-invasive microneedle-based biosensor array for simultaneous lactate and glucose monitoring in artificial interstitial fluid","volume":"31","author":"Bollella","year":"2019","journal-title":"Electroanalysis"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1846","DOI":"10.1039\/c1an00012h","article-title":"Microneedle array-based carbon paste amperometric sensors and biosensors","volume":"136","author":"Windmiller","year":"2011","journal-title":"Analyst"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"152","DOI":"10.1016\/j.bios.2018.08.010","article-title":"Microneedle-based biosensor for minimally-invasive lactate detection","volume":"123","author":"Bollella","year":"2019","journal-title":"Biosens. Bioelectron."},{"key":"ref_12","first-page":"35","article-title":"Biosensors based on electrochemical lactate detection: A comprehensive review","volume":"5","author":"Rathee","year":"2016","journal-title":"Biochem. Biophys. Rep."},{"key":"ref_13","unstructured":"Cael, F. (1925). The Influence of Insulin and Epinephrine on the Lactate Content of Blood and Tissues, State Institute for the Study of Malignant Disease."},{"key":"ref_14","unstructured":"Peter, T.K., and Heineman, W.R. (1996). Cyclic Voltammetry. Laboratory Techniques in Electroanalytical Chemistry, CRC Press."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"113054","DOI":"10.1016\/j.bios.2021.113054","article-title":"Continuous glucose monitoring systems\u2014Current status and future perspectives of the flagship technologies in biosensor research","volume":"181","author":"Lee","year":"2021","journal-title":"Biosens. Bioelectron."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1010","DOI":"10.1039\/b924545f","article-title":"Microfabricated on-chip integrated Au\u2013Ag\u2013Au three-electrode system for in situ mercury ion determination","volume":"135","author":"Chen","year":"2010","journal-title":"Analyst"},{"key":"ref_17","unstructured":"Ted Hagos (2022, January 05). Learn Android Studio 3. Available online: https:\/\/www.amazon.com\/Ted-Hagos\/e\/B07D9NW79G%3Fref=dbs_a_mng_rwt_scns_share."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1163","DOI":"10.1007\/s12010-019-03142-7","article-title":"Design of a real-time self-adjusting calibration algorithm to improve the accuracy of continuous blood glucose monitoring","volume":"190","author":"Jia","year":"2020","journal-title":"Appl. Biochem. Biotechnol."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/4\/1468\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T22:19:16Z","timestamp":1760134756000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/4\/1468"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,2,14]]},"references-count":18,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2022,2]]}},"alternative-id":["s22041468"],"URL":"https:\/\/doi.org\/10.3390\/s22041468","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,2,14]]}}}