Development and Performance Evaluation of a Hydrogel Microneedle Sensor for In Situ Monitoring of Potassium Ions in Rice Plants

Development and Performance Evaluation of a Hydrogel Microneedle Sensor for In Situ Monitoring of Potassium Ions in Rice Plants | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Development and Performance Evaluation of a Hydrogel Microneedle Sensor for In Situ Monitoring of Potassium Ions in Rice Plants Jiuxiang Li, Jinhui Zhao, Junshi Huang, Muhua Liu, Shuanggen Huang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8483124/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 31 Jan, 2026 Read the published version in Microchimica Acta → Version 1 posted 11 You are reading this latest preprint version Abstract The dynamic balance of potassium ions (K + ) in rice plants is critical to their growth, development, and stress resistance. To achieve in-situ, real-time monitoring of K + levels in rice plants and overcome the limitations of traditional destructive sampling methods, this study developed a biosensor based on ion-selective hydrogel microneedles. Key performance parameters of the sensor, including its calibration curve and sensitivity, were systematically evaluated via in vitro electrochemical tests. Meanwhile, the mechanical strength and microstructure of the microneedles were characterized using micro-force testing. The practical applicability of the sensor was validated through agarose gel recovery experiments and in vivo K + monitoring in rice plants under salt stress, with results cross-validated against ion chromatography as a reference method. The sensor exhibited a sensitivity close to the Nernstian response (59.0 ± 0.11 mV/decade), a linear detection range of 10 − 4 to 10 − 1 M, and a detection limit of 3.0×10 − 5 M. It also demonstrated a fast response time (T 95 < 20s), excellent stability, and high batch-to-batch reproducibility (relative standard deviation, RSD < 0.2%). The microneedles achieved a mechanical strength of 25 mN, which is well above the threshold required for penetrating the rice plant epidermis. During in vivo testing, the sensor successfully tracked the rapid K + loss in rice leaves under salt stress, showing a strong correlation with the standard method (R 2 = 0.985). In conclusion, the developed hydrogel microneedle sensor is a stable, reliable, and effective tool for in-situ K + analysis in rice plants, providing valuable insights into plant ion physiology and the mechanisms underlying responses to environmental stress. Potassium ion Real-time detection Electrochemical sensing Hydrogel microneedle sensor Full Text Additional Declarations No competing interests reported. Supplementary Files GelsandBlotsimages4.png GelsandBlotsimages2.png GelsandBlotsimages3.png GelsandBlotsimages1.png GelsandBlotsimages5.png GelsandBlotsimages6.png Cite Share Download PDF Status: Published Journal Publication published 31 Jan, 2026 Read the published version in Microchimica Acta → Version 1 posted Editorial decision: Revision requested 08 Jan, 2026 Reviews received at journal 07 Jan, 2026 Reviews received at journal 06 Jan, 2026 Reviews received at journal 06 Jan, 2026 Reviewers agreed at journal 05 Jan, 2026 Reviewers agreed at journal 05 Jan, 2026 Reviewers agreed at journal 05 Jan, 2026 Reviewers invited by journal 05 Jan, 2026 Editor assigned by journal 02 Jan, 2026 Submission checks completed at journal 02 Jan, 2026 First submitted to journal 30 Dec, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8483124","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":570043442,"identity":"d0508bbf-ba47-4c81-b6d3-4af6cccd0031","order_by":0,"name":"Jiuxiang Li","email":"","orcid":"","institution":"Jiangxi Agricultural University","correspondingAuthor":false,"prefix":"","firstName":"Jiuxiang","middleName":"","lastName":"Li","suffix":""},{"id":570043443,"identity":"821c0a19-4285-4ee8-b7f8-6a8e7ea3e290","order_by":1,"name":"Jinhui 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Plants","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"microchimica-acta","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"miac","sideBox":"Learn more about [Microchimica Acta](https://link.springer.com/journal/604)","snPcode":"604","submissionUrl":"https://submission.springernature.com/new-submission/604/3","title":"Microchimica Acta","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Potassium ion, Real-time detection, Electrochemical sensing, Hydrogel microneedle sensor","lastPublishedDoi":"10.21203/rs.3.rs-8483124/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8483124/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe dynamic balance of potassium ions (K\u003csup\u003e+\u003c/sup\u003e) in rice plants is critical to their growth, development, and stress resistance. To achieve in-situ, real-time monitoring of K\u003csup\u003e+\u003c/sup\u003e levels in rice plants and overcome the limitations of traditional destructive sampling methods, this study developed a biosensor based on ion-selective hydrogel microneedles. Key performance parameters of the sensor, including its calibration curve and sensitivity, were systematically evaluated via in vitro electrochemical tests. Meanwhile, the mechanical strength and microstructure of the microneedles were characterized using micro-force testing. The practical applicability of the sensor was validated through agarose gel recovery experiments and in vivo K\u003csup\u003e+\u003c/sup\u003e monitoring in rice plants under salt stress, with results cross-validated against ion chromatography as a reference method. The sensor exhibited a sensitivity close to the Nernstian response (59.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11 mV/decade), a linear detection range of 10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e to 10\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003eM, and a detection limit of 3.0\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003eM. It also demonstrated a fast response time (T\u003csub\u003e95\u003c/sub\u003e\u0026thinsp;\u0026lt;\u0026thinsp;20s), excellent stability, and high batch-to-batch reproducibility (relative standard deviation, RSD\u0026thinsp;\u0026lt;\u0026thinsp;0.2%). The microneedles achieved a mechanical strength of 25 mN, which is well above the threshold required for penetrating the rice plant epidermis. During in vivo testing, the sensor successfully tracked the rapid K\u003csup\u003e+\u003c/sup\u003e loss in rice leaves under salt stress, showing a strong correlation with the standard method (R\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.985). In conclusion, the developed hydrogel microneedle sensor is a stable, reliable, and effective tool for in-situ K\u003csup\u003e+\u003c/sup\u003e analysis in rice plants, providing valuable insights into plant ion physiology and the mechanisms underlying responses to environmental stress.\u003c/p\u003e","manuscriptTitle":"Development and Performance Evaluation of a Hydrogel Microneedle Sensor for In Situ Monitoring of Potassium Ions in Rice Plants","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-07 10:59:20","doi":"10.21203/rs.3.rs-8483124/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-01-08T11:24:03+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-07T20:41:01+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-07T03:29:48+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-06T08:13:16+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"118646728034058934552724032376615400899","date":"2026-01-05T21:46:39+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"208268801633213191172095439625318036559","date":"2026-01-05T10:48:55+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"96051133032586435319730540745765019107","date":"2026-01-05T10:26:34+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-01-05T09:55:59+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-01-02T09:43:26+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-01-02T09:41:38+00:00","index":"","fulltext":""},{"type":"submitted","content":"Microchimica Acta","date":"2025-12-30T16:30:18+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"microchimica-acta","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"miac","sideBox":"Learn more about [Microchimica Acta](https://link.springer.com/journal/604)","snPcode":"604","submissionUrl":"https://submission.springernature.com/new-submission/604/3","title":"Microchimica Acta","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"4a72a9cb-9947-458a-9ac3-9c8d5e653da8","owner":[],"postedDate":"January 7th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-02-02T16:11:09+00:00","versionOfRecord":{"articleIdentity":"rs-8483124","link":"https://doi.org/10.1007/s00604-026-07900-3","journal":{"identity":"microchimica-acta","isVorOnly":false,"title":"Microchimica Acta"},"publishedOn":"2026-01-31 15:59:25","publishedOnDateReadable":"January 31st, 2026"},"versionCreatedAt":"2026-01-07 10:59:20","video":"","vorDoi":"10.1007/s00604-026-07900-3","vorDoiUrl":"https://doi.org/10.1007/s00604-026-07900-3","workflowStages":[]},"version":"v1","identity":"rs-8483124","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8483124","identity":"rs-8483124","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}