Biomimetic Surface Engineering of Polydopamine-Modified Carbon Quantum Dots Enables Light-Switchable Peroxidase/Catalase Activity

Biomimetic Surface Engineering of Polydopamine-Modified Carbon Quantum Dots Enables Light-Switchable Peroxidase/Catalase Activity | 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 Biomimetic Surface Engineering of Polydopamine-Modified Carbon Quantum Dots Enables Light-Switchable Peroxidase/Catalase Activity Amir Landarani-Isfahani This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8500544/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 11 You are reading this latest preprint version Abstract The use of light as an external trigger enables dynamic control over enzyme-mimicking nanomaterials is an attractive method for smart and switchable nanozyme systems. Herein, we report a metal-free, bioinspired nanozyme platform based on polydopamine-functionalized carbon quantum dots (PDA@CQDs) synthesized from recycled polyethylene terephthalate (PET) via a two-step carbonization–hydrothermal strategy followed by controlled surface polymerization. Comprehensive structural and spectroscopic characterizations, including FT-IR, XPS, XRD, DLS, and 13 C NMR analyses, clearly confirmed the formation of a nitrogen- and oxygen-rich polydopamine shell on the CQDs. Kinetic studies revealed that PDA@CQDs exhibit outstanding peroxidase-like activity in the dark with a V max of 11.6 × 10 − 7 M·s − 1 and an exceptionally low K m of 0.14 mM, outperforming horseradish peroxidase and many reported nanozymes. Remarkably, upon light irradiation, the catalytic behavior showed a complete and reversible switch to dominant catalase-like activity (V max = 14.5 × 10 − 7 M·s − 1 , K m = 0.83 mM), efficiently decomposing H 2 O 2 into H 2 O and O 2 while suppressing peroxidase activity. This photo-triggered duality is governed by surface-engineered quinone/semiquinone redox states within PDA and light-driven electron transfer from surface of CQD. The presented work establishes surface-engineered quantum dots as programmable nanozymes, offering a sustainable and tunable strategy for next-generation catalytic, biomedical, and environmental technologies. Carbon qountom dot Polydopamine Peroxidase-like Catalase-like Nanozyme Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Revision requested 13 Feb, 2026 Reviews received at journal 12 Feb, 2026 Reviews received at journal 02 Feb, 2026 Reviews received at journal 31 Jan, 2026 Reviewers agreed at journal 22 Jan, 2026 Reviewers agreed at journal 21 Jan, 2026 Reviewers agreed at journal 21 Jan, 2026 Reviewers invited by journal 21 Jan, 2026 Editor assigned by journal 13 Jan, 2026 Submission checks completed at journal 02 Jan, 2026 First submitted to journal 02 Jan, 2026 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. 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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-8500544","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":578775663,"identity":"e72b65b4-9c43-4007-82a1-6ecb0ac3a7f6","order_by":0,"name":"Amir 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Activity","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"photochemical-and-photobiological-sciences","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ppss","sideBox":"Learn more about [Photochemical \u0026 Photobiological Sciences](https://link.springer.com/journal/43630)","snPcode":"43630","submissionUrl":"https://www.editorialmanager.com/ppss/","title":"Photochemical \u0026 Photobiological Sciences","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Carbon qountom dot, Polydopamine, Peroxidase-like, Catalase-like, Nanozyme","lastPublishedDoi":"10.21203/rs.3.rs-8500544/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8500544/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe use of light as an external trigger enables dynamic control over enzyme-mimicking nanomaterials is an attractive method for smart and switchable nanozyme systems. Herein, we report a metal-free, bioinspired nanozyme platform based on polydopamine-functionalized carbon quantum dots (PDA@CQDs) synthesized from recycled polyethylene terephthalate (PET) via a two-step carbonization\u0026ndash;hydrothermal strategy followed by controlled surface polymerization. Comprehensive structural and spectroscopic characterizations, including FT-IR, XPS, XRD, DLS, and \u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003eC NMR analyses, clearly confirmed the formation of a nitrogen- and oxygen-rich polydopamine shell on the CQDs. Kinetic studies revealed that PDA@CQDs exhibit outstanding peroxidase-like activity in the dark with a V\u003csub\u003emax\u003c/sub\u003e of 11.6 \u0026times; 10\u003csup\u003e\u0026minus;\u0026thinsp;7\u003c/sup\u003e M\u0026middot;s\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and an exceptionally low K\u003csub\u003em\u003c/sub\u003e of 0.14 mM, outperforming horseradish peroxidase and many reported nanozymes. Remarkably, upon light irradiation, the catalytic behavior showed a complete and reversible switch to dominant catalase-like activity (V\u003csub\u003emax\u003c/sub\u003e = 14.5 \u0026times; 10\u003csup\u003e\u0026minus;\u0026thinsp;7\u003c/sup\u003e M\u0026middot;s\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, K\u003csub\u003em\u003c/sub\u003e = 0.83 mM), efficiently decomposing H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e into H\u003csub\u003e2\u003c/sub\u003eO and O\u003csub\u003e2\u003c/sub\u003e while suppressing peroxidase activity. This photo-triggered duality is governed by surface-engineered quinone/semiquinone redox states within PDA and light-driven electron transfer from surface of CQD. The presented work establishes surface-engineered quantum dots as programmable nanozymes, offering a sustainable and tunable strategy for next-generation catalytic, biomedical, and environmental technologies.\u003c/p\u003e","manuscriptTitle":"Biomimetic Surface Engineering of Polydopamine-Modified Carbon Quantum Dots Enables Light-Switchable Peroxidase/Catalase Activity","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-23 14:19:59","doi":"10.21203/rs.3.rs-8500544/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-02-13T07:46:13+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-12T20:09:36+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-02T23:29:18+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-31T06:49:45+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"312955462404601150919369062393815118161","date":"2026-01-23T00:42:30+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"115623445631903132896003015711930581927","date":"2026-01-21T22:56:00+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"179166091824716693300550686751001614564","date":"2026-01-21T21:11:36+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-01-21T20:25:44+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-01-13T11:03:09+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-01-02T11:38:42+00:00","index":"","fulltext":""},{"type":"submitted","content":"Photochemical \u0026 Photobiological Sciences","date":"2026-01-02T11:21:30+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"photochemical-and-photobiological-sciences","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ppss","sideBox":"Learn more about [Photochemical \u0026 Photobiological Sciences](https://link.springer.com/journal/43630)","snPcode":"43630","submissionUrl":"https://www.editorialmanager.com/ppss/","title":"Photochemical \u0026 Photobiological Sciences","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"b99918e9-b4e4-4f54-a1ea-0bfb4e2b08bc","owner":[],"postedDate":"January 23rd, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"in-revision","subjectAreas":[],"tags":[],"updatedAt":"2026-02-13T07:55:55+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-23 14:19:59","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8500544","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8500544","identity":"rs-8500544","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}