Competing effect of activity and non-inert crowding on the dynamics of self-propelled tracer particles

Competing effect of activity and non-inert crowding on the dynamics of self-propelled tracer particles | 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 Article Competing effect of activity and non-inert crowding on the dynamics of self-propelled tracer particles Baburao Simma, Vrinda Garg, Radha Ramana, Surya K. Ghosh This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7138866/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 29 Oct, 2025 Read the published version in Scientific Reports → Version 1 posted 10 You are reading this latest preprint version Abstract Transport of single molecules via passive or active processes is crucial for biological functioning. In this study, we investigate the dynamics of point-like self-propelled tracer particles in a non-inert, ordered crowded environment using underdamped Langevin dynamics. The crowders are modeled by creating a biologically relevant setting with high damping and attractive centers. We analyze the diffusion of passive and self-propelled tracers as a function of crowder stickiness and packing fraction. Passive tracers exhibit subdiffusive behavior, while self-propelled tracers show superdiffusion despite obstruction by crowders. At intermediate packing fractions, diffusion is suppressed due to perfectly separated attractive centers, an effect overcome by active propulsion, which enhances tracer mobility. In extreme crowding situations, the attractive potential valleys start to overlap, contributing to enhanced diffusion. The displacement probability distribution of passive tracers is non-Gaussian at intermediate packing fractions, displaying a double-Gaussian structure. This non-Gaussianity is reduced for active tracers, whose distributions exhibit soft multi-step features arising from repeated hopping and trapping events. Furthermore, propulsion restores ergodicity, which is otherwise broken due to the presence of sticky crowders. Biological sciences/Biophysics Physical sciences/Mathematics and computing Physical sciences/Physics Langevin dynamics Self-propelled particle Ordered crowding van Hove correlation Anomalous Diffusion Ergodicity Breaking. Full Text Additional Declarations No competing interests reported. Supplementary Files SciRepSISKG.pdf Cite Share Download PDF Status: Published Journal Publication published 29 Oct, 2025 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 06 Aug, 2025 Reviews received at journal 02 Aug, 2025 Reviews received at journal 31 Jul, 2025 Reviewers agreed at journal 23 Jul, 2025 Reviewers agreed at journal 23 Jul, 2025 Reviewers invited by journal 23 Jul, 2025 Editor assigned by journal 22 Jul, 2025 Editor invited by journal 22 Jul, 2025 Submission checks completed at journal 19 Jul, 2025 First submitted to journal 19 Jul, 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. 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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-7138866","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":490001961,"identity":"be329d75-c952-4b20-a7e1-0ab0f64b6624","order_by":0,"name":"Baburao Simma","email":"","orcid":"","institution":"National Institute of Technology Warangal","correspondingAuthor":false,"prefix":"","firstName":"Baburao","middleName":"","lastName":"Simma","suffix":""},{"id":490001962,"identity":"53eb9177-01d5-48f0-bde5-b6c7f98ce5de","order_by":1,"name":"Vrinda Garg","email":"","orcid":"","institution":"National Institute of Technology Warangal","correspondingAuthor":false,"prefix":"","firstName":"Vrinda","middleName":"","lastName":"Garg","suffix":""},{"id":490001963,"identity":"d5d38cc2-1e9f-486b-80fe-eba0c457b4b6","order_by":2,"name":"Radha Ramana","email":"","orcid":"","institution":"National Institute of Technology Warangal","correspondingAuthor":false,"prefix":"","firstName":"Radha","middleName":"","lastName":"Ramana","suffix":""},{"id":490001964,"identity":"f620d4af-62a2-48b7-9f3d-72f3470504f9","order_by":3,"name":"Surya K. 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In this study, we investigate the dynamics of point-like self-propelled tracer particles in a non-inert, ordered crowded environment using underdamped Langevin dynamics. The crowders are modeled by creating a biologically relevant setting with high damping and attractive centers. We analyze the diffusion of passive and self-propelled tracers as a function of crowder stickiness and packing fraction. Passive tracers exhibit subdiffusive behavior, while self-propelled tracers show superdiffusion despite obstruction by crowders. At intermediate packing fractions, diffusion is suppressed due to perfectly separated attractive centers, an effect overcome by active propulsion, which enhances tracer mobility. In extreme crowding situations, the attractive potential valleys start to overlap, contributing to enhanced diffusion. The displacement probability distribution of passive tracers is non-Gaussian at intermediate packing fractions, displaying a double-Gaussian structure. 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