Selective Photoacoustic Handling of Microparticles via Annular Laser Beams

Selective Photoacoustic Handling of Microparticles via Annular Laser Beams | 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 Selective Photoacoustic Handling of Microparticles via Annular Laser Beams Zhongqing Su, Luo Guojie, Yi He, Wanglinhan Zhang, David Collins, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9028290/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 11 You are reading this latest preprint version Abstract Precise manipulation of bioparticles in micro- and nano-fluidic environments is crucial for applications in cancer diagnostics, drug delivery, and single‑cell analysis. Despite the optical and acoustic tweezers provide high accuracy and stability, their flexibility and selectivity are often constrained by factors such as laser‑induced heating, reliance on the optical properties of target particles, and the labor‑ and time‑intensive fabrication of interdigital transducers (IDTs). In this study, we develop an annular beam-driven photoacoustic tweezer (PAT) to implement high precision, selective handling of microparticles via annular beam-generated transient photoacoustic waves (T-PAWs). Realized via an axicon enabled optical setup, a nanosecond laser beam is shaped into a ring pattern and focused on a polycrystalline silicon substrate coated with chromium and aurum layers, which supports a confined liquid layer. The annular laser beam photoacoustically generates water-borne T PAWs and establishes an annular acoustic potential well (APW), which in turn establishes a radially inward acoustic radiation force (ARF), to continuously guide target microparticles, and simultaneously a concurrent outward‑propagating pressure along the ring periphery to exclude non-target microparticles. To elucidate the mechanism of laser‑induced T PAWs, we develop a multiphysical finite element model integrating photo‑thermo‑acoustic coupling, and experimentally validate the capability of the developed PAT in selectively capturing, assembling, and isolating single and multiple silicon microparticles and hydrogel microspheres. This annular PAT bridges selective, label-free trapping with fabrication simplicity by eliminating the need for IDTs, offering a rapidly reconfigurable method and non-contact approach for versatile bioparticle manipulation. Physical sciences/Engineering Physical sciences/Optics and photonics photoacoustics acoustofluidics ultrasonics single-cell manipulation label-free trapping Full Text Additional Declarations There is no conflict of interest Supplementary Files Video6.mp4 Video 6: Exclusion of the non-target hydrogel microsphere (2 μJ) Video1.avi Video 1: Selective single particle manipulation (2 μJ) Video2.mp4 Video 2: Selective single particle manipulation by ARF & PA cavitation (5 µJ) Video3.mp4 Video 3: Multi-particles assembly Video5.mp4 Video 5: Capture and collective transport of multi-hydrogel microspheres (2 μJ) Video4.mp4 Video 4: Selective manipulation of a single hydrogel microsphere (2 μJ) Cite Share Download PDF Status: Under Review Version 1 posted Reviewer # 5 agreed at journal 24 Apr, 2026 Reviewer # 4 agreed at journal 24 Apr, 2026 Review # 2 received at journal 22 Apr, 2026 Review # 3 received at journal 09 Apr, 2026 Reviewer # 3 agreed at journal 22 Mar, 2026 Reviewer # 2 agreed at journal 19 Mar, 2026 Reviewer # 1 agreed at journal 18 Mar, 2026 Reviewers invited by journal 18 Mar, 2026 Submission checks completed at journal 04 Mar, 2026 Editor assigned by journal 04 Mar, 2026 First submitted to journal 04 Mar, 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. 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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-9028290","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":608380790,"identity":"2f3ce820-aa95-47ee-8ff7-32655f5baf92","order_by":0,"name":"Zhongqing 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