{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T21:05:35Z","timestamp":1792789535950,"version":"4.5.0"},"reference-count":26,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T00:00:00Z","timestamp":1787788800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Key Research and Development Project of Henan Province, China","award":["261111223600"],"award-info":[{"award-number":["261111223600"]}]},{"DOI":"10.13039\/501100009101","name":"General Project of Henan Provincial Educational Science Planning","doi-asserted-by":"publisher","award":["2026YB0288"],"award-info":[{"award-number":["2026YB0288"]}],"id":[{"id":"10.13039\/501100009101","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100009101","name":"Soft Science Research Project of Henan Province, China","doi-asserted-by":"publisher","award":["262400410111"],"award-info":[{"award-number":["262400410111"]}],"id":[{"id":"10.13039\/501100009101","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Micromachines"],"abstract":"<jats:p>Complex hollow metallic microstructures are essential for microelectromechanical systems (MEMS), lab-on-a-chip microfluidics, and bio-integrated devices, yet their fabrication remains challenging because geometric complexity, microscale precision, and high aspect ratios must be satisfied simultaneously. This study proposes filament-guided electrolyte\u2013column electrodeposition (FG-ECD), which couples a removable filament template with a nozzle-confined electrolyte column to define internal channels in situ during localized metal growth, thereby avoiding the collapse risks associated with conventional template removal routes. A two-dimensional axisymmetric multiphysics model reveals that the embedded filament reorganizes the electrolyte into a stable annular flow and shifts the cathodic current density maximum from the substrate toward the advancing dome front, establishing a self-consistent, quasi-stable localized reaction zone, while a parametric sweep shows that the total current scales the current density magnitude without altering its spatial profile. Experiments demonstrate that a current of 3.6 mA produces smooth dome front growth at approximately 20 \u03bcm\/min, whereas 5.5 mA triggers sustained hydrogen evolution and a transition to cellular deposition. Under optimized conditions, straight, 540\u00b0 spiral, and R-shaped dual-channel hollow nickel microstructures were fabricated with continuous, collapse-free internal channels of 50 \u00b1 5 \u03bcm, aspect ratios exceeding 10:1, and dimensional accuracy within \u00b135 \u03bcm. FG-ECD provides a low-temperature processing route for complex hollow metallic architectures and offers process regulation principles based on co-regulation of the flow field and current density for electrochemical microfabrication.<\/jats:p>","DOI":"10.3390\/mi17091011","type":"journal-article","created":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T09:00:35Z","timestamp":1787821235000},"page":"1011","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["In Situ Fabrication of Complex Hollow Nickel Microstructures via Filament-Guided Electrolyte\u2013Column Electrodeposition"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3825-4420","authenticated-orcid":false,"given":"Wei","family":"Wang","sequence":"first","affiliation":[{"name":"School of Mechanical Engineering, Henan Institute of Technology, Xinxiang 453003, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Taiyu","family":"Li","sequence":"additional","affiliation":[{"name":"School of Mechanical Engineering, Henan Institute of Technology, Xinxiang 453003, China"},{"name":"School of Mechanical and Electrical Engineering, Henan Institute of Science and Technology, Xinxiang 453000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7949-5709","authenticated-orcid":false,"given":"Yongfeng","family":"Li","sequence":"additional","affiliation":[{"name":"School of Mechanical and Electrical Engineering, Henan Institute of Science and Technology, Xinxiang 453000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Linchao","family":"An","sequence":"additional","affiliation":[{"name":"School of Mechanical Engineering, Henan Institute of Technology, Xinxiang 453003, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yunyan","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Mechanical Engineering, Henan Institute of Technology, Xinxiang 453003, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lan","family":"Chen","sequence":"additional","affiliation":[{"name":"School of Intelligent Manufacturing, Henan Institute of Information Science and Technology, Hebi 458030, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2942","DOI":"10.1039\/D2LC01076C","article-title":"Integrated lab-on-a-chip microfluidic systems for isolation, enrichment, and analysis of cancer biomarkers","volume":"23","author":"Surappa","year":"2023","journal-title":"Lab Chip"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"384","DOI":"10.1016\/j.snb.2017.08.030","article-title":"A three-dimensional and bevel-angled ultrahigh aspect ratio microneedle for minimally invasive and painless blood sampling","volume":"255","author":"Lee","year":"2018","journal-title":"Sens. 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