{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,7]],"date-time":"2026-08-07T15:13:42Z","timestamp":1786115622013,"version":"build-2736575974"},"reference-count":41,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2026,8,3]],"date-time":"2026-08-03T00:00:00Z","timestamp":1785715200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Key International S&amp;T Cooperation Project","award":["2025YFE0119400"],"award-info":[{"award-number":["2025YFE0119400"]}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["32573290"],"award-info":[{"award-number":["32573290"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"award":["32573290"],"award-info":[{"award-number":["32573290"]}],"id":[{"id":"https:\/\/ror.org\/01h0zpd94","id-type":"ROR","asserted-by":"publisher"}]},{"name":"National Key Laboratory of Animal Nutrition and Feeding","award":["2004DA125184G2616"],"award-info":[{"award-number":["2004DA125184G2616"]}]},{"name":"CAAS ASTIP Science Center","award":["CAAS-CSSAE-202402"],"award-info":[{"award-number":["CAAS-CSSAE-202402"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biosensors"],"abstract":"<jats:p>Precise quantitative monitoring of 17\u03b2-estradiol (E2) is important for reproductive management in precision livestock farming. However, E2 determination in complex biological matrices remains challenging because of matrix-derived background and signal variability. Here, we developed a nanoconfinement-assisted solid-state ratiometric fluorescent aptasensor integrating target-induced strand displacement (TISD), magnetic separation, and anodic aluminum oxide (AAO) nanochannel confinement. The sensing probe consisted of streptavidin-coated magnetic nanoparticles (MNPs) carrying a FAM-labeled cDNA internal reference and a Texas Red-labeled E2 aptamer reporter. E2 binding promoted dissociation of the Texas Red-labeled aptamer from the magnetic probe. Magnetic separation and washing reduced soluble matrix-derived interference, while subsequent deposition of the sensing complexes onto an AAO membrane mitigated coffee-ring-associated nonuniformity and produced a more spatially uniform dual-color fluorescence distribution for ratiometric analysis. Under matrix-matched calibration conditions, linear ranges of 5.0\u201350.0 pM were obtained in tap water and sow saliva, 5.0\u201340.0 pM in whole milk, and 5.0\u201315.0 pM in post-estrus sow urine. The LOD determined in tap water was 3.62 pM. The different calibration slopes obtained among the four matrices indicated that residual matrix-dependent effects remained and that matrix-specific calibration was required for quantitative analysis. Matrix-matched spike recoveries ranged from 86.92% to 119.54% across the investigated matrices. The aptasensor exhibited the strongest response toward 17\u03b2-E2 among the tested compounds; however, cross-reactivities of 77.3% for E3 and 47.3% for 17\u03b1-E2 indicated preferential rather than exclusive recognition. Molecular docking suggested a putative binding pose but did not experimentally establish the molecular recognition mechanism. Overall, the platform demonstrated laboratory-scale analytical feasibility in pretreated tap water, sow saliva, whole milk, and post-estrus sow urine. Further development of sample preparation, magnetic handling, membrane loading, probe selectivity, and portable fluorescence readout will be required before in situ or on-site application.<\/jats:p>","DOI":"10.3390\/bios16080419","type":"journal-article","created":{"date-parts":[[2026,8,3]],"date-time":"2026-08-03T12:57:56Z","timestamp":1785761876000},"page":"419","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Nanoconfinement-Driven Solid-State Ratiometric Fluorescent Aptasensor for 17\u03b2-Estradiol Detection in Complex Matrices"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0004-9134-5561","authenticated-orcid":false,"given":"Shanshan","family":"Zheng","sequence":"first","affiliation":[{"name":"State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0041-5957","authenticated-orcid":false,"given":"Hui","family":"Wang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhixue","family":"Yu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-3308-4441","authenticated-orcid":false,"given":"Ruipeng","family":"Chen","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7547-8381","authenticated-orcid":false,"given":"Liang","family":"Yang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Benhai","family":"Xiong","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiangfang","family":"Tang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"skad206","DOI":"10.1093\/jas\/skad206","article-title":"Invited Review: Integration of Technologies and Systems for Precision Animal Agriculture\u2014A Case Study on Precision Dairy Farming","volume":"101","author":"Kaur","year":"2023","journal-title":"J. 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