{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,29]],"date-time":"2026-06-29T06:32:28Z","timestamp":1782714748370,"version":"3.54.5"},"reference-count":44,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2026,1,21]],"date-time":"2026-01-21T00:00:00Z","timestamp":1768953600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Marine Drugs"],"abstract":"<jats:p>In recent years, harmful algal blooms have led to frequent occurrences of shellfish toxin contamination, posing a significant threat to the safety of aquatic products and public health. As a potent neurotoxin, domoic acid (DA) can accumulate in shellfish, highlighting the urgent need for rapid and highly sensitive detection methods. In this study, we developed a fluorescent aptasensor based on a dual-signal amplification system by combining G-quadruplex (G4) dimers with multi-walled carbon nanotubes (CNTs). The sensor is designed with a hairpin-structured aptamer as the recognition probe, where short multi-walled CNTs serve as both a fluorescence quencher and platform, and G4 dimers are incorporated into the sensing interface to enhance signal output. In the absence of the target, the hairpin-structured aptamer remains closed, keeping the fluorescence signal \u201coff\u201d. Upon binding to DA, the aptamer undergoes a specific conformational change that exposes the G4-dimer sequence. The exposed sequence then binds to thioflavin T (ThT), which in turn generates a greatly enhanced fluorescence signal, leading to a substantial fluorescence enhancement and completing the second stage of the cascade amplification. Under optimal conditions, the constructed sensor achieves rapid detection of DA within 5 min, with a low detection limit of 1.1 ng\/mL. This work presents a valuable tool for the rapid and sensitive detection of DA in shellfish, with promising applications in marine environmental monitoring and food safety regulation.<\/jats:p>","DOI":"10.3390\/md24010050","type":"journal-article","created":{"date-parts":[[2026,1,21]],"date-time":"2026-01-21T13:59:54Z","timestamp":1769003994000},"page":"50","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Aptamer-Based Dual-Cascade Signal Amplification System Lights up G-Quadruplex Dimers for Ultrasensitive Detection of Domoic Acid"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0009-0000-1056-6866","authenticated-orcid":false,"given":"Jiansen","family":"Li","sequence":"first","affiliation":[{"name":"Naval Medical Center of PLA, Naval Medical University, Shanghai 200433, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhenfei","family":"Xu","sequence":"additional","affiliation":[{"name":"Lab of Biosystem and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zexuan","family":"Zhang","sequence":"additional","affiliation":[{"name":"Naval Medical Center of PLA, Naval Medical University, Shanghai 200433, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rui","family":"Liu","sequence":"additional","affiliation":[{"name":"Naval Medical Center of PLA, Naval Medical University, Shanghai 200433, China"},{"name":"College of Marine Food and Bioengineering, Jiangsu Ocean University, Lianyungang 222005, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuping","family":"Zhu","sequence":"additional","affiliation":[{"name":"College of Basic Medical Sciences, Naval Medical University, Shanghai 200433, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1151-562X","authenticated-orcid":false,"given":"Xiaoling","family":"Lu","sequence":"additional","affiliation":[{"name":"College of Basic Medical Sciences, Naval Medical University, Shanghai 200433, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5730-197X","authenticated-orcid":false,"given":"Huiying","family":"Xu","sequence":"additional","affiliation":[{"name":"Lab of Biosystem and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3723-5711","authenticated-orcid":false,"given":"Xiaoyu","family":"Liu","sequence":"additional","affiliation":[{"name":"Naval Medical Center of PLA, Naval Medical University, Shanghai 200433, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhe","family":"Ning","sequence":"additional","affiliation":[{"name":"Naval Medical Center of PLA, Naval Medical University, Shanghai 200433, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xinyuan","family":"Wang","sequence":"additional","affiliation":[{"name":"Naval Medical Center of PLA, Naval Medical University, Shanghai 200433, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0516-4664","authenticated-orcid":false,"given":"Haobing","family":"Yu","sequence":"additional","affiliation":[{"name":"Naval Medical Center of PLA, Naval Medical University, Shanghai 200433, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0001-7342-9508","authenticated-orcid":false,"given":"Bo","family":"Hu","sequence":"additional","affiliation":[{"name":"Naval Medical Center of PLA, Naval Medical University, Shanghai 200433, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,1,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"143274","DOI":"10.1016\/j.chemosphere.2024.143274","article-title":"Rapid and sensitive detection of domoic acid in shellfish using a magnetic bead-based competitive ELISA with a high-affinity peptide as a molecular binder","volume":"364","author":"Kim","year":"2024","journal-title":"Chemosphere"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"7873","DOI":"10.1038\/s41467-023-43265-4","article-title":"Marine toxin domoic acid alters nitrogen cycling in sediments","volume":"14","author":"Li","year":"2023","journal-title":"Nat. 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