{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T10:26:42Z","timestamp":1780396002687,"version":"3.54.1"},"reference-count":38,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2025,9,12]],"date-time":"2025-09-12T00:00:00Z","timestamp":1757635200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Research Foundation of Korea (NRF) grant funded by the Korean Government (MSIT)","award":["RS-2023-00208684"],"award-info":[{"award-number":["RS-2023-00208684"]}]},{"name":"National Research Foundation of Korea (NRF) grant funded by the Korean Government (MSIT)","award":["RS-2021-NR060117"],"award-info":[{"award-number":["RS-2021-NR060117"]}]},{"name":"Basic Science Research Program through the NRF funded by the Ministry of Education","award":["RS-2023-00208684"],"award-info":[{"award-number":["RS-2023-00208684"]}]},{"name":"Basic Science Research Program through the NRF funded by the Ministry of Education","award":["RS-2021-NR060117"],"award-info":[{"award-number":["RS-2021-NR060117"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biosensors"],"abstract":"<jats:p>This study introduces a novel nucleic acid testing (NAT) protocol that integrates rapid deoxyribonucleic acid (DNA) extraction, isothermal amplification, and visual detection to enable efficient analysis of opportunistic pathogens. Polyethylenimine-functionalized iron oxide (PEI-Fe3O4) nanoparticles were prepared by combining PEI, acting as a stabilizing agent, with iron salt, which was utilized as the metal ion precursor by the ultrasonication-assisted co-precipitation method, and characterized for structural, optical, and magnetic properties. PEI-Fe3O4 exhibited cationic and anionic behavior in response to pH variations, enhancing adaptability for DNA binding and release. PEI-Fe3O4 enabled efficient extraction of E. faecium DNA within 10 min at 40 \u00b0C, yielding 17.4 ng\/\u00b5L and achieving an extraction efficiency of ~59% compared to a commercial kit (29.5 ng\/\u00b5L). The extracted DNA was efficiently amplified by loop-mediated isothermal amplification (LAMP) at 65 \u00b0C for 45 min. Pyrogallol-rich poly(tannic acid)-stabilized gold nanoparticles (PTA-AuNPs) served as colorimetric probes for direct visual detection of the DNA amplified using LAMP. The magnetic-nanogold (PEI-Fe3O4\/PTA-AuNPs) hybrid system achieved a limit of quantification of 1 fg\/\u00b5L. To facilitate field deployment, smartphone-based RGB analysis enabled quantitative and equipment-free readouts. Overall, the PEI-Fe3O4\/PTA-AuNPs hybrid system used in NAT offers a rapid, cost-effective, and portable solution for DNA detection, making the system suitable for microbial monitoring.<\/jats:p>","DOI":"10.3390\/bios15090601","type":"journal-article","created":{"date-parts":[[2025,9,12]],"date-time":"2025-09-12T12:08:16Z","timestamp":1757678896000},"page":"601","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["PEI-Fe3O4\/PTA-AuNPs Hybrid System for Rapid DNA Extraction and Colorimetric LAMP Detection of E. faecium"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9121-9897","authenticated-orcid":false,"given":"Muniyandi","family":"Maruthupandi","sequence":"first","affiliation":[{"name":"Department of BioNano Convergence, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si 13120, Gyeonggi-do, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0000-4164-3801","authenticated-orcid":false,"given":"Haang Seok","family":"Choi","sequence":"additional","affiliation":[{"name":"Department of BioNano Technology, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si 13120, Gyeonggi-do, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5029-4009","authenticated-orcid":false,"given":"Nae Yoon","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of BioNano Technology, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si 13120, Gyeonggi-do, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,9,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"143626","DOI":"10.1016\/j.foodchem.2025.143626","article-title":"Advancements in Magnetic Nanomaterial-Assisted Sensitive Detection of Foodborne Bacteria: Dual-Recognition Strategies, Functionalities, and Multiplexing Applications","volume":"478","author":"Gao","year":"2025","journal-title":"Food Chem."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"15968","DOI":"10.1039\/D4SC05317F","article-title":"Chemical Diversity of Reagents That Modify RNA 2\u2032-OH in Water: A Review","volume":"15","author":"Shioi","year":"2024","journal-title":"Chem. 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