{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,5]],"date-time":"2026-01-05T11:14:34Z","timestamp":1767611674342,"version":"build-2065373602"},"reference-count":46,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2020,9,15]],"date-time":"2020-09-15T00:00:00Z","timestamp":1600128000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003052","name":"Ministry of Trade, Industry and Energy","doi-asserted-by":"publisher","award":["10077599"],"award-info":[{"award-number":["10077599"]}],"id":[{"id":"10.13039\/501100003052","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["2019R1F1A1062208","2017R1A6A1A03015642"],"award-info":[{"award-number":["2019R1F1A1062208","2017R1A6A1A03015642"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Graphene oxide (GO)\/peptide complexes as a promising disease biomarker analysis platform have been used to detect proteolytic activity by observing the turn-on signal of the quenched fluorescence upon the release of peptide fragments. However, the purification steps are often cumbersome during surface modification of nano-\/micro-sized GO. In addition, it is still challenging to incorporate the specific peptides into GO with proper orientation using conventional immobilization methods based on pre-synthesized peptides. Here, we demonstrate a robust magnetic GO (MGO) fluorescence resonance energy transfer (FRET) platform based on in situ sequence-specific peptide synthesis of MGO. The magnetization of GO was achieved by co-precipitation of an iron precursor solution. Magnetic purification\/isolation enabled efficient incorporation of amino-polyethylene glycol spacers and subsequent solid-phase peptide synthesis of MGO to ensure the oriented immobilization of the peptide, which was evaluated by mass spectrometry after photocleavage. The FRET peptide MGO responded to proteases such as trypsin, thrombin, and \u03b2-secretase in a concentration-dependent manner. Particularly, \u03b2-secretase, as an important Alzheimer\u2019s disease marker, was assayed down to 0.125 ng\/mL. Overall, the MGO platform is applicable to the detection of other proteases by using various peptide substrates, with a potential to be used in an automated synthesis system operating in a high throughput configuration.<\/jats:p>","DOI":"10.3390\/s20185275","type":"journal-article","created":{"date-parts":[[2020,9,15]],"date-time":"2020-09-15T10:24:09Z","timestamp":1600165449000},"page":"5275","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Robust Magnetized Graphene Oxide Platform for In Situ Peptide Synthesis and FRET-Based Protease Detection"],"prefix":"10.3390","volume":"20","author":[{"given":"Seongsoo","family":"Kim","sequence":"first","affiliation":[{"name":"Division of Chemical and Bioengineering, Kangwon National University, Gangwon-do 24341, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sang-Myung","family":"Lee","sequence":"additional","affiliation":[{"name":"Division of Chemical and Bioengineering, Kangwon National University, Gangwon-do 24341, Korea"},{"name":"Department of Research and Development, Cantis Inc., Ansan-si, Gyeonggi-do 15588, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Je Pil","family":"Yoon","sequence":"additional","affiliation":[{"name":"Division of Chemical and Bioengineering, Kangwon National University, Gangwon-do 24341, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Namhun","family":"Lee","sequence":"additional","affiliation":[{"name":"Division of Chemical and Bioengineering, Kangwon National University, Gangwon-do 24341, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jinhyo","family":"Chung","sequence":"additional","affiliation":[{"name":"Department of Integrative Biotechnology, Sungkyunkwan University, Suwon 16419, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6746-5599","authenticated-orcid":false,"given":"Woo-Jae","family":"Chung","sequence":"additional","affiliation":[{"name":"Department of Integrative Biotechnology, Sungkyunkwan University, Suwon 16419, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8101-0793","authenticated-orcid":false,"given":"Dong-Sik","family":"Shin","sequence":"additional","affiliation":[{"name":"Department of Chemical and Biological Engineering, Sookmyung Women\u2019s University, Yongsan-gu, Seoul 04310, Korea"},{"name":"Industry Collaboration Center, Sookmyung Women\u2019s University, Yongsan-gu, Seoul 04310, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,9,15]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1179","DOI":"10.2166\/wst.2017.634","article-title":"Anti-fouling graphene oxide based nanocomposites membrane for oil-water emulsion separation","volume":"77","author":"Feng","year":"2018","journal-title":"Water Sci. 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