{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,19]],"date-time":"2026-01-19T06:44:57Z","timestamp":1768805097109,"version":"3.49.0"},"reference-count":29,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2021,7,26]],"date-time":"2021-07-26T00:00:00Z","timestamp":1627257600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003555","name":"Ministry of Strategy and Finance","doi-asserted-by":"publisher","award":["PEO21112"],"award-info":[{"award-number":["PEO21112"]}],"id":[{"id":"10.13039\/501100003555","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["2019R1A2C1087459"],"award-info":[{"award-number":["2019R1A2C1087459"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biosensors"],"abstract":"<jats:p>Amino acid arrays comprising bioluminescent amino acid auxotrophic Escherichia coli are effective systems to quantitatively determine multiple amino acids. However, there is a need to develop a method for convenient long-term preservation of the array to enable its practical applications. Here, we reported a potential strategy to efficiently maintain cell viability within the portable array. The method involves immobilization of cells within agarose gel supplemented with an appropriate cryoprotectant in individual wells of a 96-well plate, followed by storage under freezing conditions. Six cryoprotectants, namely dimethyl sulfoxide, glycerol, ethylene glycol, polyethylene glycol, sucrose, and trehalose, were tested in the methionine (Met) auxotroph-based array. Carbohydrate-type cryoprotectants (glycerol, sucrose, and trehalose) efficiently preserved the linearity of determination of Met concentration. In particular, the array with 5% trehalose exhibited the best performance. The Met array with 5% trehalose could determine Met concentration with high linearity (R2 value = approximately 0.99) even after storage at \u221220 \u00b0C for up to 3 months. The clinical utilities of the Met and Leu array, preserved at \u221220 \u00b0C for 3 months, were also verified by successfully quantifying Met and Leu in spiked blood serum samples for the diagnosis of the corresponding metabolic diseases. This long-term preservation protocol enables the development of a ready-to-use bioluminescent E. coli-based amino acid array to quantify multiple amino acids and can replace the currently used laborious analytical methods.<\/jats:p>","DOI":"10.3390\/bios11080252","type":"journal-article","created":{"date-parts":[[2021,7,26]],"date-time":"2021-07-26T22:22:46Z","timestamp":1627338166000},"page":"252","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Effective Cryopreservation of a Bioluminescent Auxotrophic Escherichia coli-Based Amino Acid Array to Enable Long-Term Ready-to-Use Applications"],"prefix":"10.3390","volume":"11","author":[{"given":"Hee Tae","family":"Ahn","sequence":"first","affiliation":[{"name":"Department of BioNano Technology, Gachon University, 1342 Seongnamdae-ro, Sujeong-gu, Seongnam 13120, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"In Seung","family":"Jang","sequence":"additional","affiliation":[{"name":"Green and Sustainable Materials R&D Department, Research Institute of Clean Manufacturing System, Korea Institute of Industrial Technology (KITECH), Cheonan 31056, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1264-2724","authenticated-orcid":false,"given":"Thinh Viet","family":"Dang","sequence":"additional","affiliation":[{"name":"Department of BioNano Technology, Gachon University, 1342 Seongnamdae-ro, Sujeong-gu, Seongnam 13120, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yi Hyang","family":"Kim","sequence":"additional","affiliation":[{"name":"Green and Sustainable Materials R&D Department, Research Institute of Clean Manufacturing System, Korea Institute of Industrial Technology (KITECH), Cheonan 31056, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dong Hoon","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of BioNano Technology, Gachon University, 1342 Seongnamdae-ro, Sujeong-gu, Seongnam 13120, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hyeun Seok","family":"Choi","sequence":"additional","affiliation":[{"name":"Green and Sustainable Materials R&D Department, Research Institute of Clean Manufacturing System, Korea Institute of Industrial Technology (KITECH), Cheonan 31056, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Byung Jo","family":"Yu","sequence":"additional","affiliation":[{"name":"Green and Sustainable Materials R&D Department, Research Institute of Clean Manufacturing System, Korea Institute of Industrial Technology (KITECH), Cheonan 31056, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1844-0939","authenticated-orcid":false,"given":"Moon Il","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of BioNano Technology, Gachon University, 1342 Seongnamdae-ro, Sujeong-gu, Seongnam 13120, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,7,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s00726-009-0269-0","article-title":"Amino acids: Metabolism, functions, and nutrition","volume":"37","author":"Wu","year":"2009","journal-title":"Amino Acids"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1007\/s00726-009-0234-y","article-title":"Amino acid requirements in humans: With a special emphasis on the metabolic availability of amino acids","volume":"37","author":"Elango","year":"2009","journal-title":"Amino Acids"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1016\/j.cccn.2004.11.016","article-title":"Analysis of plasma amino acids by HPLC with photodiode array and fluorescence detection","volume":"354","author":"Schwarz","year":"2005","journal-title":"Clin. 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