{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T02:53:46Z","timestamp":1760237626103,"version":"build-2065373602"},"reference-count":44,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2020,6,2]],"date-time":"2020-06-02T00:00:00Z","timestamp":1591056000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Grant-in-Aid for Scientific Research on Innovative Areas\u201d \u201cSingularity biology\u201d, JST SENTAN KEISOKU program \u201cDevelopment of all in one chemiluminescence microscopeInterplay of developmental clock and extracellular environment in brain formation;","award":["No. 18H05410, No. JP16H06487"],"award-info":[{"award-number":["No. 18H05410, No. JP16H06487"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Water hardness (WH) is a useful parameter for testing household water, such as drinking, cooking, and washing water. Many countries around the world use pipeline water in their houses, but there is a need to monitor the WH because hard water has a negative impact on appliances. Currently, WH is often measured using chemical dye-based WH indicators, and these techniques require expensive equipment, and trained personnel. Therefore, a low-cost and simple measurement method has been desired. Here, we report LOTUS-W, which consists of a luciferase, Nanoluc, a yellow fluorescent protein Venus, and a Ca2+\/Mg2+ detection domain of human centrin 3. The binding of Ca2+\/Mg2+ to this indicator changes the conformation of human centrin 3, and induces bioluminescence resonance energy transfer (BRET) from Nanoluc to Venus, which changes its emission spectrum about 140%. The dissociation constants of LOTUS-W for Ca2+\/Mg2+ are approximately several mM, making it suitable for measuring WH in the household water. With this indicator in combination with a smartphone, we have demonstrated that it is possible to evaluate WH easily and quickly. This novel indicator has the potential to be used for measuring not only household water but also water used in the food industry, etc.<\/jats:p>","DOI":"10.3390\/s20113164","type":"journal-article","created":{"date-parts":[[2020,6,3]],"date-time":"2020-06-03T04:12:09Z","timestamp":1591157529000},"page":"3164","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Bioluminescent Ratiometric Indicator for Analysis of Water Hardness in Household Water"],"prefix":"10.3390","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8086-8939","authenticated-orcid":false,"given":"Md Nadim","family":"Hossain","sequence":"first","affiliation":[{"name":"The Institute of Scientific and Industrial Research (SANKEN), Osaka University, 8-1 Mihogaoka, Ibaraki 567-0047, Japan"},{"name":"Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ryuichi","family":"Ishida","sequence":"additional","affiliation":[{"name":"The Institute of Scientific and Industrial Research (SANKEN), Osaka University, 8-1 Mihogaoka, Ibaraki 567-0047, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mitsuru","family":"Hattori","sequence":"additional","affiliation":[{"name":"The Institute of Scientific and Industrial Research (SANKEN), Osaka University, 8-1 Mihogaoka, Ibaraki 567-0047, Japan"},{"name":"Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tomoki","family":"Matsuda","sequence":"additional","affiliation":[{"name":"The Institute of Scientific and Industrial Research (SANKEN), Osaka University, 8-1 Mihogaoka, Ibaraki 567-0047, Japan"},{"name":"Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Takeharu","family":"Nagai","sequence":"additional","affiliation":[{"name":"The Institute of Scientific and Industrial Research (SANKEN), Osaka University, 8-1 Mihogaoka, Ibaraki 567-0047, Japan"},{"name":"Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,6,2]]},"reference":[{"key":"ref_1","unstructured":"Cotruvo, J.A., and Bartram, J. (2009). WHO Calcium and Magnesium in Drinking-Water: Public Health Significance, WHO."},{"key":"ref_2","first-page":"866","article-title":"Potential health impacts of hard water","volume":"4","author":"Sengupta","year":"2013","journal-title":"Int. J. Prev. Med."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"105","DOI":"10.1016\/j.aca.2008.01.031","article-title":"Rapid determination of total hardness in water using fluorescent molecular aptamer beacon","volume":"610","author":"Lerga","year":"2008","journal-title":"Anal. Chim. Acta"},{"key":"ref_4","unstructured":"(2017). WHO Guidelines for Drinking-Water Quality, WHO. [4th ed.]."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Dieter, C.A., Maupin, M.A., Caldwell, R.R., Harris, M.A., Ivahnenko, T.I., Lovelace, J.K., Barber, N.L., and Linsey, K.S. (2020, June 01). Estimated Use of Water in the United States in 2015: U.S. Geological Survey Circular 1441. Available online: https:\/\/doi.org\/10.3133\/cir1441.","DOI":"10.3133\/cir1441"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1021\/es00115a611","article-title":"Drinking water contaminants","volume":"17","author":"Smeenk","year":"1983","journal-title":"Environ. Sci. Technol."},{"key":"ref_7","unstructured":"Ling, E.J., Associate, E., Engineering, B.S., and Tech, V. (2011). Virginia household water quality program: Hardness in household water. VCE Publication, Virginia Cooperative Extension."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"68","DOI":"10.1016\/j.jid.2017.08.037","article-title":"The effect of water hardness on surfactant deposition after washing and subsequent skin irritation in atopic dermatitis patients and healthy control subjects","volume":"138","author":"Danby","year":"2018","journal-title":"J. Investig. Dermatol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"217","DOI":"10.1007\/s10653-004-1612-8","article-title":"Concentrations of inorganic elements in bottled waters on the Swedish market","volume":"27","author":"Rosborg","year":"2005","journal-title":"Environ. Geochem. Health"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"819","DOI":"10.1109\/JSEN.2014.2351813","article-title":"A fluidic colorimetric sensor design for water hardness detection","volume":"15","author":"Bhattacharjee","year":"2015","journal-title":"IEEE Sens. J."},{"key":"ref_11","first-page":"291","article-title":"Phyllanthus emblica-A biopotential for hard water treatment","volume":"3","author":"Padmapriya","year":"2015","journal-title":"Int. J. Pure App. Biosci."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"60","DOI":"10.1111\/ijcs.12149","article-title":"Impact of water hardness on consumers\u2019 perception of laundry washing result in five European countries","volume":"39","author":"Abeliotis","year":"2015","journal-title":"Int. J. Consum. Stud."},{"key":"ref_13","first-page":"73","article-title":"Impact of water hardness in instinctive laundry system based on fuzzy logic controller","volume":"2","author":"Riaz","year":"2019","journal-title":"J. Math."},{"key":"ref_14","unstructured":"Mitsumoto, H. (2007). Hardness Measurement Reagent. (7202090 B2), U.S. Patent."},{"key":"ref_15","unstructured":"Nakajima, J., Mizogami, K., and Ykena, Y. (2003). Hardness Indicator Composition and Method of Water hardness Analysis. (USOO6599748B1), U.S. Patent."},{"key":"ref_16","unstructured":"Monarca, B.S., Zerbini, I., and Donato, F. (2004). Rolling Revision of the WHO Guidelines for Drinking-Water Quality, WHO."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"877","DOI":"10.1021\/ja02261a014","article-title":"A study of indicators for the determination of temporary hardness in water","volume":"38","author":"Norton","year":"1916","journal-title":"J. Am. Chem. Soc."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1186","DOI":"10.1021\/ac60067a031","article-title":"Determination of calcium and magnesium in limestones and dolomites","volume":"24","author":"Banewicz","year":"1952","journal-title":"Anal. Chem."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"236","DOI":"10.1016\/j.talanta.2012.10.038","article-title":"Feasibility of digital image colorimetry-Application for water calcium hardness determination","volume":"103","author":"Cubero","year":"2013","journal-title":"Talanta"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"268","DOI":"10.1016\/j.snb.2013.04.077","article-title":"Sensors and actuators B: Chemical development of hard water sensor using fluorescence resonance energy transfer","volume":"184","author":"Dey","year":"2013","journal-title":"Sens. Actuators B. Chem."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1016\/S0003-2670(03)00073-4","article-title":"Characterisation of a transparent optical test strip for quantification of water hardness","volume":"481","year":"2003","journal-title":"Anal. Chim. Acta"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1016\/S0010-8545(00)00242-3","article-title":"Luminescent chemosensors for transition metal ions","volume":"205","author":"Prodi","year":"2000","journal-title":"Coord. Chem. Rev."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1237","DOI":"10.1007\/s00216-017-0661-7","article-title":"A novel bioluminescent NanoLuc yeast-estrogen screen biosensor (nanoYES) with a compact wireless camera for effect-based detection of endocrine-disrupting chemicals","volume":"410","author":"Cevenini","year":"2018","journal-title":"Anal. Bioanal. Chem."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1825","DOI":"10.1021\/acssensors.9b00531","article-title":"Genetically encoded fluorescence\/bioluminescence bimodal indicators for Ca2+ imaging","volume":"4","author":"Farhana","year":"2019","journal-title":"Acs Sens."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Broyles, C., Robinson, P., and Daniels, M. (2018). Fluorescent, bioluminescent, and optogenetic approaches to study excitable physiology in the single cardiomyocyte. Cells, 7.","DOI":"10.3390\/cells7060051"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"382","DOI":"10.1016\/j.snb.2014.01.065","article-title":"Development of an ion-sensor using fluorescence resonance energy transfer","volume":"195","author":"Dey","year":"2014","journal-title":"Sens. Actuators B Chem."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1038\/ncomms13718","article-title":"Five colour variants of bright luminescent protein for real-time multicolour bioimaging","volume":"7","author":"Suzuki","year":"2016","journal-title":"Nat. Commun."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"42398","DOI":"10.1038\/srep42398","article-title":"Genetically encoded bioluminescent voltage indicator for multi-purpose use in wide range of bioimaging","volume":"7","author":"Inagaki","year":"2017","journal-title":"Sci. Rep."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1146\/annurev-anchem-061318-115027","article-title":"Development and applications of bioluminescent and chemiluminescent reporters and biosensors","volume":"12","author":"Yeh","year":"2019","journal-title":"Annu. Rev. Anal. Chem."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"20","DOI":"10.1021\/acssensors.8b01381","article-title":"Ratiometric bioluminescent sensor proteins based on intramolecular split luciferase complementation","volume":"4","author":"Ni","year":"2019","journal-title":"Acs Sens."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"7299","DOI":"10.1021\/ac502137s","article-title":"Integrating biochemiluminescence detection on smartphones: Mobile chemistry platform for point-of-need analysis","volume":"86","author":"Roda","year":"2014","journal-title":"Anal. Chem."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"40203","DOI":"10.1038\/srep40203","article-title":"Smartphone-based low light detection for bioluminescence application","volume":"7","author":"Kim","year":"2017","journal-title":"Sci. Rep."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"4525","DOI":"10.1021\/acs.analchem.6b00534","article-title":"Detection of antibodies in blood plasma using bioluminescent sensor proteins and a smartphone","volume":"88","author":"Arts","year":"2016","journal-title":"Anal. Chem."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Saito, K., Hatsugai, N., Horikawa, K., Kobayashi, K., Matsu-Ura, T., Mikoshiba, K., and Nagai, T. (2010). Auto-luminescent genetically-encoded ratiometric indicator for real-time Ca2+ imaging at the single cell level. PLoS ONE, 5.","DOI":"10.1371\/journal.pone.0009935"},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Lindenburg, L.H., Vinkenborg, J.L., Oortwijn, J., Aper, S.J.A., and Merkx, M. (2013). MagFRET: The first genetically encoded fluorescent Mg2+ sensor. PLoS ONE, 8.","DOI":"10.1371\/journal.pone.0082009"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"11990","DOI":"10.1073\/pnas.97.22.11990","article-title":"The structure of the chromophore within DsRed, a red fluorescent protein from coral","volume":"97","author":"Gross","year":"2000","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"407","DOI":"10.1038\/nmeth.2413","article-title":"A bright monomeric green fluorescent protein derived from Branchiostoma lanceolatum","volume":"10","author":"Shaner","year":"2013","journal-title":"Nat. Methods"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1888","DOI":"10.1126\/science.1208592","article-title":"An expanded palette of genetically encoded Ca2+ indicators","volume":"333","author":"Zhao","year":"2011","journal-title":"Science"},{"key":"ref_39","first-page":"18","article-title":"Understanding water hardness","volume":"24","author":"Wurts","year":"1993","journal-title":"World Aquac."},{"key":"ref_40","first-page":"4","article-title":"Determination of water hardness from common water sources using flame atomic absorbance spectrometry","volume":"1","author":"Campbell","year":"2010","journal-title":"Concordia Coll. J. Anal. Chem."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"203","DOI":"10.31024\/ajpp.2018.4.2.17","article-title":"Determination of the hardness of drinking packaged water of Kalyani area, West Bengal","volume":"4","author":"Pal","year":"2018","journal-title":"Asian J. Pharm. Pharmacol."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"10554","DOI":"10.1073\/pnas.0400417101","article-title":"Expanded dynamic range of fluorescent indicators for Ca2+ by circularly permuted yellow fluorescent proteins","volume":"101","author":"Nagai","year":"2004","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_43","doi-asserted-by":"crossref","unstructured":"Geng, Z., Zhang, X., Fan, Z., Lv, X., Su, Y., and Chen, H. (2017). Recent progress in optical biosensors based on smartphone platforms. Sensors, 17.","DOI":"10.3390\/s17112449"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"414","DOI":"10.1289\/ehp.0900782","article-title":"Relationship between tap water hardness, magnesium, and calcium concentration and mortality due to ischemic heart disease or stroke in the Netherlands","volume":"118","author":"Leurs","year":"2010","journal-title":"Environ. Health Perspect."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/11\/3164\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T09:35:08Z","timestamp":1760175308000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/11\/3164"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,6,2]]},"references-count":44,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2020,6]]}},"alternative-id":["s20113164"],"URL":"https:\/\/doi.org\/10.3390\/s20113164","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2020,6,2]]}}}