{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,27]],"date-time":"2026-10-27T22:39:22Z","timestamp":1793140762816,"version":"4.5.0"},"reference-count":56,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2021,12,3]],"date-time":"2021-12-03T00:00:00Z","timestamp":1638489600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Bioeng. Biotechnol."],"abstract":"<jats:p>\n                    Although many whole-cell biosensors (WCBs) for the detection of Cd\n                    <jats:sup>2+<\/jats:sup>\n                    have been developed over the years, most lack sensitivity and specificity. In this paper, we developed a Cd\n                    <jats:sup>2+<\/jats:sup>\n                    WCB with a negative feedback amplifier in\n                    <jats:italic>P. putida<\/jats:italic>\n                    KT2440. Based on the slope of the linear detection curve as a measure of sensitivity, WCB with negative feedback amplifier greatly increased the output signal of the reporter mCherry, resulting in 33% greater sensitivity than in an equivalent WCB without the negative feedback circuit. Moreover, WCB with negative feedback amplifier exhibited increased Cd\n                    <jats:sup>2+<\/jats:sup>\n                    tolerance and a lower detection limit of 0.1\u00a0nM, a remarkable 400-fold improvement compared to the WCB without the negative feedback circuit, which is significantly below the World Health Organization standard of 27\u00a0nM (0.003\u00a0mg\/L) for cadmium in drinking water. Due to the superior amplification of the output signal, WCB with negative feedback amplifier can provide a detectable signal in a much shorter time, and a fast response is highly preferable for real field applications. In addition, the WCB with negative feedback amplifier showed an unusually high specificity for Cd\n                    <jats:sup>2+<\/jats:sup>\n                    compared to other metal ions, giving signals with other metals that were between 17.6 and 41.4 times weaker than with Cd\n                    <jats:sup>2+<\/jats:sup>\n                    . In summary, the negative feedback amplifier WCB designed in this work meets the requirements of Cd\n                    <jats:sup>2+<\/jats:sup>\n                    detection with very high sensitivity and specificity, which also demonstrates that genetic negative feedback amplifiers are excellent tools for improving the performance of WCBs.\n                  <\/jats:p>","DOI":"10.3389\/fbioe.2021.799781","type":"journal-article","created":{"date-parts":[[2021,12,3]],"date-time":"2021-12-03T01:32:15Z","timestamp":1638495135000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":23,"title":["Highly Sensitive Whole-Cell Biosensor for Cadmium Detection Based on a Negative Feedback Circuit"],"prefix":"10.3389","volume":"9","author":[{"given":"Guangbao","family":"Zhang","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shuting","family":"Hu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaoqiang","family":"Jia","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2021,12,3]]},"reference":[{"key":"B1","volume-title":"Cadmium: Environ Aspects","author":"Albert","year":"1992"},{"key":"B2","volume-title":"Toxicological Profile for Cadmium","author":"Ashizawa","year":"2012"},{"key":"B3","doi-asserted-by":"publisher","first-page":"953","DOI":"10.1016\/j.bios.2003.09.010","article-title":"The Use of Yeast and Moulds as Sensing Elements in Biosensors","volume":"19","author":"Baronian","year":"2004","journal-title":"Biosens. 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