{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T21:16:16Z","timestamp":1760217376671,"version":"build-2065373602"},"reference-count":34,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2015,2,12]],"date-time":"2015-02-12T00:00:00Z","timestamp":1423699200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Microbial biofilm colonies will in many cases form a smart material capable of responding to external threats dependent on their size and internal state. The microbial community accordingly switches between passive, protective, or attack modes of action. In order to decide which strategy to employ, it is essential for the biofilm community to be able to sense its own size. The sensor designed to perform this task is termed a quorum sensor, since it only permits collective behaviour once a sufficiently large assembly of microbes have been established. The generic quorum sensor construct involves two genes, one coding for the production of a diffusible signal molecule and one coding for a regulator protein dedicated to sensing the signal molecules. A positive feedback in the signal molecule production sets a well-defined condition for switching into the collective mode. The activation of the regulator involves a slow dimerization, which allows low-pass filtering of the activation of the collective mode. Here, we review and combine the model components that form the basic quorum sensor in a number of Gram-negative bacteria, e.g., Pseudomonas aeruginosa.<\/jats:p>","DOI":"10.3390\/s150204229","type":"journal-article","created":{"date-parts":[[2015,2,12]],"date-time":"2015-02-12T12:08:24Z","timestamp":1423742904000},"page":"4229-4241","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Microbial Biofilm as a Smart Material"],"prefix":"10.3390","volume":"15","author":[{"given":"Christian","family":"Garde","sequence":"first","affiliation":[{"name":"Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, Kemitorvet 208, DK-2800 Kongens Lyngby, Denmark"}]},{"given":"Martin","family":"Welch","sequence":"additional","affiliation":[{"name":"Department of Biochemistry, University of Cambridge, Hopkins Building, Downing Site, Cambridge CB2 1QW, UK"}]},{"given":"Jesper","family":"Ferkinghoff-Borg","sequence":"additional","affiliation":[{"name":"Biotech Research & Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, Ole Maal\u00f8es Vej 5, DK-2200 Copenhagen N, Denmark"}]},{"given":"Thomas","family":"Sams","sequence":"additional","affiliation":[{"name":"Biomedical Engineering, Department of Electrical Engineering, Technical University of Denmark, \u00d8rsteds Plads 349, DK-2800 Kongens Lyngby, Denmark"}]}],"member":"1968","published-online":{"date-parts":[[2015,2,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"787","DOI":"10.1016\/j.resmic.2007.09.001","article-title":"Structure and evolution of gene regulatory networks in microbial genomes","volume":"158","author":"Janga","year":"2007","journal-title":"Res. 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