Cyclodextrin-immobilized microspheres for uptake of the quorum-sensing signaling molecule N-acylhomoserine lactone

ABSTRACT β‐Cyclodextrins (CDs) were immobilized on microspheres possessing poly(methacrylic acid) shell layers over polystyrene cores to effectively interact with N‐acylhomoserine lactone (AHL), the main signaling molecule for the bacterial cell‐to‐cell communication system known as quorum sensing (QS). Furthermore, these CD‐immobilized microspheres inhibited the expression of a QS‐dependent gene, pig cluster, in Serratia marcescens AS‐1. The AHL‐mediated production of prodigiosin was suppressed to approximately 30% when the culture was started in the presence of 9.1% (w/w) core/shell microspheres immobilized with β‐CD in a liquid broth, with shaking. This result suggested that the AHL concentration was maintained below the threshold of QS activation because transcription of the target genes would be activated via a stable AHL–receptor complex under high concentrations of AHL. The AHL reporter assay with Chromobacterium violaceum CV026 showed that the AHL concentration in the culture broth distinctly decreased after addition of the microspheres, confirming that uptake by the immobilized β‐CDs was responsible for the observed QS suppression. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43198.