Fluorescence Enhancement from Nitro-Compound-Sensitive Bacteria within Spherical Hydrogel Scaffolds.

ACS applied materials & interfaces (2019-03-27)
Soohyun Kim, Hyunji Kim, Tian Qiao, Chaenyung Cha, Sung Kuk Lee, Kangseok Lee, Hyun Ji Ro, Youngkyun Kim, Wonmok Lee, Hyunjung Lee
RESUMEN

For the safety of both production and life, it is a very significant issue to detect explosive nitro compounds in a remote way or over a long distance. Here, we report that nitro compounds were detected by the bacterial sensor based on hydrogel microbeads as a platform. Green fluorescent protein-producing Escherichia coli, which was genetically engineered to be sensitive to nitro compounds, was loaded within poly(2-hydroxyethyl methacrylate) [poly(HEMA)]-based hydrogel beads, in which fluorescent signals from bacteria were concentrated and strong enough to be easily detected. For efficient loading of negatively charged bacteria, the surface charge of poly(HEMA)-based beads was controlled by copolymerization with 2-(methacryloyloxy)ethyltrimethylammonium chloride (MAETC) as a cationic monomer. With the addition of MAETC, the cell affinity was nine times enhanced by the interaction between the positively charged poly(HEMA- co-MAETC) beads and negatively charged bacteria. The increased cell affinity resulted in an enhancement of a sensing signal. After exposure to 2,4,6-trinitrotoluene, a typical explosive nitro compound, the fluorescence intensity of bacterial sensors using poly(HEMA- co-MAETC) beads having 80 wt % MAETC was five times increased compared to those based on poly(HEMA) beads. This amplification of the fluorescent signal enables easier detection of explosives efficiently by a remote detection, even over a long distance.

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Sigma-Aldrich
Ethylene glycol dimethacrylate, 98%, contains 90-110 ppm monomethyl ether hydroquinone as inhibitor
Sigma-Aldrich
2,2-Dimethoxy-2-phenylacetophenone, 99%
Sigma-Aldrich
[2-(Methacryloyloxy)ethyl]trimethylammonium chloride solution, 75 wt. % in H2O