Layer-by-layer self-assembled chitosan/poly(thiophene-3-acetic acid) and organophosphorus hydrolase multilayers.
The aim of this study is to immobilize an enzyme, namely, organophosphorus hydrolase (OPH), and to detect the presence of paraoxon, which is an organophosphorus compound, using the layer-by-layer (LbL) deposition technique. To lift the OPH from the solid substrate, a pair of polyelectrolytes (positively charged chitosan (CS) and negatively charged poly(thiophene-3-acetic acid) (PTAA)) were combined. These species were made charged by altering the pH of the solutions. LbL involved alternate adsorption of the oppositely charged polyions from dilute aqueous solutions onto a hydrophilic quartz slide. This polyion cushion was held together by the electrostatic attraction between CS and PTAA. The growing process was monitored by fluorescence spectroscopy. OPH was then adsorbed onto the five-bilayer CS/PTAA system. This five-bilayer macromolecular structure compared to the solid substrate rendered stability to the enzyme by giving functional integrity in addition to the ability to react with paraoxon solutions. The ultimate goal is to use such a system to detect the presence of organophosphorus compounds with speed and sensitivity using the absorption and fluorescence detection methodologies.
Constantine
Celeste A
CA
Department of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146, USA.
Mello
Sarita V
SV
Dupont
Annie
A
Cao
Xihui
X
Santos
David
D
Oliveira
Osvaldo N
ON
Strixino
Francisco T
FT
Pereira
Ernesto C
EC
Cheng
Tu-Chen
TC
Defrank
Joseph J
JJ
Leblanc
Roger M
RM
D000085:Acetates / Q000737:chemistry*; D000327:Adsorption; D043303:Aryldialkylphosphatase; D002686:Chitin / Q000031:analogs & derivatives* / Q000737:chemistry*; D048271:Chitosan; D004573:Electrolytes / Q000737:chemistry; D004800:Enzymes, Immobilized / Q000737:chemistry*; D004950:Esterases / Q000737:chemistry*; D008856:Microscopy, Fluorescence; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013876:Thiophenes / Q000737:chemistry*
D000085:Acetates; D004573:Electrolytes; D004800:Enzymes, Immobilized; D013876:Thiophenes; C472956:poly(thiophene-3-acetic acid); D002686:Chitin; D048271:Chitosan; D004950:Esterases; D043303:Aryldialkylphosphatase