title: Bioresponsive systems based on polygalacturonate containing hydrogels.
abstract: Polysaccharide acid (PSA) based devices (consisting of alginic acid and polygalacturonic acid) were investigated for the detection of contaminating microorganisms. PSA-CaCl(2) hydrogel systems were compared to systems involving covalent cross-linking of PSA with glycidylmethacrylate (PSA-GMA) which was confirmed with Fourier Transformed Infrared (FTIR) analysis. Incubation of PSA-CaCl(2) and PSA-GMA beads loaded with Alizarin as a model ingredient with trigger enzymes (polygalacturonases or pectate lyases) or bacteria lead to a smoothening of the surface and exposure of Alizarin according to Environmental Scanning Electron Microscopy (ESEM) analysis. Enzyme triggered release of Alizarin was demonstrated for a commercial enzyme preparation from Aspergillus niger and with purified polygalacturonase and pectate lyase from S. rolfsii and B. pumilus, respectively. In contrast to the PSA-CaCl(2) beads, cross-linking (PSA-GMA beads) restricted the release of Alizarin in absence of enzymes. There was a linear relation between release of Alizarin (5-348 μM) and enzyme activity in a range of 0-300 U ml(-1) dosed. In addition to enzymes, both PSA-CaCl(2) and PSA-GMA beads were incubated with Bacillus subtilis and Yersinia entercolitica as model contaminating microorganism. After 72 h, a release between 10 μM and 57 μM Alizarin was detected. For protection of the hydrogels, an enzymatically modified PET membrane was covalently attached onto the surface. This lead to a slower release and improve long term storage stability based on less than 1% release of dye after 21 days. Additionally, this allowed simple detection by visual inspection of the device due to a colour change of the white membrane to orange upon enzyme triggered release of the dye.
authors: Austrian Center of Industrial Biotechnology, Petersgasse 14, 8010 Graz, Austria. k.schneider@tugraz.at
authors: Konstantin P
authors: KP
authors: Schneider
authors: Alexandra
authors: A
authors: Rollett
authors: Eva
authors: E
authors: Wehrschuetz-Sigl
authors: Andrea
authors: A
authors: Hasmann
authors: Armin
authors: A
authors: Zankel
authors: Andreas
authors: A
authors: Muehlebach
authors: Franz
authors: F
authors: Kaufmann
authors: Georg M
authors: GM
authors: Guebitz
mesh_terms: D000880:Anthraquinones / Q000378:metabolism*; D001234:Aspergillus niger / Q000201:enzymology; D001412:Bacillus subtilis / Q000254:growth & development; D015374:Biosensing Techniques; D001709:Biotechnology / Q000379:methods*; D002122:Calcium Chloride / Q000737:chemistry; D003470:Culture Media; D004852:Epoxy Compounds / Q000737:chemistry; D020100:Hydrogels / Q000737:chemistry*; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010368:Pectins / Q000737:chemistry*; D011096:Polygalacturonase / Q000378:metabolism*; D011133:Polysaccharide-Lyases / Q000378:metabolism*; D015008:Yersinia enterocolitica / Q000254:growth & development
chemical_list: D000880:Anthraquinones; D003470:Culture Media; D004852:Epoxy Compounds; D020100:Hydrogels; D008689:Methacrylates; C010078:alizarin; D010368:Pectins; D011096:Polygalacturonase; D011133:Polysaccharide-Lyases; C023911:pectate lyase; D002122:Calcium Chloride; C007870:glycidyl methacrylate; C003181:polygalacturonic acid