title: Optical oxygen sensors based on Pt(II) porphyrin dye immobilized on S-layer protein matrices.
abstract: This paper describes the development of planar and fiber optic oxygen sensors utilizing surface layer (S-layer) proteins as immobilization matrix for oxygen sensitive dyes. S-layer proteins have the intrinsic capability to reassemble into two-dimensional arrays in suspension and at interfaces. Due to their crystalline character the distribution of functional groups, such as carboxylic groups, is repeated with the periodicity of the lattice and thus allows the reproducible and geometrically distinct binding of functional molecules. For the development of oxygen sensors an oxygen sensitive Pt(II) porphyrin dye was covalently bound to the S-layer matrix. Measurement of the oxygen concentration was performed by phase modulation fluorimetry. Setups comprising low cost optoelectronic components like LEDs and silicon photodiodes were constructed. For both sensor setups (planar and fiber optic) variations in the oxygen concentrations resulted in distinct and reproducible changes in luminescence lifetime and intensity. The luminescence quenching efficiency of these sensors was found to be 1.5-1.9 (expressed as the ratio of signal under nitrogen and air) which compares well to other sensor systems using luminophores embedded in polymer matrices. These results demonstrated the application potential of S-layers as immobilization matrices in the development of (bio-)sensors.
authors.affiliation: Karl Franzens University Graz, Institute of Chemistry, Heinrichstrasse 28, A-8010 Graz, Austria. syl.scheicher@uni-graz.at
authors.forename: Sylvia R
authors.initials: SR
authors.lastname: Scheicher
authors.forename: Birgit
authors.initials: B
authors.lastname: Kainz
authors.forename: Stefan
authors.initials: S
authors.lastname: Köstler
authors.forename: Michael
authors.initials: M
authors.lastname: Suppan
authors.forename: Alessandro
authors.initials: A
authors.lastname: Bizzarri
authors.forename: Dietmar
authors.initials: D
authors.lastname: Pum
authors.forename: Uwe B
authors.initials: UB
authors.lastname: Sleytr
authors.forename: Volker
authors.initials: V
authors.lastname: Ribitsch
mesh_terms: D000327:Adsorption; D001665:Binding Sites; D015374:Biosensing Techniques / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005470:Fluorometry / Q000295:instrumentation*; D008562:Membrane Glycoproteins / Q000737:chemistry*; D055096:Optical Devices; D010100:Oxygen / Q000032:analysis* / Q000737:chemistry; D011166:Porphyrins / Q000737:chemistry*; D011485:Protein Binding
chemical_list: D008562:Membrane Glycoproteins; D011166:Porphyrins; C055764:S-layer proteins; D010100:Oxygen