title: Photoelectrochemical sensor based on quantum dots and sarcosine oxidase.
abstract: In this study, a photobioelectrochemical sensor for the detection of sarcosine is reported. For this purpose, CdSe/ZnS quantum dot (QD) modified electrodes are prepared and the oxygen-dependent photocurrent is evaluated under illumination. By using sarcosine oxidase (SOD), the photocurrent can be suppressed because of biocatalytic oxygen reduction. For the construction of a sensor, SOD is immobilised on the QDs by means of the polyelectrolyte poly(allylamine hydrochloride) (PAH). Multi-layer systems have been built up to six bilayers through electrostatic interactions. The assembly can be verified by surface plasmon resonance measurements. By varying the number of layers, the influence of the amount of enzyme on the sensitivity of the sensor can be shown. The [SOD/PAH]6-layer system results in a signal change of 0.041% μM(-1) in the linear range from 100 μM to 1 mM of sarcosine.
authors.affiliation: Biosystems Technology, Technical University of Applied Sciences Wildau, Bahnhofstraße 1, 15745 Wildau, Germany.
authors.forename: Marc
authors.initials: M
authors.lastname: Riedel
authors.forename: Gero
authors.initials: G
authors.lastname: Göbel
authors.forename: Abuelmagd M
authors.initials: AM
authors.lastname: Abdelmonem
authors.forename: Wolfgang J
authors.initials: WJ
authors.lastname: Parak
authors.forename: Fred
authors.initials: F
authors.lastname: Lisdat
mesh_terms: D055162:Biocatalysis; D015374:Biosensing Techniques / Q000295:instrumentation; D019187:Cadmium Compounds / Q000737:chemistry / Q000378:metabolism; D055664:Electrochemical Techniques / Q000295:instrumentation; D004566:Electrodes; D008958:Models, Molecular; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry / Q000378:metabolism; D055668:Photochemical Processes; D011073:Polyamines / Q000737:chemistry / Q000378:metabolism; D045663:Quantum Dots; D012521:Sarcosine / Q000032:analysis; D050879:Sarcosine Oxidase / Q000737:chemistry / Q000378:metabolism*; D018036:Selenium Compounds / Q000737:chemistry / Q000378:metabolism; D020349:Surface Plasmon Resonance; D013499:Surface Properties; D019287:Zinc Sulfate / Q000737:chemistry / Q000378:metabolism
chemical_list: D019187:Cadmium Compounds; D011073:Polyamines; D018036:Selenium Compounds; C063994:polyallylamine; D019287:Zinc Sulfate; C058667:cadmium selenide; D050879:Sarcosine Oxidase; D010100:Oxygen; D012521:Sarcosine
keywords: electrochemistry; enzymes; photochemistry; quantum dots; sensors