Photoelectrochemical Sensor Based on Quantum Dots and Sarcosine Oxidase

• Published in: Chemphyschem 2013-07, Vol.14 (10), p.2338-2342
• Main Authors: Riedel, Marc, Göbel, Gero, Abdelmonem, Abuelmagd M., Parak, Wolfgang J., Lisdat, Fred
• Format: Article
• Language: English
• Subjects: Biocatalysis; Biosensing Techniques - instrumentation; Cadmium Compounds - chemistry; Cadmium Compounds - metabolism; Chemistry; Electrochemical Techniques - instrumentation; Electrochemistry; Electrodes; enzymes; Exact sciences and technology; General and physical chemistry; Models, Molecular; Oxidation-Reduction; Oxygen - chemistry; Oxygen - metabolism; Photochemical Processes; Photochemistry; Photoelectrochemistry. Electrochemiluminescence; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Polyamines - chemistry; Polyamines - metabolism; Quantum Dots; Sarcosine - analysis; Sarcosine Oxidase - chemistry; Sarcosine Oxidase - metabolism; Selenium Compounds - chemistry; Selenium Compounds - metabolism; sensors; Surface Plasmon Resonance; Surface Properties; Zinc Sulfate - chemistry; Zinc Sulfate - metabolism
• ISSN: 1439-4235; 1439-7641
• DOI: 10.1002/cphc.201201036

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. Sarcosine sensor: A photobioelectrochemical sensor based on the combination of quantum dots (QDs) with an enzyme is developed to allow a light‐directed sensor read‐out (see picture). The generation of charge carriers in the QDs by illumination is coupled to charge transfer with the electrode and the co‐substrate of the enzyme.