A microlagal-based carbonaceous sensor for enzymatic determination of glucose in blood serum

In the present work, Chlorella vulgaris , a well-known microalga was used as a carbonic precursor, to synthesis the water-soluble carbon dots (CDs) via hydrothermal method. To improve the properties, acidic carbon dots (ACDs) were also synthesized via ultrasoncation of microalgal biomass after acidic hydrolysis (using diluted acidic solution). The aqueous solution of ACDs was used as a sensor for glucose determination based on glucose oxidase enzyme (GOx) reaction and fluorescence quenching of ACDs in the presence of Fe 3+ ions under the optimized conditions. The linear range of glucose in the blood serum was measured from a range of 5 µM to 500 µM with a limit of detection (LOD) 2.84 µM. Additionally, the hydrogen peroxide, as the conventional reactive oxygen species (ROS) was determined based on the Fenton reaction. The linear range of H 2 O 2 was obtained from 10 µM to 200 µM with LOD of 975 nM. In all of these applications, fluorescence quenching of ACDs was followed according to photo-induced electron transfer (PET) mechanism in the presence of generated Fe 3+ ions by Fenton reaction.